Outfall Monitoring Science Advisory Panel Meeting Notes and Agendas (1998-2002)

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OMSAP MEG Meeting Report, March 18, 2002
Submitted to OMSAP April 29, 2002

1. Introduction

The Bays Eutrophication Model Evaluation Group (BEMEG) met on March 18, 2002 at U Mass Boston to review work conducted by HydroQual for the Massachusetts Water Resources Authority (MWRA) in response to questions and recommendations raised by BEMEG in 1999 and 2001. In particular, BEMEG was asked to review and comment on the following reports:

  1. Calibration of the Massachusetts and Cape Cod Bays Hydrodynamic Model: 1998-1999. Report 2001-12. (Preliminary report reviewed March 2001.)

  2. Addendum to "Bays Eutrophication Model (BEM): modeling analysis for the period of 1992-1994." Report 2001-13.

  3. Boundary sensitivity analysis for the Bays Eutrophication Model (BEM). Report 2001-14.

  4. Analysis of the addition of a third algal group to the Bays Eutrophication Model (BEM) kinetics. Report 2001-15.

BEMEG also heard a preliminary report on the efforts underway at U Mass Boston to transition the USGS/HydroQual Bays Hydrodynamic Model (BHM) and BEM to their new home at U Mass Boston, and an analysis of DO and chlorophyll variability found in the recent Battelle monitoring data. The meeting agenda and list of attendees are included in Appendices 1 and 2, and lists of previous HydroQual and MEG reports in Appendices 3 and 4 for completeness.

This report summarizes next the discussion, comments and concerns about the above HydroQual reports (with comments directed to the authors) and the U Mass Boston transition effort, and concludes with recommendations made by BEMEG for future work.

2. Review of HydroQual Reports

2.1 Calibration of the Hydrodynamic Model: 1998-1999 (Report 2001-12)

This report presents the Bays Hydrodynamic Model (BHM) results and comparisons with in-situ data for the period 1998-1999. The model is identical to that used for the earlier 1992-1994 model calibration period with the one modification that incident shortwave radiation is now allowed to penetrate into the water column rather than be absorbed entirely in the surface grid layer. This change improved the model's ability to predict near-surface temperatures. Overall the model results appear to be adequately "calibrated" and ready for use in the water quality modeling for this time period.

The BHM uses the Mellor-Yamada level 2.5 (MY2.5) turbulence closure model with the Galperin et al extensions to compute the vertical turbulent viscosity/diffusivities at each time step. Recent studies suggest that MY2.5 may underestimate vertical mixing in the presence of strong stratification and weak shear, i.e., those conditions typically found in the thermocline/pycnocline. The background minimum viscosity/diffusivities used here is Km = 0.05 cm(2)/s, consistent with the thermocline dye study of Geyer and Ledwell (1994). Hilton et al (1998) found that using Km = 0.5 cm(2)/s provided better simulations of near-surface mixing in Boston Inner Harbor. To help provide some insight into this issue, please add plot(s) showing the vertical viscosity and thermal diffusivity as a function of depth at two sites (one at/near the new outfall and the other in the center of Stellwagen Basin) over a tidal cycle during several representative periods (e.g., a calm summer (winter) day when vertical stratification is near its seasonal maximum (minimum)), plus a comparison of these results with relevant observations (preferably in Mass Bays or if none available, in the literature).

This report contains a lot of model documentation, but it is not clear if this is intended to be the definitive model documentation requested by BEMEG. If it is intended as the definitive documentation, then it is incomplete. Additional information about the following is needed:

  1. Shortwave penetration (page 2-6). Many investigators use the two spectral component model to describe the vertical distribution of shortwave radiation : I(z) = I0 (a1 e(-k1z) + a2 e(-k2z)

    where Io is the total incident shortwave radiation corrected for reflection, a1 and a2 are the fraction of radiation carried by the shorter and longer wavelength components (with a1 + a2 = 1), and k1 and k2 are their extinction coefficients. Typical values for the southern flank of Georges Bank are a1 = 0.8, k1 = 1/1.4m, a2 = 0.2, and k2 = 1/6.3m. To help justify the one component model (equation 2-7) used here, please include model/data comparison plot(s) and describe the range of the extinction coefficient ke.
     

  2. Surface heat flux (page 2-7). What input and model data and equations are used to compute the surface heat flux components? Since modeled heat flux depends on water surface temperature, whose prediction varies over a large number of surface grid cells and time steps, how does the model perform these calculations? The text suggests that surface evaporation (E) and precipitation (P) offset each other so that E+P is set to zero in the surface mass flux (which seems reasonable). Based on recent email from Rich Isleib, we understand that surface heat flux due to evaporation is included, but MEG would appreciate more details.

  3. Boundary T/S relaxation times (page 2-11). The use of relaxation times for inflow conditions on the open boundaries is appropriate, but how were the values of 3 to 30 days chosen and were these calibrated?

  4. GOMM (page 2-12). What is the Gulf of Maine Model (GOMM) referred to here?

2.2 Addendum to "Bays Eutrophication Model (BEM): modeling analysis for the period of 1992-1994" (Report 2001-13)

This report documents the boundary conditions used in the original and revised 1992 BEM simulations, plus the few changes in model coefficients made between these two simulations. The boundary conditions and water quality kinetics and model parameters used in the 1992-1994 calibration simulation are also documented.

This report also compares the BEM results for 1994 with the BEM solution computed using the same horizontal/vertical grid resolution used in the hydrodynamic model. As expected, the two solutions are similar overall, and the past BEM model projections made using grid aggregation should not be affected significantly. The higher spatial resolution model results exhibit reduced numerical diffusion, especially for properties like nitrite/nitrate that have relatively strong spatial gradients as compared with, say salinity, and provide a more detailed picture of spatial structure. For these reasons, all future BEM simulations should be run using the hydrodynamic model grid within the BEM domain.

2.3 Boundary sensitivity analysis for the BEM (Report 2001-14)

This report explores the sensitivity of BEM-predicted DO and DIN concentrations within the bays near the outfall (the near field (NF)) to changes in these variables imposed along the open boundary (i.e., the specified far field (FF) concentrations). The model results show a strong correlation of FF and NF DO, implying that oxygen is being imported to the NF more than generated within the model domain. However, because DO does not significantly affect other state variables, uncertainties in the boundary conditions for DO are not as critical as they might be. On the other hand, there is little correlation of NF and FF DIN concentrations, but a strong correlation of other NF variables to the FF DIN. That is, changes in the FF DIN concentration affect other variables within the model domain, more than changes in the FF DO concentration. These results point out the need for more data on the open boundary.

2.4 Analysis of the addition of a third algal group to BEM (Report 2001-15)

A third algal group was added to BEM to investigate if the fall phytoplankton bloom frequently observed in the bays could be accurately predicted for the period 1992-1994. With this fall diatom group included, the BEM did predict an annual fall bloom but the model-data agreement was only slightly better than without the fall group. The BEM could still not reproduce the chlorophyll maximum observed in October 1993, and model calibration had to be effected by changing the carbon/chlorophyll ratio and the boundary loadings, indicating that the fall algal group model was not capturing the actual internal algal dynamics. Despite the limited success, the effort of adding the third algal group was worth doing as it illustrates the limitations of our current understanding.

3. U Mass Boston Model Transition

The U Mass Boston (UMB) modeling group has successfully configured the latest version of the HydroQual hydrodynamic model code to run on the UMB computer system, and showed a comparison between their model simulation for 1994 and the existing HydroQual simulation. The two solutions were very similar, differing only in the near-surface temperature field due to the inclusion of vertical penetration of shortwave radiation in the latest model code. Further comparison cases will be conducted with identical physics and forcing to ensure that the HydroQual and UMB hydrodynamic models are producing identical solutions within machine error. After these tests, the UMB hydrodynamic model will be ready to use to produce the input fields required for the BEM. The UMB group has started working on the transition of the BEM, with the long-term objective being to simulate the 1998-2002 period for comparison with the field data during the pre- and post-start of the outfall.

4. Recommendations

Based on the presentations and discussions held at the meeting, the BEMEG makes the following recommendations for future work and consideration:

  1. HydroQual be asked to run the BEM for 1998-1999 both with and without the third algal group, using the hydrodynamic model grid. These two simulations are of intrinsic interest for several reasons. The closing of the Nut Island treatment plant and start of secondary treatment at the Deer Island treatment plant in 1998 made a significant change in the distribution and forms of nutrient input to Boston Harbor, and it will interesting to determine if the higher spatial resolution BEM simulations will capture the effects of these input changes in and near Boston Harbor, especially the increased chlorophyll observed in Boston Harbor, and whether the addition of the fall algal group is more successful in these years. These simulations also allow more localized mass balance studies of different nutrients. The boundary forcing in 1998 and 1999 were considerably different, so these model simulations should provide additional insight into the bays behavior. The two-algal group simulation will also serve as the final test solution for the transition of BEM from HydroQual to UMB.

  2. Additional documentation about the HydroQual hydrodynamic model following section 2.1 above should be added to the "Calibration of the Hydrodynamic Model: 1998-1999" report, so that this report when completed will be the definitive report on this model.

  3. As shown effective by HydroQual, UMB should plan to run the BEM using the same spatial resolution used in the hydrodynamic model. In addition, UMB should consider if co-locating the BEM open boundary with the hydrodynamic model would improve BEM simulations.

  4. The space and time scales resolved in the Bays hydrodynamic model are insufficient to simulate directly the physical processes that control the discharge of effluent from the outfall diffusers and immediate mixing with ambient fluid. To bridge this gap between "far-field" and "near-field", a mass- conservation approach is used to estimate the properties of the mixed water in the grid cells immediately over the outfall, which in turn is advected and mixed away from the outfall by the larger-scale physical processes represented in the hydrodynamic model. This approach has been examined by Blumberg et al. (1996) and Zhang and Adams (1998) through comparisons of the far-field model predictions with those from a near-field engineering model. Both groups find support for the approach, especially in looking at the far-field effects of the outfall effluent. The monitoring data recently collected after the outfall started operation provides an excellent opportunity to revisit the question of just how well the Bays hydrodynamic model does in predicting near-field mixing and plume behavior. In particular, the quality and quantity of in-situ near-field data now allow a detailed comparison with the hydrodynamic model predictions. BEMEG encourages UMB to conduct this study before conducting final post-outfall simulations, to determine the accuracy of this approach and give confidence that the hydrodynamic model is providing the correct near-field currents, water structure and effluent concentrations as input to the BEM sufficient for the environmental questions being asked by MWRA and EPA. Since the Bays model development effort was completed, Blumberg and co-investigators have developed a more direct approach to the scale mismatch problem, i.e., embedding a near-field model in the far-field model (P. Roberts, personal communication). Initial results reported by Connolly et al. (1999) and Roberts (1999) show that this approach predicts the outfall plume behavior well. The results of the detailed comparison between the present Bays hydrodynamic model and recent monitoring data requested above will help determine if this newer, more direct approach is needed in the Bays modeling effort.

  5. These recent reports plus the Battelle presentation all point to the importance of the western Gulf of Maine on water properties and marine life in especially Massachusetts Bay. There is a clear need for continued and improved sampling of water properties along the upstream open boundary near Cape Ann. The addition of the GoMOOS buoys in this area is an important step forward, and MWRA should consider how to supplement the proposed measurements with nutrient sensors to improve our knowledge of the advective nutrient input into the bays, plus more frequent shipboard sampling to provide the spatial context for the moored measurements. The question of near-bottom advection of DO from the far field to the near field could be investigated with moored DO measurements at several sites, including at the Boston buoy near the outfall. Again, BEMEG encourages MWRA and UMB to think of ways to improve the in-situ sampling of the key variables that strongly influence the physics and biology in the bays, especially in the near-field around the outfall.

  6. The HydroQual hydrodynamic model results for 1998-1999 exhibit several fascinating events (e.g., the wind-mixing event during May 7-14, 1998; Figure 3-30). If possible, MWRA should encourage detailed scientific study of some of these events where there is sufficient field data for model/data comparison. Such a study might be an excellent M.S. or Ph.D. thesis project that provides both deeper insight to how the bay works, and the strengths and weakness of the present models.

References

Blumberg, A.F., Z.-G. Ji, and C.K. Ziegler, 1996. Modeling Near-Field Plume Behavior using a Far-Field Circulation Model. Journal of Hydraulic Engineering, 122, 610-616.

Connolly, J.P., A.F. Blumberg, and J.D. Quadrini, 1999. Modeling fate of pathogenic organisms in coastal waters of Oahu, Hawaii. J. Environmental Engineering, 398-406.

Galperin, B., Kantha, L. H., Hassid, S., and Rosati, A., 1988. A quasi-equilibrium turbulent energy model for geophysical flows. J. Atmospheric Sci., 45, 55-62.

Geyer, W.R. and J. Ledwell, 1994. Final Report, Massachusetts Bay Dye Study. MWRA. Report ENQUAD 1994-17, pp 39.

Hilton, A., McGillivary, E., and Adams, E., 1998. Residence time of freshwater in Boston's Inner Harbor, J. Waterway, Port, Coastal and Ocean Engineering, 124(2): 82-89.

Roberts, P.J.W., 1999. Modeling Mamala Bay Outfall Plumes. I: Near field. J. Hydraulic Engineering, 565-573.

Zhang, X.-Y., and E.E. Adams, 1998. Simulating near field plumes with a far-field model. J. Hydraulic Engineering, 125,233-241.

Appendix A1. Meeting Agenda

Outfall Monitoring Science Advisory Panel
Bays Eutrophication Model Evaluation Group Meeting
March 18, 2002, 10:00 AM to 4:00 PM
U Mass Boston, Provost's Conference Room, 8th Floor Healey Library

Agenda

10:00 - 10:15
Welcome, Purpose of Meeting, and Introductions
Bob Beardsley, WHOI, MEG Chair

10:15 - 10:30
Schedule for Future Modeling
Meng Zhou, U Mass Boston

10:30 - 11:15
Response to 1999 and 2001 MEG Recommendations
Jim Fitzpatrick and Richard Isleib, HydroQual

11:15 - 12:00
Questions Posed to the MEG:
- Is the Model Documentation Adequate
- Should We Use the Fine Grid Resolution?
- Is the Third Algal Group Justified?
- How Substantial is the Influence of the Boundary Conditions?
- Is the Hydrodynamic Run for 1998-1999 Adequate?
Jim Fitzpatrick and Richard Isleib, HydroQual
Mike Mickelson, MWRA

12:00 - 1:00
Lunch

1:00 - 1:30
Insights from the Data into the DO and Chlorophyll Response
Scott Libby and Carlton Hunt, Battelle

1:30 - 3:30
MEG Discussion and Comments for the Final MEG Report
Adjourn

Appendix A2. Meeting Attendees

MEG Members: Bob Beardsley (chair), WHOI; Eric Adams, MIT; Jeff Cornwell, U. Maryland; Don Harleman, MIT; Jack Kelly, EPA Duluth MN Research Lab; Jay O'Reilly, NOAA Narragansett Lab; and John Paul, EPA Narragansett Lab.

Observers: Brad Butman, USGS; Cathy Coniaris, MADEP; Dave Dow, NMFS; Jim Fitzpatrick, HydroQual; Bernie Gardner, UMass Boston; Anne Giblin, MBL; Doug Hersh, MWRA; Carlton Hunt, Battelle; Russ Isaac, MADEP; Rich Isleib, HydroQual; Mingshun Jiang, UMass Boston; Ben Kelly, Save the Harbor/Save the Bay; Wendy Leo, MWRA; Pierre Lermusiaux, Harvard; Suh Yuen Liang, MWRA; Scott Libby, Battelle; Matt Liebman, EPA; Mike Mickelson, MWRA; Andrea Rex, MWRA; Dave Taylor, MWRA; Sal Testaverde, NMFS; John Warner, USGS; and Meng Zhou, UMass Boston.

Appendix A3. List of HydroQual Reports

(1) Water Quality Model: >1989-1991
"A water quality model for Massachusetts Bay and Cape Cod Bay: model design and initial calibration." Report 1993-05.

(2) Water Quality Model: 1989-1992
"A water quality model for Massachusetts and Cape Cod Bays: Calibration of the Bays Eutrophication Model (BEM)." Report 1995-08.

Final report reviewed by MEG in 1995.

(3) Water Quality Model: 1993-1994 with revised 1992
"Bays Eutrophication Model (BEM): modeling analysis for the period 1992-1994." Report 2000-02.

Final report reviewed by MEG in 1999.

(4) Hydrodynamic Model: 1998-1999

"Calibration of the Massachusetts and Cape Cod Bays Hydrodynamic Model: 1998-1999." Report 2001-12.

Preliminary report reviewed by MEG March 14,2001.
Final report reviewed by MEG March 18, 2002.

(5) Water Quality Model: 1992-1994 with revised 1992 --- Additional documentation and exploration of grid disaggregation for 1994

"Addendum to "Bays Eutrophication Model (BEM): modeling analysis for the period of 1992-1994." Report 2001-13.

Final report reviewed by MEG March 18, 2002.

(6) Water Quality Model: explore 1992 with reference to range of 1994-1999 boundary conditions

"Boundary sensitivity for the Bays Eutrophication Model (BEM)." Report 2001-14.

Final report reviewed by MEG March 18, 2002.

(7) Water Quality Model: explore 3rd algal group for 1992-1993

"Analysis of the addition of a third algal group to the Bays Eutrophication Model (BEM) kinetics." Report 2001-15.

Final report reviewed by MEG March 18, 2002.

Appendix A4. List of BEMEG Reports

  1. Beardsley R, Adams EE, Harleman D, Giblin AE, Kelly JR, O'Reilly JE, Paul JF. 1995. Report of the MWRA hydrodynamic and water quality model evaluation group. Boston: Massachusetts Water Resources Authority. Report ENQUAD ms-037. 58 p.

  2. Report of Bays Eutrophication Model Evaluation Group to OMSAP, June 13, 2000 https://www.epa.gov/region01/omsap/meg1299.html

  3. Bays Eutrophication Model Evaluation Group comments on draft HydroQual report "Preliminary Calibration of the Massachusetts and Cape Cod Bays Hydrodynamic Model: 1998-1999", March 14, 2001
    Will be posted at: https://www.epa.gov/region1/omsap/

OMSAP Public Workshop, October 23 & 30, 2001

"Massachusetts Bays and the Outfall: A Look Back and A Look Forward"

Tuesday, October 23, 2001, 6:00 to 8:30 PM
MA Department of Environmental Protection,
1 Winter St., Boston, MA 02108

and

Tuesday, October 30, 2001, 7:00 to 9:30 PM
Barnstable High School,
744 West Main St., Hyannis, MA 02601

WORKSHOP PROCEEDINGS

WELCOME
BOSTON WORKSHOP: Mr. Glenn Haas, MA Department of Environmental Protection
HYANNIS WORKSHOP: Mr. Roger Janson, US Environmental Protection Agency

The US Environmental Protection Agency (EPA), along with the MA Department of Environmental Protection (MADEP) would like to welcome everyone here this evening to the Outfall Monitoring Science Advisory Panel public workshop. We are here tonight to hear and discuss results of monitoring in Boston Harbor, Massachusetts Bay and Cape Cod Bay one year after the Massachusetts Water Resources Authority’s Deer Island outfall began operating in September 2000. It is gratifying to see that after twenty years of planning we are at a point where we can begin to “look back”. After only one year of operation, we are confident that the Monitoring Program and Contingency Plan in place will help us successfully look forward to an improved marine environment as a result of improved wastewater management.

EPA and MADEP regulate the discharge of treated wastewater from the MWRA’s Deer Island Treatment Plant, through the National Pollutant Discharge Elimination System (NPDES) program. The MWRA discharge permit has extensive requirements for treatment and discharge, unprecedented amounts of sampling, reporting, and oversight, and has often been called the toughest and most stringent discharge permit in the United States. It is tough in order to address public concerns and to assure that the marine environment and public health are protected. EPA and MADEP mandated that MWRA’s Monitoring Program and Contingency Plan be attached to their discharge permit because of the importance of protecting the marine ecosystem.

The purpose of the Monitoring Program is to test for compliance with the limits of the NPDES permit, to look for changes in the environment, and to determine whether predictions made during the planning of the outfall are within expected ranges. The Monitoring Program was developed about 10 years ago so that baseline information could be collected before the outfall was relocated from Boston Harbor to Massachusetts Bay. Now that the outfall has gone on-line, the Monitoring Program is designed to look for potential changes in that baseline that are important to the public and to the living resources in Massachusetts and Cape Cod bays. For example, contaminants in fish or the amount of algae in the water are measured and reported.

In addition, the Monitoring Program is designed to determine whether changes in the environment – or thresholds – in the Contingency Plan are exceeded. The Contingency Plan was originally recommended by the National Marine Fisheries Service to ensure that the discharge does not harm endangered species, such as the North Atlantic Right whale. The Contingency Plan is a process to evaluate whether additional sampling, and/or corrective actions are necessary when changes in the environment based on the Monitoring Program suggest possible impacts from the MWRA outfall effluent. The NPDES Permit and the Contingency Plan require the public be notified if these changes do occur. Environmental changes may or may not be due to the MWRA outfall and must be reviewed on a case-by-case basis. It is important to note that the Contingency Plan is an evolving document that can be revised to reflect the best science available. Overall, we believe that the Contingency Plan process is working.

The design of a monitoring program, interpretation of results of the monitoring, and determination of appropriate thresholds for the Contingency Plan are complex and independent expert help was needed. In 1998, during the development of the current NPDES permit, EPA and MADEP appointed the Outfall Monitoring Science Advisory Panel (OMSAP) to advise the agencies on monitoring results. Members are independent experts from the local scientific community and are unpaid volunteers with diverse marine science and public health backgrounds. OMSAP provides credible advice on science, such as reviewing Contingency Plan revisions and permit exceedances.

They thanked, on behalf of EPA and MADEP, the OMSAP for their dedication to a balanced and independent review of the monitoring. They also thanked MWRA for the efforts they have made to provide information to OMSAP and the public. The charter for OMSAP requires that OMSAP convene a public forum once a year to present findings to the public on the Outfall Monitoring Program, to explain their significance, and to hear and respond to concerns from the public. Hopefully the presentations tonight meet these goals and we look forward to hearing from the public.

WHAT DOES OMSAP DO?
Dr. Andy Solow, Woods Hole Oceanographic Institution & OMSAP Chair

The Outfall Monitoring Science Advisory Panel (OMSAP) was established in 1998 to advise EPA and the MADEP to provide scientific advice on issues related to the outfall. The current members of OMSAP are Dr. Bob Beardsley (WHOI), Dr. Norb Jaworski, Dr. Bob Kenney (URI), Dr. Scott Nixon (URI), Dr. Judy Pederson (MIT), Dr. Mike Shiaris (UMB), Dr. Jim Shine (HSPH), and Dr. Juanita Urban-Rich (UMB). Cathy Coniaris (MADEP) is the staff person.

We are all independent scientists and are not paid by MWRA, EPA, or MADEP. There are two standing subcommittees, the Public Interest Advisory Committee, chaired by Patty Foley, that advises OMSAP on public concerns about the outfall, and the Inter-Agency Advisory Committee, chaired by Sal Testaverde that advises OMSAP on regulatory issues. OMSAP can also convene special subcommittees, that may include scientists from outside the panel to take up particular issues. For example, Dr. Bob Beardsley is currently the chair of a group looking at the evaluation of the Bays Eutrophication Model that is used to understand and predict the effects of the outfall on nutrients, productivity and other parameters in Massachusetts and Cape Cod Bays.

OMSAP meets quarterly and the meetings are open to the public. At the meetings, typically we are briefed by MWRA and its subcontractors on recent monitoring results. At our last meeting, we heard from Stormy Mayo about some results from an independent sampling program in Cape Cod Bay that was conducted by the Center for Coastal Studies in Provincetown, and it was reassuring to hear that the results from this independent group, while preliminary, show that there appears to have been no impact in Cape Cod Bay from the operation of the outfall. From time to time, we are asked by MWRA to review and approve proposed changes in the Contingency Plan and Monitoring Program. Currently we are carefully thinking about the Alexandrium red tide monitoring, and whether this threshold in the Contingency Plan should be revised.

In 1990, scientists identified four general questions that should be addressed by the monitoring: Is it safe to eat the fish and shellfish? Is it safe to swim? Are the aesthetics of Mass and Cape Cod Bays and Boston Harbor maintained? Are the resources protected? This workshop is an opportunity to hear what can be said about the answers to these questions, and it is also an opportunity for anyone in the audience to ask questions of the OMSAP and the representatives of MWRA.

WHY SHOULD THE PUBLIC BE INVOLVED?
Ms. Patty Foley, Executive Director, Save the Harbor/Save the Bay & Public Interest Advisory Committee Chair

Patty Foley acknowledged the fine work of Dr. Andy Solow, OMSAP Chair, and the other OMSAP members, Dr. Andrea Rex and her colleagues from the MWRA, and the staff at the DEP and the EPA. It is a pleasure for her to work with all of them on this very important policy issue. She also thanked the audience for attending the workshop to discuss the results of the first year’s monitoring of the Massachusetts Bay Outfall.

P. Foley then explained why she thinks that the work they do is so very important, and why it is so important that the public be involved. She learned to swim on the beaches of South Boston as a youngster, at the L Street Beach. Today, she lives on a boat in Boston Harbor, and loves to fish, swim, and sail from Cape Cod to Cape Ann. Clean water and clean beaches are a core family value here in the Bay State, one which we are prepared to fight to achieve and defend.

The ratepayers and taxpayers of our region have invested nearly $4 billion in the cleaner waters of Boston Harbor and Massachusetts Bay. By being here tonight, members of the audience are in a very real sense, protecting their investment. That investment has already begun to pay dividends in increased recreational and economic opportunity and enhanced public access on the shore, on the water, and in the Harbor Islands. And none of this would have been possible without public participation and support.

As many may remember, there were a number of proposed solutions to the pollution problems caused by the old Deer Island and Nut Island Sewage treatment plants. Judge David Mazzone appointed a special master, Charlie Haar, to sort them out and come up with a solution, a work plan, a timeline and a schedule for the completion of the project.

Consensus is always difficult to achieve, but at that time it was the consensus of scientific opinion that the Massachusetts Bay Outfall was a critical part of any solution to our pollution problems. Still, there were legitimate concerns – on Cape Cod – but not just on Cape Cod, about the short and long term effects of pumping hundreds of millions of gallons of effluent into the Bay. What would the impact of the outfall be – on shellfish and lobsters, on finfish, on plankton and on marine mammals? What would happen to water quality? What about algal blooms? What were the effects going to be on the health of both Massachusetts and Cape Cod Bay?

To answer these questions we needed to establish baselines and to keep track of any changes in the ecosystem. We needed to develop a mechanism to report any problems to regulators and decision makers, and we needed to share the facts with the public.

After spirited discussion, stakeholders came together with an elegant solution. As part of the permit, we created one of the most comprehensive monitoring programs in history, created by OMSAP, a truly independent panel of experts to assess the science, and created PIAC to represent the public in the process. She is proud to be a part of this process and believes that it is working well. She is confident that the presentations will increase the audience’s confidence as well. She urged everyone to please stay involved and thanked audience for attending. She hopes to see everyone on the Harbor, the Bay, or at the beach.

WHAT HAVE WE LEARNED ABOUT BOSTON HARBOR?
Dr. Andrea Rex, Massachusetts Water Resources Authority

A. Rex is the director of environmental quality at MWRA and her job is to oversee the monitoring that MWRA conducts in Boston Harbor and Massachusetts Bays. The Environmental Quality Department is also responsible for administering MWRA’s complicated discharge permit. She will include a discussion of Boston Harbor in her talk because the public needs to know that the investment of MWRA and the ratepayers of the Greater Boston area is working. The improvements in the Harbor that occurred before the outfall went on-line are indicative of the effects of the improved treatment as well as effects of MWRA’s active industrial regulation and pre-treatment program. It is also relevant to help understand what the impact on Mass Bay as a whole will be. Many of the fears of the outfall were predicated on a fear that we would be exporting the terrible problems of Boston Harbor 15 years ago into Mass Bay. Presenting the improvements in the Harbor will underscore the point that the outfall is not just transferring the former “harbor of shame” offshore.

Monitoring in the Harbor was designed to answer the public concerns that are relevant to both Boston Harbor and Massachusetts Bays: Are marine resources and public health protected? She showed a map of Boston Harbor and the locations of the old harbor outfalls at Nut Island and Deer Island. The newly commissioned ocean outfall is 9.5 miles from Deer Island.

She then gave a brief overview of how improved treatment at the new plant (and pretreatment) have been changing what MWRA has been discharging over the years. She showed a graph of the decreasing bacteria levels in the Deer Island effluent since 1988. In 1988, there were high bacteria counts in samples almost 140 out of 360 days in the year, with very high counts for almost 100 of those days. With better disinfection, those numbers very quickly dropped, so that after the 1990’s there were fewer than 10 days/year with high bacteria counts, and almost no very high samples.

The next graph showed the amount of solids discharged to the Harbor in average tons per day annually since 1988. Solids are important because they affect water clarity, oxygen, and toxic pollutants are generally attached to solids. In 1988, MWRA was discharging on the order of 160 tons per day of solids to the Harbor. The first major decrease came in 1992, after sludge discharges ended. Then, secondary treatment gradually came on-line at Deer Island. In July, 1998, Nut Island flow, that was only receiving primary treatment, was transferred to Deer Island for secondary treatment. By 2000, MWRA was averaging about 30 tons/day to the Harbor, only 20% of what had been previously discharged. Of course in 2001, that number will be zero. This is very important because toxic contaminants tend to attach to solids.

Even before the solids discharges were decreasing substantially, MWRA’s toxic reduction and control program was making major inroads into discharges of toxic materials through pollution prevention. MWRA levied heavy fines on industries that were violating their permit to discharge into our sewer system. That had a dramatic impact on metals discharges. In fact, most metals now come from households and eroding drinking water pipes (copper and zinc). The next graph showed the decrease in metals discharged since 1989. The results of other toxics follow a similar pattern. In 1989, metals discharges were more than 1,000 pounds per day. By 1991, those discharges had dropped to about 700 pounds per day, and thereafter the pattern parallels the pattern of solids discharges. By 2000, MWRA was discharging less than 300 lbs per day. Now, less than 10% of the metals inputs are from industry, however, managing household waste remains a challenge.

To examine whether marine ecological resources are being protected, one of the best places to look is in the sediments. Toxic pollutants and excess organic matter tend to accumulate in the sediments, and affect the benthos, or bottom community. Many animals low on the food web live here in direct contact with contaminants, and thus have potential when eaten to transmit contaminants to larger organisms. MWRA has an intensive sediment sampling program in Boston Harbor, monitoring the types and numbers of species that live here as well as toxic contaminants and degree of oxygenation of the sediments. MWRA also samples flounder and lobsters for disease and contaminant levels.

A. Rex showed a photograph of a section into the sediment near Long Island in 1990, the site of the Nut Island sludge discharges. It shows almost no oxygenated, or light-colored mud. This means that bacteria have used up all the oxygen in the sediment, and turned it anaerobic and black from sulfides (which are also toxic). There was almost nothing living in this photograph. It is likely that a large part of the problem is excess organic matter. She then showed the sediment profile at the same location in 1996. It showed a dramatic difference. The tube-dwelling shrimp-like animal Ampelisca has colonized. The aerated part of the sediment is about 5 centimeters deep, and other tiny creatures may also be present. Ampelisca is an early stage of succession. The most recent surveys indicate that another, more diverse, and natural community of worms, mollusks, and crustaceans is now moving in to replace some of the Ampelisca mats.

A. Rex then showed a map of the depth that oxygen penetrates into the sediment, called the Redox Potential Discontinuity or RPD for 1989-1990 while sludge was still being discharged, and treatment was only primary. Areas with a deeper the layer have more oxygen. Large parts of the northern harbor and Dorchester Bay had unhealthy sediment RPDs of less than 1 cm. She then showed a map of the same parameter for 1992-2000 (averaging one year after sludge discharges stopped until the ocean outfall went on-line). On average, the harbor sediments are much better aerated, with a great improvement in the north harbor.

Next was a graph showing a simple measure of biodiversity in Harbor sediments: the number of species present in a grab sample of mud. In 1991, there were about 15 species per grab throughout the Harbor on average. By 1998, that number had more than doubled, to more than 35, a substantial and significant difference.

Another important indicator organism that lives in close contact with sediments is the winter flounder. Flounder can absorb contaminants through their skin. A. Rex showed a slide of the drop in liver disease incidence in Boston Harbor flounder since 1984. In the 1980’s, Boston Harbor became infamous because it had the highest levels of flounder liver disease (almost 80%) and liver cancer of any flounder population studied. By 1989, liver disease rates had been halved to the present level, and liver tumors had become very rare. This is likely due to a decrease in toxic discharges related to the toxic reduction and control program.

MWRA takes many other measures of the health of the ecosystem of the Harbor, mostly focusing on the effect of nutrients. Because most of those changes will relate to the effect of moving the discharge offshore, and the data are not all in and analyzed yet, it is still too early to report on those effects.

One of the important public health indicators that we study is bacterial contamination – especially is it safe to swim. It is very interesting to examine this question in a historical context. She showed a contour plot of the average of fecal coliform bacteria (Enterococcus) data collected from 1987 up to the transfer of flow from the Nut Island treatment plant to Deer Island on July 8, 1998. The data are from MDC beach sampling and MWRA monitoring. The data are based on the mean, not the geometric mean, which will tend to emphasize the effects of high bacteria counts. Enterococcus is now the bacteria favored by EPA for monitoring marine waters for bathing safety. On average, the poorest water quality was in Fort Point Channel in the inner harbor, the Neponset River, the mouth of the Mystic River. The next most-impacted areas include the inner harbor, parts of the harbor affected by sludge and Deer Island, Nut Island, and along the shoreline. Historically, on average, most of the outer harbor and offshore areas of the north and south harbor generally met swimming standards, and a small part of the harbor in Hingham-Hull Bay met shellfishing standards.

A. Rex then showed a plot of the average bacteria data after flow was transferred from Nut Island to Deer Island, before the new outfall went on-line (from July of 1998 to August 2000). Reflected in the plot are the cumulative effects of the Boston Harbor project up to that point. Most of the Harbor now not only meets swimming standards, but shellfishing. The entire southern and central harbor has improved, compared to the earlier period, without degrading the area around Deer Island. Problems still remain in the rivers, inner harbor, and along the shore, presumably due to stormwater and CSOs – but the magnitude and extent of the contamination is less. So the answer to the question “is the harbor swimmable?” is generally yes. However, problems still remain – beach postings, while less frequent than a decade ago, still interfere with the use of this resource. Stormwater contamination is clearly a significant problem. CSOs have been eliminated along Constitution Beach, and will be eliminated along South Dorchester Bay. The plan to eliminate CSO and stormwater along South Boston beaches is being revisited, with storm sampling planned for this fall.

Even before the ocean outfall went on-line, the harbor had shown significant improvement in the quality of the environment, which should provide a couple of assurances. First, the investment in the Boston Harbor Project is paying off: many indicators are showing a significant improvement. She did not have time to cover all the examples, but bacteria, toxic contaminants, water clarity, and biodiversity are all measurably improved. Second, the outfall is not transporting the old problems of Boston Harbor offshore. Third, we have to remember that the Harbor and Bay are not separate systems, one is not being sacrificed for the sake of the other: The health of the harbor and the Bay are linked. Physically, through the movement of water, tidal flushing and storms. The USGS model of tidal mixing in the Harbor illustrates that the outer harbor waters, where the treatment plant discharges used to be, flush well out into the Bay. The Boston Harbor estuary also is linked to the Bay biologically, as many migratory animals move from open ocean, through the harbor. Shallow, warmer waters like the harbor are important nurseries for juvenile lobster, that then migrate out to the cooler waters of the Bay. She showed a photograph of smelt, photographed in the Fore River in the Southern Harbor, just one example of several fish species that need both river and the sea.

The Bay is full of precious resources, and home to endangered species. MWRA through its permit, contingency plan, and monitoring, is actively involved in ensuring that these resources remain healthy, as the new outfall is used.

HOW ARE WE MONITORING THE OUTFALL AND THE ECOSYSTEM?
WHAT HAVE WE LEARNED ABOUT MASSACHUSETTS BAYS?
Dr. Mike Mickelson, Massachusetts Water Resources Authority

This presentation has two parts, first a brief overview of what we are measuring and then a summary of what we have observed. The Monitoring Program was designed by OMSAP’s predecessor, the Outfall Monitoring Task Force, to address public concerns about the new outfall that on September 6, 2000 began discharging treated sewage effluent in Mass Bay, 9.5 miles offshore of Boston. The monitoring is required by MWRA’s discharge permit, and its goal is to test whether the effluent is as clean as it should be, whether expectations for environmental quality are met, and whether the effects of the outfall match those expected from modeling.

Measurements begin in the Deer Island sewage treatment plant. Primary treatment settles out solids in the sewage effluent, secondary treatment oxidizes the organic material, and then the disinfection process kills pathogens. He showed where effluent leaves the disinfection basin before entering the long tunnel traveling to the outfall in Mass Bay. The following measurements ensure that all parts of the treatment process are working well and that environmental effects are minimized: pathogen indicators, residual chlorine, total suspended solids, biochemical oxygen demand, toxicity testing, PCBs, flow, pH, nitrogen loading, and numerous organic and inorganic contaminants. EPA and MADEP limit the allowed concentrations through the discharge permit.

The following measurements in the receiving waters are designed to detect environmental effects: nutrients, chlorophyll, dissolved oxygen (DO), temperature, salinity, light, water clarity, solids, phytoplankton, nuisance and noxious algae, zooplankton, photosynthesis, respiration, remote sensing, moored instruments, marine mammal observations, bacterial indicators, viruses, and diffuser mixing. The outfall could increase the naturally present nitrogen and then increase abundance of phytoplankton algae. Too much nitrogen can lead to high chlorophyll (an indicator of plant biomass), discolored water, harmful algae, and low oxygen in bottom waters when the algae sink and decay.

The monitoring in Mass Bay focuses on the area around the outfall. The effluent travels over about 10 hours through the underground tunnel to the outfall diffuser in Mass Bay. He outlined the area around the outfall called the “nearfield”. MWRA also measures beyond the nearfield, to see changes in Boston Harbor, to determine how waters from the Gulf of Maine affect the Bay, and whether there are effects as far as Cape Cod Bay.

A dedicated whale observer is on board during the nearfield surveys, and the winter-spring farfield surveys. The data supplement the whale sighting database. Sightings indicate that whales are present but infrequent near the outfall. Two right whales were observed in 1999, but none in 2000. The 2001 data have not been analyzed yet.

Organic material and toxic material can settle out on the sea floor in soft-bottom or muddy areas. Monitoring looks for toxics in the mud and for diversity of the benthic community. The sea floor near the outfall is very patchy, eroding from some areas and accumulating sand and mud in other areas. He showed the areas where it is possible to take a grab of sediment and MWRA has stations near the outfall and mentioned that there are also farfield stations. In addition to effluent, water column, and sediments, MWRA also monitors fish and shellfish. MWRA measures toxics and health of flounder, lobster, and transplanted mussels at three areas, the outfall, Boston Harbor, and Cape Cod Bay.

M. Mickelson then compared monitoring data to computer modeling. He showed results of a model that simulated the ocean and the old and new outfalls on a computer. He then showed real monitoring data for ammonium collected by water column monitoring with the same pattern as the model – higher levels of ammonium near the old and new outfalls. He then showed a transect of model results from Boston Harbor, through the nearfield, and down to Cape Cod Bay to show that effluent concentration varies with depth and distance. Model results from October 1999 show effluent from the Harbor outfall reaching the sea surface. In October 2000, with the new outfall, the model shows effluent is trapped in bottom waters and does not reach the sea surface.

Monitoring data for ammonia, taken in October, after the outfall went on-line, show a similar pattern, with effluent trapped below the surface in October 2000. These comparisons give some confidence in the models used in decisions about siting the outfall. This compared only part of the modeling effort. MWRA is currently working on testing real data against the model that predicts levels of chlorophyll and dissolved oxygen.

In addition to model comparisons, the monitoring data also show whether the treatment plant is working well, and whether expectations for environmental quality are met. If they are not, as reflected by exceedances of certain thresholds, then the CP specifies a timely response as shown in this decision diagram. If a threshold is exceeded, MWRA provides notification within five days (to regulators, OMSAP, the web, Hyannis Library) and the problem is corrected, reviewed, or more measurements are made. If a warning level is exceeded, there is additional response with an evaluation of whether MWRA caused an adverse environmental impact. There is also ongoing planning and reporting until the problem is resolved.

M. Mickelson then described the two warning level exceedances in 2000, and both were in the treatment plant. MWRA added too much disinfecting chlorine to the effluent in December during a storm. This showed the need for extra control equipment, which had not yet been installed, but was shortly afterwards. Since then, there have been no exceedances for chlorine. Second, the effluent measured too acidic, with a pH below 6, in December. MWRA’s effluent leans toward slightly acidic due to addition of pure oxygen during secondary treatment, leading to supersaturation by carbon dioxide (CO2) which is a weak acid. MWRA now agitates the samples to allow the CO2 to escape, which mimics what happens as the effluent falls down into the outfall tunnel.

In Mass Bay, there were two caution level exceedances in 2000: one for high chlorophyll and one for low DO saturation. The evidence is that both were natural events, had no adverse impact, and are not recurring in 2001. The chlorophyll threshold exceedance is a good example of how the Contingency Plan process worked, and how all ways we monitor the bay can be helpful in understanding an unusual occurrence.

Chlorophyll, a measure of the amount of phytoplankton algae in the water, was as high as we have ever recorded in the Mass Bay in the fall of 2000, and it exceeded the threshold. MWRA assembled supporting data on this for OMSAP review. The phytoplankton community was normal. DO, benthic chlorophyll, and benthic respiration were normal. Particulate organic carbon, (another indication of biomass) and phytoplankton cell counts were moderate and peaked in early September before the chlorophyll bloom. It looks like it was part of a large regional bloom having cells that were particularly rich in the plant pigment chlorophyll. Fall 2000 satellite imagery confirmed that there was a region-wide algal bloom from New Jersey north to the Bay of Fundy. The bloom developed in a south-north direction beginning in August. Though the chlorophyll was high, there were no harmful blooms or low dissolved oxygen associated with the bloom. Chlorophyll so far has been normal in 2001.

The plankton community was normal in autumn 2000 even though the Bay has a history of three types of harmful algae: Alexandrium, Phaeocystis, and Pseudonitzschia. There was a bloom of Alexandrium in 1993 in the region, with high cell counts and shellfish closures due to paralytic shellfish poisoning (PSP). The cells appear to flow down from Maine with currents and may or may not enter Mass Bay depending on the oceanography. Maine had a lot of PSP in 2000, and high cell counts in 2001. These may be cells from Maine. The nuisance alga Phaeocystis only appears in April and only in some years and it seems to repel whales. Spring of 2001 was a good year for right whales, with 31 calves born. Although Pseudonitzschia are found in occasionally high levels in Mass Bay, amnesic shellfish poisoning has not been detected in Mass Bay shellfish.

The algae bloom of 2000 did not cause abnormally low levels of DO. DO was actually much lower in 1999 than in 2000 and 2001 so far seems like a normal year. OMSAP reviewed the data and recommended that the thresholds for DO take into account the natural background levels. This is more consistent with the state DO standard.

M. Mickelson ended his presentation with a video taken as part of the monitoring of the rocky cobble community near the outfall. He reviewed the geometry of the outfall tunnel in relation to Deer Island and showed a sketch of one of the 55 diffuser caps on the sea floor in 100 feet of water. Each cap is about 12 feet high. He then showed a photograph of the remote observing vehicle (ROV) that took the video. The video began with the ROV is approaching one of the risers. Marine “snow” was visible and is normal. Overall, the rocks looked normal, the appearance of the life on the diffuser cap was consistent with it just being just another big rock. Discharge of the effluent was visible. The apparent color of the effluent is due to an index of refraction. Many animals were visible living on and around the diffuser cap, including anemones, sea squirts, cunner, flounder, and lobster.

DISCUSSION & QUESTIONS
BOSTON

S. Redlich: What are the predictions for further recovery of Boston Harbor sediments?

A. Rex: We expect it to continue as the metals and contaminants are flushed out. The Ampelisca tube mats are being replaced, in a process of succession, by animals that are more typical of a more pristine ecosystem. Also, the seafloor communities are becoming a little more diverse. I expect that more and more of the harbor will begin to look more like the cleaner southern part of the harbor (Hingham and Hull Bays) and hopefully even seagrass will return.

R. Buchsbaum: Why hasn’t the sediment quality has improved in Quincy Bay?

A. Rex: Quincy Bay is not well flushed, and the water is particularly turbid, however, we do not know exactly why the sediment quality has not improved.

D. Tomey: Have you seen a decrease in carbon loading in the sediments, relative to the sediment flushing?

A. Rex: I do not have that data here, but I would think yes.

W. Sung: Are the sediments actually a source of pollution to the harbor?

A. Rex: MWRA measures contaminants in mussel tissue in the Inner Harbor and results indicate that the water is still polluted, but I am not sure whether the contaminants are flushed out of the sediments.

D. Tomey: With a decrease in carbon, there could be a flux with metals.

J. Shine: Or sulfides.

A. Rex: I agree. It is an interesting conundrum, that when organic matter is removed, in fact, metals are mobilized. However, I doubt that the harbor has reached this point. Also, the harbor is so well flushed that any contaminants that were migrating into the water column would be flushed out of the harbor relatively quickly.

M. Liebman: Dredging data from the harbor (around 1998 when the Nut Island Treatment Plant closed) did measure contaminants in the water column, but there were no exceedances of the water quality criteria.

J. Shine: What is the overall contribution of bacteria to Boston Harbor from other sources? Has this changed very much?

A. Rex: We have seen reductions in some areas where MWRA, together with the communities, have disconnected illegal sewer connections into storm drains (e.g. Constitution Beach). Also, with the increased pumping capacity of the treatment plant, the system does not back up as much, and there are not as many combined sewer overflows (CSOs). However, there have not been enough large rainstorms since the outfall has been online to determine what exactly what changes there have been. But it certainly should reduce CSOs. Keep in mind that there are other sources like dogs, boats, and birds. There is still a lot of work to do and contaminated stormwater is probably the biggest and most difficult problem to deal with, because it is so diffuse.

R. Buchsbaum: It is my impression that there were a fair number of beach closures this past summer as a result of contaminated stormwater.

A. Rex: The newspapers did report several beach closures this past summer. However, over the past five years, beach postings have remained fairly constant. MWRA has done some intense monitoring, sampling daily at several Boston Harbor beaches. In 2001 Pleasure Bay was closed 9% of the time, Constitution 17%, Carson 23% (higher than usual), Tenean 34%, and Wollaston 36%. In some years, Wollaston has been closed more than half the time.

R. Buchsbaum: It seemed like it was a bad year for beach closures in Salem.

A. Rex: Summer 2001 was a little rainier, but there was also extra publicity. This is actually typical for what it has been for the past five years. In the 1980’s, before MWRA started doing any work at all, there were noticeably more beach postings. Some say that changing to the new Enterococcus standard may explain some increased postings. One advantage of using Enterococcus is that it does not die off as quickly in the sample cup, as coliform does. If you have agencies that may not be bringing the sample as quickly to the lab as they should, then the Enterococcus may be a more realistic sample of what is actually in the water. MWRA does not have a problem with transport time because we have our own lab.

B. Berman: Is this a list of compiled bacterial exceedances?

A. Rex: These are beach postings, a more conservative estimate. These are days when at least one sample per beach day meets the Enterococcus limit and most of the beaches do not get posted unless two samples meet.

W. Sung: I am surprised that the attendance tonight is low. Will there be more aggressive public outreach for the next workshop?

A. Rex: There were more than 1000 mailings, posting on several websites, emails, newsletters, and a press release.

P. Foley: It is perhaps not surprising, but a little bit disappointing for us to have a small turnout. All of us, OMSAP, PIAC, and the agencies, not only have put an enormous amount of thought and time into the message this evening to the public, how to deliver it, and make sure that it is understandable to the public. We did an enormous amount of mailings, we posted it on websites, we advertised with the Coastal Advisory Network, and sent notifications to a host of email serving lists. We did press releases, sent it off to community newspapers, so I think that our outreach was intense and aggressive and not at all last minute. I think that all of us in this planning process had a feeling that because there is no controversy right now, and because there are so many other things happening in people’s lives, while we hoped that the turnout would be better, unfortunately, it was not. We will do some follow-up using the same vehicles to let people know what transpired at these workshops.

R. Buchsbaum: Perhaps the message is to declare victory [with the Boston Harbor Project].

A. Solow: Thanks to everyone for attending this evening.

DISCUSSION & QUESTIONS
HYANNIS

B. Adler: I represent the MA Lobstermen’s Association and one of the things that our Boston Harbor fishermen noticed in the harbor before the new outfall opened was that MWRA was making the water too clean, like a swimming pool. The chlorine at times was quite intense, and there wasn’t anything living in the harbor. I am concerned about the temperature, salinity, and chlorine and metals concentrations of the effluent.

A. Rex: The old Deer Island Treatment Plant did not dechlorinate, but the new one does. MWRA’s permit has a very strict (i.e. very low) chlorine residual limit that we have to meet. One of the benefits of secondary treatment is that it takes a lot of the solids out of the waste stream, and making it much easier to disinfect, so we actually use a lot less chlorine now than when we were just doing primary treatment and discharging in the harbor. MWRA also dechlorinates which was never done before, so that really should not be an issue.

B. Adler: The lobstermen did indicate that once the outfall was diverted to the bay, the habitat in the harbor has grown back. While the discharge did not kill the animals, it kept them out of the harbor. But I am still concerned about the temperature, salinity, and chlorine effect on the bottom now that the new outfall is on-line.

B. Berman: One of the things that I noticed was that lobsters like dead and decaying matter. Is it possible that one of the reasons why there are not so many lobsters in the harbor because MWRA is no longer discharging partially treated sewage into the harbor?

A. Rex: It could be. There used to be a lot of lobster pots in and around the discharge areas in Boston Harbor. Also, lobster biology is very complicated. Lobsters migrate depending on local temperature and salinity regimes.

M. Mickelson: The effluent from the new outfall discharges upwards and is diluted fairly quickly. The temperature is slightly lower than bottom water. It is nearly fresh water (approximately 3 parts per thousand). Chlorine is within the permit limit, and is actually fairly low due to the long travel time in the tunnel. Juvenile lobsters tend to not be in this area, although the adult lobsters are.

W. Bergeron: First, MWRA gave a fine presentation, it was done in understandable terms for the public, and the presentations were very clear. Second, I want to ask about the potential long-term effects. Impacts of outfalls frequently do not have a catastrophic effect, but rather there is degradation over a long period of time. This was a presentation of the status of a year when things look healthy and hopefully it will look the same 10 years from now. However, having said that, from OMSAP’s viewpoint, do you have any plans to drop any of the monitoring over a period of time? It is our feeling that we are just beginning this process, and we do not want to lose the monitoring or thresholds just because nothing happened in one year.

A. Solow: I do not think there is any plan to drop any of the monitoring of the variables that are being monitored. I think that it is important that we are alert chronic low-grade impacts, and we are always trying to think about ways of looking at changes in the system that are subtle. Ecological systems can respond in very subtle ways and we need to try to understand the system and be alert to this kind of change, not just single threshold exceedances occurring one at a time. We share your concern, and we will be vigilant in that regard.

P. Foley: On behalf of Save the Harbor/Save the Bay, we think that ongoing monitoring efforts are critically important, not simply a year from now, or 2 years from now. One of our important public policy initiatives will be to continue to track appropriations for monitoring and if it appears that monitoring will be cut, we will be contacting you and others in the region to work with us in advocacy and educating to make sure that monitoring is not reduced.

M. Loebig: Will threshold values will be dropped or changed?

A. Solow: We are still learning about the levels that trigger caution or warning thresholds, and as we learn about them, they may be revised. If we have a caution or warning threshold that is exceeded often and it is clear that it is not related to the outfall, then we may recommend a revision. However, we will not just make changes that make thresholds more lenient until we never see any problems so we can say that everything is working well. Again, we do not want to be “slaves” to the thresholds, we need to be holistic, in a sense, and examine the monitoring data to try to understand if we are seeing subtle changes.

B. Beardsley: Another use of the monitoring data is to help us learn more about the system and provide data to models. One of the benefits of this program, which is unusual, is to have this long time series of data. There are two models, circulation and water quality, and they are tested and refined by comparing the results of the models for each year verses the monitoring data collected. These models could possibly be used some day to predict local impacts of climate change, so it is critical from my point of view, to keep the monitoring going, to keep trying to improve the predictive capabilities of the modeling.

Audience: Is there any other comparable monitoring program in the country with MWRA’s scope, detail, and frequency? Also, is the effluent of biotechnology companies regulated, and if so, are they required to treat biologically active compounds?

M. Mickelson: Each institution and university has a safety committee that reviews what is discharged and how it is treated. Small amounts of chlorine effectively kill organisms in effluent.

Audience: Are there thresholds for pharmaceutical chemicals in wastewater?

A. Rex: There are no limits for pharmaceuticals. MWRA is studying estrogen-mimicking chemicals in its effluent, in Boston Harbor, and in Mass Bay. The understanding of effects of these chemicals in the environment is still an evolving science, and there needs to be more done in the regulatory area as well.

M. Mickelson: Perhaps the most comparable monitoring program to MWRA is in southern California. Another large monitoring program is in Puget Sound in Washington State. MWRA is currently the largest effluent monitoring program in the world.

Audience: Why have there been so many beach closing on Cape Cod in the summer of 2001? Is this caused by the MWRA outfall pipe?

A. Solow: The beach closings are not from the outfall.

A. Rex: We are very confident that the beach closings are not caused by the outfall. We do monitoring in the area around the outfall pipe, and we rarely detect any sewage-related bacteria out there. The beaches on Cape Cod are so far away from the outfall, that it is not plausible that there would be any impact. The Cape problems are probably similar to Boston problems. There are shoreline sources of bacteria such as contaminated stormwater, boat discharges, septic systems, animals, and birds. Boston has combined sewer overflow problems as well. It takes a lot of work to figure out exactly what caused a beach closing.

B. Berman: I agree, and there was also a lot more media coverage this year. The BEACH Bill, resulted in standards and testing on beaches that we assumed were clean. A beautiful beach on the south side of Cape Cod was closed, and everyone had assumed it was clean. It had even won a national award for being one of the cleanest beaches in the nation. It was the first time that it had ever been tested and it turned out that there was a septic problem related to a back-up. Some of the large beaches in Boston are closed 20% of the time, and as you look on a finer level, it is due to a broken pipe, birds, boaters, CSOs, or filthy stormwater. These problems need to be solved on a community-by-community, or even a beach-by-beach basis.

Audience: Do you only monitor by the outfall?

A. Solow: No, there are monitoring stations in Cape Cod Bay.

M. Mickelson: [showed an overhead of monitoring stations] Cape Cod Bay is sampled six times a year.

B. Beardsley: It is interesting to note that model results show various places along the coast where there were local “hot spots” of high chlorophyll due to local effects. I think people need to look more locally to find out the cause of events.

Audience: How long will the monitoring continue?

A. Solow: There are no plans to discontinue the monitoring.

Audience: Who is funding this monitoring?

A. Rex: MWRA ratepayers are funding this monitoring, about $4 million a year.

Audience: The excessive building on the Cape, the limited size of the Cape, the large number of new homes, the large number of septic systems, all of this can cause problems to the ocean and drinking water. This is one of the big problems for the Cape.

A. Solow: I agree.

B. Adler: Are MWRA’s monitoring stations separate from those of the Center for Coastal Studies?

P. Borrelli: I’m Peter Borrelli, director of the Center for Coastal Studies in Provincetown. The Center for Coastal Studies has set up an independent monitoring program that involves 10 stations in Cape Cod Bay, and some stations further north near the outfall. The stations in Cape Cod Bay do not overlap the MWRA stations. They were selected from the 20 historical stations that the Center for Coastal Studies has been sampling for the past 15-20 years. Recently we have found some interesting data off of Plymouth in deep water, which may be an indication of local effects, totally unrelated to the southward flow from the outfall. Several of the Cape Cod Commissioners have suggested that we look at impacts from the Cape communities themselves, particularly as the build out of the Cape increases. The closure mentioned earlier, Coast Guard Beach, inside the Cape Cod National Seashore, had been given an award for being one of the best beaches in the United States. It turned out that the Cape Cod National Seashore’s bathhouses were impacting the beach. This may have been occurring for years, but because the water sampling began this past summer, we just became aware of the problem.

S. Mayo: Though the Center for Coastal Studies’ stations do not overlap with MWRA’s stations, most are generally in the same vicinity. At some point, we would like to get together with MWRA and see if we have similar results.

A. Laughnane: I am a town counselor for Barnstable and member of the Bays Legal Fund Board of Trustees. We should give a lot of credit to the Bays Legal Fund and all the other organizations that lobbied and testified for so long to have the monitoring and the Contingency Plan for this large experiment, the outfall pipe. We should not become complacent because of good findings for the first year. There are some things in there that could be used as a warning, for instance paralytic shellfish poisoning in the Gulf of Maine, and the fresh water and temperature of the outfall. I am very happy to see that we have monitoring the outfall, but we cannot let down our guard because there could be a future malfunction, or there could be subtle changes in the environment.

A. Solow: I think we all agree. It is important that the public stays on top of this and OMSAP’s Public Interest Advisory Committee has been very consistent. I myself would have liked to have seen more people at this workshop. But things are going well so far, and there is a tendency to become complacent, and it is important that this does not happen. It is important to keep people interested in this issue.

B. Berman: Just to be clear, OMSAP examines the monitoring results, and is not paid. Everyone wants to make sure that there is integrity in the data.

M. Mickelson: In addition, MWRA makes every effort to fund collaborative studies, and helped fund the Center for Coastal Studies’ project. MWRA is also becoming involved with the Gulf of Maine Ocean Observing System (GoMOOS), part of a national movement to coordinate monitoring activities. GoMOOS recently installed a mooring off of Cape Ann that continuously records oceanographic parameters, as recommended by OMSAP. Interestingly, Harvard, in conjunction with NATO’s largest research vessel conducted a detailed survey of Mass Bay in June 2001. Their data are quickly posted on the web and they also conduct comprehensive modeling. The USGS has been key in providing some of the most valuable monitoring information. They have been maintaining a mooring in Mass Bay and they have been studying sediment and contamination transport, as well as other topics. There are several posters in the hall showing the work of USGS.

S. Mayo: Our CCS project is not as extensive as the MWRA program, but I hope someday it may be. While indeed this first year of our work is broadly supportive of what MWRA has been saying, it is only the first year, and our observations are indeed preliminary. The project is attempting to track the effluent by looking at the different nitrogen compounds. Though this work generally supports what MWRA has stated about impacts to Cape Cod Bay, but we are still in a new situation and things could change. We have to continue our sampling, just as MWRA needs to continue it’s monitoring.

M. Bothner: I work for the USGS and I would like to emphasize that this long term monitoring is giving us some very important scientific information. Not only are we learning about the outfall, but we also learn more about how the system works. This is valuable information. An example of this is our study of sediments near the outfall for various levels of metals. Concentrations of metals in the surface sediments, well before the outfall went on-line, were very high. In the early 1990’s, the No-Name or “Perfect Storm” caused tremendous resuspension of the bottom sediments and moved contaminated fine-grained sediments. Silver concentrations increased by at least a factor of three and they went decreased. With this storm, we learned a lot about what a storm could do to the inventories of contaminants in the sediments.

Audience: Stormy, do you have any comment on the idea that Phaeocystis actually repels right whales?

S. Mayo: I have observed that phenomenon with whales but it may well be happening with other species. However, this type of observation is difficult to update and quantify.

Audience: How about other species?

S. Mayo: We have seen one example when there was a major mortality of humpback whales supposedly caused by mackerel [containing red tide toxin] and there was some human health concern since mackerel are fished.

A. Solow: Thank you everyone for attending this evening.

ATTENDEES, BOSTON: Bruce Berman, Save the Harbor/Save the Bay/PIAC; Robert Buchsbaum, Audubon/PIAC; Margaret Callanan, Cape Cod Commission; David Coles; Cathy Coniaris, MADEP; Mike Delaney, MWRA; Patty Foley, Save the Harbor/Save the Bay/PIAC; Glenn Haas, MADEP; Carlton Hunt, Battelle; Marilee Hunt; Bob Kenney, URI/OMSAP; Michael Kozu, Project Right; Matt Liebman, EPA/IAAC; Steve Lipman, MADEP/IAAC; Mike Mickelson, MWRA; Elizabeth Murray, MWRA; Judy Pederson, MIT SeaGrant/OMSAP; Susan Redlich, MADEP; Andrea Rex, MWRA; Jim Shine, Harvard School of Public Health/OMSAP; Andy Solow, Woods Hole Oceanographic Institution/OMSAP; Windsor Sung, MWRA; Dave Tomey, EPA/IAAC; Grace Vitale, MWRA; Karen Wepsic, Jamaica Pond Association; and David Wu, MWRA.

ATTENDEES, HYANNIS: Bill Adler, MA Lobstermen’s Association; Fred Albert, STOP; Ruth Albert, STOP; Bob Beardsley, Woods Hole Oceanographic Institution/OMSAP; Wayne Bergeron, Bays Legal Fund/PIAC; Bruce Berman, Save the Harbor/Save the Bay/PIAC; Peter Borrelli, Center for Coastal Studies/PIAC; Mike Bothner, USGS; Mary Buck; Margaret Callanan, Cape Cod Commission; Cathy Coniaris, MADEP; David Dow, NMFS/IAAC; Robert Duncanson, Barnstable County CRC; Patty Foley, Save the Harbor/Save the Bay/PIAC; Cynthia Franklin; Dave Gilmartin, MWRA; Jennifer Hackin, AT&T 3 News; Ben Cowie-Haskell, NMFS/Stellwagen Bank; Roger Janson, EPA; Audrey Laughnane, Bays Legal Fund; Matt Liebman, EPA/IAAC; John Lipman, Cape Cod Commission/PIAC; Steve Lipman, MADEP/IAAC; Mary Loebig, STOP; Irene McHugh; Ed Maroney, Barnstable Patriot; Stormy Mayo, Center for Coastal Studies; Mike Mickelson, MWRA; Douglas Pluciennik; Helen Pluciennik; Andrea Rex, MWRA; Susan Rohebach, asst. to Sen. Robert O’Leary; Jim Shine, Harvard School of Public Health/OMSAP; Andy Solow, Woods Hole Oceanographic Institution/OMSAP; Steve Tucker, Cape Cod Commission/PIAC; and Nick Vakalopoulos.

Summary prepared by C. Coniaris. Post-workshop comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

OMSAP Meeting, Tuesday, October 16, 2001
10:00 AM - 2:00 PM
Boston, MA
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Bob Kenney, URI; Judy Pederson, MIT/Sea Grant; Mike Shiaris, UMass Boston; Jim Shine, Harvard School of Public Health; and Juanita Urban-Rich, UMass Boston.

Observers: Bruce Berman, Save the Harbor/Save the Bay; Peter Borrelli, Center for Coastal Studies; Mike Borucke, MIT; Cathy Coniaris, MADEP; Kelly Coughlin, MWRA; Mike Delaney, MWRA; David Dow, NMFS; Marty Dowgert, USFDA; David Duest, MWRA; Marianne Farrington, New England Aquarium; Patricia Foley, Save the Harbor/Save the Bay; Carlton Hunt, Battelle; Russell Isaac, MADEP; Chris John, MWRA; Ken Keay, MWRA; Christian Krahforst, MCZM; Wendy Leo, MWRA; Matt Liebman, EPA; Steve Lipman, MADEP; Rich Masters, Normandeau; Stormy Mayo, Center for Coastal Studies; Mike Mickelson, MWRA; Cornelia Potter, MWRA Advisory Board; Andrea Rex, MWRA; Larry Schafer, retired; Jack Schwartz, MADMF; Sal Testaverde, NMFS; Steve Tucker, Cape Cod Commission; Gordon Wallace, UMass Boston; David Wu, MWRA; and Meng Zhou, UMass Boston.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. OMSAP approved the April 4, 2001 minutes with no amendments.
  2. OMSAP recommends that EPA and MADEP approve of the addition of “unless background conditions are lower” to the DO percent saturation and concentration Contingency Plan thresholds and approved of the approach for calculating the background DO.
  3. OMSAP recommends that EPA and MADEP approve of the change in the Alexandrium abundance Contingency Plan threshold to 100 cells/L.

MINUTES

WELCOME & REVIEW OF APRIL 2001 DRAFT MINUTES
ACTION: OMSAP approved the April 4, 2001 minutes with no amendments.

C. Coniaris summarized the morning Inter-Agency Advisory Committee (IAAC) meeting. The committee discussed their mission. S. Testaverde decided to continue with IAAC’s current role of advising OMSAP on regulatory issues. OMSAP may call upon them whenever they feel that it is necessary, and IAAC will convene to discuss issues of interest to the agencies, e.g. DO criteria.

BAYS EUTROPHICATION MODELING SCHEDULE
M. Mickelson outlined the status of the modeling effort and described the four reports that need OMSAP Model Evaluation Group (MEG) review. The first report is an addendum to the 1992-4 modeling. Several years ago, MEG requested that 1992-4 be run to test the models because of interesting features in 1993 (unusual high fall chlorophyll) and 1994 (very low dissolved oxygen). MEG reviewed the model results in March 2001 and recommended that that report have an addendum to document boundary conditions and model equation and that other additional questions be answered.

M. Mickelson then summarized the conclusions of the second report that addresses whether fine grid resolution should be used. The MEG had considered that perhaps the fit for dissolved oxygen (DO) would be improved if a fine grid were used for the water quality modeling. HydroQual reports that the fine grid did not considerably improve fit for DO but it was conceptually more accurate and should be used. Furthermore, it improves resolution in Boston Harbor.

M. Mickelson then described the third report, results of a boundary sensitivity analysis based on a question from MEG on the extent that the nearfield is influenced by the northern boundary. HydroQual found that DO in the nearfield is very sensitive to DO concentrations at the boundary. Nitrogen concentrations are less sensitive because there are other inputs. Cape Cod Bay is less influenced because of its distance from the boundary.

M. Mickelson then reviewed the fourth report that describes the results of HydroQual modeling using a third algal group as requested by MEG. The water quality model has always used two algal groups (winter and summer) that coexisted throughout the year. Algae abundances are varied through the year by changing the ratios of nutrients and boundary conditions. MEG will be asked to review the results. HydroQual will proceed with doing the 1998-1999 water quality modeling. UMass Boston is beginning practice runs of the hydrodynamic and water quality models to smooth the transition from HydroQual. After that, they will begin the post-discharge modeling, beginning with the year 2000. A. Solow asked if HydroQual recommends the incorporation of the third algal species. M. Mickelson replied that it appears to be a level of complexity that may not be needed. The inclusion of a third algal group would increase the modeling effort and cost, and it was not obvious that it was necessary but MEG will review this.

A. Solow asked about the fine grid and DO. M. Mickelson explained that the finer grid actually gave a slightly higher DO than the coarse grid. This was due to numerical dispersion. When HydroQual applied low DO boundary conditions, it moved faster with the coarse grid because the grid sizes are bigger from the boundary to the nearfield. The fine grid has smaller boxes and an input of low DO water at the boundary takes more time to reach the nearfield and thus it has less of an effect.

J. Urban-Rich asked how MWRA decided what years to model. M. Mickelson replied that MEG has in the past recommended what years to run. We actually learn a lot about biology and modeling from model shortcomings. R. Isaac is not sure if the third algal species will give a more complete or confusing picture. M. Mickelson will send R. Isaac a copy of the report on the third algal species. D. Dow asked if using a third algal species would allow a better prediction of the nuisance algal blooms like Phaeocystis and Pseudonitzschia that seem to occur in late winter/early spring. M. Mickelson replied that the third algal species was developed to try to model the fall of 1993 Asterionellopsis bloom. This not a nuisance algae, it just had a high ratio of chlorophyll to carbon. D. Dow wondered if the models could be improved to better predict nuisance algae blooms. M. Mickelson thinks this is an issue that could be brought up at the MEG meeting. J. Pederson asked to be reminded of the MEG membership. C. Coniaris listed the MEG members: Bob Beardsley (chair), Eric Adams, Jeff Cornwell, Don Harleman, Jack Kelly, Jay O’Reilly, and John Paul.

BAYS EUTROPHICATION MODEL'S NEW HOME: U MASS BOSTON
M. Zhou introduced himself and explained that he was recently joined U Mass Boston and is co-funded by MWRA to maintain, enhance, and apply the Massachusetts Bay hydrodynamic and water quality models. The principal investigators in this project are Meng Zhou, Gordon Wallace, and Bernie Gardner. Project goals are to: 1) maintain, enhance and apply the existing Massachusetts Bay hydrodynamic and water quality models; 2) provide model runs to MWRA; and 3) enhance the model by incorporating advances in modeling techniques and oceanographic understanding. M. Zhou then outlined their schedule for setting up their lab and running the models.

M. Shiaris said that M. Mickelson had said earlier that the dissolved oxygen is highly influenced by the boundary. M. Shiaris then asked how that would be taken into account as the model is improved. M. Zhou replied that the code in the model for horizontal mixing can be adjusted. It may be that the code does not currently accurately represent fine scale mixing but we will try to solve that problem. We will also try to improve the plankton components to the model. J. Pederson suggested that UMass have a phytoplankton or zooplankton biologist as part of their advisory group since one of the major purposes of the model was to try to look at the biology. M. Zhou agreed that it is important to combine physics and biology in the modeling and he does have a biology background.

D. Dow commented that he thought the problem with the poor DO fit is due to the fact that there are large scale advective processes in the Gulf of Maine that change the boundary conditions and not actual problems with the model. M. Zhou added that he thinks that the model needs to continue to be improved will be working on ways to better integrate the monitoring and modeling. We also need to see if we can deploy additional moorings at the boundary to collect more information.

M. Mickelson noted that M. Zhou has another project in which he is collecting, processing, mapping, and publishing optical plankton counter data from all over the world. M. Zhou added that this is a project that he has been working on with GLOBEC (GLOBal ocean ECosystems dynamics).

A. Rex welcomed M. Zhou and said that MWRA is excited that they are getting the academic resources of UMass for the modeling. In the past we have used the model as a planning tool. The discharge permit requires MWRA to continue to run the model every year to look for outfall effects and we anticipate the use of the model more as a diagnostic tool to help us understand anything unusual that occurs in Mass bays. She also pointed out that M. Zhou is a zooplankton expert so that should be helpful. G. Wallace added that UMass has made a substantial investment purchasing hardware such as an in situ nutrient analyzer that they plan to attach to GoMOOS’ (Gulf of Maine Ocean Observing System) Cape Ann mooring to hopefully provide continuous boundary data.

PLUME TRACKING DYE STUDY UPDATE & REPORTING SCHEDULE
C. Hunt described the plume tracking studies that were conducted in April and July 2001. The discharge permit states that MWRA shall “implement plume tracking, including the use of acoustical technology, to understand the dilution available for the discharge” and “field test and certify whether the outfall’s minimum dilution is equal to, or greater than, the predicted minimum dilution specified in the following document, ‘Hydraulic Model Study of the Boston Wastewater Outfall II: Environmental Performance’, 1993 by Roberts and Snyder”. MWRA first conducted an April “shakedown” survey to test the protocols planned for the certification study and develop information on dilution during unstratified conditions (the plan was to have a March survey but there were weather delays, by April, there was some stratification). The purpose of the July survey was to certify the dilution under strongly stratified water column conditions. The primary tracer was Rhodamine WT dye added continuously at the Deer Island Treatment Plant for a measured amount of time.

C. Hunt then described how Battelle addressed various concerns including: temperature calibration of the dye, turbidity, background fluorescence in effluent and seawater, chlorine, bromine, photodegradation, and sensor calibration. Overall, we did not have to worry about all of these potential factors that could affect the data, and so from an interpretive perspective we have a clean set of data from the effluent and offshore, but we had to do a lot of work to get to that conclusion. He then explained how the dye minimum detection limit was calculated.

C. Hunt described the survey plan and results of the April 2001 dye study. Dye was added continuously to the effluent for six hours at ~50 ppb and discrete samples at Deer Island were collected as planned. Dye addition had to be adjusted to take into account changes in volumes of flow at the treatment plant. They did have to change the location of the dye addition so that there was better mixing before chlorination. Offshore, the following was accomplished: background survey, one segment survey (set of fixed depths sampled in rapid succession over short segments of the diffuser), partial planned hydraulic mixing zone (HMZ) survey, two modified HMZ surveys, discrete sampling, Acoustic Doppler Current Profiler (ADCP) data collection, and farfield survey. Using the ADCP current data, they adjusted the survey plans to make sure they were sampling the plume. The plume was found to be to the NNW of the diffusers. Dilution calculated using the dye concentration data was 105-200 and dilution calculated using the ammonium data was 100-107. Overall, a six hour addition of ~50 ppb dye was enough to easily define the plume field and track it for at least three days.

C. Hunt then described the survey plan and results of the July 2001 certification dye study. Dye was added for six hours at ~84 ppb. Offshore, the following was accomplished: background survey along the diffusers, upstream background sampling, three HMZ surveys, ADCP data collection, 2 days of farfield sampling, and successful survey coordination with EPA and NOAA. The dye emerged from the risers at high slack tide within 10 minutes of the time predicted by the MWRA treatment plant operators. The currents ran ENE parallel to the diffuser for most of the day. The plume broadened and thinned towards the east and was trapped below the pycnocline at about 8-10 meters depth. M. Shiaris said that it almost looked like the effluent is reaching the surface near the diffuser. C. Hunt said that there is some “fluting” in the data; he would have expected the data to be much smoother and are still analyzing the data. M. Liebman said that they had noticed a rebound effect where the effluent flowed up and then rebounded back downwards. B. Berman noted that it also looks like there is some bottom fluting or rebounding. He asked if there is a change of depth along the diffuser line that might explain this. C. Hunt replied that all of the diffusers are at a fairly constant depth of ~35m. M. Mickelson said the fluting is an artifact of the lag in the instruments. A. Solow said that since the fluting tracks the data, it is interpolation error and that can be re-examined. C. Hunt added that it could also be a time lag of the dye cleaning out of the sensors in the tow-yo making the edges of the data not as smooth as they should be. The important point is that the effluent is off the bottom. Overall, it was a very successful survey and we are very confident that we sampled in the initial mixing area.

L. Schafer asked how far south could the plume be potentially measured before the signal was lost. C. Hunt replied that Battelle’s task was to focus on the hydraulic mixing zone so that the dilution of the outfall could be certified, but he will show some farfield results. M. Zhou asked what the tow speed and the circulation rate of the instrument sensor were. C. Hunt replied that the tow speed was ~1 knot vertically and 4 knots horizontally and the sensor was running at ~4 hertz.

C. Hunt then presented the farfield results. The path of the plume was consistent with model predictions, moving southeast overnight and SSW on the second farfield day. The plume stayed just below the pycnocline and there seem to be some fine scale topography influences. They decided not to do the third day of plume tracking because it had become difficult to find and map the plume. C. Hunt then presented a table of data. The dilution based on dye was 91-138 and the dilution based on ammonium was 89-127. As with the April survey, no water quality criteria were exceeded after initial mixing; also, the other potential plume tracers such as phosphate, total suspended solids, chloride (used in salinity-based dilution calculations), copper, silver, and Enterococcus were not used to calculate initial dilution because of the variability in the data.

B. Berman asked why the calculation of the dilution from the copper data was so much different than the calculated dilution from the dye and ammonium. C. Hunt replied that it could be due to the variability of copper concentrations in the water samples and the low sample number for copper. The main reason why we collected samples for copper analysis was to see if the water quality criterion was exceeded, and it was not. G. Wallace asked where the background samples were taken. C. Hunt replied that the samples were collected to the north and east, towards Cape Ann. J. Schwartz asked about the chloride measurements. C. Hunt replied that the MWRA measures chloride because there is some seawater intrusion in the system. C. Hunt then presented Battelle’s reporting schedule with their final report scheduled for completion by April 30, 2002.

REVIEW OF MODIFICATIONS TO CONTINGENCY PLAN THRESHOLDS FOR DISSOLVED OXYGEN (DO) & ALEXANDRIUM CELL COUNT
W. Leo described the DO percent saturation and concentration and Alexandrium interim threshold revisions that were put in place in summer 2001. The permit states that interim modifications can be introduced at any time during the year and are adopted within 30 days, unless EPA/MADEP object. They then get resubmitted in an annual list of Contingency Plan modifications by November 15th of each year. EPA and MADEP approved these changes on an interim basis but asked that OMSAP review them.

W. Leo presented an overview of the proposed revision to the dissolved oxygen thresholds. In 1997, the Outfall Monitoring Task Force recommended the deletion of the DO percent saturation threshold because this threshold was frequently violated before the new outfall went on-line. However, DO percent saturation is one of the state water quality standards, and so the regulatory agencies preferred to keep that standard. EPA and MADEP instead recommended that “unless background conditions are lower” be added to both the DO percent saturation and concentration thresholds to make them more consistent with the state standard. W. Leo then presented MWRA’s approach for calculating the background. The lowest DO survey means in the nearfield and Stellwagen Basin for each of the baseline years are plotted and fit a normal distribution to the points. Then calculate the background as the 5th percentile of this fitted distribution. The background calculations are all below the thresholds (except for DO concentration in Stellwagen Basin).

S. Tucker noted that the DO fluctuates annually on a cyclical basis. He asked why they are trying to move away from the water quality standards (WQS) instead of trying to capture that cycle in the thresholds. W. Leo replied that this threshold revision would bring MWRA more in line with the WQS because the state standards recognize that there are areas where the DO will naturally fall below 6 mg/L and 75% saturation. Also there is only an ecological concern during the late summer/fall when the DO is at its lowest. EPA in the process is in the process of revising their guidance for water quality standards for dissolved oxygen and that will probably result in a lower level considered to be a concern. She also explained that there is another DO threshold, the rate of change over other summer, so if we were to see an accelerated drop in DO, that would trigger the threshold.

G. Wallace asked if there have been any trend analyses conducted and if there were any year-to-year trends seen that might provide any kind of indication of steady state. W. Leo replied that those types of analyses would be found in the water column synthesis reports whereas the thresholds are quicker calculations for early warning, rather than an in-depth look at the data. C. Hunt added that Rocky Geyer, Anne Giblin, and Scott Libby are looking at the low DO and examining how much is local verses external. M. Shiaris thinks it might make sense to do a temporally high resolution DO analysis to use for the trends analysis. W. Leo said that the MWRA late summer/fall data are collected about every two weeks. Temporally high resolution data would come from the USGS mooring. M. Mickelson pointed out that they do not have that data because the sensor fouled too quickly. MWRA does have respiration data and perhaps we could determine why the DO is declining, e.g. is it due to respiration, low DO flowing in from other areas, or vertical mixing. M. Shiaris thinks more resolution would be useful because MWRA might be missing low points between surveys. M. Mickelson said that the patterns of DO are smooth enough that they do not think that they are missing significant changes. J. Shine pointed out that in some years, there is just one point that connects the minimum to maximum. J. Urban-Rich thinks more sampling points would outline the minima better. J. Shine thought then the issue would be resources, would it really be better to give up stations so there could be more frequent sampling (i.e. space vs. time). A. Rex pointed out that the threshold is a survey average of all of the nearfield stations. C. Hunt thinks the question is, does the DO go below a level within two weeks to cause the biology to shut down. He thinks this system cannot respond that fast because it is relatively cold, and respiration is slow.

J. Pederson thinks that the inclusion of the “unless background conditions are lower” is reasonable because it addresses some of the concerns that OMSAP had previously because the threshold was being triggered during the baseline period. This inclusion seems more realistic based on what we know about the environment and it addresses the ecology, which is what the concern is about. It also makes it more consistent with the state regulations. A. Solow thinks this is quite a small change and it is bringing the thresholds into conformity with existing standards. M. Liebman asked OMSAP what they thought about MWRA’s approach for calculating the background. A. Solow thinks it is certainly consistent with some of the other thresholds. ACTION: OMSAP recommends that EPA and MADEP approve of the addition of “unless background conditions are lower” to the DO percent saturation and concentration Contingency Plan thresholds and approved of the approach for calculating the background DO.

W. Leo then described the proposed change in the nearfield Alexandrium cell count threshold to 100 cells/liter in any sample rather than the 95th percentile of the seasonal mean. Alexandrium is patchy, both spatially and temporally, and there are other monitoring programs focusing on Alexandrium or paralytic shellfish poisoning (PSP) that better characterize this occurrence. For those reasons, and the fact that there was a new PSP threshold under development, OMSAP recommended in July 2000 that the cell count threshold be deleted. EPA and MADEP declined to allow this but suggested an alternative threshold of 100 cells/liter, and that was based on the maximum observed value of 163 cells/liter during the baseline. She showed MWRA’s Alexandrium data and explained the advantages of 100 cells/liter over the original 95th percentile of baseline means threshold. 100 cells/liter is well below 300 cells/liter which is the value at which toxicity seems to begin occurring. Yet it seems high enough to avoid false alarms, since it was exceeded only once in the baseline period. The original method of calculating the 95th percentile produced an unrealistically low number because of all of the zeros in the data. J. Urban-Rich asked if this threshold would apply to the average nearfield. W. Leo replied that it would apply to any individual sample, however if there were sample replicates, an average would be taken. Alexandrium tamarense and other Alexandrium species will be added together. She presented recent Alexandrium data and there are a total of seven samples that have measurable Alexandrium. W. Leo added that the PSP threshold mentioned earlier will hopefully be ready in the spring of 2002.

M. Shiaris asked if anyone monitors further north since these blooms begin as far north as the Bay of Fundy, perhaps there was a way to get an early warning. M. Mickelson replied that the MA Division of Marine Fisheries (MADMF) communicates with the state of Maine sampling program. In 2000 there was a lot of toxicity in coastal Maine, with less in 2001. Mass Bay has not seen any toxicity in the past two years except in Nauset Bay which has recurring toxicity problems.

S. Tucker thinks a 100 cells/liter revised threshold is reasonable, but the Cape is still concerned about downstream effects of the outfall. W. Leo replied that the PSP threshold is based on existing PSP monitoring and covers the entire coastline. If any of the samples were to exceed the 100 cells/liter, MWRA would notify MADMF, OMSAP, and others. S. Tucker asked if there was a plan to compare the PSP sampling on the shore with the MWRA sampling at sea. M. Mickelson replied that the correlation between cell counts and PSP toxicity is something that is in the purview of MADMF and that Mike Hickey from MADMF has said that the correlation is not great but it is something that they will continue to examine. S. Tucker wondered what would happen if there was a cell count exceedance, and whether there would be enough information available to determine the cause. J. Schwartz replied that developing a threshold is an imperfect science, but it does offer a flag. He is curious about the recent low values of Alexandrium because the last bloom was a while ago, in 1993. He is looking forward to seeing the new PSP threshold. A. Solow said that what is interesting about the PSP data is the spatial pattern and the timing of the toxicity and he thinks the important information is not whether a station exceeded a threshold, but the pattern of the toxicity.

J. Pederson asked what the original question was, i.e. why was this cell count threshold developed. Are we just looking to see if there is an exceedance that is close to a level of concern or are we looking for something else. M. Liebman replied he thinks we are trying to do both. This is a caution “flag” that is designed to show us if something different is occurring and it means we need to gather more information to learn what is going on. It was designed to be at a level lower than when toxicity develops and it was chosen statistically because there was a sample over 100 cells/liter only once in the nine years of baseline. A. Solow is inclined to support this revision because it can be revised as more information becomes available. He thinks there should be such a threshold for political and scientific reasons. J. Pederson added that this is better than what we had before which was so low that it did not make any sense. J. Schwartz told the group that MADMF supports this revision, until an improved threshold is developed. P. Borrelli asked that this issue be revisited no later than a year from now. M. Shiaris would only want to revisit this if there was better scientific information. P. Borrelli thinks it is very important that OMSAP revisit this. A. Solow thinks there is a strong expectation that OMSAP will be revisiting this as soon as there is better scientific information available. ACTION: OMSAP recommends that EPA and MADEP approve of the change in the Alexandrium abundance Contingency Plan threshold to 100 cells/L.

RECENT CHLOROPHYLL MONITORING RESULTS, COMPARISONS TO THRESHOLDS, AND UPDATE ON DATA CORRECTIONS
M. Mickelson described the fall 2000 chlorophyll exceedance. An intense region-wide bloom was seen in satellite data in September to October 2000. The monitoring program measured high fluorescence during this time, however particulate carbon and phytoplankton cell counts were not unusually high and DO was not lower than usual. Lower zooplankton counts in some areas may have been due to large numbers of comb jellies that prey on zooplankton. These high chlorophyll values were not seen in 2001. After correcting their data for analytical errors, MWRA calculated the chlorophyll threshold based on OMSAP guidance. M. Mickelson then presented the chlorophyll data and the seasonal threshold values. He then showed recent data of the nuisance algae species, Alexandrium, Phaeocystis, and Pseudonitzschia as well as dissolved oxygen. D. Dow asked if MWRA monitors for domoic acid since not all species of Pseudonitzschia produce the toxin. M. Mickelson replied that they count all species of Pseudonitzschia but do not measure domoic acid. The threshold is the 95th percentile of seasonal abundance.

CAPE COD BAY MONITORING PROJECT
P. Borrelli described the Center for Coastal Studies (CCS) monitoring project. This is an independent program, separate from the MWRA, although MWRA has been very helpful in splitting samples from the nearfield. The project samples ~10 stations in Cape Cod Bay based on CCS station locations. The project is mostly privately funded though the Massachusetts Environmental Trust has been a major contributor. We anticipate maintaining the program at its current level for a total of three years and next year we plan to add a few more stations in the nearfield (MWRA station locations).

S. Mayo outlined the impetus for this project. First, he hopes that information collected will help manage an embayment that is of great interest to many people. Second, there are still concerns about MWRA and he hopes the project can help answer some of those questions. Lastly, we hope to add to the data collection in Cape Cod Bay related to the MWRA outfall. One of the main concerns is the southward flow of currents from the outfall, towards Cape Cod Bay. He still maintains that there is a lot to learn about Cape Cod Bay and he is particularly interested in the zooplankton dynamics in the spring in eastern Cape Cod Bay. The two mains goals of the project are to set up a baseline against which to judge future results and to look at indicators such as stable isotopes of nitrogen.

S. Mayo then described the structure of the project and presented preliminary results [see report: http://www.coastalstudies.org/research/monitoringupdates.htm]. There are 10 stations sampled monthly at three depths in Cape Cod Bay. Parameters include stable nitrogen isotopes, phytoplankton, zooplankton, chlorophyll a, and CTD parameters. We plan on adding stations wherever we find interesting features. In the last year, they have seen no indication of an effect of the outfall on the density or species composition of the zooplankton. The data do not seem to have changed very much since Bigelow did his work in the 1920’s and though the phytoplankton data are variable, there is nothing out of the ordinary to suggest a change due to outfall nitrogen. We did see some nuisance algae but not in numbers of concern. A. Solow asked what would have indicated an outfall influence. S. Mayo replied that since the project is only one year old, they would have had to seen some type of extraordinary event. He supposed that a dramatic change in the zooplankton species or density could be an indicator. His point to those who are still concerned about the outfall is that right now they are not seeing a disaster scenario.

S. Mayo then described the stable nitrogen isotope sampling that may help track the outfall nitrogen. δ15N is a ratio of 15N (less common in the marine environment) to 14N. Sewage is richer in 15N, giving it a higher δ15N. M. Mickelson noted that this occurs when there is incomplete sewage treatment [unlike MWRA] due to the loss of ammonia to the atmosphere – the lighter 14N tends to escape first. When there is complete sewage treatment, there is no significant change in the isotopic ratio. S. Mayo added that biological processes tend to favor the accumulation of 15N. M. Mickelson pointed out that because of more complete treatment, MWRA’s effluent does not have a δ15N signal. D. Dow asked if it is possible to use this method to discern from septic sources on Cape Cod from the MWRA outfall. S. Mayo replied that all 15N is the same and so it all depends on the ratio. It is not a marker but rather information that needs to be interpreted.

B. Berman asked about the lack of signal from the MWRA outfall. S. Mayo replied that his understanding was that Joe Montoya sees a δ15N that is ~8, well above the receiving waters. M. Mickelson countered that uptake by phytoplankton could be creating this same signal. A. Solow asked if we can use the δ15N to track effluent. M. Shiaris (and others) replied maybe, it is very complicated. J. Urban-Rich added that there are many ways of calculating the δ15N. C. Hunt said that if the source is not discharging a substantially different δ15N, then it could not be used as a tracer over a large distance. S. Mayo said that there do seem to be gradients of δ15N as you move away from the outfall. He then showed δ15N data from archived samples and there do not seem to be any changes or trends since the 1990’s – although there is a concern that the samples may not have all been preserved properly. Next he showed the post discharge data. Soon after the outfall went on-line, there was a small increase in the δ15N but it may be related to a cyclical seasonal shift in the uptake and incorporation of nitrogenous compounds in organisms. He then showed the results from the MWRA samples. They are not preserved the same way that J. Montoya preserves his samples and we are reviewing the effects of these differences. Results show that δ15N is fairly low in Cape Cod Bay, but higher further north. Lastly, he compared δ15N by distance from the outfall that showed a similar pattern but there are still a lot of questions that need to be addressed. He emphasized that these results are preliminary.

P. Borrelli thinks it is useful to point out the 30-mile station. S. Mayo agreed. Looking at the δ15N data, there appears to be something occurring along the shore off of Plymouth but this needs to be examined further. There is no clear gradient in the ammonia assay of δ15N in the 1999 samples, but there seems to be a fairly clear δ15N signal from effluent spreading southwards towards the entrance to Cape Cod Bay in the October 2000 data assayed from nitrate. C. Hunt thinks the lower δ15N in Cape Cod Bay may not be outfall related. It could be that Cape Cod Bay, which is more of a closed embayment than Mass Bay, processes nitrogen differently. S. Mayo agreed.

OMSAP PUBLIC WORKSHOP TALKING POINTS
C. Coniaris gave an overview of the workshop format and public outreach to date. The OMSAP charter states that OMSAP is to host a public workshop annually to present results of the monitoring. The workshop will be held at two locations, Boston and Hyannis. The workshop will begin with EPA and MADEP will describing permit and Contingency Plan, Andy Solow will describe OMSAP and its roles, and Patty Foley will discuss why public should be involved in this process. Then Andrea Rex and Mike Mickelson will present the monitoring and results for 2000 and the public will be given the chance to ask OMSAP questions at the end. A. Rex then discussed the topics that she and Mike Mickelson planned to present at the workshop.

M. Shiaris thinks the public would like to hear about the beaches and they are linked to MWRA because of CSOs. J. Pederson and A. Solow agreed. D. Dow thought discussing shellfish closures would be interesting. A. Solow is concerned that if you try to pack too much into a short presentation, people are going to be lost. A. Rex agreed and asked if OMSAP thought there was anything on the list of topics that could be removed. M. Shiaris thought that the public would not be very interested in the benthic community data since it is not something that they can relate to. J. Pederson thinks that the public should understand biodiversity and she thinks they should keep the benthic community discussion but perhaps drop flounder liver disease. A. Solow thinks it is important to make sure the audience is told what a benthic community is. A. Rex said that her presentation will be similar to her presentation at the Boston Harbor Symposium was understandable and interesting to the general public. P. Foley thought it was. She also agrees with J. Pederson in that the public needs to be educated.

W. Leo brought up beaches again. A. Rex would be happy to discuss beaches, but it is not a part of the Boston Harbor Project. B. Berman pointed out that whenever the press attempts to write about the outfall, they end up writing about the beaches. J. Pederson suggested leaving beaches to the end and be prepared to address it. A. Solow thought that maybe one way to save time is to mention a list of parameters monitored, but only discuss a few of them in any detail. J. Pederson thinks it is important to include in the introduction the four original questions to put things in perspective: Is it safe to swim? Is it safe to eat the shellfish? Are the aesthetics being maintained? And are we protecting the natural resources? A. Solow thinks that one of the important to show the benefits of the outfall. W. Leo thinks one of the things that can be shown is that now there are fewer blooms occurring in Boston Harbor that are exported to the bay. D. Dow asked if the audience will be allowed to ask questions during the presentations. A. Solow thought it would be more efficient for the audience to ask questions at the end. C. Coniaris offered to prepare a fact sheet and glossary to help the audience with terms they are not familiar with. W. Leo asked if A. Rex is planning on describing the improvements in treatment. A. Rex replied that it will be covered briefly. D. Duest asked if the treatment process will be described. A. Rex thinks that can be described in handouts. P. Foley thought that was fine. She likes the outline but thinks we also have to be flexible because the audience may want to discuss other issues.

A. Rex asked how the marine mammal observations should be reported. S. Testaverde thinks that the public needs to know that there are marine mammals, including right whales out there. A. Rex said that she could show the map of whale observations. B. Berman thinks it would be useful to include other independent research such as the Center for Coastal Studies work. The fact that there is not a broad divergence in MWRA and independent monitoring efforts is a powerful point to convey to the public. A. Solow thought that was a good idea. S. Mayo agreed that A. Solow could mention the project, as long as it is made clear that the results and conclusions are preliminary and the project has just begun. A. Rex then outlined the handouts and posters that they will prepare. She said that MWRA will also be prepared to answer questions on topics not covered in the presentations. She noted that the post-discharge benthic and fish and shellfish data are not ready to present. A. Solow thinks it is still important that the public know that they are being monitored.

PUBLIC INTEREST ADVISORY COMMITTEE UPDATE
P. Foley discussed the public outreach that PIAC has helped with. There has been a great effort to work to inform the public that these workshops are going to take place. We have reached out to newspapers to notify them of the workshops and see if there is interest in covering these meetings. However, since we are not in crisis mode, there is not much interest from the press, but we will continue with that effort. She thanked OMSAP and all of the government agencies that have helped with outreach in this effort.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • October 2001 OMSAP/PIAC/IAAC membership lists
  • April 2001 draft OMSAP minutes
  • MWRA information briefings and copies of presentations

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

OMSAP Meeting, Wednesday, April 4, 2001
10:00 AM - 2:00 PM
Woods Hole
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Norb Jaworski, retired; Bob Kenney, URI; Scott Nixon, URI; Judy Pederson, MIT/Sea Grant; and Jim Shine, Harvard School of Public Health.

Observers: Bruce Berman, Save the Harbor/Save the Bay; Grace Bigornia-Vitale, MWRA; Peter Borrelli, Center for Coastal Studies; Jeanine Boyle, Battelle; Cathy Coniaris, MADEP; Peter DiMilla; David Dow, NMFS; David Duest, MWRA; Patricia Foley, Save the Harbor/Save the Bay; Maggie Geist, Association for the Preservation of Cape Cod; Dave Gilmartin, MWRA; Maury Hall, MWRA; Pam Heidell, MWRA; Carlton Hunt, Battelle; Russell Isaac, MADEP; Chris John, MWRA; Ken Keay, MWRA; Christian Krahforst, MCZM; Janet Labonte, EPA; Wendy Leo, MWRA; Scott Libby, Battelle; Matt Liebman, EPA; John Lipman, Cape Cod Commission; Steve Lipman, MADEP; Stormy Mayo, Center for Coastal Studies; Mike Mickelson, MWRA; Dale Miller, Normandeau Associates; Jack Pearce, Buzzards Bay Lab; Andrea Rex, MWRA; Seth Rolbein, Cape Cod Voice; Larry Schafer, retired; Jack Schwartz, MADMF; Ted Smayda, URI; Elizabeth Steele, MWRA; Steve Tucker, Cape Cod Commission; and David Wu, MWRA.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  • OMSAP recommends that the chlorophyll baseline for the annual threshold be calculated using a shifted calendar year that begins in September and ends in August. This would take into account the outfall start-up date, September 6, 2000, i.e. the year 2000 was an incomplete baseline year. January to August 1992 data will not be used for the calculation of the annual mean but will be used to calculate the seasonal means.
  • OMSAP approved the November 16, 2000 minutes with no amendments.

MINUTES

PUBLIC INTEREST ADVISORY COMMITTEE (PIAC) UPDATE
P. Foley, executive director of Save the Harbor/Save the Bay, introduced herself. She is pleased to be the newly elected chair of PIAC. PIAC’s plan is to promote a better understanding of the science so that public policy can better serve the public interest. PIAC is looking forward in working with OMSAP, and other interested parties, to make sure that the public workshop is productive and informative.

MODEL EVALUATION GROUP UPDATE
C. Coniaris gave a brief Model Evaluation Group (MEG) update. The MEG, formed in 1995, has been reconvened to review recent modeling results. There was a conference call to comment on a preliminary report on the calibration of the hydrodynamic model and there will be additional review this summer [Update: this review has been delayed, pending availability of modeling results]. Please contact C. Coniaris if you would like a copy of the MEG’s comments. MEG members are as follows: Bob Beardsley (WHOI, OMSAP, MEG chair), Eric Adams (MIT), Jeff Cornwell (U. Maryland), Don Harleman (MIT), Jack Kelly (EPA), Jay O’Reilly (NMFS), and John Paul (EPA Narragansett).

EPA/MADEP RESPONSE TO PROPOSED CONTINGENCY PLAN MODIFICATIONS
M. Liebman described the Contingency Plan, which is a plan for actions to be taken by the MWRA when thresholds are exceeded, and includes caution and warning thresholds for which to compare monitoring results to. The Contingency Plan is attached to the permit that was issued in August 2000, and is considered a “living” document in that it can be updated as new information becomes available without reopening the permit. The permit states that by Nov 15th of each year, the MWRA may request changes to the Contingency Plan, including thresholds. MWRA submitted a request for changes in October 2000 and EPA/MADEP have responded in a letter dated April 3, 2001 that describes how the agencies approve or disapprove of changes and includes some additional conditions that the MWRA should meet. The MWRA will submit a revised Contingency Plan within 30 days of today with those changes. He then summarized the April 3, 2001 EPA/MADEP letter [for a copy, contact [email protected]].

S. Tucker asked if there is an expectation that a standard for appreciable change for zooplankton will be developed or will it be based on professional judgment. He also asked if guidelines for appreciable change will be determined by MWRA and OMSAP. M. Liebman replied that it will be based on professional judgment and EPA/MADEP will rely on the current scientific findings in research and monitoring. Guidelines for appreciable change will be developed by MWRA and OMSAP but will be reviewed by EPA/MADEP.

T. Smayda said given that the model used assigns a certain percentage based on temperature and grazing extent, without coupling it to actual zooplankton biomass, it follows that there is no threshold, or a more rigorous statement as to what is defined as appreciable. M. Liebman replied that these issues will be evaluated in the next few years. There is ongoing research and monitoring and an effort and commitment by MWRA to look at the data that has been collected to determine any impacts to the zooplankton community. NOAA Fisheries has suggested that a trophic food web pathway workshop be convened soon to look at these issues, and follow-up on the ideas of a food web model. D. Dow supported T. Smayda in that there should be some process-oriented studies to augment the multivariate statistical analyses to learn more about meaningful change. If there is some kind of multivariate change, it may or may not be biologically significant. An event that is statistically significant is not necessarily biologically significant.

A. Solow thinks there is an expectation that conclusions will take into account existing scientific knowledge. Now is a good time to submit any suggestions in areas where there are concerns to MWRA, OMSAP, EPA, or MADEP. M. Liebman added that the workshop could be a good focal point for those ideas. Related to that, EPA, MWRA, and NOAA have funded Dr. Cabell Davis (WHOI) to conduct fine-scale monitoring of zooplankton communities using a Video Plankton Recorder [report located at: https://www.mwra.com/sites/default/files/2023-11/2000-03.pdf]

J. Shine asked if the new 100 cells/L Alexandrium threshold was chosen because 100 cell/L was exceeded only once in 10 years of baseline or if there was some objective understanding of a dose-response relationship between what cell counts would cause toxicity. M. Liebman replied that both aspects were taken into account, however, the dose-response is not clear enough yet. There is usually some kind of toxicity observed when 300 cells/L is exceeded. 100 cells/L was exceeded once in 10 years, similar, in a sense, to a 90th percentile. In other words, if this is exceeded in the future, chances are there is something occurring that is different from the baseline. He added that this threshold is a caution, meaning that if there is an exceedance, all ancillary data should be examined for a better understanding of the occurrence.

B. Berman asked if the MWRA will report annually on appreciable changes to the zooplankton community. A. Rex replied that the MWRA drafts annual reports that evaluate the zooplankton community and is also conducting the additional statistical studies as requested by OMSAP. K. Keay added that the Outfall Monitoring Overview is due on November 15th of each year.

T. Smayda asked over what area the 100 cells/L Alexandrium threshold pertains to. M. Liebman replied that it relates to any of the monitoring stations, at any depth. T. Smayda is concerned about the fact that there are pulse introductions of Alexandrium entering Mass Bay related to the run-off of the Maine rivers. The point of entry into Mass Bay is close to the point of nutrient injection [the outfall]. He feels that rather than relying on the introduction and subsequent behavior of an Alexandrium bloom, perhaps information from the north should somehow be considered in the development of a threshold as an early warning. He would like to see this revisited rather than finalized because he is concerned about the practicality of this approach given the kinetics and behavior of the Alexandrium populations. It has been established that even one cell ingested by herring larvae leads to die-off, so while there is the potential for a human impact, there is also the potential for a natural resources impact. M. Liebman agreed that looking at the data from a regional perspective is very important in determining what kind of action would be taken. J. Pederson added that the MADMF receives a pre-warning of Alexandrium blooms from the state of Maine when blooms begin moving down the coast towards Massachusetts.

D. Dow asked if shellfish advisories were observed where they have not been seen before (e.g. east of Sandwich) would there be a study to see if this relates to the outfall pipe. M. Liebman replied that this would be examined and there is another threshold in the Contingency Plan that considers “new incidence” of PSP toxicity.

J. Labonte described background to the floatables threshold and then outlined the requirements in the April 3, 2001 letter to MWRA. EPA/MADEP are requesting that MWRA devise another way to sample floatables and develop a new warning threshold for floatables. She then showed several photographs of floatables collection devices at the Deer Island Treatment Plant. S. Lipman added that the key is to optimize the operations of the plant and to control the floatables throughout the entire treatment system.

L. Schafer asked about the magnitude of the floatables problem. S. Lipman replied that it does not appear to be a significant problem but the tip tube system that collects floatables needs to be improved. N. Jaworski thinks monitoring floatables is important since it is a fairly good indication of an upset or system flushes and thinks the monitoring could be done using a video camera.

D. Dow asked if MWRA will be monitoring for floatables during rainstorms when some flow bypasses secondary. D. Duest replied that all flows come in through the three main pump stations, so all flows pass through the same grit removal and primary treatment facilities where floatables are monitored. B. Berman asked if the net tows for floatables during MWRA surveys in Mass Bay have been capturing much debris because he has not seen very much himself. M. Mickelson replied no, most debris sampled has been broken lobster pots.

EXPECTATIONS OF OMSAP WHEN CONTINGENCY PLAN EXCEEDANCES OCCUR
M. Liebman explained that one of the main roles of the OMSAP is to advise EPA and MADEP whenever there is a Contingency Plan exceedance. This process needs to operate efficiently in terms of communication and response. There are four responses that depend on the type of exceedance: discuss at next OMSAP meeting, conference call open to public, OMSAP comments independently, or perhaps no discussion needed. C. Coniaris suggested that the OMSAP chair could decide which action OMSAP takes. A. Solow felt uncomfortable having that responsibility on his own. He sees two kinds of notifications: (1) an exceedance that is understood, and a meeting is not needed, and (2) one that is not well understood, at which point OMSAP should discuss over conference call to decide whether or not to meet in person.

B. Berman suggested that the OMSAP staff person poll the Panel to determine whether a meeting is required.
He thinks it is important to save time by making sure that any written comments go directly to the MWRA and not necessarily through the regulators. M. Liebman said this was a good start and they will work this out further with OMSAP.

RECENT EXTREME WET WEATHER & TREATMENT PLANT PERFORMANCE
D. Duest, manager of process monitoring at the Deer Island Treatment Plant (DITP) described plant performance during the recent extreme wet weather events on March 22 and 30. The DITP normally treats 375 million gallons per day (mgd). On March 21st at 7:00 PM, the plant was operating at 550 mgd and within four hours, flow increased to 1.2 billion gallons a day (bgd). Contaminant loadings to the plant did not change very much, but concentrations actually dropped because of stormwater dilution. Flows averaged 1.136 bgd during the March 22 storm and there was an instantaneous maximum of 1.236 bgd. Secondary battery C was started up on March 8 and there was an average of 456 mgd (~ 40%) of the total flow receiving secondary treatment. All flows were disinfected and dechlorinated. Though the tide levels were three feet above the normal maximum high tide levels, the outfall operated very well. During the March 22 storm, the plant ran 44 hours straight above 1 bgd, with no pump or system failures. During the March 30 storm, the plant ran 18 hours straight over 1 bgd.

C. Hunt asked if the outfall was successful in relieving some of the CSO discharges. D. Duest replied that there was no major flooding on the Boston side. He could not speak for the entire collection system, but there were no major incidents.

S. Nixon was interested in the influence of water level on how much effluent the plant can process and discharge. He wondered what would happen if there was a high inverse barometer effect, higher than the March 22 tides, as well as a very large storm. D. Duest replied that with 1.27 bgd capacity, the plant was running at about 40 feet elevation difference. Additional capacity can be obtained by opening additional ports. To reduce saltwater intrusion into the outfall at low flow conditions, MWRA has not opened all of the ports (271 out of 440 are open now). Low flow defined right now is about 80-120 mgd. One of the problems of saltwater intrusion is that it reduces dilution in the receiving waters. S. Nixon asked if the ports could be opened and closed at the flip of a dial. D. Duest replied no, they have to send divers and it would take several weeks to complete the task. When the outfall is new, there are less frictional losses due to encrusting organisms and thus there is a higher capacity. MWRA is starting to see some limitations in the capacity, and this means that it is time to start thinking about opening up additional ports to maintain the maximum capacity, but we also have to think about the minimum capacity as well. N. Jaworski asked if they have looked ahead to consider what global warming and sea level rise would mean for plant performance. D. Duest replied that this was considered in the long-term design of the facility.

FALL 2000 PLANKTON BLOOM OBSERVATIONS FROM MA BAY AND THE MWRA NEARFIELD
C. Hunt showed SeaWiFS (Sea-viewing Wide Field-of-view Sensor) chlorophyll satellite imagery from NASA of a region-wide phytoplankton bloom that occurred from late August through October 2000. R. Isaac asked what the resolution is on the satellite imagery. C. Hunt replied there is a 1 km pixel. There are three different groups that analyze the satellite data and they vary on how they handle the algorithms and finalize the data. MWRA uses the NASA calculations since they seem very consistent and M. Mickelson can obtain the data quickly. J. Shine pointed out that the satellite only captures the top few meters and cannot capture subsurface maxima.

C. Hunt then showed September chlorophyll satellite data from 1997 to 2000, and it appears that blooms have been becoming more intense. L. Schafer asked if this bloom could be correlated with the outfall start-up. C. Hunt replied no, this is a region-wide bloom from the Gulf of Maine to southern New England, into Long Island Sound. He then showed phytoplankton, in situ fluorescence, particulate organic carbon and nitrogen data, primary productivity, dissolved oxygen, nutrient, and zooplankton data. In situ fluorescence was shown because the chlorophyll extracted data are still under review [see next section].

S. Nixon asked how the satellite data compares with in situ results from the MWRA monitoring program. C. Hunt replied that they are still analyzing the data. He then showed phytoplankton abundance for the entire baseline period. The data show that there has been a fall bloom for five out of the nine baseline years, however, the system generally has similar abundances from year to year. In March 2001, there was a Phaeocystis bloom. The large system-wide bloom began in late August through September and declined as winter approached. D. Dow asked if that was considered to be normal phytoplankton composition. C. Hunt replied that the composition is much like previous years.

A. Solow asked C. Hunt to briefly summarize what they have seen, what is important, and whether this bloom was unexpected. C. Hunt replied that the fall bloom is not unexpected. However, the duration of the high chlorophyll of the regional event and the fact that high chlorophyll values were measured from the surface to the pycnocline were surprising. Typically there is just a subsurface maximum. However, the data are still being evaluated.

N. Jaworski asked if the river flows in the Gulf of Maine were unusual during this time. C. Hunt replied no, Dr. Rocky Geyer has taken a look at that. There does not appear to be anything unusual with the wind, river flows, or temperature profiles. There appeared to be a slightly more rapid cooling between early September and late September, but this is still within the baseline range. There may have been less upwelling because the summer was slightly warmer, but that is also within baseline range.

S. Mayo noted that the southwestern nearfield station had the highest values and asked if there were any other stations with values that high. M. Mickelson replied that it was only one survey that had high levels for the southwestern station. S. Libby added that throughout the entire baseline period, the southwestern nearfield station, N10, had continuously higher chlorophyll levels. This was attributed to the outflow from the harbor, but may also be due to the fact that this is one of the shallower stations that allows for greater nutrient mixing throughout the water column.

S. Nixon noted that most parameters measured seem to be subtly trending upwards in the last 5-6 years, even in Boston Harbor. C. Hunt agreed but MWRA has not examined this statistically. N. Jaworski pointed out that atmospheric nitrogen deposition has been increasing. C. Hunt added that in mid-1998, secondary treatment began, increasing the amount of ammonia discharged. S. Libby said that one of the sampling stations is right at the harbor outfall, and this may have skewed the harbor averages up.

C. Hunt reviewed the zooplankton data. Lowest numbers were seen in a harbor most likely because there was a major ctenophore (comb jelly) bloom in the harbor ctenophores feed on zooplankton. This ctenophore bloom was also seen in other areas, including Buzzards Bay. He then presented water quality data, all of which was within the ranges observed in the past. S. Mayo asked if these figures will be posted on the web. C. Hunt replied yes, and it will be made clear that this is a work in progress.

J. Schwartz noticed that the ammonia values in the monitoring data seem to be trending upwards. He asked if anyone has looked at the census figures to see if this increase correlates with a population increase in the Boston area. M. Hall replied that MWRA influent nitrogen concentrations have been about the same for the last decade and the effluent nitrogen has decreased (~10%), but the ammonia component of that total nitrogen has increased as a result of secondary treatment and liquids from the Fore River fertilizer pelletizing plant.

B. Berman asked if the zooplankton numbers were still extremely low in Boston Harbor. C. Hunt replied that he did not have the latest zooplankton data from February but guessed that the ctenophores would not survive through the cold weather.

S. Nixon pointed out that there was a significantly higher standing crop of phytoplankton observed in Mass Bay, but not a particularly higher production. He wondered if that was due to less zooplankton grazing and asked if that was seen in the data. C. Hunt replied that they have not looked at this closely yet, but there do not appear to be significantly lower zooplankton numbers.

S. Nixon thought that it was interesting that this does not follow the “textbook story”. It is also interesting to see that this large bloom has not depressed nutrient concentrations significantly. He thinks it will take some time to learn what happened. D. Dow asked there was a relationship between the silicate levels and the spring Phaeocystis bloom. S. Libby replied that the Phaeocystis did not have an effect on the silica levels.

T. Smayda asked how the natural inshore/offshore gradient and north/south gradient could be incorporated into a zooplankton threshold. C. Hunt explained that the low zooplankton in the harbor can be explained by the large ctenophore bloom that grazed on the zooplankton. Changes in the nearfield will be better understood after a full statistical review.

T. Smayda pointed out that this large bloom is an example of an appreciable change/difference. He wondered how this kind of observation may be used to develop some type of threshold. He noted the chlorophyll build-up at the pycnocline, and given the phototaxic ability and the nutrient-gathering migrations that many of the flagellates have, as well as fall mixing that brings nutrients to the surface, he maintains that the outfall has the potential to contribute periodically to significant bloom events, including Alexandrium.

J. Shine asked what made the plume visible on the surface, whether there were microlayers or slicks. M. Mickelson replied that the plume is visible primarily due to physics. Water moves up to the surface, calming the waves coming in. There is no evidence of dissolved organic matter causing any slicks.

S. Nixon thinks the monitoring program will be able to pick up any changes. R. Isaac asked if chlorine would be a better tracer than ammonia. C. Hunt replied that both ammonia and salinity are comparable tracers. They will learn more with the plume tracking.

CHLOROPHYLL DATA QUALITY ISSUES
M. Mickelson described errors in MWRA standard operating procedure for measuring chlorophyll in the laboratory. There are many method to measure chlorophyll, and MWRA measures fluorometrically with acidification. The method involves filtering a known volume of seawater, freezing the filters until they can be analyzed, and then grinding them with 90% acetone and analyzing them on a Turner Designs digital fluorometer. Problems with the data relate to standardization or calibration. The concentration of a sample is based on comparison to a standard, of known concentration. If the lab technician believes the standard is 100 ug/L, and it is only 50 ug/L, then the samples appear to be much higher than they really are. Standards are weighed and exact chlorophyll concentrations are provided by the supplier. Chemical impurities and water can alter the standard concentration, leading to inaccurate data results. MWRA is currently testing new standards with other methods to determine their actual concentrations and the data will be recalculated using these new standards.

S. Nixon asked how they can back-correct for water content in a standard they no longer have. M. Mickelson replied that the standard ampules have a “lot number” of purity. Two lots were used over this time period and there are enough ampules left of one lot that was used for the majority of the program to be able to check for purity. There is also the manufacturer’s statement about purity. Correcting for the older standard will be a bit more problematic, and they are still working this out. A sealed ampule can pick up water through tiny pinholes. The supplier apologized and said that they have had problems trying to control this issue. S. Nixon noted that this means that they are not the only lab to have problems with chlorophyll concentrations.

M. Mickelson said that this investigation was triggered because MWRA’s values were not agreeing with S. Mayo’s and others further north. MWRA calculated chlorophyll values were very high with very large negative phaeophytin values. The sample could also degrade in terms of its fluorescence response. If the acid ratio of the sample is greater than the acid ratio of the standard, there could be a large negative phaeophytin and high chlorophyll values as seen in the data. MWRA is revising its Standard Operating Procedures to outline signs of this problem. This occurred with the 2000 D, E, and F survey samples, and will be corrected.

C. Hunt said that the lab makes standards up every 30 days whereas other labs make a standard and use it for two years. This practice will help in the correction process. The lab also verifies the standard curve using a check standard that is used for an entire year. He is confident that the data can be corrected.

D. Dow asked if there is calibration with the chlorophyll standard both before and after a survey. C. Hunt replied that there is calibration after the survey. N. Jaworski asked how bad the problem is. M. Mickelson replied that the results were overestimated. For the 2000 D, E, and F surveys, it is about 40% higher. This water weight problem produced values that were ~10%-20% higher.

J. Shine asked if the particulate organic carbon is sampled from the same bottle. C. Hunt replied yes. J. Shine suggested looking at carbon to chlorophyll ratio to see if there was anything out of the ordinary. C. Hunt said that that was also one of the things that tipped them off that there was a problem with the chlorophyll data. N. Jaworski asked if they knew how widespread this problem was, since other labs use the same standard. M. Mickelson replied that if they use a spectrophotometer as a back-up, such as URI, they have no problem.

T. Smayda asked if the corrections will take changes of abundances of phytoplankton like that Asterionellopsis vs. microflagellates into consideration. C. Hunt replied that they will go back correct the standard curves and recalculate the data. T. Smayda thinks perhaps it may be better to not correct the error, if corrections involve any guessing.

CHLOROPHYLL CONTINGENCY PLAN THRESHOLD (HOW CALCULATED AND AGGREGATED)
M. Mickelson described how MWRA plans to calculate the means for the annual chlorophyll threshold. This threshold is based on the mean of the baseline annual means. MWRA is asking OMSAP for a way to calculate this threshold that is more statistically precise, since the year 2000 was not a complete baseline year with the outfall going on-line on September 6, 2000. He described two proposals from MWRA [see MWRA information briefing]. Station mean is calculated by averaging samples from each depth. S. Nixon noted that the samples are not vertically integrated. Integration is a better estimate of what the real water column mean is because the sampling depth intervals are not equal and they change from cruise to cruise. J. Shine did not think vertical integration was difficult to do. T. Smayda agreed with S. Nixon. S. Nixon thinks as long as the depth of the station is known, it can be expressed in per square meter or vertically weighted mean concentration per unit volume. S. Libby said that they did run an integration using the downcast for all the years, using 0.5 m binned averages, and it is relatively simple to do. Survey mean integrated chlorophyll vs. the average show similar patterns.

A. Solow thinks that in this case, it would be better to use averages and not integrate. Integration however, might show some interesting changes at one depth that are offset in the average by changes at another depth that would not be seen using averages. S. Nixon said that it depends on the question being asked and integration can address whether there are some interesting features in the vertical distribution. A. Solow thinks the only problem is that it is possible that there could be changes in the vertical profile that are not examined unless there is a threshold exceedance. He agreed that it depends on what the question is, and if the vertical structure of chlorophyll needs to be monitored for changes, then that hypothesis should be taken into account in the calculation of the threshold.

J. Pederson pointed out that not everyone agrees that threshold numbers have meaning, but they are in the permit. The issue of examining the different depths for changes in chlorophyll is certainly interesting and important right now. This is the kind of topic that Sea Grant can help fund, to look at the data more in-depth.

N. Jaworski thinks integration is a better way of averaging. M. Mickelson pointed out that integration gives future flexibility in the monitoring program, if the number of stations were to increased or reduced. S. Libby stated that the monitoring program samples fewer stations in February, March, April, October, November, and December than we do in the summer because of bad weather. Thus there is biasing to summer conditions, and that is one of the main reasons for using this approach. M. Mickelson repeated what he was hearing from OMSAP, that MWRA try and calculate using integration, allowing for the vertical depths, since it is not that much more difficult. OMSAP agreed.

S. Nixon pointed out that Jack Kelly and others published a model for Mass Bay that could account for the primary production based on light extinction, light, and chlorophyll. If this model continues to hold up, with the high explanation of the variance in the primary production, would MWRA at some point stop measuring primary production and just work with the chlorophyll data. C. Hunt replied that Aimee Keller is still working on that. S. Nixon asked for an update later this year.

M. Mickelson then described the problem in calculating the annual chlorophyll threshold that is based on baseline conditions. The outfall went on-line on September 6, 2000 and thus the year 2000 is not a complete baseline year. He asked OMSAP how to address this problem and suggested that fall 2000 be filled in using an average of the previous baseline years.

N. Jaworski suggested filling in with data from fall 2000 from areas north of the outfall area to take into account the unusual fall bloom. J. Shine said that is introducing a lot of uncertainty. S. Nixon suggested not using the year 2000 data in the threshold calculation. There is plenty of data since more baseline years were collected than initially expected. Why contaminate the threshold number by filling in the fall of 2000 with other data. T. Smayda is frustrated that this has not been worked out sooner. He would not recommend filling in the fall of 2000 with other data, and instead recommended ending the baseline in August 2000. A. Solow disagreed. S. Nixon also disagreed because there is seasonality in the data.

P. Borrelli suggested pushing the data back so that the year ends in the fall for all of the data. The early 1992 data would not be used. S. Nixon agreed to switch the annual cycle to start at day 250. The 1992 data are not thrown away; they exist in the memory and are all part of the analysis. He agreed with J. Shine in that there is going to be a variance in error in that relationship inevitably and the baseline will be contaminated if those numbers are from somewhere else.

A. Solow asked if there were any other proposals on how to aggregate the data. The approach on the table is to shift the seasons and not use the data from the early part of 1992. No one else had any other proposals. N. Jaworski thinks that fall 2000 data need to be incorporated someplace. A. Solow said that when the data are examined in context, it will be noted that there were high chlorophyll values over a large region, not just in the nearfield. M. Mickelson replied that this will be discussed in the annual report data discussion.

ACTION: OMSAP voted to recommend that the chlorophyll baseline for the annual threshold be calculated using a shifted calendar year that begins in September and ends in August. This would take into account the outfall start-up date, September 6, 2000, i.e. the year 2000 was an incomplete baseline year. January to August 1992 data will not be used for the calculation of the annual mean but will be used to calculate the seasonal means.

REVIEW OF NOVEMBER 2000 MINUTES
ACTION: OMSAP approved the November 16, 2000 minutes with no amendments.

CONTINGENCY PLAN EXCEEDANCE UPDATE: ARBACIA TOXICITY TEST
M. Hall described test results from the Arbacia punctulata (sea urchin) chronic fertilization test that failed in January 2001. The other three toxicity tests for January passed. He described the test protocols and then discussed what MWRA understands to be the reason why the test failed. The animals are collected in NC and FL via the contract lab since this species is normally distributed from NC to the West Indies. This toxicity test examines the gametes, not the animals themselves. The gametes are obtained by injecting potassium chloride into the animals. The sperm are exposed to the effluent dilutions for one hour and then the eggs are added. After 20 minutes, the samples are preserved and looked at under the microscope to determine the number of fertilized vs. unfertilized eggs per sample. The test evaluates seven dilutions of effluent: 0%, 1.5%, 6.25%, up to 100% effluent. There are four replicates for each of the treatments in the dilution series, and for each of the replicates, 100 eggs are evaluated for fertilization. The test can only be considered valid if 70% of the control eggs are fertilized. Compliance is determined by statistically comparing the various effluent dilutions with the controls.

The NOEC (No Observed Effects Concentration) is the lowest effluent concentration that is not statistically different from the controls. The MWRA threshold requires that the NOEC for this test is 1.5% or greater and is based on worst-case dilution assumptions in the nearfield (100% divided by a dilution of 68, is approximately 1.5%). The January test resulted in an NOEC of less that 1.5%, therefore the results did not meet the permit limit. For the January samples, there were at least 275 separate parameters that were measured along with the toxicity test. The NOEC progressively improved in the February and March samples. The control fertilization, for the January test was relatively low (72.5%), whereas the February control was 79.8%. It is also important to note that the January samples were almost entirely (~95%) secondarily treated, and in general, as the percent secondary decreases, the effluent quality decreases.

M. Hall showed results of chemical analyses of effluent and the results were within safe limits. MWRA believes that two factors played a role in the test failure. First, the animals themselves were probably not in optimal condition for the test. Second, there was a slight increase in chlorine that may have released some of the more bioavailable metals.

M. Hall then explained why it is highly unlikely that there was an impact to the environment. The flow on that day was 339 mgd, low compared to the average and there was no stratification at this time of year, thus dilution was much greater than the worst-case prediction of 68. In addition, there is little biological activity in the area in the middle of January. The Deer Island Treatment Plant now has two autoanalyzers for chlorine in the disinfection basins that will provide more immediate feedback as to the chlorine residuals. Also, the third battery of secondary came on-line in March 2001. Secondary treatment removes the bacteria more effectively, allowing for less chlorination.

S. Nixon did not understand why MWRA is still required in their NPDES permit to conduct monthly toxicity tests. J. Labonte replied that toxicity test results can provide useful information if it tells us that there was something wrong with the effluent. S. Nixon pointed out that the test results correlate inversely with all the other parameters measured. The question is whether the effluent has an impact in the environment, and this is monitored extensively. In addition, MWRA is measuring all of the contaminants in the effluent that would be causes for toxicity. This test has shown at least a 20% variation in just three months on the survivability of the gametes. These are gametes of animals which do not live here, have been transported, and put through a process which members of the scientific community have disagreed with for decades as a way to set toxicity of effluent. He is amazed that EPA still requires toxicity testing.

M. Liebman said that the reason why toxicity is measured in the effluent is because it is impossible to measure toxicity in the field. S. Nixon does not think a result from a toxicity test is an information-rich number, because if an animal dies, nobody knows why because effluent contains many compounds that undergo many reactions. N. Jaworski said that a lot of work went into developing effluent toxicity tests, and they have their place with large effluent discharges. The question is, does MWRA need to run four tests every month.

J. Schwartz asked if pH was measured during the test. M. Hall replied yes, and it was within range. J. Schwartz asked if any polymers were used when the test was conducted. M. Hall replied no.

FALL 2001 OMSAP PUBLIC WORKSHOP & MEETING SCHEDULING
C. Coniaris explained that the OMSAP charter states that OMSAP will host a public workshop annually to present the monitoring results for the previous year. Planning will begin for the workshops and the PIAC has expressed interest in helping to plan for this meeting and she asked OMSAP to begin thinking about the format of the workshop. J. Pederson suggested having one day of presentations, and then a month later reconvening again for a more in-depth discussion. OMSAP has not been doing this lately since OMSAP has been so tied up with the Contingency Plan thresholds. S. Nixon added that some of the OMSAP meetings could go until 4:00, and we do not necessarily have to meet back to back with PIAC. M. Mickelson asked who the audience would be for these meetings and would it be a science meeting, a public meeting, or something in between. S. Nixon agreed with J. Pederson, in that it would be nice to have some science meetings where we can review the data in depth, and this would not be geared for the public, so it would not be the fall public workshop. The focus of the public workshop seems to be a broader, summary presentation for outside this group. B. Berman thinks it would be great if we could use the fall opportunity to educate the scientific and public policy press on this process.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • April 2001 OMSAP/PIAC/IAAC membership lists
  • November 2000 draft OMSAP minutes
  • MWRA information briefings and copies of presentations

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

OMSAP MEG Conference Call, Wednesday, March 14, 2001
FINAL Summary

Participants: Eric Adams (MIT), Bob Beardsley (WHOI), and John Paul (EPA).

Summary prepared by: Cathy Coniaris (MADEP) and Mike Mickelson (MWRA).

Purpose

The Model Evaluation Group (MEG) reviewers met to discuss comments on the draft HydroQual report "Preliminary Calibration of the Massachusetts and Cape Cod Bays Hydrodynamic Model: 1998-1999". Jim Fitzpatrick and Rich Isleib (HydroQual) were contacted during the conference call to answer questions

Background

Over the past decade, the Massachusetts Water Resources Authority (MWRA) has been working with colleagues to develop and utilize two models, the Hydrodynamic Model and Bays Eutrophication Water Quality Model (BEM) for Massachusetts and Cape Cod Bays. The Hydrodynamic Model was recently transferred from USGS to HydroQual. The draft report under review describes preliminary model runs conducted after this transfer. In 2002, both models will be moved to U. Massachusetts Boston where they will be maintained and utilized by MWRA and others.

Recognizing the need for independent peer review, the MEG was formed in 1995 to provide outside advice and recommendations during model development. In 1999, the Outfall Monitoring Science Advisory Panel reconvened the MEG to review 1992-1994 BEM runs. In early 2001, the MEG was contacted to review recent Hydrodynamic Model runs.

MEG Review

In general, the MEG reviewers believe that this draft report, "Preliminary Calibration of the Massachusetts and Cape Cod Bays Hydrodynamic Model: 1998-1999", is a step in the right direction. However they feel that there are several areas in the report that require more information. HydroQual is in the process of preparing a more detailed report that will be provided to the MEG in the April/May 2001 time frame. MEG's comments fall into several categories, listed below.

Heat Flux

  • Show more information on implementation of the new heat flux formulation. Include equations
  • Show some results using the old heat flux formulation. Use a case-study layout to show runs that needed further attention, and how they were improved.
  • Explain rationale for change in heat flux formulation.
  • Excerpt heat flux descriptions from Cole and Buchak (1994) and Ahsan and Blumberg (1999), page 2-5.
  • Was the treatment of the long and short-wave radiation separated?
  • Are the choices of extinction coefficients realistic for long-wave radiation?
  • Is the heat flux spatially variable?
  • The description of TR on page 4-7 and 4-9 is a bit confusing. We recommend shortening it to say TR is the (longer wavelength) fraction of shortwave radiation which is unable to penetrate beyond the first layer. Our experience with lake modeling is that TR should be of order 0.5; thus it is confusing as to why they chose 0. Is there a value of TR implicit in the WQ model or is this irrelevant since the upper layer of the WQ model is much thicker?
  • Were the values of ke chosen based on a calibrated relationship with turbidity or other measure of water clarity?

Obtaining Boundary Conditions

  • Explain the boundary condition methodology. What is the interpolation method?
  • Were the quality and quantity of data enough to obviate the need for a GOM model run?
  • One suggestion to test the adequacy of the boundary condition interpolation is to subtract data and see if the MatLab program can replicate the results.
  • Is table 4-1 specific for temperature and salinity data?
  • Explain how the timing of the boundary conditions may be modified (page 4-7, paragraph 3). MEG recommendation #2 dated 6/13/00 regarding spatial resolution is relevant here (see MEG report, December 15, 1999).

Changes from Previous Model Runs

  • Document all changes from previous years' runs.
  • Were heat flux and boundary interpolation the only changes?
  • Describe the effect of these changes.
  • What parts of the model were added by HydroQual?
  • Compare model results before and after any changes. This could be done using schematic diagrams or a list, whichever is less time consuming.

Posterity and Thorough Documentation

  • This report could evolve to become the definitive description of the use of the Hydrodynamic Model. Therefore it would be useful to excerpt other reports rather than just use citations. HydroQual can add these sections as an appendix or as part of the main text.
  • The appendix of monthly boundary station locations is useful but it is not possible to determine if there has been a significant change in available data compared to earlier model runs. Please provide this information for the planned addendum to the 1992-94 report.
  • Table and figure legends need to be more explicit.
  • What is meant by "realistic" on page 2-1, line 5?
  • Please clarify "For this study, Zo was assumed to be uniform throughout the domain…." (page 2-4, line 4 from bottom). Does this mean Zo can be varied?
  • How was the number for Zo determined? Most drag coefficients are stated at 1m above the surface. Was the Zo number chosen to produce more realistic tides?
  • Provide a more detailed specification of the temporal and spatial variability of the open ocean boundary conditions including the flow field.
  • Is http://crusty.er.usgs.gov/mbayospen/mbayopen.html identical to the Signell citation you listed or should it be added?
  • Provide a list or table like the sample below of all the model inputs and highlight those that can be subjectively adjusted:
    Example: Description of model input variables
    - Zo is fixed at 0.003. This value was chosen to provides realistic tides.
    - Wind stress is measured every hour and assumed to be spatially uniform.
    - Solar radiation is measured every hour and assumed to be spatially uniform.
    - Boundary values of temperature and salinity are specified at monthly intervals and linearly interpolated from mid-month to mid-month. The monthly value may be adjusted to improve model fit.
    - etc.

Subjectivity

  • Which parameters are adjustable and which are not?
  • Are any boundary conditions subjectively adjusted?
  • Can the velocity field be adjusted?
  • Were any of the subjective steps transferred from USGS or changed?

Transfer from USGS

  • The MEG believes it is important to learn more about the transfer of the Hydrodynamic Model from USGS to HydroQual. Describe the handoff, including what was actually transferred to HydroQual.
  • Request that Rich Signell (USGS) review the next draft of this report if he is to be kept as an author.

Results versus Data

  • How do we know when the model is good enough?
  • With the limited information presented in this report, the MEG cannot determine whether this model run was better or worse than previous ones. Please include more comparisons in the next draft.
  • How close were prior runs? Demonstrate this by including some of the previous figures for the same stations. What is the skill of the present model with present conditions compared to the skill of the previous model with previous conditions? This information will help the MEG address the questions listed on page 4-9.
  • What are the vertical lines in figures 3-5 and 3-6? Also note the reversed legends in some figures.

OMSAP Meeting, Thursday, November 16, 2000
10:00 AM - 2:00 PM
Boston, MA
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Norb Jaworski, retired; Scott Nixon, URI; Judy Pederson, MIT/Sea Grant; Mike Shiaris, UMass Boston; Jim Shine, Harvard School of Public Health; and Juanita Urban-Rich, UMass Boston.

Observers: Bruce Berman, Save the Harbor/Save the Bay; Peter Borrelli, Center for Coastal Studies; Mike Bothner, USGS; Brad Butman, USGS; Margaret Callanan, Cape Cod Commission; Cathy Coniaris, OMSAP staff; Mike Delaney, MWRA; David Dow, NMFS; Marianne Farrington, New England Aquarium; Patricia Foley, Save the Harbor/Save the Bay; Maggie Geist, Association for the Preservation of Cape Cod; Barbara Hecker, Hecker Environmental; Carlton Hunt, Battelle; Russell Isaac, MADEP; Chris John, MWRA; Ken Keay, MWRA; Christian Krahforst, MCZM; Matt Liebman, EPA; John Lipman, Cape Cod Commission; Steve Lipman, MADEP; Mike Mickelson, MWRA; Dale Miller, Normandeau Associates; Katherine O’Meara, Wastewater Advisory Committee; Andrea Rex, MWRA; Larry Schafer, retired; Rich Signell, USGS; Dave Taylor, MWRA; Sal Testaverde, NMFS; and Jeff Turner, UMass Dartmouth.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. June 21, 2000 minutes were approved with no amendments.
  2. OMSAP voted unanimously to recommend that EPA/MADEP modify the MWRA pH permit language to: “pH shall not be less than 6.0 or more than 9.0 unless these values are exceeded due to natural causes or as a result of approved treatment processes and provided the effluent does not cause a violation of water quality standards for the receiving water."
  3. OMSAP approved of MWRA’s approach to analyzing the zooplankton data. They requested that adult and copepodite stages of zooplankton be kept separate in the analyses and not grouped together. They also urged MWRA to keep in mind the hypotheses and goals of the study to help guide the analyses.

MINUTES

A. Solow welcomed Dr. Juanita Urban-Rich from U Mass Boston to OMSAP. She is a plankton ecologist with an interest in zooplankton. J. Urban-Rich thanked A. Solow and added that she studies zooplankton, primarily looking at carbon and nutrient cycling, grazing, and fecal pellets.

JUNE 2000 MINUTES
There were no comments on the minutes. OMSAP unanimously approved the June 2000 minutes with no amendments.

GENERAL UPDATE ON PLANT PERFORMANCE TO DATE
RECENT AND UPCOMING PERMIT DELIVERABLES
M. Mickelson reminded everyone that Bob Beardsley (OMSAP) had urged him to pay attention to work in the Gulf of Maine, particularly the Gulf of Maine Ocean Observing System (GoMOOS). M. Mickelson found out that there will be a buoy placed at the entrance to Mass Bay, offshore of Cape Ann. Measurements will include conductivity, temperature, fluorescence, and dissolved oxygen. They measure additional parameters at other locations in the Gulf of Maine. This will provide useful information in the future. He then stated that the treatment plant has been working well, with CBOD (carbonaceous biochemical oxygen demand) and TSS (total suspended solids) values of less than 10 towards the end of October. M. Mickelson then described the types of reports at the MWRA website.

DISSOLVED OXYGEN (DO) SATURATION CAUTION EXCEEDANCE
A. Rex described and showed data of the early October exceedance of the caution level for the existing DO percent saturation level in the outfall nearfield and in Stellwagen Basin. DO percent saturation is slightly below the 80% caution level in those areas, however, the actual concentration is well above the class SA standard of 6 mg/L. She then showed how this appears to be a seasonal pattern that has occurred annually in the late summer/fall during the monitoring period 1992-2000. For this reason, the Outfall Monitoring Task Force (OMTF) recommended that this threshold be deleted back in 1997 and OMSAP concurred. MWRA has formally requested the deletion of this threshold in a letter to EPA/MADEP dated October 13, 2000.

J. Shine pointed out that in the absence of any permit modifications, this will occur again next year. S. Nixon asked why after three years after OMTF recommended deletion of the threshold, it still has not been deleted. A. Rex replied that the Contingency Plan was "frozen in time" in 1997 when it was attached to the permit, and there was no process for making revisions. There are a lot of changes that need to be reviewed now that the permit is in effect.

J. Shine asked if the DO concentration threshold will remain the same. A. Rex replied, yes, for the time being. EPA is working on finalizing its draft regulations on dissolved oxygen and this may affect MWRA’s threshold. A. Rex thinks that DO percent saturation is a very useful parameter to help understand how the system is working, but not so useful for measuring treatment plant performance or environmental impacts. C. Hunt thinks the low DO percent saturation may be due to slightly warmer bottom temperatures.

D. Dow thought that the change in the DO percent saturation was more likely due to biological activity, not so much due to temperature and salinity changes in the bottom water. A. Solow pointed out that that would also decrease the DO concentration, and that was not measured. D. Dow does not think it is a good idea to delete this threshold because it is useful when trying to learn about what is going on in the system. A. Rex said that even if the DO percent saturation was deleted, it would still be calculated and used for interpreting future data. She pointed out that the state standards include a phrase with the DO percent saturation “unless due to naturally occurring background conditions”. This phrase did not make it into the Contingency Plan.

A. Solow asked what would happen if the threshold is dropped and then for some reason it kept dropping, or something else unusual occurred. A. Rex replied that MWRA would ask for advice from OMSAP. J. Shine thinks it would be fine to delete the DO percent saturation threshold since the concentration will remain as a threshold. If that decreases, biological activity, temperature, salinity, DO saturation, and other factors will be examined. A. Solow agreed that DO saturation is a supportive parameter. S. Nixon thinks having DO saturation as a threshold is superfluous since DO concentration, the critical parameter, is a threshold. N. Jaworski added that calculating DO saturation is good information, but it does not have to be a threshold.

M. Shiaris asked what would happen if the data went below the DO concentration went below the thresholds. A. Rex said that it would trigger Contingency Plan notification and OMSAP would provide advice. She also pointed out that DO concentration has gone below the thresholds during the baseline period. S. Nixon added that the standard (6.0 mg/L) is based on a freshwater standard. M. Shiaris noted that the DO saturation is based on a calculation using the DO concentration which is also a threshold.

REQUEST FOR CHANGE IN EFFLUENT pH PERMIT LANGUAGE
M. Mickelson showed influent and effluent pH data over time (1998 to present). The influent pH exhibits a pattern over time, and MWRA is currently investigating this pattern which may be partially due to drinking water corrosion control. He noted that the effluent is almost 0.2 of a pH lower than the influent. This can easily be explained by high effluent carbon dioxide (CO2). Pure oxygen is injected into the secondary reactors increasing the production of CO2 by bacteria. Equilibrating this increase in CO2 with the atmosphere and taking alkalinity into account to calculate pH corresponds to what is measured in the effluent. This evidence suggests the decrease in pH is due to the CO2 rather than the production of acetic acid or addition of other acids. However, MWRA plans to further confirm this.

N. Jaworski asked if the effluent is being nitrified. M. Mickelson replied no. He then described the pH permit language being proposed by MWRA.

Current language:
"The pH of the discharge shall not be less than 6.0 nor greater than 9.0 at any time to meet the criteria of 6.5 to 8.5 in the receiving water, and shall not change the pH of the receiving water more than 0.2 standard units outside of the normally occurring pH range. There shall be no change from background conditions that would impair any use assigned to class SA waters, unless the cause of the excursion from criteria is due solely to naturally occurring background conditions." (from MWRA NPDES permit, section I.1.c)

Proposed language:
"The effluent values for pH shall be maintained within the limits of 6.0 to 9.0 unless the publicly owned treatment works demonstrates that: (1) inorganic chemicals are not added to the waste stream as part of the treatment process; and (2) contributions from industrial sources do not cause the pH of the effluent to be less than 6.0 or greater than 9.0." (from federal regulations 40CFR133)
or
"pH shall not be less than 6.0 or more than 9.0 unless these values are exceeded due to natural causes or as a result of approved treatment processes and provided the effluent does not cause a violation of water quality standards for the receiving water." (from other discharge permits)

M. Mickelson asked OMSAP if they would recommend adding some flexibility to the current permit language to allow MWRA to reduce the pH relative to the influent due to the approved secondary treatment process.

N. Jaworski asked about acid rain deposition and corrosion control of the drinking water. M. Mickelson replied that sodium carbonate and CO2 are added to drinking water to reduce corrosion. N. Jaworski and M. Mickelson then had a brief discussion about Quabbin Reservoir water quality and atmospheric nitrate and sulfate deposition. J. Shine pointed out that regardless of the pH at the reservoir, MWRA increases the pH to 8-9 to reduce pipe corrosion. He thought that the group should discuss whether decreasing the pH by 0.2 below 6.0 is due to an “approved treatment process”.

A. Solow asked if MWRA is confident that they can determine whether an exceedance would be due to an approved treatment process. M. Mickelson replied that MWRA can confirm the cause of a decrease in pH using air equilibration. He asked if EPA and MADEP need more guidance on this issue. R. Isaac thought that the state water quality standard focuses on the receiving waters, i.e. that the pH does not change significantly in Mass Bay. If travel through the outfall tunnel and mixing are considered, the pH is probably not going to change very much.

J. Pederson asked where MWRA is measuring the effluent pH. M. Mickelson replied that the pH measurements are taken at the end of the sample loop that simulates the 850’ distance in the tunnel where the sodium bisulfate (dechlorination) is added. This sample loop is a sealed tube that does not allow the CO2 to escape. M. Delaney added that the sample loop collects effluent at the beginning of the disinfection basin. However, the effluent actually flows for about an hour through the open-air disinfection basin where the CO2 can dissipate. Samples taken by MWRA indicate that the effluent is 0.4 pH higher at the end of the disinfection basin compared to the start of the disinfection basin. The purpose of the closed sample loop is to simulate the distance in the tunnel where the sodium bisulfate is added so that it can be dosed accurately.

S. Nixon asked if the monitoring program has measured any evidence that there is a significant impact on the pH in the receiving water. M. Delaney replied no. MWRA has also made calculations using effluent pH and alkalinity, Mass Bay pH and alkalinity, and dilution at the outfall. The pH at the diffusers would decrease by 0.2 with a 50:1 dilution (initial turbulent dilution under the worst-case scenario flow) and an alkalinity of 2.5 milliequivalents per liter.

ACTION: OMSAP voted unanimously to recommend that EPA/MADEP modify the MWRA pH permit language to: "pH shall not be less than 6.0 or more than 9.0 unless these values are exceeded due to natural causes or as a result of approved treatment processes and provided the effluent does not cause a violation of water quality standards for the receiving water."

UPDATE ON MWRA’S NPDES PERMIT AND PROPOSED CONTINGENCY PLAN MODIFICATIONS
M. Liebman gave a brief update on the proposed modifications to the Contingency Plan (CP) dated November 1997. It was not until the permit was issued in August 2000 that a process was set up to allow revisions to the CP, which is understood to be an evolving document, as better scientific information becomes available. MWRA has developed several proposed revisions over the last three years and OMSAP has deliberated and provided recommendations on them. EPA/MADEP received the official letter from MWRA dated October 13, 2000. The issues that specifically relate to the CP are dissolved oxygen percent saturation, floatables, benthic diversity, zooplankton, and nuisance algae species. MWRA’s food web model scope of work is also being evaluated. OMSAP deliberations and recommendations are playing an important role in this evaluation.

UPDATE ON PRELIMINARY RESULTS OF DISCHARGE SURVEYS IN BOTH HARBOR AND BAY
M. Mickelson described the September 29, 2000 bypass incident at the Deer Island Treatment Plant and the corrective actions that are being implemented [for information, see Nov. 2000 PIAC minutes]. He then described measures underway to improve floatables removal and a possible surveillance system to monitor floatables in the disinfection basin.

S. Testaverde asked if sampling on September 29th actually captured the event. M. Delaney replied that there was sampling of the final effluent before, during, and after the bypass event. S. Testaverde asked if the effluent will be very turbid (as seen on the 29th) each time there is a large storm. M. Delaney replied no, because on that day, mixed liquor, the waste activated sludge from the secondary reactors, had draining into the effluent channel, increasing turbidity. A. Rex added that effluent is more diluted during storms.

S. Testaverde asked if the data presented were individual samples or 24-composites. M. Delaney replied that the notification letter included data from the 11:09 AM and 1:37 PM bacteria grab samples. At 11:00 AM, total suspended solids were measured at 28 mg/L, 2.5 times higher than the usual 24-hour composite. However, this still meets the weekly maximum permit limit of 45 mg/L (there is no daily maximum).

THE HARBOR
D. Taylor described recent observations in Boston Harbor since the transfer of the Deer Island discharges to Mass Bay on September 6, 2000. In the northern part of the harbor, there has been a decrease in dissolved inorganic nitrogen (DIN) concentrations. The decrease is more apparent in the ammonia data. There seems to be a decrease in the southern harbor, although it may be too early to discern patterns. He compared the Fall 2000 decrease in the southern harbor to 1998 when the Nut Island flows were transferred to Deer Island.

R. Signell thought that 1999 DIN in the southern harbor would be noticeably lower than the previous years, but this is not apparent in the data. D. Taylor replied that there other factors affecting the DIN concentrations. S. Nixon added that it could be due to a relaxation of the biological demand. D. Taylor agreed that there is a very strong metabolic signal in the harbor. Jack Kelly had noticed this several years ago, that despite the rapid flushing of the harbor, there was a very strong metabolic signal. During summer, nitrogen occurred mainly in the particulate form and in the winter, as dissolved inorganic nitrogen. MWRA has been observing a long-term increase in the DIN in the harbor during winter that appears to be positively correlated with an increase in minimum winter water temperatures. As the harbor is warming, there is presumably, increased mineralization and increased buildup of ammonium in the harbor.

S. Nixon asked what D. Taylor thought the "memory" of the harbor is. D. Taylor predicted that DIN will decrease. S. Nixon noted that some feel that there is a build-up in the sediments and it will take years before a significant decrease is seen. D. Taylor agreed and pointed out that the "memory" is seen when storms resuspend bottom sediment causing periods of poor water quality. J. Shine added that the amphipods are already working a lot of the sediment. S. Nixon predicted that chlorophyll and nitrogen will be lower next summer, with significant improvements in water quality. He thinks the sediments will recover quickly.

D. Taylor then showed somewhat increasing secchi depth data from the northern and southern parts of the harbor. S. Nixon asked why MWRA still uses a secchi disk when better technology has been available for decades. D. Taylor replied that it is a measure that the public understands. MWRA also uses a transpiezometer to measure vertical light PAR attenuation. A. Rex said that they find the secchi data useful for comparison to old data. S. Nixon agreed that was a good reason.

D. Taylor showed total suspended solids data and stated that changes are not being observed. He then showed chlorophyll data. There does not appear to be a significant decrease in chlorophyll in either region within the harbor. There has been a historic debate about whether phytoplankton are light or nutrient limited and it appears that with the transfer offshore, water clarity is increasing, stimulating the phytoplankton growth in the harbor and compensating any decrease as a result of the reduction of nitrogen loading to the region. Another explanation is the large, ctenophores bloom within the harbor that may be grazing the zooplankton, allowing the phytoplankton populations to build up.

S. Nixon thinks that the present conditions in the harbor should not compare to the 1998 transfer of Nut Island flows to Deer Island because that only moved the discharge within the harbor. Now the flows have been moved offshore. D. Taylor agreed.

R. Signell asked why there was not a significant change in total suspended solids even though there was an increase in secchi disk depth. S. Nixon replied that in coastal areas, the total suspended solids measurement does not correlate well with light penetration. D. Taylor agreed and added that dissolved organic material affects water quality more than total suspended solids.

J. Shine asked about changes in salinity in the harbor since the outfall was relocated to Mass Bay. D. Taylor replied that he has not looked at the data yet. Past sampling at the harbor outfall discharge where the wastewater plume reached the surface indicated very rapid mixing of the wastewater, even within the harbor, and the salinity signal was only one part per thousand. Thus a large change in salinity is not expected. S. Nixon noted that MWRA has a great data set to work with.

THE BAY
C. Hunt described preliminary results of monitoring in Mass Bay and Cape Cod Bay from September 1 to October 24, 2000. He showed salinity and density data that indicated stratification and no significant change in the salinity of the system. The plume can be discerned from the salinity data, but only close to the diffusers because of the rapid mixing.

L. Schafer thought the preliminary prevailing current was southward. C. Hunt replied that instantaneous or daily currents can go in any direction but the long-term net drift is to the south. On Sept. 28th, there was a much more extensive survey tow-yoing back and forth on either side of the diffuser line, coming in very close to the diffusers. He showed data results including a salinity deviation as expected from the plume as they passed over a diffuser, through the hydraulic mixing zone. There was also a slight increase in beam attenuation, temperature and, sigma-t. He then showed temperature-salinity plots and how they determine background salinity the system is mixing into, as well as evidence of the plume. Using flow at the treatment plant, tides, winds, and the salinity of the effluent and Mass Bay, they estimated that the diffuser is working as predicted, with rapid dilution of at least 100:1.

C. Hunt then noted that bottom water dissolved oxygen concentrations also seemed unaffected by the outfall. Values were typical for the fall at 7.0-7.5 mg/L. He then showed satellite imagery of a regional chlorophyll bloom from September-October. Initial phytoplankton counts show a healthy, robust and diversified diatom bloom in September. The satellite indicated that there was a reduction in the system-wide bloom in October. He also pointed out that Phaeocystis occurred in spring of 2000 and so it seems to be repeating on a 3-4 year cycle. He then presented DIN and ammonia data. The ammonia data indicate that the plume is flowing somewhat to the north on this survey day and concentrations are within range of predicted values. C. Hunt noted that there is the ctenophore bloom seen in Boston Harbor and Buzzards Bay is not as prominent offshore, but it may be influencing some of the measured chlorophyll response. J. Pederson asked about temperatures during the ctenophore bloom. C. Hunt replied they appeared normal. J. Pederson thought that the ctenophore was common in the harbor. J. Turner responded that this is the first time they have seen appreciable numbers in MWRA monitoring, whereas it is typically very abundant in enclosed embayments such as Narragansett Bay and New Bedford Harbor in the summertime.

M. Liebman asked about the chlorophyll bloom in western Mass Bay that began in the fall of 1999. C. Hunt said that the chlorophyll has been quite variable but elevated since late 1998 and may have something to do with the transfer of flows from Nut Island to Deer Island. M. Liebman asked if there is an explanation for this. C. Hunt thinks it may be due to an increase in the discharge of ammonium from Deer Island and increased light penetration due to better treatment of effluent.

S. Nixon asked how sure they are that the apparent increase is due to the relocation of the Nut Island discharge. C. Hunt said that this will be examined further. S. Nixon urged caution in attributing an increase in chlorophyll to the diversion of the Nut Island flows, unless there is compelling evidence.

R. Signell asked if the dilutions in Cape Cod were calculated. C. Hunt replied that they have not been calculated yet, but guessed that they were probably around 500:1. R. Signell thought that was consistent with the model predictions.

N. Jaworski asked if they have looked at the total phosphorus data yet since it could prove to be a good tracer. C. Hunt replied that they have not but will soon examine all of the measured parameters. He is glad that the results so far indicate no surprises in Mass Bay.

PROGRESS ON OMSAP-REQUESTED ZOOPLANKTON ANALYSES, PROPOSED ANALYTICAL DIRECTION AND SPECIES LIST, MWRA STAFF
K. Keay stated that at the February 2000 meeting, OMSAP recommended that MWRA present a plan to OMSAP in Fall 2000 for analyzing the zooplankton (ZP) using a system-wide approach. This plan should pay particular attention to the understanding that the Mass Bay (MB)/Cape Cod Bay (CCB) system flows like a conveyor belt from north to south. Data should be examined temporally and spatially to contrast differences in the system. For example, there may be no concern if changes were seen in CCB concurrent with changes in the northern boundary system. However, an alarm may be raised if changes in CCB did not seem to be related to anything entering the system. The first step in the plan is to review the baseline ZP data (1992-2000). He then briefly reviewed previous MWRA zooplankton reports. MWRA will also review and summarize the understanding of the biology of ZP species in the bays. Then MWRA will analyze the entire baseline dataset using a multivariate approach to test differences in community composition and abundance. This will be an exploratory data analysis starting with clustering and principle components analysis to hopefully identify characteristic station and species groups, and compare them to past interpretations. The last set of analyses that planned are multivariable correlation and regression analyses to see if changes in the abundance of Acartia in the nearfield (NF) can be correlated to run-off, rainfall, and other climate forcing functions. He then showed the station locations and described the analyses in detail. He noted that Dr. Jeff Turner has finished counting the final baseline ZP samples and results will be available shortly. They have reviewed the baseline and developed a good species list in terms of what has been consistently identified through time. He asked OMSAP if this sounds like a reasonable approach given the questions that they asked MWRA to address.

J. Shine asked about the clustering analyses. K. Keay replied that it will help to identify more quantitatively the similarities in the offshore community and provide information to verify that the CCB communities resemble the source of the ZP in the Gulf of Maine. If the analyses do not show that, then perhaps the conveyor belt hypothesis needs a closer look, or the data needs to be looked at differently. This is an exploratory analysis of the baseline data and the results will help in thinking about what sort of change could be outfall related, were they to be seen. J. Shine wondered how a caution and warning threshold could ever be developed from this information. K. Keay could not give an answer to that until the analysis is carried out and evaluated.

D. Dow asked if the clusters will be based on annual averages for the different years. K. Keay replied no, they will be based on the ZP samples collected every year. Each sample will be treated independently. D. Dow asked if there will be a separate cluster for each time period. K. Keay replied no, not necessarily. MWRA will be examining whether there is seasonal signature in the clustering. D. Dow would be interested in learning whether the clusters change seasonally in relation to where the right whales feed or are distributed. K. Keay agreed and said that with this type of analysis, they can focus on the winter/spring and see whether the CCB stations are clustering very strongly with the boundary stations.

A. Solow thinks that the first step is to confirm the conveyor belt theory. If it is confirmed, then predictions could be made on what to expect in the ZP community in CCB based on what is measured at the northern boundary of Mass Bay and then those predictions could be tested. He wondered if cluster analysis was the right approach. K. Keay described several analyses MWRA will undertake to examine the ZP community.

A. Solow approved of the plan. He wondered what would happen if the conveyor belt hypothesis was confirmed, and a northern community was identified, but the population naturally changed by the time it was transported to Cape Cod Bay. In this case, there would be a good prediction of what to expect but the results might look quite different. K. Keay thinks one way to address that concern is to pay special attention to the monitoring results. C. Hunt added that Rocky Geyer will be examining the physics in the system and this will hopefully provide important information. J. Pederson agreed with A. Solow’s concern and wondered how comprehensive the MWRA ZP species list is. J. Turner said that the list is comprehensive, only excluding the meroplankton.

J. Urban-Rich asked if the ZP are fairly evenly distributed through the entire area. J. Turner replied yes, with the exception of the two Acartia species that are found in higher numbers in Boston Harbor. J. Urban-Rich asked if all of the stages of ZP will be used in the analyses, i.e. copepodite I to adults. J. Turner replied that adult male and female copepods are identified to species and copepodites are identified to genus. He then described the sample analysis. Copepodites have not been staged to each one of the 6 stages, but they have been distinguished from the adult males and females. He also noted that samples are archived for future re-analysis, if needed.

P. Borrelli asked how the proposed analysis addresses ZP patch formation in the south. K. Keay replied that it does not because the MWRA monitoring does not sample the ZP patches. P. Borrelli noted that this means that MWRA will have abundance, but not distribution.

A. Solow asked why the copepodites will not be kept separate from adults for all of the analyses since a difference in the age distribution, from the north to the south is predicted if there is a conveyor. K. Keay thinks they could keep the copepodites of Calanus and some of the other taxa separate in the analyses.

J. Urban-Rich pointed out that even if the adults and total copepodites numbers are lumped, this may affect the cluster analysis because there may be more copepodites than adults. She suggested that it would be useful to know exactly how the stages are separated, instead of lumping all of the data. K. Keay thought it would be possible to include in the analyses the copepodite and the adult forms as separate taxa and said that they will take another look at the species list with this in mind.

M. Farrington said that the approach depends on what question is being asked, i.e. is there a conveyor belt; does the outfall have a change on the ZP community. K. Keay agreed and said this approach will help shed some light on the conveyor belt question by perhaps providing another tool to look at changes between the north and the south parts of the system. A. Solow feels that there is important information in the age structure of the ZP. OMSAP continued to discuss ZP dynamics and the proposed study plan.

A. Solow then asked OMSAP if they approved of the plan. J. Shine approved with the plan as long as the life stages are considered separately and not grouped together.

M. Shiaris thought it might be useful to be more hypothesis-driven in terms of focusing on how many stations, and exactly what is going to test the hypothesis.

J. Urban-Rich suggested a literature review on ZP genetics in this area before the cluster analysis is done. J. Turner summarized genetic work that would relate to this. It appears that the Calanus and Pseudocalanus populations are the same for the Gulf of Maine. There are no genetically distinct populations. J. Urban-Rich said to go ahead with the clustering then.

ACTION: OMSAP approved of MWRA’s approach to analyzing the zooplankton data. They requested that adult and copepodite stages of zooplankton be kept separate in the analyses and not grouped together. They also urged MWRA to keep in mind the hypotheses and goals of the study to help guide the analyses.

EPA LISTSERVER
M. Liebman asked if people received the DO percent saturation exceedance listserver message. If anyone would like to subscribe, send their email address to [email protected].

ANIMATION OF CURRENTS
R. Signell showed a computer animation of currents from the USGS long term monitoring station about 2 km SSE of the outfall. This animation gives a feeling of the kind of temporal variability of the currents and also the structure of the currents from top to bottom. Sometimes it looks like the whole water column is going in the same direction, even when it is strongly stratified, which seems unusual, and at other times even when it is not stratified, there is a lot of shear. So it is very complicated. This data from July shows that there is no prevailing current and very complicated top to bottom structure. This is not something a model can predict on a day to day basis.

S. Nixon asked if it is common that the highest lateral flow at the pycnocline rather than above or below. R. Signell replied that it is not. The winds and the currents are not very well correlated at this location. R. Isaac asked what this information provides. R. Signell replied that this information will aid the interpretation and evaluation of the plume tracking data.

C. Hunt asked when the USGS data will be available. R. Signell replied that this data (through the end of September 2000) is available now. B. Butman added that the fall data will be available in February 2001. C. Hunt asked when the data will be interpreted. R. Signell replied that USGS can set up a mechanism for Battelle to receive information as quickly as possible so that it can be used for the plume tracking. He has looked at data three weeks pre-discharge and three weeks post-discharge, examined the average currents and found that there was too much natural variability in the system to notice any changes in the currents due to the outfall. There will have to be a much longer averaging period to discern any outfall effects.

UPDATE ON CONTINGENCY PLAN EMERGENCY SIMULATION PLAN AND DRY RUN FOR RED TIDE/CHLORINATION EXCEEDANCES, MWRA STAFF
M. Mickelson stated that the permit requires MWRA to conduct a dry run of two threshold exceedances, a chlorination upset and a red tide exceedance. The dry run was conducted in August 2000. MWRA will be drafting a final report shortly. The most important result was the development of a notification list. He asked OMSAP for some guidance on how they would deal with the notification of an exceedance. J. Shine thinks that the decision to meet should be based on the severity of the exceedance. A. Solow agreed that it would be a judgment call on a case-by-case basis. N. Jaworski added that conference calling was always an option. C. Coniaris pointed out that a conference call would be open to the public, they could come to a meeting room and listen in.

B. Berman anticipates that there will be exceedances in the future and the press will contact members of PIAC before they ever call OMSAP. That said, it might be sensible to have a system of rapid PIAC notification set-up, at least involving the chair.

REVISED PLUME TRACKING STUDY DESIGN, CARLTON HUNT
C. Hunt described the plume tracking study design that has been revised based on input from peer review. The purpose of the plume tracking is to field test and certify whether the minimum dilution of the outfall is equal to or greater than the minimum dilution specified in the permit. [Plume tracking study design is located at: https://www.mwra.com/sites/default/files/2023-11/2000-ms-58.pdf]. Two surveys are planned. In March 2001 (unstratified conditions) there will be “shakedown” survey to test the dye addition protocols. The July 2001survey (stratified conditions) will be the actual dilution certification survey.

Before the March survey, there will be laboratory studies to evaluate dye interference and degradation. Right before the surveys, turbidity and background fluorescence will be measured. For both surveys, non-toxic Rhodamine dye will be added at the Deer Island Treatment Plant, measured in the effluent, and tracked in the field. In addition, other parameters will also be measured including temperature, salinity, coliform, ammonia, phosphate, chlorine, chloride, suspended solids, silver, and copper.

J. Shine asked how instantaneous the flow measurements from the plant are to adjust the dye addition. C. Hunt replied that flow measurements will be in real time and explained the procedure. He then showed where the dye will be added. J. Pederson asked how much dye will be used. K. Keay replied three 55-gallon drums for a 28-hour experiment. J. Shine asked what the toxicity of Rhodamine dye is. M. Mickelson replied that the levels that will be discharged would be drinkable. N. Jaworski noted that in his experience, the amount of dye to add is often underestimated. C. Hunt said that they are well aware of this issue and will have plenty available. They have already conducted dye studies with harbor discharge #5 so they have a good idea of how much will be needed. C. Hunt then detailed the survey sampling plans.

N. Jaworki asked if the duration of the study will be long enough to reach steady-state or if this will be a batch addition. C. Hunt replied that steady-state will be reached in about two hours. M. Mickelson noted that steady-state will be reached in the nearfield but it will be considered batch addition in the farfield. C. Hunt added that during those two hours, the ship will be towing instruments to find and define where the plume is and an ADCP [Acoustic Doppler Current Profiler] will be measuring currents in real time. Instruments will also be taking water column profiles and discrete water samples and will be brought as close to the seafloor as possible. He then described details in the sampling procedure.

R. Signell asked what kind of weather conditions can be tolerated for the surveys. C. Hunt replied that it has to be relatively calm to stay within the track lines, however, once the experiment begins, it cannot be halted. He then described the sampling plans and reporting schedule.

A. Solow asked why they are sampling the entire diffuser field, instead of focusing in on a smaller area in greater detail. C. Hunt replied that they are trying to get a more robust set of initial dilution conditions and the best way to do that is to sample the entire loop around the diffusers. The July survey plan may be adjusted based on what is learned during the March survey. C. Hunt then reviewed data shown earlier in the day to outline recent patterns of salinity and temperature that indicate evidence of the effluent plume. Mixing appears rapid, with the hydraulic mixing zone close to the diffusers, within the expected range of 5-20 m.

N. Jaworski asked if the design or operation of the diffusers can ever be changed. He thought one adjustment would be to alter the amount of salt water entrained with the buoyant plume. C. Hunt replied that the physical design cannot be changed, but the operations may be adjusted. M. Mickelson noted that only five of the eight caps were opened on each diffuser but tests (using a small-scale diffuser discharging dye in a tank) showed that opening more caps would not enhance dilution. J. Shine asked if a 500:1 dilution is the best they can measure. C. Hunt thinks they can measure to an even greater dilution, but it depends on the background correction factors.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • November 2000 OMSAP/PIAC/IAAC membership lists
  • June 2000 draft OMSAP minutes
  • MWRA information briefings and copies of overheads: recent monitoring results, dissolved oxygen, effluent pH, zooplankton, plume tracking, and Contingency Plan notification
  • MWRA proposed Contingency Plan modifications dated Oct. 13, 2000

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

OMSAP Recommendations, July 2000

Ronald Manfredonia
Associate Director, Water Quality Policy
EPA Region 1, New England
1 Congress Street, Suite 1100 (CAA)
Boston, MA 02114

Arleen O'Donnell
Assistant Commissioner
Massachusetts Department of Environmental Protection
1 Winter St.
Boston, MA 02108

Dear Ron and Arleen,

On behalf of the Outfall Monitoring Science Advisory Panel (OMSAP), I would like to forward several recommendations to the Environmental Protection Agency Region 1 and the Massachusetts Department of Environmental Protection. The following recommendations pertain to the National Pollutant Discharge Elimination System (NPDES) permit requirement that the Massachusetts Water Resources Authority (MWRA) develop a food web model scope of work as well as revisions to thresholds in the MWRA Contingency Plan.

MWRA'S FOOD WEB MODEL SCOPE OF WORK

As described on page nine of the MWRA NPDES outfall discharge permit, MWRA has developed and submitted a food web model scope of work to characterize the seasonal abundance of important prey of endangered species in Massachusetts and Cape Cod Bays. MWRA proposes an incremental approach, beginning with an examination of the likelihood that the environmental conditions in the bays will worsen as a result of the outfall relocation.

Recommendation: OMSAP recommends that EPA and MADEP accept MWRA's food web model scope of work statement as final and having fulfilled the permit requirement. Additionally, OMSAP invites concerned parties such as the Barnstable County Science Advisory Panel to submit proposals of modifications to the monitoring program that address their issues of concern. Of course, any revision to the monitoring program must be based on valid scientific considerations.

Recommendation: While the development of a quantitative, predictive food web model would provide information useful for the design of the monitoring program, OMSAP members believe that the development of such a model is not feasible. The development of such a model would require an understanding of the complex physical, chemical, and biological linkages in the bays that is well beyond current capabilities. However, OMSAP believes that careful monitoring and analysis based on a qualitative understanding of the bays ecosystems is critical and, moreover, that review and refinement of the monitoring program must be ongoing.

ZOOPLANKTON THRESHOLD

Several years ago, the Outfall Monitoring Task Force (OMTF) asked that MWRA attempt to develop a zooplankton threshold. MWRA has since made two attempts at developing such a threshold. The first, which is included in the Contingency Plan, is based on the so-called Acartia hypothesis and is aimed at detecting a "shift towards an inshore community". Acartia hudsonica and Acartia tonsa are common in inshore waters, but not offshore. When the Acartia hypothesis was originally developed, it was thought that the limiting growth factor for Acartia is nutrient concentration, so that an increase in Acartia abundance offshore would be indicative of eutrophication. However, further review has shown that Acartia may instead be limited by salinity and temperature. If this is true, then, as the new outfall will not significantly affect salinity in Massachusetts Bay, there is no reason to believe that an increase in Acartia abundance offshore would be a good indicator of an outfall effect. It is important to note that the OMTF did not officially approve the Acartia threshold during the permitting process and, because it was part of the Contingency Plan, it was accepted as part of the permit without full scientific review.

After finding that the Acartia threshold would not be a useful indicator of change, MWRA began to develop an alternative zooplankton threshold aimed at detecting a decline in mean abundance of five species (including Calanus finmarchicus) during the winter and spring. However, baseline monitoring results show dramatic differences in abundances among the sampling regions, suggesting that this approach would not be a sensitive indicator of change.

Recommendation: OMSAP does not support the current narrative zooplankton threshold as it is currently formulated and recommends its deletion from the Contingency Plan. However, OMSAP believes that continued zooplankton monitoring is extremely important and requests that MWRA present a plan to OMSAP in fall 2000 for analyzing zooplankton data using a system-wide approach. Since the Massachusetts and Cape Cod Bays system flows like a "conveyor belt" from north to south, MWRA should develop a method for analyzing the current data spatially and temporally to contrast differences between the northern boundary stations and Cape Cod Bay. If changes in the zooplankton communities in Massachusetts and Cape Cod Bays were, in fact, due to variations in input from the Gulf of Maine, then this should not raise an alarm about the effect of the outfall. On the other hand, changes in Cape Cod Bay that cannot be explained by changes in input from the north would be of greater concern. MWRA may also propose an alternative to this suggested method of analysis.

ALEXANDRIUM CELL COUNT THRESHOLD

The current Contingency Plan threshold for the toxic dinoflagellate Alexandrium tamarense states that "the baseline seasonal mean shall not exceed the 95th percentile" in the nearfield. At its March meeting, OMSAP reviewed two sampling programs: those of MWRA and Dr. Don Anderson (Woods Hole Oceanographic Institution). Dr. Anderson's sampling effort is more effective in capturing Alexandrium in the water column. The program concentrates sampling along several transects between April and June, when Alexandrium blooms most commonly occur. The 95th percentile Alexandrium threshold based on the MWRA data is 10 cells per liter, while that based on Anderson's data is 71 cells per liter. Though the MWRA and Anderson datasets differ, both detected the large 1993 bloom.

Dr. Anderson is also currently funded by Sea Grant to determine whether spatial or temporal patterns of baseline shellfish toxicity can be used to develop a pattern-based threshold. This study is based on a 30-year record of paralytic shellfish toxicity constructed and maintained by the MA Division of Marine Fisheries. Preliminary analysis indicates that significant toxicity in northern stations can be used to predict later toxicity at southern stations. This is consistent with the theory that the source area for Alexandrium lies to the north of Massachusetts Bay, with transport to the south by a coastal current. Toxicity occurs during most years in southern Maine and northern Massachusetts, but cells seldom enter Massachusetts Bay in sufficient numbers to bloom substantially and cause toxicity. If Alexandrium cells were stimulated by nutrients from the outfall, then the effects would be expected to be seen "downstream" due to the circulation through Massachusetts Bay. This suggests that post-relocation occurrence of toxicity at the seven southern stations without a prior bloom at the northern stations would be indicative of an outfall effect, since there is no record of toxicity within the bay without a bloom further north. Another potential indicator of an outfall effect may be high toxicity at a southern station and low toxicity at the northern stations.

Recommendation: There is convincing evidence that Alexandrium is extremely variable and patchy in terms of occurrence. It is unclear whether it is more important to document abundances in areas where it is found infrequently or where it has never been found. Given all of these uncertainties, and the fact that there is a better, more integrated measure under development, OMSAP recommends deletion of the current Alexandrium cell count threshold. OMSAP is interested in evaluating the new paralytic shellfish toxicity threshold being developed by WHOI that uses the long-term shellfish monitoring.

FLOATABLES THRESHOLD

The Contingency Plan threshold for floatables states that "floatables shall not exceed five gallons/day in the final collections device." However, the Deer Island Treatment Plant (DITP) design makes it impracticable and somewhat dangerous to sample the final collections device. MWRA has other measurements of plant performance such as sludge and scum removal, and fats, oil, and grease effluent concentrations. These measurements are an indication of plant performance and are made daily in primary treatment, reported in the monthly discharge report, and eventually posted on the Internet. There is also a field program that will net sample over a measured distance to capture floatables during each of the nearfield surveys seventeen times per year. Results of this field information will be summarized in the annual Outfall Monitoring Overview reports.

Recommendation: OMSAP believes that the current measurements of sludge and scum removed by the DITP as well as fats, oils, and grease measurements in the treated effluent adequately address the NPDES permit requirements for aesthetics. OMSAP recommends that MWRA delete the current floatables threshold in the Contingency Plan. OMSAP also recommends that MWRA report the sludge, scum, fats, oil, and grease measurements in the annual Outfall Monitoring Overview; address concerns regarding floatables if there is an adverse DITP event; and "fingerprint" the floatables from the DITP in a special study.

GENERAL COMMENTS ON THRESHOLDS

OMSAP strongly believes that there is no value in maintaining thresholds shown to be scientifically invalid (zooplankton and Alexandrium), or impossible to evaluate due to treatment plant design (floatables). Retaining such thresholds would undermine the purpose of the Contingency Plan – to detect changes due to the operation of the outfall. As our knowledge of the ecosystem improves, thresholds may be refined or added. In the meantime, we feel that it would be a disservice to rely on thresholds in which we have no confidence.

Sincerely,

Dr. Andrew Solow
Woods Hole Oceanographic Institution
Outfall Monitoring Science Advisory Panel Chair

cc: Cathy Coniaris, NEIWPCC

OMSAP Meeting, Wednesday, June 21, 2000
10:00 AM – 2:00 PM
Boston, MA
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Robert Beardsley, WHOI; Bob Kenney, URI; Judy Pederson, MIT/Sea Grant; and Jim Shine, Harvard School of Public Health.

Observers: Eric Adams, MIT; Margaret Callanan, Cape Cod Commission; Cathy Coniaris, OMSAP staff; Jim Fitzpatrick, HydroQual; Carlton Hunt, Battelle; Russell Isaac, MADEP; Ken Keay, MWRA; Christian Krahforst, MCZM; Wendy Leo, MWRA; Mike Mickelson, MWRA; Andrea Rex, MWRA; Larry Schafer, observer; Jack Schwartz, MADMF; Adam Storeygard, MWRA; Heather Trulli, Battelle; Sal Testaverde, NMFS; Dave Tomey, EPA; Steve Tucker, Cape Cod Commission/Bays Legal Fund.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. OMSAP approved the minutes of the March 28, 2000 meeting as amended.
  2. OMSAP approved recommendations of the Bays Eutrophication Model Evaluation Group and will forward their final report to EPA and MADEP.
  3. OMSAP approved their draft letter to EPA and MADEP outlining their recent recommendations on MWRA's food web model scope of work, zooplankton, Alexandrium, and floatables thresholds.
  4. OMSAP agreed to recommend three revisions to the benthic thresholds: 1) stations considered in the threshold calculations should include the nearfield stations plus the three adjacent western Mass Bay stations; 2) the benthic threshold test for annual mean species diversity should not fall outside the central 95th percentile of the baseline data; and 3) the existing pollution opportunist threshold should be tightened to make it more environmentally protective (caution from 25% to 10% and warning from 50% to 25%).

FINAL MINUTES

March 2000 Minutes

J. Fitzpatrick corrected a statement in the March minutes in that the Army Corps of Engineers developed the Chesapeake Bay model and HydroQual was involved only in developing a sediment nutrient flux model with them. C. Coniaris offered to add that information in brackets. ACTION: OMSAP members approved the draft March 28, 2000 OMSAP minutes as amended, including the recommended revisions by Don Anderson and Jack Schwartz.

MWRA Construction Update/1999 Dissolved Oxygen (DO) & Chlorophyll

M. Mickelson estimated that secondary battery C will be operational in August 2000 and the new outfall diffuser system is scheduled to go on-line in the fall of 2000 (as early as mid-September). Presently the outfall safety plugs need to be removed. Workers had only managed to remove three safety plugs before the tragic accident that killed two workers occurred in July 1999. One plan for bringing the outfall on-line involves attaching a jack-up barge to the third riser cap using a specially built sleeve so that the tunnel can be ventilated.

M. Mickelson then described 1999 monitoring results for nearfield dissolved oxygen and chlorophyll. In 1999, there were two occasions where mean DO concentrations fell below the 6.5 mg/L caution threshold. Rocky Geyer compared the dissolved oxygen minima for each year with salinity and temperature and found that there is a correlation. He has developed a model that examines this dissolved oxygen pattern and it appears that low DO is favored by warm and more saline water.

J. Shine asked if this is an empirical observation. A. Solow replied that it is a regression model. L. Schafer asked if the anomalies are due to weather. M. Mickelson replied that the high salinity in 1999 was due to periods of drought, calmness, low river runoff, and lack of storms to stir up the bottom waters but in 1999, the salinity was higher. He added that the bottom water temperatures are largely set up by the pre-stratification winter temperature. R. Isaac thought that bottom water coming in from the boundary would be consistently cool. C. Hunt thinks that is one of the things that R. Geyer will examine next. He added that the Gulf of Maine is not deep enough to have bottom waters with a constant temperature.

J. Shine asked if R. Geyer used the data to make the model, and then used the same data to test the model. M. Mickelson replied that he used the data once, tabulated the minimum salinity, temperature, and oxygen, and then calculated the anomaly. B. Beardsley added that he is using the average near bottom dissolved oxygen for two months and the temperature/salinity variation. The hypothesis is that the more stratification, the lower the DO, and stratification can depend on both salinity and temperature. A. Solow clarified J. Shine's point in that it is not surprising that the two-parameter model fit the eight points of data, however, it may not predict future conditions as well.

M. Mickelson showed nearfield chlorophyll data for each of the baseline years of monitoring, from January to December. The seasonal threshold is the 95th percentile of the seasonal mean and the annual threshold is set at twice the baseline. If the thresholds are calculated based on only these earlier years, 1999 would have exceeded the winter/spring, fall, and annual thresholds.

M. Mickelson then compared chlorophyll and Acartia data. Current knowledge of Acartia zoology indicates that the nauplii prefer lower salinity water. In 1999, when the chlorophyll and salinity were high, Acartia was found in low abundances. This supports the notion that salinity controls Acartia abundances more than nutrient levels. J. Fitzpatrick added that there are years with high Acartia and moderately high salinities so it may be a combination of factors. M. Mickelson thinks it could also be possible that the nauplii are farther "upstream", in the inner harbor. MWRA should look at New England Aquarium and MWRA harbor monitoring data for inner harbor salinity data.

Review of the Model Evaluation Group (MEG) Report

B. Beardsley presented a summary of the draft MEG report. OMSAP tasked the Bays Eutrophication Model (BEM) Evaluation Group with reviewing the HydroQual report "Bays Eutrophication Modeling Analysis for the Period 1992 to 1994" and recommending changes to either the model or the monitoring program to improve the model's skill for water quality predictions. The MEG consisted of himself, Jeff Cornwell (U. Maryland), Don Harleman (MIT), Eric Adams (MIT), Jack Kelly (EPA, Duluth MN), John Paul (EPA, Narragansett, RI), and Jay O'Reilly (NMFS, Narragansett, RI). The MEG had an open meeting in Woods Hole in December 1999 to review the model results for 1992-4. In 1995, an earlier Model Evaluation Group requested that the model be run for 1993 and 1994 since these years included interesting features in the monitoring data including an intense fall bloom in 1993 and low dissolved oxygen in 1994.

B. Beardsley stated that in general, the MEG was pleased that the additional model runs had been done. The group felt that the simulations through 1994 provided additional experience with the model, for a variety of conditions, and further tested its ability to capture both seasonal and episodic events. The model successfully reproduced the timing and spatial pattern of the winter/spring bloom, the limiting roles of silica in Cape Cod Bay during winter and spring, inorganic nitrogen concentrations in Massachusetts Bay during the summer, the seasonal variation of dissolved oxygen, and several other phenomena. The group did note that the model did not capture the high diatom concentrations observed during the fall of 1993 and it did not completely capture the low dissolved oxygen observed in late 1994. In 1994, the dissolved oxygen prediction was lower than in previous years, but did not get as low as what was actually observed. The model also could not reproduce the large dynamic range for phytoplankton concentrations and this raises questions about how well the model can distinguish changes due to the outfall and from natural variability. Much of the mismatch between the model and observations may be associated with unresolved variability.

B. Beardsley then summarized the MEG's seven general recommendations:

  1. Add a third algae component to BEM for direct simulation of the fall diatom bloom (this may strongly impact the fall and spring bottom water DO).
     
  2. Match the BEM grid to the hydrodynamic model within the BEM domain to eliminate questions of grid collapsing.
     
  3. Make "projection" runs (i.e., model runs comparing conditions with existing versus future outfall locations, and with primary versus secondary treatment) to help assess the relative impacts of anthropogenic change versus ambient variability.
     
  4. The nutrient flux around Cape Ann is poorly sampled by the present monitoring program, so that changes within the Mass Bays system due to real changes in the upstream boundary conditions will be missed in model simulations.

    MEG recommends three actions:
    1. Determine the sensitivity of the 1992-94 BEM runs to realistic changes in the upstream boundary conditions.
    2. Develop a plan to begin collecting measurements of currents and water properties along the upstream section of the model open boundary.
    3. Investigate recent efforts to develop a Gulf of Maine Ocean Observing System (GoMOOS) to see if a collaborative effort might provide better open boundary data for future BEM simulations.
       
  5. The closing of the Nut Island treatment plant (NITP) in 1998 and switch to secondary treatment at Deer Island made a significant change in the distribution and forms of nutrient input to Boston Harbor (data analysis by D. Harleman). MEG recommends that the BEM be used to simulate the 1998-1999 period to see how well the model captures the increased chlorophyll observed near the Boston Harbor/Mass Bay boundary.
     
  6. Conduct BEM mass balance studies to determine the relative importance of outfall versus open boundary sources of ammonium (NH3) within the Mass Bays system.
     
  7. Before the addition of a benthic diatom state variable, BEM results and field data should be analyzed for the predicted/observed light levels at the sediment-water interface. The predicted areal pattern of light could be used to assist in deciding whether the inclusion of this potential source of oxygen to the model is warranted. If it is, the experimental benthic flux work should include an illuminated treatment.

J. Pederson suggested that folks let OMSAP know if anyone has specific recommendations for the GoMOOS group. B. Beardsley agreed. GoMOOS is funded and he thinks it will also be a vehicle for other activities. M. Mickelson asked how long GoMOOS is funded for. B. Beardsley believes two years. C. Hunt asked if GoMOOS will study deep circulation. B. Beardsley did not think so. One objective of GoMOOS is to look at the influx of freshwater into the system. However, there are other moorings in the Gulf of Maine that study deep ocean circulation.

B. Beardsley then described the data analysis by Don Harleman. He obtained data from MWRA to examine the effects of the closing of the NITP and the start of secondary treatment. It appears that secondary treatment increased the percentage of ammonium in the treated effluent. D. Harleman showed that about half of this increase is due to secondary treatment, and the other half is due to the increase in the input (from the transfer of the NITP flows). D. Harleman believes that this may have caused the rise in chlorophyll near the Boston Harbor/Mass Bay boundary.

J. Fitzpatrick thinks that this could also be due to better solids removal, increasing the light fields in Boston Harbor, and stimulating additional growth and higher chlorophyll measurements. J. Shine pointed out that ammonium is more immediately available to phytoplankton than organic nitrogen. W. Leo noted that this increase in chlorophyll is not seen inside the harbor between Deer Island and Hull, but outside the harbor, in western Mass Bay near President Roads. M. Mickelson suggested that the figure presented showing D. Harleman's calculations include information for Nut Island and also take flows into account to calculate loads. C. Hunt noted that the total loading into the system is not changing, it is simply the loading from one specific outfall.

B. Beardsley then listed MEG's recommendations for BEM report addenda:

  1. Complete documentation of the circulation and BEM parameters used in the 1992-1994 simulation.
     
  2. Complete documentation of the boundary conditions used in the 1992-1994 simulation.
     
  3. A comparison of simultaneous temperature, salinity, and density from the BEM and circulation model should be made for the 1992-1994 period and presented with a discussion about the skill of the BEM to capture the vertical stratification seen in the hydrodynamic model.
     
  4. The experimental uncertainties inherent in the field data due to instrumental and methodological [replace "problems" with "errors", see below] and the spatial and temporal scales of natural variability should be estimated as best as possible and shown in all model/data comparison figures.
     
  5. The BEM simulation for the nearfield bottom water DO during the 1994 stratified season was lower than in previous years, but did not reach the observed minima. The model also predicted a relatively constant decline in DO during the stratified season, while the observed rate of decline was slower in early summer and faster towards fall. If the BEM is to be used to predict bottom water DO minima on both the event and seasonal time scales, MEG recommends:
     
    1. model sensitivity analyses and
    2. comparison of observational uncertainties be made to help resolve the apparent model-observational differences.

C. Hunt asked what was meant in number 4, "uncertainties inherent in field data". The statement implies that perhaps something is not being measured correctly. B. Beardsley did not think that was what the statement implied, however, the word "errors" could substitute "problems".

J. Fitzpatrick asked for clarification on recommendation 5b. B. Beardsley replied that the MEG is asking that knowledge learned regarding dissolved oxygen be applied to the model. J. Fitzpatrick asked if this means trying to relate some of the variability of the physical processes to dissolved oxygen. B. Beardsley agreed. J. Fitzpatrick thinks they are going to be fairly limited in addressing recommendations 4 and 5 since there are not many datasets available that provide enough detail. B. Beardsley thinks if there is no observational database, earlier simulations that considered wind variability could be used to provide some sense of the variability to expect. This information could be used for the 1993 and 1994 model runs.

M. Mickelson asked if recommendation 5b verges on a statistical test of the hypothesis that the model output and the observations are the same. In other words, did the model actually do well for 1994 when error is taken into account? E. Adams thought that was a fair statement.

A. Solow listed the two parts to the question. The model is not perfect, so what kinds of things is it sensitive to, and what kinds of changes to the model would produce the observed conditions. Then there is the question of the accuracy of the observations, or if the difference is due to measurement error or undersampling. J. Pederson pointed out that both the water quality and hydrodynamic models average information over time. B. Beardsley added that changes to the boundary conditions were done monthly. J. Pederson always assumed that the model would only be able to predict when to expect a minimum or maximum and not provide absolute values that were going to be of use to the managers. B. Beardsley thinks no matter how much resolution the model has, it is still a temporal and spatial average. The point is to look at what data are available to address this. The recommended sensitivity studies would also examine the processes themselves to make sure that the model is calculating approximately the right answer for the right reasons.

J. Shine asked what the time scale of the model output is. J. Fitzpatrick replied that it is generally 2-day averages. B. Beardsley added that the model was actually run on a much finer time scale. J. Fitzpatrick pointed out that information inputted into the hydrodynamic model is updated more frequently than the water quality model. R. Isaac suggested for added insight, loading the system until the point where changes are predicted to see what the loads are.

M. Mickelson welcomed the MEG comments. The Chesapeake Bay model may be in trouble possibly because they did not have a MEG early on. He thanked Wendy Leo who first noticed the need for independent scientific feedback during model development. He thinks the modeling efforts are in good shape, and MWRA will continue to listen carefully to the MEG. MWRA needs to think about what is a possible sequence for approaching all of the recommendations as well as its main goal in mind. He sees the preparation of an addendum to the report as something that MWRA would do early on. Some of the recommendations are related to testing the attributes of the model, and are most likely one-time tests. Others are to modify the model permanently, e.g. grid scale and adding a third algal species. Of course, these things need to make sense in relation to the extra effort needed. Others relate to better boundary sampling. The main goal is to have a suitable model, as the permit requires. It is interesting to note that the large influence of the boundary is partially due to MWRA having a lesser influence, and this detracts from MWRA interest in funding a major share of the modeling. There is now a more regional perspective and broader utility for modeling as a research tool, clearly not something MWRA intended when this exercise began.

J. Fitzpatrick thanked the MEG and believes that they establish credibility for the model. MWRA has agreed to work on the report addenda. He then discussed the other MEG recommendations. In terms of matching the grids, one of the reasons HydroQual collapsed the grid was computational burden. They can now go to the full scale grid, but that will increase the running time from 4 hour runs for one year to 25-40 hours. However, computational speed may increase by a factor of two within the next year. HydroQual will continue to do model projections. The nutrient flux around Cape Ann is certainly an important issue. The model has helped to identify the importance of the boundary condition relative to MWRA's input.

J. Fitzpatrick showed monitoring data of the nitrate long-term trend highlighting the importance of the boundary conditions. He thinks it would be desirable, at least from a modeling point of view, to have more data collected at the boundary by MWRA and/or any other members of the scientific community.

J. Fitzpatrick then discussed MEG's concerns regarding DO. In 1994, the average DO dropped to about 6 mg/L. The model picked up a good portion of this drop, but did not pick up the absolute minima, and this should be addressed. The model also had a difficult time with the reduction in DO decline between February-April possibly due to reventilation as seen in the 1992, 1993, and 1995 monitoring data. One problem is that for the early calibration analysis, there were only 2 stations that specified the boundary condition. He had made the assumption that the DO declined gradually at the boundary, as opposed to a marked drop and reventilation. At the time of the calibration analysis, no one envisioned that the boundary would be as important. In 1994, two stations were added closer to the Cape Ann boundary to better specify the boundary conditions. Now that there is another event in 1997 similar to 1992, it may be possible to impose the boundary condition back over to 1992 and see if it improves the model for DO. Jack Kelly hypothesized that in 1994, the pycnocline may have deepened late in the summer. In effect, this would decrease the volume of the bottom waters and in turn increase the effect of the sediment-oxygen demand (SOD). The pycnocline did deepen during that period of time, and that may have exacerbated the SOD given the vertical resolution in the hydrodynamic model. Thus adding vertical resolution, at least as a sensitivity analysis for the two models, would help determine if a physical component is missing and HydroQual would consider attempting this.

J. Fitzpatrick took a little exception as to whether the model did indeed miss the 1993 bloom. Chlorophyll is a surrogate for phytoplankton biomass because particulate organic carbon (POC) measurements give no indication as to how much is algal versus detritus. Chlorophyll is a type of integrator of variables, however, it is carbon that affects the DO. In terms of the amount of carbon and primary production, the model may be doing a reasonable job of predicting the fall biomass, though it may not successfully predict the fall chlorophyll. J. Fitzpatrick showed data from the fall of 1993, when samples were very strongly dominated by the diatom Asterionellopsis, and the cells had a very low carbon to chlorophyll ratio. There is a lot more chlorophyll but there may not be as much carbon biomass. So the fact that the model missed chlorophyll may not be as important. Models in this country only include two phytoplankton functional groups and he is only aware of the Dutch who attempt to model species.

J. Fitzpatrick feels that in terms of POC, the model seems to be doing a reasonably good job. Models may not get the week to week variation, but can catch some seasonal variability. He then showed how HydroQual attempts to examine the temporal plots on a seasonal basis. Another way of trying to gauge whether the model is doing reasonably well is to look at primary production data. The highest productivity is usually observed in the springtime, between 1-3 gC/m2/day. August was the second highest productive period, with values averaging just under 1 gC/m2/day. The model calculates the highest productivity in the early springtime between 1-3 gC/m2/day, comparing reasonably well with the data. The model is a little late for the next peak in productivity in September, but the seasonal signal is about right. Thus the model's computation of the annual carbon production appears correct. He thinks that though the model missed the chlorophyll component if the 1993 bloom, it is capturing the carbon biomass.

J. Fitzpatrick then showed a plot of the temperature growth rate with optimum nutrients and light. The model uses temperature to control the diatom groups. A fall diatom group would need to be "grown" in a specific temperature optimum of 15-16 degrees Celsius. This same temperature range is seen in the spring, tempting the model to grow the fall group then, unless a special "finger-of-God" routine is added to control the seeding of the fall diatom, but he does not think it would be successful. He does not think that the model results are missing phytoplankton biomass in the fall of 1993.

R. Isaac asked if there are other data besides DO that suggest a ventilation event had occurred. J. Fitzpatrick did not think that the increase in DO during the spring is a top-down ventilation event. He believes that it has to do with water entering from the Gulf of Maine, and/or a significant reduction in the oxygen-consuming processes, with possibly some side ventilation.

A. Solow thinks it is not convincing to make the argument on one missed bloom, that happened to not affect the carbon, to assume that any missed bloom will not affect the carbon. J. Fitzpatrick agreed, but does not think chlorophyll is the best indicator. It is the carbon that affects the DO, not the chlorophyll. If there is a bloom that causes high POC deposition that the model misses, then it would be imperative to consider improving the model. HydroQual is beginning to collaborate with the Dutch who have a slightly different modeling framework, untested in our coastal systems. There is a standard way that eutrophication models are built in the United States and he is not sure about adding this additional group. The only way to get the high chlorophyll values observed in 1993 would be to change the carbon to chlorophyll ratio to 20 and the problem is that this event does not occur every year. Unless the physiology is well understood, and can be added to the modeling, no model will be able to predict what years this will occur.

A. Solow said that he is not arguing that every year's variability needs to be reproduced, but the model should be able to capture a fall bloom, even a small one yet significant one. J. Fitzpatrick would like to refocus efforts to do that. M. Mickelson asked J. Fitzpatrick to explain to the group how the carbon to chlorophyll ratio works. J. Fitzpatrick explained that phytoplankton produce chlorophyll as an energy source. Under low light conditions, phytoplankton tend to produce more chlorophyll to make better use of that light. The carbon to chlorophyll ratio also adjusts under nutrient-stressed conditions. All of this is built into the model, allowing it to be able to compute the subsurface chlorophyll maximum observed in the field. He thinks if he changes the low end of the carbon to chlorophyll ratio from 40 to 20 to accommodate Asterionellopsis, then the model will end up calculating a lot more chlorophyll during the winter-spring bloom, that is currently calculated reasonably well by the model.

ACTION: OMSAP voted unanimously to approve the MEG report and will forward it to EPA and MADEP.

Review of Draft OMSAP Letter to EPA/MADEP

OMSAP reviewed the draft letter. A. Solow decided to submit the letter as it is currently drafted and then include the MEG report and benthic threshold revisions in another letter.

L. Schafer thinks it is extremely important that the monitoring program keeps sampling the sea surface for floatables. Though not particularly scientific, this is an issue where the public is apt to become involved. M. Mickelson pointed out that they do have sea sampling of floatables. Often they do not capture floatables but this time they did find a candy wrapper and a piece of packaging. A. Solow pointed out that this field program is mentioned in the OMSAP letter. L. Schafer thinks more information about monitoring methods and frequency should be included.

J. Shine asked how big the field sampling net is. C. Hunt replied that it is 10' long with one opening 2 m wide. The netting is 0.55 mm wide. They are sampling in the nearfield, 2 transect locations between 2 stations, for every nearfield survey, 17 times a year.

S. Testaverde asked if there is any in-plant sampling for floatables. M. Mickelson said that the in-plant study agreed to at the February 2000 OMSAP meeting has not been designed yet. S. Testaverde volunteered to help with the sampling design for the in-plant sampling.

ACTION: OMSAP unanimously approved their draft letter to EPA and MADEP outlining their recent recommendations on MWRA's food web model scope of work, zooplankton, Alexandrium, and floatables thresholds.

Benthic Diversity Threshold Review

K. Keay described the benthic community thresholds, species diversity, and relative abundance of identified opportunist species. He requested that OMSAP review how MWRA plans to implement the existing narrative threshold for benthic diversity and consider tightening the opportunistic threshold. The Contingency Plan (CP) has a narrative caution threshold for benthic diversity that considers appreciable change. There was a typographic omission in the CP of the existing opportunistic species threshold. The existing threshold is detailed in the Outfall Monitoring Plan with a caution level set at 25% of abundance and the warning level set at 50%.

K. Keay described the development history of the benthic diversity threshold. In 1988, EPA attempted to predict the effect of the future outfall by modeling the deposition of solids and organic carbon from the discharge to the surrounding area. They predicted for the worst case scenario, primary effluent with strong stratification, the area later chosen for the future outfall would have modest organic enrichment that would impact, but not degrade, the benthos within only a relatively small area. Early monitoring by MWRA and USGS documented the impacts of sporadic severe storms, both on sediment transport and on the benthic communities. In addition, the monitoring data show strong year-to-year variability.

K. Keay then showed EPA model runs from the Environmental Impact Statement. EPA determined that with primary treatment, there would be an area of degradation around the outfall and then an area of less degradation a little further out due to organic carbon deposition. For full secondary, they predicted a substantially smaller area of change in habitats. Thus the first iteration of benthic thresholds considered a nearfield/midfield concept because modest changes were expected in the vicinity of the outfall, with few outfall changes further away. Preliminary hypotheses expected changes within roughly 2 km of the discharge, approximately equaling a total of 12 km2 that will not trigger the thresholds. An appreciable change at midfield communities further away, not attributable to sediment transport from a major storm, would trigger the threshold.

K. Keay then showed a map of sampling stations. MWRA collects three faunal samples at each farfield station, and three nearfield stations. A single sample is collected at the remainder of the nearfield stations. There are some shortcomings to the nearfield/midfield approach due to the fact that the outfall is to go on-line with secondary treatment with areal impacts predicted to be substantially smaller. In addition, the Bays Eutrophication Model projections predict an inshore offset (east of Winthrop) of POC deposition from the outfall discharge that is smaller than but identically located to the one predicted with the harbor discharges. Thus expecting changes to be centered on the outfall appears unsupported. J. Shine and B. Beardsley noted that the model takes treatment plants on the North Shore into account. K. Keay said that the area of higher POC deposition has been observed in all three of the modeled years (1992-1994). J. Fitzpatrick pointed out that the Lynn treatment plant discharges in that area and that load is in the model but not the flow. He said that they will look to see if this remains a dominant feature on a finer scale.

K. Keay said that these results suggest that MWRA should be examining the entire suite of stations in the nearfield. Thus MWRA is longer pursuing the nearfield/midfield approach. MWRA is recommending that they average the data over all samples collected in the nearfield plus the three western Mass Bay stations, including the area predicted to have the maximum summer POC for all of the benthic thresholds, including the contaminant and RPD thresholds.

K. Keay then described the four threshold diversity indices used by MWRA. Two examine species richness, total species (simplest biodiversity measure, easy to explain) and Fisher's log series alpha (initial slope of the species accumulation curve). The total species measurement is somewhat sample-size dependent, i.e. samples with higher abundances tend to have higher numbers of species (log series alpha corrects for this). Shannon-Wiener is the classic diversity measure, and is sensitive to both richness and diversity. Pielou's J prime calculates evenness and is similarly widely used and relatively well understood by ecologists.

K. Keay then showed evidence in the nearfield of a 25-30% decrease in species richness between 1992-1993. There is strong supportive evidence that this is the result of the 100-year storm, the "no name nor'easter". There is some argument as to whether the increase after the storm is all recovery or whether it is part of a long-term cycle in species richness, as identified in other systems.

B. Beardsley asked if these data are total number of species per grab. K. Keay replied, yes, total identifiable species. A. Solow did not think that the number of total individuals per grab was taken into account, because that can be explained by abundance. K. Keay agreed and noted that abundance in the nearfield has increased quite a bit. Log series alpha only considers species richness, not sample size. A. Solow thinks that even though the grab size and sampling location do not change, there are still different numbers of individuals in samples. K. Keay agreed but stated that the log series alpha corrects for that. He then showed species richness with log series alpha, showing the same pattern as with total good species.

A. Solow noted that none of the measures take into account species identities. There could be the same number of species, but completely different species, possibly a large ecological change, and none of these measures would pick that up. K. Keay agreed and pointed out that that the time pressures for reporting on thresholds do not permit for a detailed analysis the samples, that is why there is the opportunistic taxa threshold. The diversity measures available do not look at community composition. A. Solow liked the approach.

K. Keay then reviewed baseline monitoring results showing strong apparent trends in baseline diversity measures. The Mass Bay samples are much more diverse, species rich, and more evenly distributed than in Boston Harbor. It is important to note that organic enrichment can cause either enhancement at moderately low levels or a strong decrease at higher levels in faunal abundance and diversity. Thus it was decided to use a two-tailed test that viewed either a substantial increase or a decrease as a potential cause for concern. After reviewing the baseline data, MWRA recommends a threshold test for the narrative species diversity threshold that states the annual mean diversity for any of the four (species richness, log series alpha, Shannon-Wiener diversity, and Pielou's J prime) will not fall outside the central 95th percentile of the baseline data. No exceedances were observed during baseline monitoring in the nearfield through 1999 with the thresholds calculated in this way, and more importantly, these threshold ranges appear reasonable given the variability. The nearfield results are all well above the highest values measured in Boston Harbor.

A. Solow was a little bothered by the apparent trends over time and the fact that the whole nature of this kind of threshold argument is based on the assumption that there is variability around a mean. Much of the variability is due to the observed trend. K. Keay agreed and said that MWRA has struggled with this, but he thinks if there is a pattern that is different from what was seen in the baseline, even if it does not actually exceed the threshold, MWRA will still conduct a detailed data analysis and interpretive report. The thresholds should pick up a large change and subtle changes should be discerned for the annual synthesis report. A. Solow thought that was a good answer.

K. Keay noted that if the farfield data continue to pursue an 8-year cyclical pattern in response to hydrographic forcing, but the same pattern is not seen in the nearfield, it may be evidence of some stimulation of the community. J. Fitzpatrick suggested MWRA examine the recovery of the old Boston Harbor sludge dumpsite to test this theory. K. Keay replied that they could certainly look at that, though there are not enough quantitative baseline samples. He pointed out that in 1998, species richness in Boston Harbor was a lot higher than the harbor average and was approximately twice the species richness than measured in 1991.

M. Mickelson brought up the question asked by A. Solow again. How does a trend fit in with MWRA's simple use of a normal distribution? Perhaps if one did include trend or seasonality, it would cause the thresholds to be even tighter. K. Keay thought it would be possible to at least qualitatively fit a sine wave to the data and add confidence intervals. M. Mickelson said that it would make the thresholds tighter, and they would be too easily triggered. W. Leo added that this would increase the risk of a false alarm. C. Krahforst pointed out that if this trend is real then the data are destined to trigger the threshold.

D. Tomey asked about the MWRA 301h samples. K. Keay stated that there are 301h data available from the 1987 outfall siting process. However, a detailed comparison of the old data with more recent data would require a major reconciliation of the species lists and data sets. D. Tomey asked if this was because of a difference in sampling. K. Keay replied, yes, there were several differences including sieve sizes. One example is that there were several cases where the taxonomy was not well known for the animals and thus accurate numbers of each species could not be determined. Overall, it would take quite some time to bring the 1987 data into some comparability with the 1992 data.

B. Beardsley asked if there were any ideas about what may be causing this year-to-year variability. K. Keay replied that there are several theories such as: recolonization of frequently disturbed bottoms; release from predation from increased trawling; and recovery from frequent trawling impacts. However, MWRA does not have the data to prove any theories related to fisheries. MWRA is actively looking at some other datasets such as the Gloucester wastewater treatment plant 301h waiver program. A. Rex added that this pattern has important implications for regulators and managers when it is time to look at impacts. This looks like an oscillation, and it was fortuitously noticed during the baseline period, otherwise it may have been blamed on the outfall.

A. Solow asked which taxa are changing, which are becoming more abundant, and which are becoming less abundant. K. Keay replied that there appears to be an increase in the numbers of rare species in the average sample. The identities of the dominant taxa in Mass and Cape Cod Bays are not changing, though their abundances have increased. If it were changes seen in the 10-15 dominant species in the fauna, MWRA could hope to address that. Unfortunately there are many lesser known species that could also change. M. Mickelson asked A. Solow what he saw in the data using his statistician's eye. A. Solow thinks that though there is a lot of variability, he does agree that there appears to be a pattern.

B. Beardsley also agreed. He added that scientists have compared indices such as the North Atlantic Oscillation (NAO) database and have seen some amazing statistical relationships between, for example, zooplankton biomass on Georges Bank versus NAO. He asked if MWRA was looking at other databases outside of the monitoring data. K. Keay replied that they are. Even though MWRA cannot determine if this trend is real based on only eight years of data, if this cycle does seem to correspond with some hydrodynamic forcing function, the information would be provided in the interpretive report. R. Isaac noted that though this looks like an apparent trend, it is hard to say if there is a statistically valid pattern. K. Keay agreed. There is an apparent trend that MWRA needs to keep in mind as the data are interpreted and calculated for comparison to a threshold.

K. Keay then described the development of the pollution tolerant opportunistic species threshold. The species considered for this threshold have a good literature base in terms of being pollution-tolerant (to either toxics or organic enrichment in the sediments). MWRA is still investigating whether there are physiological constraints that might keep Ampelisca abdita and Ampelisca vadorum from building up to high abundances in the western Mass Bay sediments. The existing thresholds for opportunistic species are a caution level at 25% of mean nearfield faunal abundance and a warning level at 50%. This is determined by examining the average relative abundance within any of the 35 samples within western Mass Bay. The 1999 data continue the trend seen in previous years. These animals are present but in very low abundances throughout the entire western Mass Bay and Cape Cod Bay system, with a maximum of about 1.5% on average of the fauna in 1992, and decreasing and remaining at extremely low levels in the last few years. This is much lower than the current thresholds. In comparison, Boston Harbor has much higher values. Thus MWRA thought the thresholds should be substantially more sensitive and is recommending to tighten them to a caution level of 10% and the warning level of 25%. If as few as one third of those samples had a third of their abundance made up of the six opportunistic taxa, MWRA would be triggering that caution level threshold.

A. Solow thought that only a 5% increase would be a significant change from what has been seen up until now. K. Keay agreed but did not think that it is enough of a change, over a large enough area of the nearfield, to warrant the triggering of a threshold. He added that there are some minor predicted impacts from this outfall that could include a modest increases in abundances. Overall, MWRA thought that 10% was both protective and appropriate.

J. Shine asked about Ampelisca. K. Keay replied that MWRA will continue to look into whether Ampelisca can survive in Mass Bay, and if not, there are taxa that could replace this species in the opportunistic threshold. J. Shine and K. Keay then had a brief discussion on the survivability of other opportunists in the subtidal zone.

B. Beardsley asked about how much fishing and dragging occur in the nearfield. C. Hunt replied that dragging is not very prevalent. S. Testaverde added that there is no dragging in the nearfield since it is within state waters. It has been illegal to drag in Mass Bay since 1972. MADMF would be able to speak about the laws. [Post-meeting note: dragging is not completely prohibited in Mass Bay]. J. Pederson asked D. Tomey about the barrels picked up off of Scituate. D. Tomey replied that EPA conducted a barrel study that found quite a bit of dragging by fishermen, just east of the outfall. C. Krahforst added that MADMF is allowed to drag for their trawl surveys. B. Beardsley raised this issue because of the recovery of certain species such as scallops after some areas on Georges Bank were closed.

K. Keay noted that USGS found in 1991 that the area called Rosie's Hole near the outfall was characterized by deep and frequent trawl scars. Other suitable areas nearby did not show trawl scars, presumably because it is difficult to trawl the long axes of the drumlins there. It may be useful to revisit the USGS side scan data. B. Beardsley pointed out that MWRA should want to know the trawl history of the stations. K. Keay added that MWRA could also make assumptions on which stations could not be trawled based on topography.

K. Keay asked OMSAP if they accept MWRA's recommendations. A. Solow liked the recommendation to tighten the opportunistic species thresholds. He thought that the threshold arguments on the diversity measures are weak but the fact that MWRA is going to analyze the data in detail is the best that probably can be done. He acknowledged that it is difficult to draw inferences about changes in the Shannon-Wiener measure of diversity and added that none of the measures are sensitive to changes in the actual species. However, MWRA will be looking at the opportunistic species. His one reservation is that the interpretation of the threshold calculation is very difficult. J. Shine pointed out that MWRA will still be doing other analyses to help in the interpretation. K. Keay agreed and emphasized that the thresholds are an early warning, and not meant to replace a detailed evaluation of the data.

B. Beardsley and K. Keay then discussed salinity measurements and benthic sampling. B. Beardsley asked if the monitoring program can discern the gross effects of storms. K. Keay replied yes, this can be discerned in the sediment profile imaging. B. Beardsley pointed out that internal waves generated over Stellwagen Bank and Basin during the summer months can cause resuspension and provide a mechanism for moving fine sediment out into the basin. It was previously believed that the primary mechanism for moving fine sediment in this area were winter storms. So now it seems there is a mechanism all throughout the year to carry material into Stellwagen Basin. His point is that independent of the thresholds, MWRA will be analyzing the data in detail to look for changes.

A. Solow stated that he would vote to approve these changes on the understanding that all of these other analyses will continue, making him comfortable that we are going to do the best possible job that we can in detecting changes in the benthos. J. Shine added that if there is an exceedance of these thresholds, there is other data to help determine the cause.

ACTION: OMSAP unanimously agreed to recommend three revisions to the benthic thresholds: 1) stations considered in the threshold calculations should include the nearfield stations plus the three adjacent western Mass Bay stations; 2) the benthic threshold test for annual mean species diversity should not fall outside the central 95th percentile of the baseline data; and 3) the existing pollution opportunist threshold should be tightened to make it more environmentally protective (caution from 25% to 10% and warning from 50% to 25%). OMSAP will forward the recommendations to EPA and MADEP.

GENERAL DISCUSSION
S. Testaverde requested to revisit OMSAP's recommendation to delete the floatables threshold. NMFS opposes this and if EPA and MADEP do approve of the deletion, this means a change to the Contingency Plan attached to the permit and he would then like to open up an Endangered Species Act section 7 consultation. A. Solow replied that OMSAP approved of the letter recommending the deletion of the floatables threshold and that the letter will be forwarded to EPA and MADEP.

B. Beardsley brought up the Model Evaluation Group's next step. Their formal task, to review the model results, is complete. However, the MEG would like to continue to work with MWRA and HydroQual in determining which tasks on the MEG's list of recommendations are under MWRA's purview and can be completed. He asked OMSAP if MEG may continue to have this dialogue. A. Solow agreed and thanked B. Beardsley and the rest of the MEG for their efforts. B. Beardsley added that Rich Signell (USGS), who developed and ran the hydrodynamic model is about to leave for a 3-year fellowship. The transition of the hydrodynamic model will be very critical and the MEG wold like to help see that done. M. Mickelson thinks MWRA can prepare a workplan to examine the transition of the hydrodynamic model.

Inter-Agency Advisory Committee and Public Interest Advisory Committee Updates

C. Coniaris summarized the Public Interest Advisory Committee's (PIAC) last meeting on May 2, 2000. The group discussed OMSAP's recent recommendations regarding thresholds and the food web model scope of work. PIAC wanted to become more involved as MWRA developed its floatables in-plant special study as recommended by OMSAP at their February 2000 meeting. PIAC requested that Mike Mickelson (MWRA) present information on the Dutch Phaeocystis model and the Great Lakes zooplankton modeling at a future PIAC meeting. PIAC also requested that their next meeting be scheduled on the same day as OMSAP so that it would be easier for PIAC members to attend the OMSAP meeting and hear the Panel's discussions firsthand. There have been a few membership changes: Gillian Grossman (PIAC chair), has departed from Save the Harbor/Save the Bay and PIAC will elect a new chair at its next meeting in the fall. Susan Redlich has departed from the Wastewater Advisory Committee and thus PIAC. Both organizations would like to continue participating on PIAC.

S. Testaverde gave a brief Inter-Agency Advisory Committee (IAAC) update. The group has not met since the last OMSAP meeting. The original IAAC mission in the OMSAP charter dated October 1998 is "The committee [IAAC] will advise the OMSAP on environmental regulations." Several IAAC members felt that this mission statement was too narrow. IAAC voted to approve the following recommendation to change its mission to: "The committee will advise the OMSAP, EPA and MADEP on scientific, technical and/or regulatory matters related to discharges from and operations of the MWRA system outfalls that may directly or indirectly affect Boston Harbor, Massachusetts Bay, and Cape Cod Bay. The IAAC may review or evaluate other environmental matters as necessary." EPA and MADEP objected to that mission statement and on April 6, 2000, S. Testaverde met with Chris Mantzaris (NMFS), Ron Manfredonia (EPA), Glenn Haas (MADEP), and Cathy Coniaris (OMSAP staff) to discuss IAAC's roles and mission. There was consensus to change the mission of IAAC into a forum for information exchange among the agencies interested in MWRA's outfall permit. The forum would inform EPA and MADEP but not OMSAP directly. A. Solow said that it is his understanding that EPA and MADEP will attend a future OMSAP meeting so that we can all discuss this.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • OMSAP/IAAC/PIAC membership lists
  • Draft March 2000 OMSAP minutes
  • Draft letter of OMSAP recommendations to EPA and MADEP
  • Draft Model Evaluation Group Report to OMSAP
  • Copies of MWRA Presentation Transparencies
  • MWRA Benthic Community Threshold Information Briefing

OMSAP Meeting, Tuesday, March 28, 2000
10:00 AM – 3:00 PM
Woods Hole, MA
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Robert Beardsley, WHOI; Bob Kenney, URI; Scott Nixon, URI; Judy Pederson, MIT/Sea Grant; Mike Shiaris, UMass Boston; and Jim Shine, Harvard School of Public Health.

Observers: Don Anderson, WHOI; David Borkman, URI; Peter Borrelli, Center for Coastal Studies; Margaret Callanan, Cape Cod Commission; Phil Clapham, NMFS; Cathy Coniaris, OMSAP staff; David Dow, NMFS; Jim Fitzpatrick, HydroQual; Mike Hickey, MADMF; Carlton Hunt, Battelle; Russell Isaac, MADEP; Bruce Keafer, WHOI; Ken Keay, MWRA; Wendy Leo, MWRA; Matt Liebman, EPA; John Lipman, Cape Cod Commission; Steve Lipman, MADEP; Ron Manfredonia, EPA; Stormy Mayo, Center for Coastal Studies; Mike Mickelson, MWRA; Jack Pearce, Marine Pollution Bulletin; Virginia Renick, MWRA; Andrea Rex, MWRA; Jack Schwartz, MADMF; Rich Signell, USGS; Ted Smayda, URI; Dave Taylor, MWRA; Heather Trulli, Battelle; Steve Tucker, Cape Cod Commission/Bays Legal Fund; and Jeff Turner, UMass Dartmouth.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. February 23, 2000 minutes were approved as amended. See below.
  2. OMSAP recommends that EPA and MADEP approve MWRA's food web model scope of work as having fulfilled their NPDES permit requirement. See page 11.
  3. OMSAP recommends that MWRA delete the current Alexandrium cell count threshold and would like to review the new paralytic shellfish toxicity threshold currently under development by D. Anderson. See page 17.

MINUTES

February 2000 Minutes

C. Coniaris pointed out a correction in the draft minutes. The phytoplankton bloom [Asterionellopsis glacialis] mentioned on page 4 occurred in the fall of 1993, not 1994. OMSAP approved of the minutes as amended.

Model Evaluation Group Update

B. Beardsley stated that the Bays Eutrophication Model Evaluation Group is currently in the process of completing their final report to OMSAP. One section by Don Harleman examines the effects of the transfer of effluent from Nut Island to Deer Island on nitrate concentrations in Boston Harbor. An informational report on issues surrounding the Chesapeake Bay Model review was distributed by email. The situation for the Chesapeake Bay effort is somewhat different, but there are some parallels. He hopes to have the MEG report finalized within the month, sent to OMSAP, and discussed at the next meeting.

Chesapeake Bay Model Evaluation

S. Nixon gave a brief summary of the recent Chesapeake Bay model evaluation, of which he was a reviewer. The evaluation was requested by the Scientific and Technical Advisory Committee for the Chesapeake Bay Project, but the Chesapeake Bay Project had no desire for this review, thus the evaluation was hampered by politics. The model group was unprepared for a review and the model had not been well documented since 1994. This made review by the panel difficult. The strategy of the model evaluation was to sample three of the most important basic areas of the model: primary production, vertical density structure, and nutrient cycling/respiration in the water column and the sediments.

The $2 million/year Chesapeake Bay model has been used in a large number of scenarios by the modeling committee (composed of management agencies). The group in Annapolis conducting the modeling for the Chesapeake Bay Project did not manipulate the model well and provide the Chesapeake Bay Model Evaluation Group (CBMEG) the requested diagnostic output.

In the view of the CBMEG, the primary production was seriously undercomputed, water column stratification was over-computed, water column respiration was underestimated, benthic oxygen uptake matched well, the basic relationship between nitrogen inputs and the fixation of organic carbon was not well captured, nutrient regeneration was not well-captured, and preferential uptake of the nitrogen by the phytoplankton was misrepresented. Model results showed that Chesapeake Bay was heterotrophic whereas observations suggest that it is either near production and respiration balance or autotrophic. There were also problems comparing observational and computed data due to the model grid and field sampling designs. These were serious enough concerns that CBMEG felt that it was inappropriate to use the model in making management decisions and were quite critical in their final report. The group did not think that the model was very credible. Another problem was that the Chesapeake Bay Project believed that if the model worked well for one parameter, there was no need to investigate further. For example, the dissolved oxygen (DO) seemed to be modeled well, however, the primary production was so low that there had to have been other compensating serious errors in the model in order to produce the correct DO.

R. Signell asked if there was a feeling from the review panel that these problems could be corrected in the model. S. Nixon replied that opinions varied, but overall, CBMEG thought the problems could potentially be fixed. The model was originally developed by HydroQual and is currently maintained by the US Army Corps of Engineers. At the June 2000 OMSAP meeting, Jim Fitzpatrick clarified that HydroQual was not directly involved in the development of the Chesapeake Bay Model. HydroQual only worked on the development of the Chesapeake Bay Sediment nutrient flux model. The term "model" refers to both the hydrodynamic and water quality models because they run coupled. CBMEG also recommended that the Chesapeake Bay Project modeling committee conducts additional reviews, bring in new people, and document the model better. Until now, the push was to run as many scenarios as possible. People have bought so much into the process that they cannot criticize it. He hopes that the Massachusetts Bays Eutrophication Model is open and does not "over-sell" itself. He also hopes that reviews of the model are done with doubt and skepticism and that the model is always examined with "fresh eyes". His sense is that the MWRA modeling is in much better shape than the Chesapeake Bay modeling.

R. Signell stated that there has been an effort in the BEM/HD models to describe strengths and weaknesses, as opposed to the Chesapeake Bay modeling. S. Nixon thinks that is an important difference. With the Chesapeake Bay model there seemed to be a fear of admitting to managers and the public the limitations of the model.

R. Isaac asked whether the present or redesigned field program could answer any questions in Chesapeake Bay. S. Nixon replied yes. One criticism from the CBMEG was that the monitoring and modeling programs were not designed to interact enough. For example, there had not been a systematic comparison of the model and monitoring primary production. R. Isaac wondered if there are any models with smaller margins of uncertainties. S. Nixon does not think that there are. Another problem with the Chesapeake Bay model was that no one could provide information on initial design requirements. The group would have liked to have seen a document describing modeling goals and abilities.

S. Nixon does not think we can model complex nature on 10-year time scales, e.g. if nitrogen decreases, what will happen in 10 years. A. Solow asked whether the MEG's findings for the Massachusetts Bays Eutrophication Model will be as negative as the one for Chesapeake Bay. B. Beardsley said no, however, there will be some recommendations for model revisions.

A Refresher on MWRA's Food Web Model Scope of Work (FWMSOW)

C. Hunt described the FWMSOW dated May 21, 1999 ["Scope of work for a food web model to characterize the seasonal abundance for important prey species of endangered species in Massachusetts and Cape Cod Bays" is available at: https://www.mwra.com/sites/default/files/2023-11/1999-09.pdf]. The FWMSOW is an incremental stepwise scope of work that examines whether the environmental conditions in Massachusetts Bay will worsen as a result of the outfall relocation. He then summarized a recent report ["A review of issues related to the development of a food web model for important prey of endangered species in Massachusetts and Cape Cod Bays is available at: https://www.mwra.com/sites/default/files/2023-11/1999-14.pdf]. The purpose of the report is to make an effort to understand where we are in the system, i.e. "step 1" in the FWMSOW. Two food web modelers were asked to describe their particular modeling approaches, including advantages and shortcomings. Peter Yodzis utilizes a trophodynamic approach. This evaluates dynamic interactions between and among the species in a food web and can be used to evaluate perturbations. Robert Ulanowicz utilizes network analysis, a more static approach that is not predictive, but more effective in understanding energy flow. Both of these approaches require an understanding of the functions and roles of all species relevant to the food web model. Each of these modeling approaches requires extensive data at the correct scale in order to be effective.

Based on these reviews, the development of a food web model that attempts to link the discharge to the occurrence of right whales in Massachusetts Bay will likely be an exercise in futility because: (1) food web models are most effective when addressing measurable perturbations in a system, and such perturbations are not expected to result from outfall relocation; (2) food web models must have complete and accurate species-by-species biomass information which is generally not available; (3) uncertainty in the overall importance of the Bays to the energetics of the whales (i.e. inability to close the food web domain); and (4) food web model development at a local or habitat specific scale is unwarranted given the importance of external factors that affect the distribution of whales. The MWRA NPDES permit indicates that the scope of work has been developed for the seasonal abundance of the important prey species. According to the permit, OMSAP is to provide MWRA with comments on the scope of work. Within 90 days MWRA is required to submit to EPA and MADEP a revised scope of work, after which EPA and MADEP will determine whether implementation of the food web is warranted.

M. Shiaris asked C. Hunt to comment on Ulanowicz' model and how well it could be used here. C. Hunt thinks we can model energetics and linkages if there is enough data. Ulanowicz probably cannot perturb a compartment and then determine how the whole system changes. His model functions with a certain steady state and is interpretive rather the predictive and it can be used to gain a better understanding of the system.

A. Solow said that one reason a food web model was requested to better integrate the monitoring data. OMSAP agreed that a detailed, predictive, numerical, and quantitative model was not possible at this time. However, there may be a qualitative model that can be used for integrating these data. C. Hunt thinks a qualitative model would be a good research tool to help us focus our questions and better understand the information differently but it could not be used to determine if there has been an impact from the outfall on the right whale in Massachusetts Bay.

J. Shine pointed out that the food web model scope of work flowchart includes "is such a change likely to harm whales?" In order to answer this question, there needs to be some qualitative idea of what might be harmful to whales. C. Hunt said that the assumption is that the prey of the whales would be adversely impacted. M. Mickelson added that this qualitative model is included in a report by Jack Kelly et al. with commentary from Bob Kenney that describes the "big picture" of right whales. K. Keay added that the presentations at the OMSAP workshop in September 1999 attempted to put the individual study results in a context of the food web using diagrams showing where the individual monitoring components fit into the ecosystem.

D. Dow thinks that it would be difficult to model Phaeocystis, even qualitatively. J. Fitzpatrick said that the Dutch are modeling Phaeocystis in the North Sea. The problem with steady state food web modeling, such as the Ulanowicz model is that Phaeocystis does not appear every year and that type of food web modeling would not be predictive and answer the necessary questions. T. Smayda thinks the Ulanowicz network type of modeling is not static. J. Fitzpatrick pointed out that the Ulanowicz model will would not be capable of describing when Phaeocystis will occur.

D. Borkman added that there seems to be a 3-4 year periodicity in the Phaeocystis occurrence in the Dutch work which closely matches two of three recent outbreaks here so what seems to be developing is a large-scale, almost ocean basin farfield influence. He asked how big a model would have to be to address this. J. Fitzpatrick replied that there may be an opportunity to take a look at expanding the BEM to examine this. HydroQual will most likely explore this further but he had reservation about certain food web approaches since they do not address some spatial questions. The BEM predicts that the influence of nitrogen from the outfall in Cape Cod Bay is ~5-10% and with these low percentages, he does not believe that the model coefficients and the biomass estimates will be accurate enough and thus will not give much confidence in the predictions.

S. Nixon believes the current modeling effort has proceeded in a deliberate and thoughtful way. OMSAP's job is to weigh the probabilities and the preponderance of evidence. It would be great to learn more about these questions, but there is no evidence suggesting that it is the burden of the MWRA ratepayers. There is also no indication that there will be any major change associated with the new outfall and the federal review process does not believe there will be an impact on the whales. The default "no" in the FWMSOW flowchart requires continued monitoring and evaluation. For now, the case has been made that there is no compelling evidence to require a numerical food web model. J. Shine added that zooplankton will continue to be monitored and MWRA will develop a better way of examining the zooplankton dynamics with the current data.

C. Hunt suggested people read the report by Cabell Davis on results of his late February 1999 Video Plankton Recorder survey ["Data Report for Video Plankton Recorder Cruise R/V Peter W. Anderson, February 23-28, 1999" is available at: https://www.mwra.com/sites/default/files/2023-11/2000-03.pdf]. He has high resolution information on a variety of phytoplankton and zooplankton distributions throughout the entire bays. C. Hunt also pointed out that spring 2000 rapid screening samples indicate that there is a Phaeocystis bloom in the nearfield area.

Barnstable County Science Advisory Panel's Alternative to MWRA's Food Web Model Scope of Work

S. Tucker stated that the Cape Cod Commission believes that examining the right whale in the context of trophic levels is advantageous for a number of reasons. The primary producers are the creatures most likely to show an impact from the discharge of effluent. It is known there is a direct pathway from this level of primary production to the apex predator in this system, in this case the North Atlantic right whale. Collecting data pertaining to this tropic relationship and analyzing that data in terms of the model about to be presented will help to clarify any effects of the effluent discharge on these populations. Right whales exist in very low numbers and the population is showing a reproductive decline.

These facts have led us to a conclusion that a precautionary management stance is warranted when considering alterations to the right whale habitat. This is not to say that we expect the negative to be proven. Work can be done to pre-emptively illustrate that there will be absolutely no negative effects resulting from the project. It is incumbent upon us to take advantage of the tools that are at our disposal to monitor the status of the bays system as it responds to the outfall, especially during its first months and years of its operation. Tools have already been developed that help decision makers identify the likelihood and intensity of the effects of the discharge. Though the BEM does not capture some anomalous events, it is a tremendous accomplishment. However, it is not a perfect tool, and there is a degree of uncertainty in applying its outcomes in a descriptive or a predictive manner. Hopefully it will become a sound tool and an important key element for providing context to future management decisions.

At the last OMSAP meeting, OMSAP and MWRA discussed removing the zooplankton threshold from the existing safeguards in the NPDES permit. While we appreciate that both OMSAP and MWRA recognize the importance of continued monitoring, we do not want to see the thresholds changed without the institution of a suitable substitute. After OMSAP accepted the MWRA assertion that the Acartia tonsa hypothesis was inadequate, the discussion reflected an interest in reconsidering the context in which the zooplankton data would be analyzed. At the end of the discussion, the panel's final recommendation was to recommend a shift to a system-wide approach for zooplankton analysis. Our proposed model began as a comprehensive and systemic effort but has been refined to focus on the most proximal, and arguably the most important parameters of that system, including zooplankton, and affecting right whales directly. We think that this food web model may be the right tool for the proper approach for zooplankton analysis recommended by the panel members as well as addressing our larger systemic concerns. We hope that OMSAP will agree that the further refinement and application of this proposed food web model will give us another tool to provide context for future management decisions.

S. Mayo does not believe that the MWRA monitoring will detect problems that may occur with right whales. The Bay has a profound influence on the feeding environment of the right whale, at least with respect to copepods and the caloric content available. He outlined why he believes a model that focuses on whales should be developed. It is clear to everyone that the right whale situation is beyond grave, probably nearly lost, since the reproductive rate appears to be crashing. It is not clear whether this is part of a long term cycle, regardless, the conservative assumption is that something is occurring to the species and he believes that it has something to do with feeding, e.g. low nutrition or pollutant uptake. The only other explanation would be a genetic problem. A food web model should be developed because the right whale population is in serious trouble. Cape Cod Bay should be included in the modeling effort since it has been and will continue to be an important feeding area. Cape Cod Bay is visited yearly by about 100 individuals (one-third of population), and this year seems to be no exception. Cape Cod Bay was designated a critical habitat for right whales by NMFS, due to the large proportion of the population, including calves, that visit the bay. He noted that the right whales reside in Cape Cod Bay over the winter, not just the spring (approximately December to April/May).

He agrees that there is a lot of uncertainty about the environment but it troubles him that we believe in the "no jeopardy" prediction and yet admit that we cannot develop a predictive food web model the system. Currently there are no strong indications that toxic effects are affecting the reproduction of right whales but there are some hints that there are reduced food resources and that could impact the reproduction of the animals. Ongoing work by Michael Moore and suggests that the blubber thickness of right whales is lowest in the North Atlantic population. This is significant since feeding is the main activity of right whales in Cape Cod Bay.

Based on research at the Center of Coastal Studies (CCS), we have identified a feeding threshold, i.e. the number of zooplankton at which right whales begin feeding. We originally calculated 3900 organisms per cubic meter, with a correction factor for the varied calorie content of different species, however, this calculation has been revised to about 3750 organisms per cubic meter. This threshold is based on 3000-4000 samples collected near feeding right whales. The mean density within the path of feeding right whales in Cape Cod Bay is around 26,700 organisms per cubic meter. Since we have researched the filtering abilities of right whales, these values are based on what the right whale can capture in its baleen. The maximum integrated density of zooplankton is about 250,000 organisms per cubic meter. He then showed calculations of caloric intake and a model of the density of a surface patch from southeastern Cape Cod Bay in 1999. We know that right whales congregate in certain areas where there seems to be a significant plankton resource and these areas should be carefully examined. He showed a distribution plot of right whales that corresponds to high chlorophyll values and patch distributions in the eastern and southern part of Cape Cod Bay. He considers Cape Cod Bay a very interesting system that is highly partitioned and non-uniform. However, there is a fair amount of information that a modeler could use to develop a food web model.

He does not understand what occurred in 1997 when Phaeocystis was very dense over a wide area, especially in the eastern part of the Cape Cod Bay. He has been misquoted as saying that the whales left because the Phaeocystis bloomed – he does not know if this is only a coincidence.

He showed results of their modeling in which caloric availability and capture in Cape Cod Bay was calculated. 0.69 kcal/m3 is the estimated caloric requirement for a skim-feeding right whale based on several assumptions. For most of the years, the whales are capturing 2.4 times this basal need for food, so if the calculations are correct, they are doing relatively well. He then showed different ways of looking at the maximum available and captured energy that varies on an annual basis. He has calculated 3750 organisms per cubic meter as the feeding threshold in the eastern two-thirds of Cape Cod Bay. He feels that there are not enough samples but results give an indication of what could be done from a modeling point of view.

M. Mickelson asked whether 1992 and 1997 were low zooplankton years, or whether no CCS data were available. S. Mayo replied that they are just now realizing that when the water column is mixed, the zooplankton resource may be found in either the upper or bottom few meters, however, in 1997 the zooplankton resource was low in the surface and the bottom.

S. Mayo showed his first attempt at estimating what would happen if there were changes in the taxonomy of the zooplankton in right whale feeding areas taking into consideration that the taxa are filtered differentially by the whales. The data are based on the typical mixed plankton resource, existing caloric density, and average density of zooplankton. Conceptually adjusting the zooplankton community relative to size either increased or decreased the capturability of the food per cubic meter of water. He then showed another model experiment involving a small taxonomic enrichment and a step-wise reduction of biomass to examine how sensitive the animals or their capture might be to a change in both taxonomic composition and biomass. These are examples of the types of model experiments that MWRA could conduct.

J. Fitzpatrick feels it is important to note that the area of habitat from year to year suitable for right whales varies by at least an order of magnitude. He does not see how MWRA, which currently exports ~90% of its effluent into Mass Bay is responsible, assuming a fairly constant effluent load, for all the variation. S. Mayo agreed, but thinks that assumptions need to be proven. There are plenty of examples in the news of undeveloped and untested hypotheses that have been proven wrong. It is important that we be particularly conservative about the eastern two-thirds of Cape Cod Bay when dealing with a very sensitive species on the brink of extinction.

T. Smayda pointed out that this is a very complex and nitrogen-sensitive system. He thinks S. Mayo has nicely shown much of the kinetics and data that are available. He is concerned that many of the model runs were shown for only April and October. MWRA argues that the constrained water mass below the pycnocline prevents nutrients from entering the productive pool – he believes this is not the case, and that photosynthesis does occur below the pycnocline. J. Fitzpatrick pointed out that the plots shown today were total nitrogen but that organic nitrogen, ammonia, and nitrate have also been modeled. Summer stratification is taken into account and built into the model framework. Chlorophyll was also modeled and there was little difference between pre- and post-outfall relocation.

T. Smayda noted that S. Mayo's data show that there are zooplankton thriving in bottom waters. If there is sub-pycnocline delivery of nutrients, harvestable into phytoplankton, available for grazing, and then dispersed downstream, then indeed there is carbon or trophic input into the system. In addition, Alexandrium tamarense in the coastal current is flowing past the vicinity of the diffusers and this species is capable of phototaxic movements and nutrient retrieval migrations. These nutrients can potentially restore the population and lead to added growth available for subsequent downstream transfer. BCSAP would like to see a quantitative approach such as a model and believe that the Ulanowicz approach is the appropriate one. This would be a better position for MWRA in the event of future litigation over whether or not a negative event is due to the outfall. We believe a model is necessary for MWRA, as well as ecosystem protection.

B. Beardsley asked T. Smayda about the timing of the influx of the harmful algae in the surface layer, and whether it could be modeled. T. Smayda replied that in the case of Phaeocystis, there is a Dutch model that could be modified for this area to address the timing of these blooms. However the problem with Phaeocystis is not the number of cells, but rather the size of the turbulence tolerant gelatinous colonies. When silicate is used up by the diatoms, Phaeocystis takes over and is very efficient at phosphate uptake. Thus nutrient ratios can possibly serve as a surrogate for temporal changes.

A. Solow listed the three parts to this discussion. Part one: what are the effects of the outfall relocation on the environment? BCSAP has raised questions about the belief that effects of the outfall will be negligible or absent in Cape Cod Bay and whether these issues are addressed by modeling. Part two: if the physical environment changes, what would be the biological effects, and would there be any effects on right whales? With this issue, the BCSAP is proposing some kind of a food web model to explore, in advance, what the potential effects of changes in the physical environment would be on the right whales. Part three: monitoring will absolutely continue, even if there is no observed effect of the relocation on the physical or biological environment. B. Beardsley pointed out that monitoring at the boundary could improve in order to be able to better tease out inter-annual variability as well as biological or physical effects that have nothing to do with the outfall. A. Solow agreed.

T. Smayda thinks that MWRA will never commit to retrofitting the treatment plant because they are not collecting the correct types of data to show changes in the environment. A. Solow then asked T. Smayda if he had a proposal on how to improve the monitoring program to satisfy these concerns. T. Smayda replied that the BCSAP has submitted proposals in the past for increasing frequency and sampling locations during critical periods (e.g. summer which is nitrogen sensitive). They have also recommended that samples at discrete depths be examined individually due to stratification and not averaged together. S. Mayo added that there is a lot of excellent data being collected but he has always wanted to see more sampling in the critical eastern part of Cape Cod Bay where the right whales feed. A. Solow thinks these issues are related to revising the monitoring program and not necessarily the development of a food web model. S. Mayo thinks that the monitoring data should be used in something like a food web model in order to try to answer some questions because there are some important hypotheses that need to be tested. Thus he thinks the food web model fits in with the monitoring in that it provides a use for the data.

J. Pederson thinks it is difficult to determine what data would be needed in order to develop even a simplified food web model that would give us a better understanding of the system. She does not think models can give us all of the answers and S. Nixon's discussion earlier today concerns those of us who try to balance the monitoring and the modeling and use the results to better understand how accurate our predictions are. She thinks there are many factors, not necessarily the outfall, driving the zooplankton that the right whales feed on. B. Kenney would like the answers to the same questions S. Mayo is asking. However, in order to develop a predictive food web model that can determine what the effects of any perturbation are going to be on the prey of right whales, it must be able to predict changes in species composition, size composition at a meter scale spatial distribution. In addition, we need to understand exactly how nutrients affect zooplankton. If we cannot make these links, then constructing the model in the first place is not possible.

S. Mayo pointed out that the Cape Cod Commission draft information briefing includes some ideas of how the BCSAP thought a model should look. He agreed with B. Kenney in that we are all searching for the same answers. However, he thinks the finding of "no jeopardy" lacks the kinds of necessary connections mentioned by B. Kenney. There some way to make those missing connections, for example, trying to determine whether changes in nutrients levels will have an influence on the resources of the right whale. Both cannot be true: predicting there will be no effects and stating that predictions cannot be made.

B. Beardsley asked whether these questions might be answered by examining the MWRA and CCS databases. S. Mayo thinks it is possible but there is a problem with variability. We only recently noticed that high surface zooplankton concentrations coincided with low concentrations in bottom waters and vice-versa. This finding could mean that there is lot less variability than previously thought. B. Beardsley pointed out that S. Mayo has made a strong statement for better monitoring in the eastern part of Cape Cod Bay, but that could be done without a food web model. S. Mayo thinks it would be important to have something like a food web model. He hopes that there can be some way of associating the existing database as well as future data that can support the "no jeopardy" determination.

B. Beardsley thinks that when discussing data results, one can keep in mind cause and effect relationships relating to how the ecosystem works, in effect, a conceptual food web model. He would like to separate the question of whether or not to develop a food web model and whether it is necessary to revisit the monitoring program. Of those two, he would emphasize revisiting the monitoring program. S. Mayo liked this idea of scientific review of the monitoring program that at the very least included a conceptual food web model in the heads of the scientists. A. Solow thinks the best qualitative "food web model" for right whales is actually S. Mayo. He cannot imagine using a Ulanowicz type model here. It would not tell us anything about the maximum density of the prey species, composition, or patchiness. It may be able to predict total biomass over a large area but that is most likely irrelevant to the feeding of right whales since they prefer the very dense patches.

T. Smayda wondered how MWRA would defend itself in court, without even a semi-quantitative model, if there ever was a large Phaeocystis bloom that appeared to be "fed" by nutrients from the new outfall, and this coincided with the right whales avoiding the area. M. Shiaris thinks this scenario would be a good argument for rethinking the monitoring but asked where a food web model would fit into this. T. Smayda agreed that improved monitoring is absolutely essential and would be a major step in the right direction. He thinks modelers such as Ulanowicz could be brought in to suggest how the monitoring could be improved so that a numerical model would not be needed.

J. Pederson noted that we will continue to review the monitoring to make sure it is answering the relevant questions. In fact, this process of reviewing trigger levels is a part of this process of constantly reviewing and refining the monitoring. However, we need to always keep in mind the type of program we are advising.

S. Nixon observed that everyone seems to agree that the state of the art is not such that we have a credible predictive model for linking things such as nutrient inputs to the changes that are most important to the whales. In addition, the models are not going to be constrained well enough to be an effective legal tool. Thus the responsible thing to do is to monitor the system carefully in the face of such uncertainty and the refinement of the monitoring program will be an ongoing process. OMSAP's job is to advise EPA and MADEP as to what MWRA is required to do based on the best available science. He is skeptical of models, as mentioned earlier, but feels that modelers are good at modeling physics. Problems develop when they try to model chemical partitioning and biological processes. Phaeocystis is perhaps linked with the nitrogen, but we do not know for sure, and a model would not give us that answer. Even S. Mayo feels that maybe there is a connection with the whales, maybe there is not, so we cannot put it into a model, and certainly not into a Ulanowicz model in a credible way at this point. It is also worth noting that J. Fitzpatrick, who is in the business of developing models, is saying that a predictive food web model as it relates to whales cannot be developed at the present time. No one is claiming for sure that there will be no negative impacts from the new outfall. Nature surprises us all the time, but that is why there is a monitoring program. All we can do at this point is monitor as responsibly as possible, and model what we believe we can model reasonably well. He does not see any compelling argument for a food web model relating to whales. However he does believe there is value in re-examining the monitoring and exercising due diligence and operating on the preponderance of evidence.

S. Mayo asked whether, since there is uncertainty about effects of the outfall, the statement of "no jeopardy" with respect to whales also contains a level of uncertainty. B. Kenney replied that the section 7 statutes require NMFS to make a decision based on the best scientific evidence available at the time. Model results indicated that relocating the outfall to the new location will have no measureable change in nutrients in the eastern half of Cape Cod Bay where the right whales feed, therefore, the "no jeopardy" conclusion. S. Mayo thinks it is negligent to say there will be no effect or damage with respect to right whales or the rest of the system; "no jeopardy" implies that the story with the right whales is closed (OMSAP members disagreed). B. Kenney replied that in the event new evidence arises, section 7 consultations may be reopened, as is currently occurring with the Biological Opinion of the fishery management plans. S. Mayo thinks that if a food web model is not considered, there should at least be a different approach when considering the eastern margin of Cape Cod Bay.

J. Pederson encouraged everyone to read some of the earlier Outfall Monitoring Task Force documents. We have been dealing with this issue for about nine years and the right whale was factored into even the early monitoring decisions. 250 people commented on the original draft monitoring plan. Some felt there should only be nearfield sampling near the diffusers while others felt it was more important to monitor further out in the farfield. The Outfall Monitoring Program was the compromise, with both nearfield and farfield stations, that has evolved into what you see today. It was intended to take into account, as best we could given the resources, variables that will give some indication of what is occurring in the system. The idea was to try to develop a warning system to alert us when things were changing negatively.

The Outfall Monitoring Task Force concurred with the decision of "no jeopardy", based on current available information and model results, that there will not likely be a change in nutrients and thus phytoplankton and zooplankton production, that would negatively affect the food of the marine mammals. However, monitoring is necessary to assure that this prediction is true. We also hosted a nutrient workshop where we discussed worse case scenarios and how the monitoring program can be set up to address them before they ever occur. D. Dow pointed out that because of uncertainty with the "no jeopardy" decision, NMFS attached several conservation recommendations, one of which of led to the development of the Contingency Plan and associated thresholds.

S. Nixon thinks it is important to note that the data are made available to the public. Also, S. Mayo can in fact be considered a kind of modeler because he is quantitatively linking numbers together, determining budgets, food requirements and food availability, and modeling computations.

A. Solow thinks that the value of a food web model broadly construed is that it would inform the monitoring program, i.e. where to look for problems and effects. It would be great if we had a good predictive model, but he does not believe we are anywhere near that point, so the best we can do is monitor. As J. Pederson mentioned, the qualitative understanding of this system was used to design the monitoring program. He would like to hear if anyone thinks that this qualitative model has changed, and thus the monitoring program needs to be changed. However, that is separate from any decision to accept the food web model scope of work. He would like to try to have OMSAP reach closure on this, but leave questions about the monitoring program open. J. Shine thinks the first step is to make sure the monitoring program is collecting the right information in order to be able to determine whether there is a compelling reason to develop a full food web model.

T. Smayda asked whether OMSAP would reconsider a proposed monitoring program that had been prepared a few years ago, with several testable hypotheses. The proposed monitoring program was designed to attempt to nullify the hypotheses. A. Solow said he would reconsider that plan. However, he is sensitive to constantly coming back and "reinventing the wheel". J. Pederson agreed that we should look at any hypotheses that are brought before us but if we have already done so she would like to review the previous responses of the OMTF or OMSAP.

ACTION: S. Nixon moved that OMSAP recommend that EPA and MADEP accept MWRA's food web model scope of work statement, as having fulfilled the permit requirement for the scope of work. B. Beardsley seconded the motion. All OMSAP members voted in favor of this motion. A. Solow then invited the BCSAP to return with the proposal about modifications to the monitoring program to address these hypotheses and issues of concern.

S. Nixon agreed with J. Pederson in that many people have already spent a lot of time working on this problem. Changes to the monitoring program should be based on scientifically compelling arguments. There needs to be some burden of professional responsibility on those who want to come forward with a change in monitoring program. J. Pederson agreed and suggested that OMSAP perhaps develop some guidelines about how concerned parties should bring recommendations to revisions to the Outfall Monitoring Program before OMSAP, e.g. expected benefits of revisions, and background information. A. Solow agreed that we need to be careful when revising the monitoring. B. Beardsley agreed but thinks that OMSAP should continually encourage outside input.

J. Pederson described the process of developing and utilizing a monitoring program: ask questions, gather information, develop monitoring, obtain and analyze results, and determine if the questions are being answered. This process encourages people to come forward if they think the monitoring program is not doing its job. She suggested OMSAP review the book "Managing Troubling Waters" that describes this process and may help us define how we look at proposals to changes in the monitoring program. B. Beardsley wants this to remain an open process so that people can come forward with useful recommendations. He wants to avoid the Chesapeake Bay situation where there is a disconnect between the research, modeling, regulating, and advocacy communities. We should encourage imaginative ways of modifying the Outfall Monitoring Program to better look at the environment, always considering good science. A. Solow agreed. J. Pederson agreed and added that not only should it be "good science" but also follow the goals of MWRA's Outfall Monitoring Program.

S. Nixon asked how accessible the monitoring data are. M. Mickelson said that all data through 1999 are available on CD-ROM in Access format. J. Pederson pointed out that you can also request data from MWRA for a specific area and they will send it to you within a week. S. Nixon asked if the data are on the web. M. Mickelson replied no. S. Nixon pointed out that the Chesapeake Bay monitoring data are not readily available and cumbersome to use. A. Solow thinks MWRA's data are easily available. W. Leo added that MWRA focuses on providing synthesis reports on the web since that is what the majority of the people are interested in. Data are usually requested by graduate students and MWRA fills these requests on a routine basis. S. Nixon believes the interaction with the research community is an important and healthy. There should be a process for T. Smayda, for example, to obtain the phytoplankton and nutrient data for several stations without having to filter through the entire dataset. A. Rex said that all he has to do is call MWRA and we will send him whatever he needs.

T. Smayda asked why the last modeling year was 1994. C. Hunt replied that the MEG in 1995 requested 1993 and 1994 be modeled because there were interesting features in the monitoring data. MWRA stopped the modeling so the MEG could have the chance to review the results and provide recommendations on how to proceed.

Review of Thresholds: Nuisance Algae and PSP Toxicity

M. Mickelson described the three nuisance algae thresholds [see MWRA information briefing]. MWRA recommends changes to the way they calculate the thresholds for Phaeocystis, Alexandrium, and Pseudo-nitzschia and requests that they focus on a particular time of year for Phaeocystis and Alexandrium and whether the current use of non-zero years in calculations is appropriate. He would also like OMSAP to review the log-transformed Pseudo-nitzschia and Alexandrium calculations. M. Mickelson then described the various types of harmful algae.

Phaeocystis pouchetii is a nuisance species that can form dense gelatinous colonies and occurs between mid February and the end of April. The last major Phaeocystis bloom was in 1997 in Cape Cod Bay. He showed data from Cabell Davis' (WHOI) 1997 Video Plankton Recorder survey. High nitrate appears to increase Phaeocystis abundance. However, the MWRA discharge does not contain high enough nitrogen to stimulate Phaeocystis growth throughout Massachusetts Bay. Phaeocystis bloomed in 1992, 1994, and 1997. S. Mayo said that whale visitation to this area was down during those years, and M. Mickelson thinks we should examine this more carefully by examining the zooplankton.

The toxic pennate diatom Pseudo-nitzschia does not show evident patterns in seasonality for this species. One problem is that it is difficult to distinguish between the two species of Pseudo-nitzschia, P. multiseries (toxic) and P. pungens (non-toxic), and requires the use of a scanning electron microscope or molecular probes. A shellfish bed closure is initiated at 20 micrograms of domoic acid per gram of shellfish. The ratio of the two species varies and presence of the toxic P. multiseries appears to be transient.

The toxic dinoflagellate Alexandrium tamarense is found from Maine to about New York City. D. Dow asked what the standard is for shellfish toxicity. D. Anderson replied that 80 micrograms in 100 grams of shellfish meat is the threshold at which an area will be closed (this is twice the detection limit). Shellfish become dangerous for human consumption at levels 5-10 higher than the threshold.

M. Mickelson then showed a map of station locations and showed where MWRA has increased plankton sampling based on OMSAP recommendations at the February 2000 meeting. 200 plankton samples are taken per year. He recommended that MWRA's threshold calculation be based on a narrower period of time during the spring. The thresholds for all three nuisance species state that "the baseline seasonal mean shall not to exceed 95th percentile". The existing threshold wording involves the nearfield, but MWRA's statistician determined that it was better to use all of the baseline nearfield and farfield data in the calculations. However, he is not certain whether the entire dataset should be used during post-discharge. Another question is what season to use. MWRA has been considering dividing in the year into three seasons as opposed to four because it would better follow the natural biological season. This would change the way the 95th percentile is calculated.

There are two different approaches when responding to threshold exceedances, "urgent" versus "deliberate". With an urgent approach, if one sample were found to be very high, further monitoring and notification would be triggered quickly. The deliberate approach continues monitoring to see if the system changes over several years. He asked OMSAP which approach was best for the nuisance algal species.

D. Anderson pointed out that the only significant differences between the MWRA versus WHOI sampling programs are station locations and sampling frequency. MWRA samples once in the farfield and in the nearfield during the potential Alexandrium interval and WHOI samples every couple of weeks, but only during the season when Alexandrium occurs within the Bay – typically April through June. MWRA and WHOI data seem to have some comparability, however, since D. Anderson focuses on only Alexandrium, he is more efficient, capturing less "zero" data. R. Signell thinks there is no clear relationship between the MWRA and WHOI datasets. MWRA samples throughout the year but does not capture the extent of blooms and WHOI samples April to June. D. Anderson replied that they do not sample during other times of the year because the cells are either absent or present in very low abundances. M. Hickey added that the WHOI program targets sampling when the abundance is expected to he high.

B. Beardsley asked why there is such a big difference in abundances between the WHOI and MWRA sampling. D. Anderson replied by emphasizing the differences in station locations, sampling timing, and frequency. He thinks the differences in sampling methods are negligible. M. Mickelson thinks it would be worth looking further into the comparability of the two studies. He then explained how the 95th percentile is calculated for Pseudo-nitzschia, Phaeocystis, and Alexandrium. Years in which these species are not measured ("zero" years) are not used in the 95th percentile calculations. A. Solow cautioned MWRA to be careful when calculating the 95th percentile. He then pointed out the apparent annual trend in the Pseudo-nitzschia data, and that there do not appear to be random annual values that fit the normal distribution. He suggested this pattern be monitored.

M. Liebman asked what the minimum number of samples are needed to calculate the 95th percentile. M. Mickelson said this relates to power or confidence intervals and he does not have that information available today. The 95th percentile is 1.6 million cells per liter for Phaeocystis, 37,000 cells/L for Pseudo-nitzschia, and 10 cells/L for Alexandrium. Using the WHOI Alexandrium data, the 95th percentile is 71 cells/L. M. Mickelson then briefly described the Maine and Massachusetts paralytic shellfish (PSP) monitoring programs. The MWRA permit requires that MWRA develop two outfall contingency simulations: chlorination failure and red tide bloom, and describe responses to both of those types of emergencies.

M. Mickelson asked OMSAP if MWRA can focus on the seasons when the Phaeocystis and Alexandrium blooms occur. Seasonality was recommended at the 1996 OMTF workshop because MWRA had presented annual averages of nuisance species. The experts considered that to be a "dilution" since there were parts of the year when the species did not occur. He then asked OMSAP if it was acceptable to use only non-zero years for Phaeocystis and Alexandrium.

B. Beardsley does not think that the MWRA monitoring is capturing Alexandrium as well as WHOI. Perhaps Alexandrium exists in small numbers throughout the year. A. Solow asked if MWRA is concerned that with their data, the threshold is calculated as 10 cells/L and with WHOI data, the threshold is 70 cells/L. J. Pederson pointed out that the problems we always have in setting Contingency Plan thresholds are dependent on the amount of monitoring and long-term data comparability. Thus, as long as monitoring remains consistent for a certain suite of parameters, even if results are of no value outside of the program, as seen here with Alexandrium, it is acceptable, as long as the program remains consistent. The Contingency Plan is designed to use information from the monitoring program in order to determine whether conditions have changed in the bay enough to require action. Thus it does not matter that the MWRA and WHOI thresholds are different because the programs are designed differently. B. Beardsley agreed but thinks there is value in trying to figure out why the two programs have such different results. J. Pederson responded that if we really wanted to monitor for only Alexandrium, we are probably measuring in the wrong place. But if we wanted to monitor for Alexandrium to see whether or not the new outfall makes a difference, then we are monitoring in the right place. M. Mickelson pointed out that the threshold is set to signal a change in the natural state of the system between pre- and post-discharge years. A. Solow thinks that even though the MWRA and WHOI datasets are somewhat different, they still detected the 1993 bloom, and that is very important. He feels J. Pederson's point is that as long as the interest is in whether there has been a change rather than absolute numbers of Alexandrium, and as long as methods and sampling remain constant, the results are acceptable.

J. Shine noted that there appears to be a lot of variability within the year and thus there could be problems using the annual mean and not accounting for the annual variability. In addition, if annual data are used to calculate thresholds, if there is a problem, it will take a whole year to notice. M. Mickelson replied that the Contingency Plan blends the "urgent" and "deliberate" threshold-response approaches. However, coordinating with WHOI and notifying MADMF is something that could be done from a single high sample. The response to a single high sample should not be the retrofitting of the treatment plant. J. Shine thinks that it would be an indication that something was wrong if one sample was found to be much higher than all samples previously collected. In addition, if we rely on annual means as benchmarks, spikes in data would be diluted out. There has to be some acute benchmark level that is not diluted out by using means and including zeros. B. Beardsley supported J. Shine's comments. M. Mickelson said that if OMSAP has any ideas for better approaches, MWRA would research them. D. Dow asked whether the data with a lot of zero years were examined using any other statistical distribution in order to figure out the confidence intervals (around the means) so the zeros could be incorporated. K. Keay replied the data were examined using other methods, but that there was no standard distribution to which the data could be fit.

M. Liebman recommended that since there currently is no warning threshold for Alexandrium, to add one based on human health, similar to the PSP data results. M. Mickelson cautioned that a warning level has implications for MWRA response that may involve the preparation of a new engineering design.

M. Liebman thinks that in the case of Alexandrium and Pseudo-nitzschia, there should be some relationship between the levels measured and an actual impairment, i.e. some type of appropriate risk-based number. M. Mickelson replied that D. Anderson is working on this type of threshold with Alexandrium and will discuss preliminary results.

D. Anderson described progress on developing a method of deriving a threshold based on shellfish toxicity in the bay, based on the 30-year MA Division of Marine Fisheries dataset. He believes that the Alexandrium population that causes toxicity from Maine to Massachusetts Bay is largely derived from populations from the western coast of Maine that are transported to the south in a coastal current formed by outflow from the Kennebec and Androscoggin Rivers. Most years there is toxicity in southern Maine and northern Massachusetts but cells seldom enter the bay in sufficient numbers to bloom substantially and cause toxicity in the bay. In a sense there is a filtered delivery, i.e. most of the cells do not enter the bay and instead move along Stellwagen Bank and out to sea, such that the pattern of toxicity in the bay is sporadic. Alexandrium cells are dividing perhaps once every two days during the time of year when they are in this area. If they were stimulated by nutrients from the outfall, any effects would be expected to be seen downstream because of the mesoscale circulation through the bay.

R. Signell pointed out that USGS has been measuring currents for several years and has found that there is no preferred direction during any particular season near the outfall. Water that does make it out further east eventually joins the prevailing current. D. Anderson said that water movement in the nearfield is complicated, but at least the Alexandrium data suggest that the cells move towards the south, and grow slowly as they proceed along the South Shore.

A. Solow asked whether Phaeocystis is transported in the same direction. D. Anderson replied that we do not know but would expect that it is coming from the north and that there is not a large in situ population within the bay. T. Smayda believes that both are true – there are introduced species as well as local cohorts. A. Solow thinks this is an argument for measuring both north and south of the outfall. D. Anderson agreed and reminded the group that MWRA recently added two new plankton stations north of the outfall.

D. Anderson showed shellfish monitoring data in micrograms (ug) of saxitoxin per 100 g of shellfish meat. There was an interval in the 1980's with relatively high and frequent toxicity in the Bay. Since the large bloom in 1993, there has been almost no toxicity in subsequent years. Overall, there is very large inter-annual variability measured at the state MADMF's shellfish monitoring stations. Shellfish are great integrators of what has occurred in the water column during the past week. Thus zeros values in shellfish are better indicators that there are very few cells, if any. A single discrete seawater sample, such as those collected in the MWRA cruises, is only an indication of what is there at that point and that time.

D. Anderson feels we should worry if there is a large bloom after the outfall goes on-line. There needs to be an assessment of pre-outfall, long-term variability. His group was funded by Sea Grant to work with WHOI's Marine Policy Center to suggest thresholds based on the MADMF PSP toxin monitoring data. He then showed the MADMF stations that have been sampled since the first large bloom in this region in 1972. The team is trying to see if there is a useful pattern in these toxicity events, e.g. in bloom progression or magnitude. Data from the 1993 bloom suggests that as the bloom moves from north to south, toxicity levels decline. The same decrease was seen in the WHOI Alexandrium cell count data from several years.

D. Anderson then described how they are working on developing a threshold based on PSP. He showed a data plot of PSP data from Cohasset, Scituate, Marshfield, Plymouth, and Sandwich. Using the baseline data, conditional probabilities of toxicity at each station can be calculated based on observations of toxicity at "upstream" stations. D. Anderson's team is attempting to identify spatial and temporal patterns during the 30 years of monitoring to determine whether the pattern of post-relocation toxicity is significantly different. Most of the effort thus far has been aimed at identifying the pattern, later they will focus on the magnitude.

One preliminary conclusion is that the occurrence of significant toxicity in the northern stations appears to be a predictor of the occurrence of toxicity in the south, but this is dependent upon the size of the upstream blooms. Small blooms in the north are not often seen within the bay. On the other hand, large blooms and high toxicity north of Cape Ann frequently results in toxicity within the bay. There is also an overall tendency for the southern blooms to occur later than the blooms in the north, consistent with the transport theory. This suggests that post-relocation occurrence of toxicity at the seven southern stations without a prior bloom at the northern stations would be indicative of an outfall effect since there is no record of toxicity within the Bay without a bloom further north. Preliminary analysis also suggests that the magnitude of these blooms decreases southward. If this pattern holds, then another indicator of an outfall effect could be high toxicity at a southern station and low toxicity at the northern stations.

D. Anderson cautioned that these promising results and inferences are still preliminary. He feels very uncomfortable with the current MWRA cell count threshold. The PSP threshold being developed is based on 30 years' worth of data as opposed to seven years of spotty plankton monitoring data, making it more statistically defensible. However, this approach is not possible for Phaeocystis and Pseudo-nitzschia. For Alexandrium, thresholds based on the monitoring data should be reevaluated.

J. Fitzpatrick asked if he thought that the MWRA sampling program for the Alexandrium is insufficient. D. Anderson thinks it is insufficient to characterize the blooms of Alexandrium in Massachusetts Bay and to reveal significant change. However he also thinks that his WHOI program also does not sample frequently enough during the spring due to budget constraints, and there will be years with no WHOI sampling at all, again due to funding. However, he thinks the MWRA Phaeocystis and Pseudo-nitzschia monitoring can be useful.

R. Isaac asked why only data from 1980 to 1999 were used. D. Anderson replied that this is still a work in progress. C. Hunt thinks this effort makes a lot of sense but asked what if there is a more localized input, e.g. local groundwater or the Plymouth discharge influencing Alexandrium.

D. Anderson believes that the history of the data may help with this, unless another new source begins providing nutrient input, e.g. a new outfall in Plymouth. We are looking for a statistical difference above the baseline. However, one benefit of using this data is that the baseline period contains 30 years. He pointed out that the cells are often more abundant along the South Shore and this may be related to the nutrients being flushed out of Boston Harbor.

D. Dow asked whether storms affect the occurrence of Alexandrium and PSP in inshore shellfish. D. Anderson replied that they have not examined this carefully in Massachusetts Bay. They have examined how storms affect the rivers in Maine and it is clear that toxicity is related to heavy springtime rainfall and snow melt. OMSAP should decide whether or not nuisance species thresholds should be based on cell counts. At least for Alexandrium, the alternative may be a PSP toxicity threshold.

A. Solow asked D. Anderson if he had any ideas on how the monitoring program could be better used to shed some light on some of these unanswered questions. D. Anderson thinks since we do not have the resources to sample as many stations as we would like, one alternative is to use the rapid analysis cell counts that provide results in just a few days. Based on those observations, we can establish a trigger or threshold for the different harmful species that leads to further actions. For example, if a threshold were triggered by the rapid cell counts, a targeted cruise could be mounted to examine what is occurring "upstream" as a way of making the monitoring program for the nuisance species more proactive. For this to be effective, the turn-around time has to be quite fast for the rapid cell counts that are done in the MWRA program.

J. Turner described the differences between the toxic (P. multiseries) and non-toxic (P. pungens) species of Pseudo-nitzschia. P. multiseries produces domoic acid which can cause brain damage. Both look the same under light microscopy and in order to differentiate, shellfish tissue needs to be analyzed for domoic acid using HPLC or electron microscopy to count the number of intercostal poriods on the inner surface of the valve. P. pungens' poriods are 1-2 per row and P. multiseries are 3-4 in a row. In addition, there are molecular probes being developed by Don Anderson, Steve Bates, and Chris Scholin. P. multiseries and P. pungens do co-occur and the unofficial Canadian threshold at which high levels of toxicity begins to occur in shellfish is half a million cells per liter (total Pseudo-nitzschia). Don Anderson pointed out that the New Zealand monitoring program uses a value of 100,000 Pseudo-nitzschia cells per liter as a threshold to initiate shellfish flesh testing. This is quite a low value, and would be exceeded on many occasions in the Bay. The reason New Zealand has adopted such a conservative approach is that their shellfish industry is large and thus vulnerable to toxicity outbreaks.

J. Turner recently analyzed August 1998 samples from Boston Harbor. Stations F24 had values at the fluorescence maximum of ~445,000 cells per liter and the highest value at F31 was ~650,000 cells per liter in the surface waters. He examined the Pseudo-nitzschia samples under scanning electron microscope (SEM) and P. multiseries was found in the samples. However, determining the ratio of P. multiseries to P. pungens using SEM is very time-consuming. M. Liebman asked which species of Pseudo-nitzschia dominate during blooms. J. Turner replied that P. multiseries dominated the Canadian bloom, however we cannot generalize this finding for other areas. R. Isaac asked whether it would be quicker to run HPLC than trying to count the poroids on a recently collected sample. J. Turner replied that the sampling protocol is not geared towards preparing samples for reliable and detectable HPLC measurements. A larger volume of sample would have to be screened in order to detect domoic acid using this method. M. Mickelson added that perhaps the molecular probes under development will be helpful in the future.

D. Dow asked whether there have been any studies on what nutrient ratios favor P. multiseries verses P. pungens. J. Turner replied that Steve Bates has found that starving P. multiseries for silicate will make them more toxic.

D. Anderson asked M. Hickey what MADMF does with respect to monitoring for amnesic shellfish poisoning (ASP) toxins. M. Hickey replied that they have monitored for ASP periodically as part of the phytoplankton monitoring program, but that it is not routine.

M. Mickelson pointed out that MWRA notifies MADMF once rapid samples are analyzed. He asked OMSAP for feedback on how MWRA is doing regarding nuisance algal species monitoring. For example, should D. Anderson continue to pursue the PSP threshold development, and should the Alexandrium cell count threshold be kept. A. Solow thinks the current Alexandrium cell count threshold should be deleted.

J. Schwartz stated that MADMF is not in a position to comment on changes to the Alexandrium threshold until they receive feedback from their shellfish team. M. Mickelson said that if there is a high level of Alexandrium detected, MWRA would still have to go through the procedures outlined in the outfall contingency simulation. He asked if MWRA may still proceed with this without an Alexandrium threshold. G. Renick replied that the simulation would have to be conducted in response to what the permit requires but there could certainly be a recommendation from OMSAP that the cell count-based threshold be removed. However, MWRA does not have a mechanism on how to be relieved from the permit requirement. J. Schwartz would like to know if the simulation and existence of a threshold could be decoupled. M. Mickelson thinks they may be decoupled.

ACTION: S. Nixon put forth a motion. He believes that there is convincing evidence that Alexandrium is extremely variable and patchy in terms of occurrence. It is unclear whether it is more important to document abundances in areas where it is found infrequently or where it has never been found. Given all of these uncertainties, and the fact that there is a better, more integrated measure, being developed, OMSAP's recommendation should be to drop the current Alexandrium cell count threshold and wait to evaluate the new PSP threshold being developed by D. Anderson that uses the long term shellfish monitoring. He does not believe that there is value in the current Alexandrium cell count threshold and moved that OMSAP recommend that MWRA delete this threshold. All OMSAP members voted in favor of this recommendation.

M. Mickelson asked how OMSAP felt about the Phaeocystis and Pseudo-nitzschia thresholds. He believes that MWRA is sampling Pseudo-nitzschia well and there is a pretty good understanding of its baseline distributions. He asked whether or not MWRA should continue to work towards this confirmation procedure at high levels.

J. Schwartz asked whether MWRA will recommend revisions, and re-visitation with the group that developed the draft plan, of the draft outfall contingency simulation plan that includes the Alexandrium threshold based on the discussions from today's meeting. M. Mickelson replied yes, when the improved toxicity threshold is developed, the draft plan should be revised.

A. Solow asked whether the simulation can be drafted, i.e. procedures in the event of an emergency, without having the threshold explicitly included. K. Keay replied that the permit requires MWRA to simulate the two emergency situations. During the development of the draft simulation plan, MWRA learned of the provisional nature of the PSP incidence threshold in the permit and thus made the decision to instead use the Alexandrium cell count concentration threshold. Any revisions to thresholds in the draft plan should require revisitation by the group that developed the draft plan.

M. Mickelson asked OMSAP whether MWRA should continue with the log-normal 95th percentile with the Pseudo-nitzschia threshold. A. Solow did not want to vote on this yet but felt that MWRA should keep on the same track and report to OMSAP again in the future. M. Mickelson asked OMSAP whether MWRA should continue calculating thresholds using the three-season year approach – the only difference is using the log normal. OMSAP thought this approach was appropriate.

J. Pederson pointed out that a recent Phaeocystis blooms began in Narragansett and Buzzards Bays and southeastern Cape Cod Bay and never proceeded further north. She wondered if this was factored in the calculations. C. Hunt replied that if a high count of Phaeocystis is measured, then MWRA will try to interpret where the bloom came from. T. Smayda added that Phaeocystis blooms on a regional scale, blooms occur synchronously over 300-400 km of coast. J. Pederson wondered how a threshold can be developed relating Phaeocystis to the outfall.

M. Mickelson asked if it would be possible to look at whether a bloom is locally higher than expected but on a regional basis. Since MWRA is not monitoring the entire region, the monitoring must be compared to baseline which leads to calculating the 95th percentile taking into account zero-observance years. A. Solow thinks that would not be difficult to do. M. Mickelson asked if MWRA can focus on the season when a nuisance species occurs. A. Solow asked whether an indication of impact could be observance of a bloom during a season when it is not normally observed. M. Mickelson replied that MWRA will work on this.

S. Nixon asked T. Smayda about the observance in the North Sea that one of the main indicators of change was an increase in duration of a Phaeocystis bloom. T. Smayda said that was correct and that the duration of blooms is increasing in this region. There appears to be a threshold with respect to the availability of the silica. Once the diatoms take up the silica, there is still excess nitrogen and phosphorus allowing Phaeocystis to out-compete other plankton species. Light may also be an important factor. M. Mickelson thinks MWRA should look further into this threshold and attempt to consider those things, perhaps examining seasons when Alexandrium is not normally present and it could be an indication of an outfall change if it becomes abundant during the other seasons.

D. Anderson said that the Phaeocystis threshold used in some parts of Europe is one million cells per liter based on two scientific papers. He suggested we poll our international colleagues to see what the levels of concern are in other parts of the world. S. Nixon thinks that would be very reasonable. J. Shine pointed out that would be a benchmark of ecological concern rather than a statistical threshold based on monitoring results.

T. Smayda wondered whether there is a corporate memory within the system that remembers changes to the Outfall Monitoring Program to recognize what is a refinement, an improvement, an enhancement, and what may be a dilution. The Cape Cod Commission believes that over time there has been a dilution of expectation and effort consistent with the objectives of the program. A. Solow replied Judy Pederson is OMSAP's "historian". C. Hunt added that there are a number of MWRA reports that have addressed concerns as well as OMTF/OMSAP minutes.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • OMSAP/IAAC/PIAC membership lists
  • February 2000 OMSAP minutes
  • Cape Cod Commission food web model information briefing
  • MWRA nuisance algal bloom information briefing
  • Copies of MWRA Presentation Transparencies

OMSAP Meeting, Wednesday, February 23, 2000,
10:00 AM - 2:00 PM
EPA Boston
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Robert Beardsley, WHOI; Judy Pederson, MIT/Sea Grant; Bill Robinson, UMass Boston; and Jim Shine, Harvard School of Public Health.

Observers: Margaret Callanan, Cape Cod Commission; Cathy Coniaris, OMSAP staff; Mike Delaney, MWRA; Brian Ellis, Technology Planning and Management Corp.; Gillian Grossman, Save the Harbor/Save the Bay; Carlton Hunt, Battelle; Mike Hill, EPA; Russell Isaac, MADEP; Ken Keay, MWRA; Christian Krahforst, MCZM; Wendy Leo, MWRA; Matt Liebman, EPA; Steve Lipman, MADEP; Mike Mickelson, MWRA; Bill Ravanesi, Healthcare Without Harm; Susan Redlich, WAC; Virginia Renick, MWRA; Andrea Rex, MWRA; Larry Schafer, retired; Jack Schwartz, MADMF; Dave Taylor, MWRA; Sal Testaverde, NMFS; Dave Tomey, EPA; Heather Trulli, Battelle; Steve Tucker, Cape Cod Commission/Bays Legal Fund; and Jeff Turner, UMass Dartmouth.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. A clarification of the definition of the zone of initial dilution was added to the March 1999 minutes by Dave Tomey (EPA) and the minutes were approved as amended.
  2. The Model Evaluation Group is currently drafting their final report to OMSAP. Representatives from MADEP and EPA were asked to discuss whether the models would be useful management tools for other Massachusetts coastal discharges at an upcoming OMSAP meeting.
  3. OMSAP does not support the current narrative zooplankton threshold as it is currently formulated and recommends its deletion from the Contingency Plan. However, OMSAP believes that continued zooplankton monitoring is extremely important and requests that MWRA present a plan to OMSAP on how to analyze the zooplankton data using a system-wide approach.
  4. OMSAP believes that the current measurements of sludge and scum removed by the Deer Island Treatment Plant (DITP) as well as FOG (fats, oils, and grease) measurements in the treated effluent adequately address the NPDES permit requirements for aesthetics. OMSAP recommends that MWRA delete the current floatables threshold in the Contingency Plan. OMSAP is requesting that MWRA report the sludge, scum, and FOG measurements in the annual Outfall Monitoring Overview; that MWRA address concerns regarding floatables if there is an adverse DITP event; and that MWRA "fingerprint" the floatables from the DITP in a special study

FINAL MINUTES

MARCH 1999 MINUTES
D. Tomey pointed out that the definition of the zone of initial dilution (ZID) mentioned in the plume tracking section of the March 1999 minutes is from the 301h regulations and is defined in terms of water depth. EPA instead defined the ZID as the "edge of hydraulic mixing" in the Environmental Impact Statement for the new outfall since in this case, the classic 301h definition does not apply. The EPA definition is implicit in the ULINE model. M. Mickelson stated that MWRA would like to know if this is a significant issue since they are preparing the plume tracking work plan. For the ULINE modeling, Roberts et al. (1989) used a 52.5 meter scale for the physical model and MWRA is utilizing 60 meters for plume tracking. D. Tomey replied that though initial mixing was evaluated in the EIS, the size of the mixing zone was only approximated.

B. Robinson asked what the extent of the change in ZID would be seasonally using the EPA definition. D. Tomey responded that it could change based on flow but that using the 301h definition gives a static value. He mentioned this because he wanted to make sure the group was not thinking about the static 301h definition for the purpose of the plume tracking. Using the EPA definition, the extent of the ZID is somewhat dynamic and varies, possibly hourly, due to changes in flow.

W. Leo also pointed out that the EIS definition allows for a ZID calculation that takes changes in dilution into account. She asked whether changing the term "ZID" to "mixing zone" would clarify this issue in the minutes. D. Tomey stated that EPA used the term "initial mixing" instead of "mixing zone". M. Liebman added that since the term "ZID" was used at the March 1999 meeting, it should remain in the minutes. OMSAP agreed that a clarification of the "ZID" definition be added as a post-meeting update to the March 22, 1999 OMSAP minutes. OMSAP approved the March 1999 minutes as amended.

ACTION: The following post-meeting comment will be added to the March 22, 1999 minutes: [UPDATE: Here is a clarification of the ZID definition provided by Dave Tomey. The permit had a different definition of the mixing zone than the outfall EIR/EIS. The size of the mixing zone for the permit was not determined based on a simple depth factor, as used in the Section 301 (h) definition and implied in the March 1999 OMSAP minutes. The Fact Sheet of the MWRA permit stated: "The draft permit limitations are based on the most restrictive type of mixing zone, the area of hydraulic initial dilution, called the zone of initial dilution. For the draft permit, that area is expected to occur at approximately 60 meters (197 feet) away from the diffuser outfall, and that determination incorporated only the most conservative (i.e., 'worst case') conditions of the receiving water and discharge flow." (Note: this applies to the final permit as well as the draft). The MWRA Facilities Plan/EIR and the EPA EIS, which predated the permit, assumed a dynamic mixing zone. Both agencies agreed to define the mixing zone as a dynamic edge of hydraulic mixing, which, in reality, would vary with flow and ambient currents. The permit, on the other hand, needed a more definable area for developing a practical compliance strategy. Worst case conditions and the results of Roberts' modeling were used to delineate the permit mixing zone with the dimensions of 52.5 m in any horizontal direction from diffuser axis. (This was expanded to be about 60 m which happens to be about 2 times the depth.)

Although this distinction is not major issue, it is important to clarify the mixing zone in the context of the proposed plume tracking study. The primary objective of the study is to verify the dilution and immediate dispersion of the effluent plume as modeled in the EIR/EIS and subsequent analyses under the conditions present during the study. It will be important to find the dynamic hydraulic mixing zone first to verify the modeled dilution at that point. Then the study will follow the advection of the plume in the farfield to about 500:1 dilution after semi-steady state conditions are achieved. Whether the zone is completely encompassed within the 60 m box is only of secondary concern since the study is only a snapshot of mixing under the particular conditions of flow, ambient current and wind at the time of the study.]

MERCURY IN EFFLUENT
A. Solow informed the group that a question has arisen about MWRA’s request to change the mercury standard. M. Delaney briefly described MWRA’s industrial pretreatment program that regulates industrial discharges into the sewer system. Within this program, MWRA reviews the local limits every five years and this process, which involves public comment, is currently underway. MWRA is considering a revision to the mercury local limits. Currently MWRA prohibits mercury discharge and the action limit is 1 ppb or 1 ug/L. MWRA is planning to propose a limit of 4 ppb or 4 ug/L using calculations that consider the mercury levels in fertilizer pellets. The 4 ug/L industrial local limit standard would be adequate to safely meet the pellet limit. MWRA ENQUAD is still considering whether this is an OMSAP issue since there is no mercury limit in the final NPDES permit. Also, MWRA does not envision that this would cause a change to the Outfall Monitoring Program. At some point during the public comment period, or when MWRA submits their plan to EPA, the issue could be referred to OMSAP for review.

B. Ravanesi asked how MWRA TRAC [Toxic Reduction and Control Department] developed the proposed 4 ppb limit. He thought that OMSAP would be one of the first groups to review any such proposals. There is a lot of controversy over this proposal and he thinks it is being driven by a few non-compliant hospitals. A. Rex argued that MWRA does not have a vested interest in the limit, however it must be defensible. MWRA used an EPA-approved model to calculate this new proposed limit. B. Ravanesi feels that the calculation is not health-based. A. Rex pointed out that the main source of mercury in finfish and shellfish is atmospheric, not the MWRA effluent. B. Ravanesi said that mercury levels are increasing in flounder [from: Mike Moore, OMSAP Workshop presentation September 1999, Mercury data in nearfield flounder tissue and liver 1997-1999].

S. Testaverde requested that MWRA give a presentation at a future OMSAP meeting on the TRAC Department. He also would like to know what other thresholds could be revised using this particular pathway. A. Solow said that this could be addressed at a future meeting. S. Redlich suggested that MWRA provide information to the group by the end of the meeting about the public comment period and the steps involved with this proposed revision. She does not think that the Board of Directors have released these proposed limits yet and there are at least two public comment periods before the proposal is voted upon by the Board.

S. Testaverde suggested that OMSAP obtain the minutes or upcoming agendas of the MWRA Board of Directors meetings. A. Solow said that OMSAP will consider this. M. Delaney stated that this issue will be discussed at the March Board meeting, and the proposed revision to the mercury local limit has not been approved by them yet. If they decide on a local limit revision, the due review process (which includes public participation), takes about a year. A. Solow thanked B. Ravanesi for bringing this issue to OMSAP’s attention and said that they will wait to see what the next step is. [UPDATE: the MWRA Board of Directors is no longer considering a revision to the local limit for mercury.]

MODEL EVALUATION GROUP (MEG) UPDATE
B. Beardsley updated the group on progress of the MEG in evaluating the Bays Eutrophication Model (BEM). In March 1999, OMSAP decided to form a Bays Eutrophication model evaluation group. Members are: B. Beardsley (chair), Eric Adams, Jeff Cornwell, Don Harleman, Jack Kelly, Jay O’Reilly, and John Paul. The group had an open meeting in December at Woods Hole to review the model results of the 1992-1994 runs, discuss baseline monitoring features, and discuss revisions and the future of the model. The group is currently in the process of writing a final report for submittal to OMSAP. It will be a brief report containing an introduction, summary, general recommendations on how to improve the model, and recommendations for additions to the BEM report. There will also be recommendations on how to improve the Outfall Monitoring Program boundary sampling. S. Redlich asked if the model is being used, and if so, how actively. B. Beardsley replied that the model has been run for the 1992-1994 period. M. Mickelson added that future use of the model is on hold pending the advice of the MEG.

J. Pederson believes that one important issue is finding a permanent home for the model so that it may be used for other coastal outfalls in Massachusetts. She asked whether MEG addressed this at their meeting. B. Beardsley said that the group did have some discussion on a future home but did not have a chance to discuss its possible use with other outfalls. He reminded everyone that there are two models involved, the Hydrodynamic (HD) Model (USGS) and the Water Quality (WQ) Model (HydroQual). The MEG has not reached a clear consensus on a home for the models but the group agrees that model results are useful in the planning process and that they should be continued. The MEG is not endorsing the current model until several revisions are undertaken, and thinks that this kind of effort is important to continue, thus the issue of a permanent home for the model needs to be discussed.

M. Liebman asked how the models are actually run. B. Beardsley briefly explained that the HD model uses real data (atmospheric forcing, winds, fluxes, etc.) to calculate the velocity field and stratification. The WQ model uses that information to help calculate phytoplankton abundance, dissolved oxygen, nutrient concentrations, and other water quality parameters. The two models are not necessarily coupled but it is clear that the physics need to be accurate in order to successfully reproduce the biology. Running the models requires a lot of data and effort. It can take several months to run a single year of just the HD model. Running the models involves collecting all available data, running the physical model, and comparing results with actual data. Results then go into the biological model. Once the model is run, results are compared in detail with field observations and shortcomings are identified. For example, there was a significant fall bloom in 1993 that was not captured in the model and it was determined that the mix of phytoplankton in the model was not correct. The model can then be used to simulate various outfall scenarios. Interannual simulations and comparisons build confidence in the model and show where the are weaknesses. There is a similar model being run the Chesapeake Bay that is also being evaluated. C. Hunt added that the lag in the field data used in the HD model results from the lack of available Gulf of Maine (GOM) data, rather than Massachusetts Bay data, since the GOM is the major force driving the hydrodynamics in Massachusetts Bay.

J. Pederson feels that there are two issues: (1) what research would make the model better and (2) what should be the responsibility of MWRA and what might be another agency’s responsibility. The state and EPA should look at whether these models can be used to address other issues. She suggested that at the next meeting, the state and EPA give OMSAP an idea as to whether they are valuable in terms of other regulatory issues. USGS is more interested in refining their model, not running “what if” scenarios. Even if the models move to a university or another agency, the state should definitely support some effort towards the runs and use them to try to answer some questions. B. Beardsley feels that it is not clear whether the HD model should move from USGS since it requires a lot of work to set up. J. Pederson agreed but thinks there should be some feedback directly from the state. A. Solow agreed with J. Pederson’s suggestion and requested that it be added to the March agenda.

ACTION: The Model Evaluation Group is currently drafting their final report to OMSAP. Representatives from MADEP and EPA were asked to discuss whether the models would be useful management tools for other Massachusetts coastal discharges at an upcoming OMSAP meeting.

ZOOPLANKTON THRESHOLD REVIEW
M. Mickelson showed a map of plankton monitoring stations in the nearfield and farfield, which includes Boston Harbor, Massachusetts Bay, and Cape Cod Bay. He showed data on zooplankton from 1992 to September 1999 and pointed out that it is not easy to discern patterns in the data since there are so many species as well as stages of each species. MWRA is particularly interested in certain copepods since they are the prey of right whales. Several years ago, the Outfall Monitoring Task Force asked that MWRA attempt to develop a zooplankton threshold. MWRA has since made two attempts at developing such a threshold. The first, which is included in the Contingency Plan, is called the Acartia hypothesis and concerns a “shift towards an inshore community”. Acartia hudsonica and Acartia tonsa are common in the inshore, but not offshore where several species of copepods and Oithona are numerically dominant. Species known to be prime whale food are Calanus finmarchicus and Pseudocalanus newmani, although they also feed on other zooplankton species. Stormy Mayo has found that though Oithona are smaller, and can pass through baleen, they can still be eaten with a 30% filtering efficiency.

The average harbor salinity is about 30-31 parts per thousand (ppt) and the nearfield is slightly more saline (31-32 ppt). When the outfall is relocated, the salinity of the harbor may increase by only about a half a part per thousand since there are also other sources of freshwater to the harbor. When the Acartia hypothesis was originally developed, it was thought to be a good eutrophication threshold since it was believed that the limiting growth factor was a high concentration of nutrients. Further research into the literature has shown that Acartia is instead limited by salinity, thus MWRA began to question whether this is an appropriate threshold since the new outfall will not significantly change the salinity in Massachusetts Bay. Because of this problem, MWRA then looked for another hypothesis.

D. Tomey asked whether Acartia has ever been dominant in Cape Cod Bay. J. Turner replied that Acartia has been found there, but never in high abundances. D. Tomey asked whether Acartia reproduction is limited to areas with lower salinities, such as inshore areas. J. Turner replied yes, and that his experiments during the mid-1980’s in Beaufort NC examined this hypothesis. Key to the inshore distribution of Acartia tonsa is the fact that the nauplii do not develop past stage N3 if the salinity is greater than 20-25 ppt. Optimum temperature is approximately 20 degrees Celsius, which is why they are mainly found in this area during the summer months. A few adults and late stage copedodites can be found in Cape Cod Bay and are probably being washed out of nearshore embayments. J. Pederson pointed out that M. Mickelson showed that the salinities in Boston Harbor do not reach as low as 25 ppt very often so Acartia must be developing near the rivers. J. Turner thinks that the nauplii are developing further upstream in the harbor and the adults or late stage copepodites are washed out to the nearfield, but not in any large numbers.

M. Mickelson then described the second potential zooplankton threshold MWRA has been developing – an oceanic hypothesis in which the winter/spring mean abundance of the five species (Calanus finmarchicus, and others) would not decrease substantially below the 5th percentile of the existing baseline abundances. MWRA had its statistician examine the data to determine the 5th percentile. M. Mickelson pointed out that if there was an exceedance of the threshold, MWRA would notify OMSAP and the regulators, post the information on the Internet, as part of the Contingency Plan procedures.

M. Mickelson showed results from C. Hunt’s presentation at the September 1999 OMSAP workshop that showed regional analyses of zooplankton abundances in several zones: offshore, boundary, coastal, harbor, and Cape Cod Bay. Results show dramatic differences among the regions, thus the 95th percentile does not appear to be a very sensitive indicator. There is also a conceptual problem with this new threshold in describing how eutrophication would lead to a decrease in zooplankton species of interest. MWRA is seeking OMSAP guidance as to the next step. Should there be some other threshold, or no threshold with continued data analyses.

D. Tomey asked why the hypothesis should be limited to the nearfield. M. Mickelson replied that MWRA focuses on the nearfield for most of the thresholds because this is where impacts would most likely be observed. D. Tomey thinks that since the zooplankton community is driven by what is entering the system from the boundary and is transported into Cape Cod Bay (where the residence time is higher, increasing the chance of a response), the threshold should focus there. M. Mickelson agreed that the system is much like a conveyor belt, or “river” and the species in the nearfield are very much reflected by what is entering from the Gulf of Maine. The question is whether MWRA is somehow “dosing” this “river” and will there be an effect on the zooplankton appearing further “downstream”. MWRA will continue to monitor the Cape Cod Bay stations for changes. C. Hunt added that all modeling results indicate that the amount of nutrients from the outfall are perhaps 10%, a relatively small fraction, of what is entering from the Gulf of Maine. So the assumption is that this 10% increase will somehow have a major impact to the zooplankton downstream in Cape Cod Bay. He questions whether this will in fact occur. W. Leo also pointed out that it is important to note that MWRA will not be discharging greater amounts of nutrients with the new outfall.

A. Solow replied that MWRA will continue to monitor in Cape Cod Bay. The question is whether there is some sensible and specific threshold. What would be interesting would be to compare what is entering the nearfield from the Gulf of Maine with what is seen in Cape Cod Bay in order to put this in a regional context. If changes in Cape Cod Bay were in fact due merely to variations with the input along the “conveyor belt”, it would not cause alarm about the outfall. J. Pederson asked A. Solow how the variability in the system should be approached. She is concerned that a specific threshold would not be meaningful due to natural variations in species compositions over time. A. Solow said that he does not necessarily think that there should be a zooplankton threshold but that zooplankton monitoring should definitely be continued.

J. Shine asked how the 5th percentile value was chosen. M. Mickelson replied that it is fit it to a distribution. D. Tomey asked whether the data are normally distributed. M. Mickelson replied yes, the annual means are normally distributed. K. Keay added that January to May (spring annual mean) was plotted. Five of seven individual annual means were normally distributed for nearfield samples. The 5th percentile assumes a normal distribution. B. Beardsley asked whether there are differences between Cape Cod Bay and the nearfield. K. Keay replied that a set of summaries has not been completed for the Cape Cod Bay stations. C. Hunt added that the entire farfield was compared to the nearfield set of zooplankton data and there is no significant difference between the two data sets. The entire farfield was examined, without separating Cape Cod Bay. M. Mickelson asked OMSAP what they would like MWRA to do next.

J. Shine asked that given the variability in the data, and the fit to the distribution for the 5th percentile, the threshold must be an incredibly low number. M. Mickelson replied that it is about 2400 animals per cubic meter. J. Shine asked whether there should there be some kind of benchmark above that number which could be considered a low value. M. Mickelson said about 4000 animals per cubic meter is a number determined by Stormy Mayo. S. Testaverde added that the value at which a whale stops feeding is about 3800 animals per cubic meter or less. A. Solow added that whales do not eat the “mean”, they eat the patches which is the 95th percentile.

A. Rex stated that MWRA is proposing to remove the zooplankton threshold from the Contingency Plan but will continue to collect zooplankton data and conduct detailed data analyses and presentations for OMSAP since MWRA has not been able to develop a threshold that makes biological sense. MWRA requests OMSAP comment on this proposal.

S. Testaverde asked how many whales were seen by the surveys during that period in the nearfield. C. Hunt replied less than 10 have been seen during the Battelle surveys; it is relatively rare to see them and there is no data on how long the whales remain in the nearfield. S. Testaverde asked why MWRA is suggesting lowering thresholds before going on-line and why MWRA cannot wait until there is at least one year of post-discharge data. J. Pederson replied that the concern is having a threshold for zooplankton which is so variable. Everyone knew from the beginning that it would not be possible to collect enough samples to give a full picture and she thinks to try to set a threshold in the absence of sufficient data is irresponsible. However, monitoring should continue and perhaps there are other ways of determining whether or not there is a problem. She, at this point, feels strongly that from a biological perspective, this data is so variable that she is hesitant to set a threshold. J. Shine thinks that there is a lot of data, just that it is stochastic and so variable, that in order to see a significant change, meaningful change is missed due to the underlying variability. This variability cannot be reduced, no matter how many samples are collected.

A. Solow asked S. Testaverde why there should be thresholds that do not make sense scientifically. S. Testaverde replied that the thresholds went to public comment and were approved. He is concerned that thresholds will be changed without full public review and post-discharge information. G. Renick clarified that OMSAP does not have the authority to make threshold changes. OMSAP recommendations will go through the permit procedures that include public comment before they become final changes in the Contingency Plan. Even though the permit and outfall start-up have been delayed, OMSAP needs to be looking at data to figure out what makes sense and whether there are changes that could be recommended. However, any changes do not become final until there is the opportunity under the permit to make formal recommendations to EPA and MADEP and have public comment. This is not intended in any way to be a runaround to full public participation at the appropriate time and with the appropriate procedures. A. Solow believes that this is a good point. He thinks that the argument against the Acartia hypothesis threshold, even though the outfall is not operational, makes good scientific sense. He agreed with the other OMSAP members. OMSAP has not heard a logical scientific argument about what kind change they should be looking for, so it seems appropriate to keep the options open. There should be the flexibility to look at these data and be able to say that something else seems to be going on here that is worth a careful look. We do not want to fixate on a threshold that we do not have confidence in. He would support dropping the zooplankton threshold as long as OMSAP continues to have the opportunity to review these data.

B. Robinson asked whether it would be possible to develop a threshold on distribution/predominance of zooplankton instead of change in community structure. J. Turner thinks that since MWRA will continue to monitor, changes in distribution/predominance would be seen. The problem is interpreting what might have caused any changes. B. Robinson thinks that having a zooplankton threshold is a way of giving OMSAP the option of becoming involved if there is a problem in the future. However, there should only be a threshold if it makes scientific sense.

B. Beardsley feels that since there is such interannual variability in the biology, he would be uncomfortable setting a threshold. Even if there was a community structure threshold, data would have to be examined for at least several years in order to see if the change was significant. He thinks that it would be more worthwhile to instead try to refine the analysis on the monitoring data and perhaps instead of looking at the nearshore, examine variability at F26 and F27 (outer boundary) and track changes throughout the year. This would be something like the “state of the ecology” for the year. This information would give OMSAP a better sense of what the variability is.

R. Isaac thinks that from a regulatory standpoint, it would be important to acknowledge that any changes in the threshold are based on scientific information that was not available when the original threshold was developed in order to make a reversal scientifically sound. A. Solow asked when the threshold was submitted. M. Mickelson replied that it is in the Contingency Plan dated November 1997. J. Pederson did not think that the Outfall Monitoring Task Force approved the Acartia hypothesis threshold during the permitting process, and because it was in the Contingency Plan, it was accepted as part of the permit without full scientific review. R. Isaac thinks that it is important to present that in the final OMSAP recommendations to EPA/MADEP. D. Tomey added that the 5th percentile threshold (decrease in whale prey) is only a proposal. The Acartia hypothesis (a qualitative shift from an offshore to inshore community) threshold is the one included in the Contingency Plan as part of the permit.

A. Solow pointed out that even if OMSAP recommends deleting this threshold, that there will always be the option to develop a threshold in the future as new information and knowledge arises. He made the motion to remove the current zooplankton threshold, acknowledging that continued zooplankton monitoring is extremely important. B. Beardsley added that OMSAP should also recommend that since the Massachusetts Bays system is “flow-through” system, MWRA develop a method of analyzing the current data spatially and temporally in order to better contrast differences between the nearfield and Cape Cod Bay. A. Rex suggested that OMSAP request that MWRA develop a plan for OMSAP approval for analyzing the data. A. Solow agreed with B. Beardsley and A. Rex and emphasized that if one examined the difference between the boundary stations and the other stations, some of this variability will disappear, i.e. “differencing” stations will reduce variability and changes over time may be better discerned. Or, MWRA could also come forward to OMSAP and propose a better way of looking at the data.

A. Solow asked all in favor of the motion. OMSAP members unanimously approved of the motion. J. Schwartz asked what the motion reads as. A. Solow repeated the motion. ACTION: OMSAP does not support the current narrative zooplankton threshold as it is currently formulated and recommends its deletion from the Contingency Plan. However, OMSAP believes that continued zooplankton monitoring is extremely important and requests that MWRA present a plan to OMSAP on how to analyze the zooplankton data using a system-wide approach.

FLOATABLES THRESHOLD REVIEW
M. Mickelson described the floatables collection devices at the Deer Island Treatment Plant (DITP). The Contingency Plan threshold for floatables is: “floatables shall not exceed 5 gallons/day in the final collections device.” However, the way the DITP was designed, it has turned out to be impracticable to sample the final collections device. He described the other measures which can give confidence that the floatables problem is being efficiently addressed, as well as a description of floatables nearfield sampling [see information briefing dated February 23, 2000]. MWRA has other measurements of plant performance such as sludge and scum removal, and fats, oil, and grease (FOG) effluent concentrations. The treatment plant is very efficient at removing these as long as it is functioning properly. They are measured daily in primary treatment and reported in the monthly discharge report, and will eventually be posted on the Internet. The DITP is very effective at removing FOG and concentrations approach the 7 mg/L detection limit. Continued in-plant efficiency of the removal of sludge, scum and FOG is a surrogate measure of plant performance and implies that floatables are not discharged. The field program has also begun testing another type of sampling that involves dragging a net (two meters wide, 1 mm mesh size) over a measured distance between stations to capture floatables. This has been done by H. Trulli (Battelle) for EPA and there is an established sampling approach for this method.

L. Schafer thinks the whole issue of floatables is largely an aesthetic one and is not directly concerned with plant operations. He thinks that one of the biggest areas of vulnerability of the Outfall Monitoring Program is public perception – if there was something accumulating aesthetically in the bay, the danger is that the Authority will be blamed for it, regardless of the source. He suggests starting a sampling program that looks at the condition of the surface waters before the outfall goes on-line. He understands that floatables in the nearfield are not necessarily from the DITP but he thinks it is important that MWRA at least measure it. Upsets do occur at treatment plants and the Authority should have a well defined position so that they are able to state that floatables in the environment are not due to any upset at the DITP. He thinks that as long are there is surface water sampling, that monitoring at the plant is unnecessary. S. Lipman pointed out that most of the floatables are from stormwater drains, not from the DITP. He is not sure how sampling in the bay or harbor will give any relation to plant operations. Results from the MWRA, EPA, and MADEP floatables/CSO program show that clearly. L. Schafer agreed that there probably is no relationship but he thinks there should be some baseline data before the outfall goes on-line in order to compare pre- and post-discharge conditions. S. Lipman doubts there is a relationship.

B. Robinson asked whether the scum and sludge measurements include a high percentage of water. M. Mickelson replied that there is a fair amount of water in the samples but the results are more a measure of plant performance. C. Hunt pointed out that MWRA also quantifies how much debris is captured in the screenings. M. Mickelson added that this information is reported in the monthly discharge report and the units are “tons per day”.

H. Trulli described the field sampling methods. Battelle is using a similar sampling protocol to the EPA headquarters program that studied 20 harbors. A net is deployed on the surface in transit between two stations and an estimate of sampled surface area is made. S. Testaverde asked how many gallons of water that represents. H. Trulli replied that they are not estimating volumes since the net skims the surface, not completely submersed. S. Testaverde thinks that calculating a gallon estimate is possible and would be useful for comparison to the volume being discharged by the outfall. M. Mickelson said that they could do that but would also have to factor in dilution.

B. Beardsley asked how many tows are made. C. Hunt replied that there are at least two floatables net tows in the nearfield region. A. Solow asked what types of numbers arise from the sampling. H. Trulli replied that the survey team has not found anything yet but would record the number of plastic and paper items. A. Solow asked how long this sampling has been done. C. Hunt replied that Battelle began sampling at the new outfall site last year. Historically, only observations of floating debris have been recorded.

R. Isaac asked how ambient monitoring of floatables would discern trash from ships or other sources as opposed to the DITP. He suggested attaching a video camera to one of the skimmers. M. Mickelson thinks that this sort of sampling should be event-driven, if there is an obvious problem. H. Trulli added that as part of a separate program, Battelle sampled material at the Nut Island and Deer Island Treatment Plants about 10 years ago so there is some information on the types of floatables present. R. Isaac agreed that we know what to expect but it is still difficult to extrapolate the sources. S. Lipman still thinks it would be difficult to tell whether floatables in Massachusetts Bay were from the DITP, CSOs, stormwater discharges, ships, or other sources. M. Mickelson agreed and therefore does not think there should be an ambient threshold for floatables, but MWRA is willing to summarize the field net information in the annual Outfall Monitoring Overview report.

B. Beardsley thinks that it is not clear that the sludge and scum measurements are a good measure of changes in influent composition. M. Mickelson pointed out that these measurements are not a direct indication of plant efficiency. The graph of sludge and scum removal merely shows that the treatment plant is functioning well. S. Testaverde suggested using the field sampling net within the plant at a specific location for a specified amount of time. M. Mickelson thinks this could be done as a special study.

S. Redlich thinks that there should be records available of any bypasses of secondary treatment as measurements of plant overload. M. Mickelson believes that would not address the aesthetic issue. B. Beardsley asked whether it would be feasible to conduct a simple study when secondary treatment is bypassed (e.g. during a storm). M. Mickelson thinks that it may be possible even though the skimmers are not bypassed. B. Beardsley suggested this because in order to be able to make any causal relationship, there needs to be a measurement of any floatables discharged during times of upset. M. Mickelson agreed and thinks that this would be especially useful in the winter when the plume surfaces.

C. Hunt asked OMSAP whether the type of information presented here, as well as field data, are sufficient to address the question of aesthetics. A. Solow thinks that these data do not give an absolute measure of the plant performance, only relative performance, but how that corresponds to what is being discharged is not clear. He asked if there is there anything else MWRA can do short of the original proposed sampling that is dangerous and difficult. M. Mickelson thinks MWRA could sample within the plant to “fingerprint” the types of material and relate it to the materials sampled in the field. MWRA can also examine plant records to pinpoint any problems.

B. Beardsley asked whether floatables can be seen flowing in the effluent. M. Mickelson replied no, only the materials captured by the skimmers are visible. B. Beardsley suggested placing a camera in the plant at a place where the flow is slow. M. Mickelson thinks that since the material is sparse, the best place for a camera would be in one of the tip-tubes that accumulates material. As material accumulates upstream, the tip tube rotates slowly, fill up, rotates back up, and is flushed with effluent. The problem is that tube flushing time is not well quantified.

J. Pederson thinks the question is if a lot of material is observed in Massachusetts and Cape Cod Bays, is it because of a plant upset. MWRA could use a video camera in the event of a plant shutdown and material has an opportunity to escape, but she wondered if it would be worth the effort. She thinks that MWRA is conducting more than enough monitoring to address aesthetics. B. Beardsley agreed. He thinks obtaining some baseline nearfield data is a good idea to contrast with post-discharge and if the efficiency of the plant ever drops. He suggested that there be sampling if there is a problem as opposed to random sampling and is in favor of dropping the current threshold. A. Solow agreed and asked how the rest of the group felt.

J. Shine asked whether the transect is chosen randomly each time. C. Hunt replied that it is semi-random – location depends when the crew has time. Sampling transects are straight lines between stations. J. Shine asked if there is bias between transect stations. C. Hunt does not think so, his sense is that it will become a fairly standardized set of stations over time.

A. Solow liked B. Beardsley’s suggestion of some kind of adaptive sampling and asked whether that would require some kind of special surveys. C. Hunt stated MWRA has an adverse condition survey that is set up to sample if there is ever an adverse activity at the plant. Protocol for this type of survey is still being developed. K. Keay added that the adverse condition is part of the Memorandum of Understanding with the MADMF, primarily gauged at collecting coliform samples. Net tows could potentially be incorporated to this sampling.

J. Schwartz suggested that any OMSAP motion include whether or not they think that MWRA’s treatment plant measurements and field observations will adequately address the permit requirements for aesthetics. M. Liebman read the permit requirements [see page 7 of the NPDES permit]. J. Shine approved of the field sampling, as long as there is no bias in station/transects selection. A. Solow agreed and thinks MWRA should be willing to continue to make and report those measurements. B. Robinson thinks that the surrogate measures of plant performance (FOG, slum and scum) are the best measurements possible and should be sufficient to address aesthetics. M. Mickelson summarized that OMSAP is requesting that MWRA report the sludge, scum, and FOG measurements in the annual Outfall Monitoring Overview; that MWRA address spatial concerns if there is an adverse plant event; and “fingerprint” the floatables from the DITP as a special study. A. Solow put forth this statement as a motion which OMSAP members approved unanimously.

ACTION: OMSAP believes that the current measurements of sludge and scum removed by the Deer Island Treatment Plant (DITP) as well as FOG (fats, oils, and grease) measurements in the treated effluent adequately address the NPDES permit requirements for aesthetics. OMSAP recommends that MWRA delete the current floatables threshold in the Contingency Plan. OMSAP is requesting that MWRA report the sludge, scum, and FOG measurements in the annual Outfall Monitoring Overview; that MWRA address concerns regarding floatables if there is an adverse DITP event; and that MWRA “fingerprint” the floatables from the DITP in a special study.

DISSOLVED OXYGEN (DO) CONCENTRATION THRESHOLD DISCUSSION
M. Mickelson reviewed the current DO thresholds and suggested revisions [see information briefing dated February 23, 2000]. He then showed baseline data in order to give an idea of the types and frequencies of exceedances that are occurring during the baseline period. DO varies with time and is affected by a number of physical factors. For example in the fall of 1994, there was low bottom DO in Massachusetts Bay, and also low DO in bottoms waters entering from the Gulf of Maine implying a boundary influence. M. Mickelson then showed all farfield and nearfield baseline DO data, as well as survey averages. As seen in the data, MWRA focuses on the nearfield since this is where low DO measurements generally occur. He then showed 1994 data in detail which showed that at a given station, DO can vary by 1 mg/L within just one day (actual data, not averages). Overall, there is a lot of temporal variability that is not well characterized.

EPA has developed a new draft guidance document for DO in salt water for the Virginian Province (Cape Cod to Cape Hatteras). The MWRA 6 mg/L warning threshold is based on a freshwater criterion and the new EPA guidance document states that a salt water criterion is different. This is based on acute and chronic survival studies of representative species to the various exposures. From these studies, EPA determined that a 4.8 mg/L DO threshold concentration would be protective. The document goes on to discuss how to take temporal variability into account. EPA implies that this may be used as a national criterion. D. Tomey clarified that EPA will look at how the new threshold could apply to other areas. M. Liebman added that the guidance is on the web, and is open for public comment. There is an appendix that describes how to apply the criteria to other regions. [Available at: https://www.epa.gov/ost/standards/dissolved/ ] D. Tomey added that he and M. Liebman have yet to see a draft of the appendix. J. Pederson pointed out that Scott Nixon (OMSAP member) believes that the salt water standard for DO should not be based on the freshwater standard.

B. Robinson asked whether the chronic values considered mortality. M. Mickelson replied that they are based on growth. He then showed Bays Eutrophication Model results that show some improvement in DO in Boston Harbor and minor DO variations at the new outfall location due to relocation and secondary treatment. MWRA has exceeded the existing DO threshold a few times during the baseline period.

D. Tomey stated that the draft EPA guidance will go to public notice, federal register, and national review, but this report only pertains to the Virginian Province. A. Solow said that OMSAP should treat this as a “heads up” that there will be EPA action on the DO national criteria soon and that OMSAP will have to then re-examine the MWRA DO thresholds.

REPORT FROM THE PUBLIC INTEREST ADVISORY COMMITTEE
G. Grossman updated the group on recent PIAC membership changes. She introduced herself as the new chair, replacing Cate Doherty, also from Save the Harbor/Save the Bay. Other changes: Steve Tucker and Margaret Callanan [correction, John Lipman] replaced Jim O’Connell and Patty Daley from the Cape Cod Commission and Maggie Geist replaced Scott Mitchell from the Association for the Preservation of Cape Cod. At the last meeting (October 1999), PIAC reviewed the conclusions from the OMSAP workshop. There was also a lengthy discussion on the group’s public communication strategy and effective ways for us to reach out to constituents and disseminate information about the outfall pipe activation. PIAC considered hosting a public meeting or briefing and discussed the timing in relation to when the outfall pipe goes on-line, meeting locations, appropriate format and content, level of technical information, and who should be invited. PIAC did not agree as a group to host a public meeting, and so the committee discussed other mechanisms of public outreach such as hosting a website and radio talk shows. PIAC also discussed the Barnstable Science Advisory Panel’s (BCSAP) alternatives to MWRA’s food web model scope of work. The BCSAP is continuing their work on this and will hopefully be presenting in the near future.

REPORT FROM THE INTER-AGENCY ADVISORY COMMITTEE
S. Testaverde gave a brief IAAC update. The committee convened in May 1999 and October 1999. IAAC is still grappling with its mission, and is moving for a modification of its mission in the OMSAP charter that states that the committee will advise the OMSAP on environmental regulations. IAAC approved a new mission statement that states that “the committee will advise the OMSAP, EPA and MADEP on scientific, technical and/or regulatory matters related to discharges from and operations of the MWRA system outfalls that may directly or indirectly affect Boston Harbor, Massachusetts Bay, and Cape Cod Bay. The IAAC may review or evaluate other environmental matters as necessary.” IAAC will forward this request to EPA/MADEP. IAAC has also had discussions on the food web model scope of work, nitrogen removal technologies, and polymer usage in secondary treatment.

C. Hunt asked whether the charter mission statement revision will go through public review. S. Testaverde was not sure but will find out when he meets with EPA/MADEP. M. Liebman added that Ron Manfredonia (EPA) had said that EPA/MADEP will approve charter changes, not OMSAP, since these agencies appointed OMSAP and its subcommittees.

ADJOURN

MEETING HANDOUTS:

  • Agenda
  • OMSAP/IAAC/PIAC Membership Lists
  • March 1999 OMSAP Minutes
  • MWRA Information Briefings
  • Copies of MWRA Presentation Transparencies
  • Draft March OMSAP Agenda

OMSAP MEG Meeting, Meeting Report, December 15, 1999
Submitted to OMSAP June 21, 2000

Introduction

The Massachusetts Water Resources Authority (MWRA) initiated in 1991 a long-term research program to develop a set of tested predictive state-of-the-art circulation and water-quality models for the Massachusetts Bay/Cape Cod Bay region for understanding and predicting the impact of their facilities on the Massachusetts marine environment (including Boston Harbor). The immediate objectives of this effort were to: a) develop the coupled numerical models, b) collect field data for model initialization, forcing and calibration, c) evaluate model predictions through comparison with new field data, and d) use the models to predict potential impacts of changes in the Boston sewage treatment and ocean outfall system then being proposed. Scientists at the United States Geological Survey (USGS) and HydroQual, Inc were contracted to develop the circulation and water-quality models and conduct calibration and evaluation simulations for two one-year periods (1990 and 1992) when sufficient field data were available. The MWRA established a Model Evaluation Group (MEG) in 1992 to advise the MWRA, USGS, and HydroQual on this model development effort. The results of these model studies for 1990 and 1992 and a final review by the MEG were presented in a series of reports in 1995 (see Appendix 1).

At that time, the MEG recommended that the circulation and water-quality models be used to extend the 1992 simulation through 1994. The MWRA Mass Bays baseline-monitoring program showed two unusual water-quality events in these years, an intense phytoplankton bloom in fall 1993 and very low levels of dissolved oxygen in bottom waters in late 1994. The MEG felt that model/data comparisons for these two years would provide added insight into the regional environmental dynamics and predictive model skills. The USGS and HydroQual did examine 1993-1994, and the results are presented in the September 1999 HydroQual report "Bays Eutrophication Model (BEM): Modeling Analysis for the Period of 1992-1994". The Outfall Monitoring Science Advisory Panel (OMSAP) formed the Bays Eutrophication Model Evaluation Group (BEMEG) in late 1999 to review this recent report and recommend any changes in either the modeling and/or the monitoring program which would improve the models’ skill in circulation and water-quality prediction. The BEMEG held an open meeting at the Woods Hole Oceanographic Institution December 15, 1999 to review the model results for 1992-1994 and discuss possible areas for additional work (see Appendix 2). This report summarizes the major conclusions and recommendations of the BEMEG.

Summary

In general, the BEMEG was pleased to see that the additional modeling and data comparison effort recommended by the previous MEG had been undertaken. Extending the BEM simulations through 1994 provides additional experience with the model over different environmental conditions and a further test of the model's ability to capture both seasonal changes and episodic events. In particular, the model successfully reproduces the timing and spatial pattern of the winter/spring phytoplankton bloom, the limiting roles played by silica in Cape Cod Bay during winter/spring and inorganic nitrogen in Mass Bay during summer, and the seasonal variation in dissolved oxygen.

The BEMEG noted, however, that the model did not capture the high diatom concentrations observed in fall 1993, nor did it fully capture the low dissolved oxygen observed in late 1994 - the two events that motivated the inclusion of additional model years. Also, the model could not reproduce the large dynamic range in observed phytoplankton concentrations, raising questions as to how well a model can distinguish anthropogenic change from ambient variability. Ongoing data collection suggests that much of the ambient variability may be associated with unresolved variability in open boundary conditions.

The monitoring data presented at the December meeting showed significant increases in ammonium concentrations and chlorophyll in the northern part of Boston Harbor starting from about July 1998 when the effluent from the Deer Island (DI) wastewater treatment plant (WWTP) began to receive secondary treatment. BEMEG member Donald Harleman requested DI effluent data from MWRA for periods both before and after the beginning of secondary treatment. The first data set was for effluent from the new DI primary plant while it was receiving influent from the north system (about two-thirds of the total metropolitan flow) during the period February 1, 1995 through June 30, 1997. The second data set was for effluent from the new secondary plant during the period July 8, 1998 through December 31, 1999 when influent from the north and south systems was combined and received primary and secondary treatment.

The results of Harleman's analysis of these two effluent data sets are summarized as follows:

  1. 1. The average concentrations of ammonia (NH3) and organic nitrogen during the 2.5 years of primary-only effluent at DI prior to mid-1998 are:
    a) NH3 in primary effluent = 13.2 mg/L, with 11% removal of ammonium by primary treatment, and
    b) organic nitrogen in primary effluent = 8.2 mg/L, with 15% removal of organic nitrogen by primary treatment.
  2. The average concentrations during the 1.5 years of primary plus secondary treatment effluent at DI since mid-1998 are:
    a) NH3 in secondary effluent = 18.7 mg/L, with 7% increase of ammonium by primary plus secondary treatment, and
    b) organic nitrogen in secondary effluent = 4.7 mg/L, with 62% removal of organic nitrogen by primary plus secondary treatment.
  3. The effect of secondary effluent on chlorophyll is related to the relative change in the effluent ammonium concentration following the change from primary to biological treatment. NH3 in secondary effluent increased from 13.2 to 18.7 mg/L, an increase of 42%.
  4. The change in the average raw sewage to DI following the combining of the north and south systems in mid-1998 was as follows:
    a) NH3 increased from 14.8 to 17.5 mg/L, an increase of 18%, and
    b) organic nitrogen increased from 9.7 to 12.5 mg/L, an increase of 22%.

These results indicate that about half of the 42% increase in effluent ammonium following secondary biological treatment is from the increase in ammonium in the raw sewage due to the combination of the north and south systems. The other half is due to the ammonia generated by the biological treatment process itself. Use of these results in future model studies are discussed below.

Based on the information presented at the December meeting and in accordance with the above observations, we offer the following recommendations.

General Recommendations

  1. Massachusetts Bay exhibits a significant fall diatom bloom, which is thought to provide the last large flux of carbon to the bottom before complete winter turnover and may strongly influence benthic secondary production and other bottom processes. While the impact of the fall bloom on bottom water dissolved oxygen in the fall when bottom temperature and respiration tend to be high and in the following spring are not known, we recommend that the present water quality model be modified to include a third algae component to allow direct simulation of the fall bloom.
  2. With the significant improvement in computational speed over the last decade, we recommend that the water-quality model use the same spatial grid as the circulation model. In particular, within the existing water-quality model domain, the horizontal and vertical grid spacing should be the same as used in the circulation model. This should eliminate questions about errors introduced by the spatial collapsing scheme presently used in the water-quality model. The spatial resolution used in the circulation model should be revisited, to see if this should also be improved for future studies.
  3. Although "projection" runs (i.e., model runs comparing conditions with existing versus future outfall, and with primary versus secondary treatment) were apparently not part of the current Statement of Work, we recommend these comparisons be continued and tracked as additional changes are made to the model. New "projection" runs should be made for existing versus future outfall locations, and with primary versus secondary treatment using the organic nitrogen and ammonium effluent data presented in the Summary section above. Also, the variation among projection runs should be gauged against the year-to-year variability (both measured and simulated) to assess the relative impacts of anthropogenic change versus ambient variability.
  4. Both field data and model results indicate that the major source of nutrient input to the Mass Bays system occurs through advection of western Gulf of Maine waters around Cape Ann. The volume and property fluxes of this upstream source are poorly sampled by the present monitoring program, so that changes within the Mass Bays due to real changes in the upstream boundary conditions will be missed in model simulations conducted with poorly known "climatological" boundary conditions. We recommend three specific actions: A) Conduct model studies to determine the sensitivity of the model simulations for 1992-1994 to realistic changes in the upstream boundary conditions. B) Develop a plan to begin collecting in-situ time-series measurements of currents and water properties along the upstream section of the model open boundary. The lack of direct measurements to characterize the upstream inflow and its variability severely limits any model predictive skill. Questions concerning the types, locations, and frequency of sampling need to be addressed, e.g., should measurements be made along the open boundary of the circulation model or the open boundary of the water-quality model or both. C) Investigate recent efforts to develop a Gulf of Maine ocean observing system. The University of Maine is funded to develop such a system (GoMOOS) in the next two years, and the Regional Association for Research on the Gulf of Maine (RARGOM) is considering efforts to augment or complement the Maine GoMOOS plan. MWRA could play an important role in helping to design an effective Gulf of Maine observing system that could provide near real-time measurements of currents and water properties on the open boundaries of the MWRA circulation and water-quality models. The combination of data collected by the MWRA monitoring program and a Gulf of Maine observing system offers the best hope of providing timely accurate open boundary conditions.
  5. The closing of the Nut Island WWTP in 1998 and switch to secondary treatment at Deer Island made a significant change in the distribution and quality of the nutrient input to Boston Harbor. In particular, high levels of ammonium were observed near the northern harbor. We recommend that the BEM (with improved resolution; see recommendation 2 above) be used to simulate the 1998-1999 period to see how well the model captures the increased chlorophyll observed in and offshore of Boston Harbor. Again, the pre- and post-secondary organic nitrogen and ammonium effluent concentrations presented in the Summary section above should be used in this simulation.
  6. Related to 4 and 5 above, model mass balance studies should be conducted to determine the temporal and spatial distribution of the source of various pools of nitrogen. That is, how much of the ammonium observed at x, y, z, t is from treatment plant versus the open boundary.
  7. There is generally good agreement between the sediment model and in-situ measured fluxes of oxygen, ammonium, nitrate, phosphate, silicate, and denitrification, with the exception of some summer data for denitrification and phosphate. The report recommendation that benthic diatoms should be investigated is a good one, but prior to addition of a benthic diatom state variable, the model and field data should be analyzed for the predicted/observed light levels at the sediment-water interface. The predicted areal pattern of light could be used to assist in deciding whether the inclusion of this potential source of oxygen to the model is warranted. If it is, the experimental benthic flux work should include an illuminated treatment.

Recommendations for Report Addenda

  1. Complete documentation of the circulation and water-quality model parameters used in the 1992-1994 simulation need to be provided, especially noting which values were changed from the values resulting from the 1990/1992 calibration study and/or changed during the 1992-1994 period to better fit with observation. Also note any changes in parameter values suggested by more recent observations.
  2. Complete documentation of the boundary conditions used in the 1992-1994 simulation should be provided. This includes descriptions of the various parameters, their spatial and temporal variability, and key assumptions used to derive the values specified for the 1992-1994 study. For example, do the surface wind stress and insolation change hourly while the temperature and salinity specified along the Gulf of Maine boundary change only monthly or yearly? Since step changes in boundary conditions generally introduce disturbances that propagate through the model domain, comment on the effects of step changes versus time ramp changes in boundary conditions on the main model results and whether the time dependence of the boundary conditions should be changed in future model simulations.
  3. The water-quality model takes as input the grid-collapsed temperature and salinity fields as computed by the hydrodynamic model. A comparison of simultaneous temperature, salinity and density from both models should be made for the 1992-1994 period and presented with a discussion about the skill of the water-quality model to capture the vertical stratification seen in the hydrodynamic model. Note that if the hydrodynamic and water-quality models are run on the same grid, there is no need for grid collapse and this recommendation is not necessary.
  4. One of the major difficulties in comparing model results with in-situ measurement data is the mismatch in spatial and temporal scales between model and nature. We recommend that the experimental uncertainties inherent in the field data due to instrumental and methodological errors and the spatial and temporal scales of natural variability be estimated and shown in all model/data comparison figures.

  5. The water quality model simulations for bottom water dissolved oxygen (DO) during the 1994 stratified season were in the right direction in the sense that they tended to be lower than in previous years, but did not reach the observed minima for the 1994 season. We do not really know if the model's underestimate of the minima is due to a failure to simulate metabolism (primary production may be low in the model compared to observations) or to a lack of sufficient detail in some physical processes (coarse-scale advective or fine-scale vertical processes). Bottom-water DO is influenced by such factors, including local water column and respiration rates, rates of sub-pycnocline water column or benthic primary production, the fine-scale structure of stratification and its relationship to an irregular bottom topography, and horizontal advection of water into local areas. The progression of DO decline in the nearfield sampling area during summer stratification is very sensitive to the combination of these biological and physical factors. Other modeling has shown that different combinations of factors can approximate a given annual bottom-water DO minima, moreover, the temporal progression of decline varies with the mix of factors and specific rate processes. Significantly, the shape of the observed seasonal decline in nearfield DO was not reproduced by the model. Typically (1992-1994), bottom-water DO decline has been slower (or has no decline) early in summer and then has increased towards fall turnover; in contrast, the model tends towards a fairly constant decline for the whole period.

    Overall, the patterns suggest that the correct tendency for seasonal DO minima is produced by the model, even if not fully. But one cannot have confidence that results occur for the right reason, i.e., that the dynamics and scales acting as the mechanism for DO decline in nature are indeed drivers in the model. Without that assurance, we cannot have full confidence in the model's ability as an event-scale prediction tool, even though we are confident in it as a broader, scenario-projection tool.

If an event-level predictor is desired of the model, both sensitivity analyses of the model and comparison of observational uncertainties (each recommended above) would help resolve apparent model-observational differences. A simple place to start is to revisit the calibrated model coefficients for select physical and metabolic coefficients (including temperature functions) against the MWRA database. Comparison would note whether critical processes expressed in nature appear to be more dynamic than would be captured by a fixed (i.e., time-invariant) model coefficient.

Appendix 1. Model reports and MEG review released in 1995-6.

Beardsley R, Adams EE, Harleman D, Giblin AE, Kelly JR, O'Reilly JE, Paul JF. 1995. Report of the MWRA hydrodynamic and water quality model evaluation group. Boston: Massachusetts Water Resources Authority. Report ENQUAD ms-37. 58 p.

Blumberg, AF, Ji, Zhen-Gang, Ziegler, CK. 1996. Modeling Near-Field Plume Behavior using a Far-Field Circulation Model. Journal of Hydraulic Engineering. Vol. 122, no. 11. pp. 610-616.

Hydroqual, Normandeau. 1995. A water quality model for Massachusetts and Cape Cod Bays: Calibration of the Bays Eutrophication Model (BEM). Boston: Massachusetts Water Resources Authority. Report ENQUAD 95-08. 402 p.

Signell, R.P., Jenter, H. L. and A.F. Blumberg. 1996. Circulation and effluent dilution modeling in Massachusetts Bay: model implementation, verification and results. Open-File Report 96-015. U.S. Geological Survey. 121 p.

Appendix 2. Model Evaluation Group Membership, December 1999 Meeting Agenda, and Attendees

Outfall Monitoring Science Advisory Panel
Bays Eutrophication Model Evaluation Group Meeting
December 15, 1999, 9:00 AM to 3:30 PM
Woods Hole Oceanographic Institution, Quissett Campus, Carriage House

MEG Members:
Dr. Bob Beardsley (chair), Woods Hole Oceanographic Institution
Dr. Eric Adams, Massachusetts Institute of Technology
Dr. Jeff Cornwell, University of Maryland
Dr. Don Harleman, Massachusetts Institute of Technology
Dr. Jack Kelly, US Environmental Protection Agency
Mr. Jay O'Reilly, National Marine Fisheries Service
Dr. John Paul, US Environmental Protection Agency

Observers: Dr. Brad Butman, USGS; Ms. Cathy Coniaris, OMSAP staff; Dr. David Dow, NMFS; Mr. Jim Fitzpatrick, HydroQual; Dr. Rocky Geyer, WHOI; Dr. Anne Giblin, MBL; Dr. Carlton Hunt, Battelle; Dr. Russ Isaac, MADEP; Mr. Rich Isleib, HydroQual; Dr. Wendy Leo, MWRA; Dr. Wayne Leslie, Harvard; Dr. Matt Liebman, EPA; Dr. Jason Link, NMFS; Dr. Mike Mickelson, MWRA; Dr. Andrea Rex, MWRA; Dr. Jack Schwartz, MADMF; Dr. Rich Signell, USGS; and Mr. Steve Tucker, Cape Cod Commission.

Agenda

9:00 - 9:15
Welcome, Purpose of Meeting, and Introductions
Bob Beardsley, WHOI, MEG Chair

9:15 - 11:00
BEM Model Overview and Results for 1992-1994
Jim Fitzpatrick and Richard Isleib, HydroQual

11:00 - 11:30
Overview of 1992-1999 Baseline Monitoring Features
Carlton Hunt, Battelle

11:30 - 12:00
Questions and Discussion

12:00 - 1:00
Lunch

1:00 - 3:30
MEG Discussion and Comments for the Final MEG Report

Adjourned*

*The MEG met afterwards to draft their final report to the Outfall Monitoring Science Advisory Panel.

OMSAP Public Workshop, September 22 and 23, 1999
9:00 AM – 5:00 PM,
JFK Federal Building Conference Center, Second Floor Low Rise Building

AGENDA
WEDNESDAY, SEPTEMBER 22

9:00 - 9:45
Introduction
Arleen O'Donnell (Massachusetts Department of Environmental Protection) and Ron Manfredonia (Environmental Protection Agency)
OMSAP and Its Charge
Andy Solow (OMSAP – Woods Hole Oceanographic Institution)

9:45 - 10:45
The Boston Harbor Project Progress to Date

  • Facilities timeline, Andrea Rex (Massachusetts Water Resources Authority)
  • Effluent quality, Steve Rhode (MWRA)
  • Harbor quality, Dave Taylor (MWRA)
  • Why the outfall?, Andrea Rex (MWRA)

10:45 - 11:15 Break and Poster Viewing

11:15 - 12:15
SYNOPSIS
Monitoring Plan
Mike Mickelson and Ken Keay (MWRA)

  • Monitoring Program - adequacy and breadth
  • Thresholds - combine concerns with expectations for quality of the Bay, based on system understanding
  • Contingency Plan - framework for response
  • Communications to OMSAP and EPA/MADEP

12:15 - 1:15 Lunch

1:15 - 2:00
The Physical Environment
Rocky Geyer (WHOI)

  • Water masses
  • Hydrodynamic model and plume behavior
  • The extent to which water motion accounts for biological responses, including red tides and formation of zooplankton patches

2:00 - 3:15
Water Quality
Carlton Hunt (Battelle)

  • Nutrients, chlorophyll, and dissolved oxygen
  • Harbor signatures and gradients
  • Key plankton responses (regional)
  • Thresholds and detection of change

3:15 - 3:30 Break

3:30 - 4:00
Modeling in Support of Monitoring
Jim Fitzpatrick (HydroQual)

  • Capabilities
  • Sensitivity analysis

4:00 - 5:00
OMSAP Panel Discussion (open)
Andy Solow (OMSAP – WHOI)

Adjourn the first day

THURSDAY, SEPTEMBER 23

9:00 - 9:45
Sediment Transport and Topography
Brad Butman (United States Geological Survey)

  • Geological setting
  • Contaminants distribution

9:45 - 10:45
Benthic Communities, Ken Keay (MWRA)

  • Harbor
  • Outfall

10:45 - 11:15 Break and Poster Viewing

11:15 - 11:45
Nutrient Flux in the Harbor
Anne Giblin (Marine Biological Laboratory)

11:45 - 12:00
Hardbottom Community
Barbara Hecker (Hecker Environmental)

12:00 - 1:00 Lunch

1:00 - 1:15
Mussels and Bioaccumulation
Lisa Lefkovitz (Battelle)

1:15 - 1:45
Flounder Histology and Tissue Chemistry
Michael Moore (WHOI)

1:45 - 2:15 Break and Poster Viewing

2:15 - 5:00
OMSAP Panel Discussion (open)
Andy Solow (OMSAP – WHOI)

Adjourn the second day

POSTERS

Alexandrium in the Gulf of Maine and Massachusetts Bay
Don Anderson and Bruce Keafer (WHOI)

Sediment Contaminant Monitoring in Massachusetts and Cape Cod Bays
Deirdre Dahlen, Lisa Lefkovitz, and Carlton Hunt (Battelle)

Long-term Trends in Productivity
Aimee Keller (University of Rhode Island)

Juvenile Lobster Study
Roy Kropp (Battelle)

Sediment Profile Imaging (Harbor and Bay)
Bob Diaz (Diaz and Daughters)

Lobster Monitoring
Lisa Lefkovitz (Battelle)

Plankton Community
Jeff Turner (U Mass-Dartmouth) and Dave Borkman (URI)

Plume Tracking Study Design
Carl Albro (Battelle)

Statistical Analysis of Temporal Patterns in Harbor Bacterial Water Quality
Andrea Rex (MWRA)

Hardbottom Community
Barbara Hecker (Hecker Environmental)

1999 OMSAP WORKSHOP
INTRODUCTION

Arleen O'Donnell (MADEP)
Welcome everyone to the 1999 Outfall Monitoring Science Advisory Panel (OMSAP) Technical Workshop. I would like to take this opportunity to thank the OMSAP, which has been in existence for one year, for doing an excellent job. I have a tremendous amount of respect for the members of OMSAP and the work that they do. I would also like to thank Cathy Coniaris who has been staffing this effort. The Massachusetts Department of Environmental Protection (MADEP) and the US Environmental Protection Agency (EPA) wanted to remain as uninvolved as possible in the selection of the Panelists to make sure that the OMSAP was objective, neutral, and peer-nominated. Dr. Jerry Schubel (New England Aquarium) organized a nominating committee which selected applicants that best represented the environmental interests involved with the outfall permit. Since its inception, the OMSAP has been operating independently. This entire process is an example by which others can learn from.

To date, the OMSAP has successfully dealt with policy issues related to outfall monitoring which require scientific expertise. I was struck by how well OMSAP dealt with concerns regarding the lobster fishery and the outfall and how they have begun discussing the food web model scope of work permit requirement. Rather than having the stereotypical scientific research perspective, i.e. "we need more information on this, this is a great research project, let's study it more", the Panel has suggested very practical applications to these problems. We appreciate that the Panel consists of in-depth scientists with a practical sense about decision-making. By looking at the NPDES outfall permit for MWRA, it is clear that MADEP and EPA are going to be relying heavily on OMSAP for advice. We will be engaging in a lot of dialogue over the next few years so that we may obtain the full benefit of their input on a number of very important matters.

I would also like to mention that though the panelists are covering for all of the disciplines listed in the OMSAP charter, there are five vacancies in specialized areas – fisheries, modeling, phytoplankton, zooplankton, and benthic biology. If anyone is interested, please contact the OMSAP chair Dr. Andy Solow. Thank you for the opportunity to welcome everyone to this workshop. I hope that this will be a very informative information exchange over the next two days.

Ron Manfredonia (EPA)
On behalf of EPA, I would like to thank everyone for attending this technical workshop. I look forward to hearing the discussions on the science of the Massachusetts Bays ecosystem. I encourage the presenters to think about some of the common themes we heard when developing the MWRA permit. They include: the potential impacts of the outfall to nearshore waters and endangered species; the request for a "food web model"; and monitoring using an "ecosystem" perspective. One thing that we need to develop is a managed process by which we analyze the data and make judgments once the outfall goes on-line. If possible, I would like to ask the presenters to talk about their data in light of the caution and warning levels that have been developed. To what extent have the baseline data already exceeded caution or warning levels for the ambient conditions? I predict that, at some point after the outfall goes on-line, we will see some caution or warning level exceeded. How are we going to manage the information in order to able to make unemotional, informed decisions, based on science? Again, thank you all very much for attending and I look forward to hearing the discussions.

Andy Solow, (OMSAP chair/WHOI)
The OMSAP was formed one year ago to advise the EPA and MADEP on scientific and technical matters related to the Massachusetts Water Resources Authority's Boston outfall and any potential impacts of the discharge on its receiving waters. Its predecessor, the Outfall Monitoring Task Force, had a similar charge and worked successfully for about 10 years.

Currently there are nine members on the Panel including myself: Dr. Robert Beardsley (Woods Hole Oceanographic Institution), Dr. Norb Jaworski (retired), Dr. Robert Kenney (University of Rhode Island), Dr. Scott Nixon (URI), Dr. Judy Pederson (Massachusetts Institute of Technology), Dr. William Robinson (University of Massachusetts Boston), Dr. Michael Shiaris (UMB), and Dr. James Shine (Harvard School of Public Health).

There are two subcommittees that advise OMSAP. The first is called the Public Interest Advisory Committee (PIAC) [chaired by Gillian Grossman from Save the Harbor/Save the Bay as of October 1999] and its members consist of a representatives from a number of groups [Bays Legal Fund, Center for Coastal Studies, Massachusetts Audubon, Conservation Law Foundation, Cape Cod Commission, New England Aquarium, MWRA Advisory Board, Safer Waters in Massachusetts, Save the Harbor/Save the Bay, The Boston Harbor Association, Stop the Outfall Pipe, Association for the Preservation of Cape Cod, Wastewater Advisory Committee]. The second is called the Inter-Agency Advisory Committee (IAAC) chaired by Sal Testaverde (NMFS). [Member agencies: EPA, MADEP, MA Coastal Zone Management, MA Division of Marine Fisheries, United States Geological Survey, US Army Corps of Engineers, Stellwagen Bank National Marine Sanctuary, and National Marine Fisheries Service].

The OMSAP charter states that: "The OMSAP shall convene a public forum at least once a year to present findings, to explain their significance and to hear and respond to concerns from the public." The goals of this workshop are to:

  1. Review and discuss baseline monitoring and what it has added to our understanding of the Massachusetts Bays system.
  2. Provide a forum for discussing the potential or predicted effects of the new outfall on the Massachusetts Bays system. There will be some time for questions at the end of each presentation and there will be discussion periods at the end of each day. With that, I would like to introduce the first session.

QUESTIONS & ANSWERS
Post-workshop comments are included in [brackets]

Effluent quality

OMSAP: annual metals discharged between 1989 and 1990 declined which may have been due to industrial pretreatment in the MWRA system, but after about 1990, it looks like metals reflect simply what is happening with the solids. Does Boston have an ongoing pretreatment program for metals in their wastewater stream?

S. Rhode: yes, the Toxics Reduction and Control department have collected approximately 10,000 samples for metals and continue to strongly enforce metals and other regulated materials. Perhaps the decreases in 1989 and 1990 were the more easily obtained reductions, and now we are dealing with sources which are more difficult to reduce.

A. Rex added that households also contribute to these numbers.

S. Rhode agreed and pointed out that there was an educational campaign during that time period [which may have also led to the decrease in metals loading].

OMSAP: so metals entering the treatment plant have also decreased steadily?

S. Rhode: yes, but a lot more slowly than when the pretreatment program first began.

R. Trubiano: corrosion control has also decreased metal concentrations entering the MWRA system.

S. Rhode agreed. Corrosion control [which increased drinking water pH] was implemented about two years ago for drinking water and is expected to decrease lead and copper loading in wastewater.

OMSAP: do you measure the fingerprint of the PCBs which enters the Deer Island Treatment Plant (DITP) so that changing PCB inputs can be monitored over time?

S. Rhode: yes, but it has been difficult to make conclusions from the results. There is no consistent pattern in the 20 congeners that are routinely monitored. MWRA recently upgraded to a newer gas chromatograph which has about a 10-fold improved sensitivity, hopefully measuring more consistent detects, and possibly providing a more consistent and understandable pattern.

OMSAP: do the PCBs in the sludge end up in the pellets and back in the environment?

S. Rhode: yes, to some extent. This is why MWRA monitors the sludge extensively and must comply with many regulations.

OMSAP: is the use of the MWRA pellets supplying the PCB loading which is measured at the DITP?

S. Rhode: no because most of the pellets are sold out-of-state.

J. Shine pointed out that if we are interested in human or ecological risk, even though only a small fraction of the total concentration of PCBs are being measured, a large percentage of the potential risk may be captured if the most harmful congeners are being measured.

S. Rhode agreed and pointed out that the NOAA 20 congener list includes several of the toxic or co-planar congeners. MWRA's proposed 67 congener list includes all of the "toxic" congeners.

Harbor quality

OMSAP: is the high increase in chlorophyll in the Mystic River due to the dredging activities there?

D. Taylor: it could be that, but it also could be an exportation of nutrients from the Mystic River itself. Dredging increases the nutrient availability to phytoplankton but it also reduces water clarity [low water clarity impedes phytoplankton growth by reducing available light for photosynthesis].

Audience: do you know how big of an effect secondary start-up in 1997 might have had on the clarity in the northern harbor?

D. Taylor: MWRA has that data and can examine that question. This presentation focused on the latest change which was the transfer of MWRA south system flows to the DITP.

Audience: maybe the reason why a decrease in clarity was not measured is because the transfer occurred while there were improvements occurring at the same time in the harbor.

D. Taylor: yes, exactly.

Audience: does the dissolved inorganic nitrogen behave conservatively, and if so, could that parameter be used to calculate dilution?

D. Taylor: I have used the average salinity as a surrogate for river inputs to the system. When rainfall amounts are low, there is less nitrogen entering the harbor and thus concentrations are lower. However, in the south harbor there has been a decrease in dissolved inorganic nitrogen (DIN) which is not due to less rainfall or less freshwater input in the area, which would imply a response to the transfer. Thus, though it appears that the transfer had a positive impact in water quality in the southern harbor, there may be other factors that contributed to the water quality improvements also.

OMSAP: how much nitrogen is removed from the wastewater stream by sludge removal?

D. Taylor: less than 10%. Long-term nitrogen loading to the harbor has remained about the same, about 35 metric tons per day. Secondary treatment also does not remove very much nitrogen.

Audience: what kind of pattern is seen when dissolved organic and dissolved inorganic nitrogen are compared?

D. Taylor: MWRA has not observed a significant increase in total nitrogen in the north harbor. However, there appears to be an increase in the DIN which makes sense for two reasons: the Nut Island effluent was relatively enriched in ammonium and secondary treatment transforms more nitrogen to its dissolved inorganic form. However, MWRA has not detected changes in the dissolved organic nitrogen (DON) or particulate nitrogen concentrations in the north harbor.

Why the outfall?

Audience: will MWRA have to dechlorinate treated effluent?

A. Rex: yes, dechlorination will occur seasonally. Bacterial loading in the effluent varies according to the season. In the summer, bacteria concentrations in the effluent are higher, which means that more chlorine is needed. Thus dechlorination will occur so that the maximum chlorine permit limit (0.456 mg/L for the receiving water) is met. The outfall tunnel will help dechlorinate by increasing effluent residence time. In the winter, MWRA will be adding less chlorine and will meet permit limits without dechlorination.

Audience: will MWRA be testing for chlorine at the outfall site? If so, how frequently?

A. Rex: as part of the initial plume tracking plan MWRA will sample at the diffuser port using a diver as the effluent is discharged. MWRA monitors chlorine every half hour at the DITP and the chlorine residual limit must be met at the treatment plant.

OMSAP: what are the dissolved oxygen levels in the effluent? Will the concentration change with the new outfall?

S. Rhode: dissolved oxygen levels are relatively high after secondary treatment because the process adds oxygen. I would expect the oxygen to drop substantially over the length of the tunnel.

OMSAP: what if effluent in the tunnel becomes anaerobic? Do you expect denitrification to occur in the tunnel?

A. Rex: the effluent will not become anaerobic because of the high flow rates and denitrification will probably not occur.

J. Fitzpatrick added that though dissolved oxygen will decrease, most of the organic carbon will be removed by the treatment plant. There will not be significant impacts to dissolved oxygen in the tunnel due to the high effluent flow rates.

J. Shine pointed out that dissolved oxygen depleting organisms would not survive chlorination and thus would not cause a problem.

Monitoring Plan

OMSAP: what are the monitoring and reporting costs and how do they compare to the operating costs of the treatment plant (not including construction)?

M. Mickelson, K. Keay, S. Rhode: the receiving monitoring budget (water column, benthos, and fish/shellfish) is typically $2.5 million a year. Effluent monitoring is about $0.5 million a year. The annual operating budget is on the order of $45 million. The construction is on the order of $6 billion.

Audience: does MWRA have to report to the court?

M. Mickelson: yes, MWRA reports to the court through its law division.

Audience: is it possible that EPA/MADEP could respond to an exceedance before obtaining advice from OMSAP?

R. Manfredonia: EPA/MADEP have created OMSAP to secure independent scientific advice. If there is a violation of any effluent requirements, EPA/MADEP will take immediate action. In terms of the ambient monitoring program, it depends on the severity of what happens. But EPA/MADEP will certainly look to OMSAP for scientific advice on these matters.

OMSAP: I would like to see further discussion of thresholds at future OMSAP meetings.

J. Shine suggested dedicating an entire OMSAP meeting to thresholds.

M. Moore suggested MWRA work with the New England Aquarium and their whale watch staff to survey the comeback of harbor porpoise in Boston Harbor.

OMSAP: will the MWRA reports be available on the Internet as ".pdf" Acrobat Reader files?

M. Mickelson: yes, MWRA has already begun making reports available in this format.

The Physical Environment

Audience: how long did it take for drifters to travel from the new outfall site to Cape Cod Bay?

R. Geyer: typically 1-2 weeks. Though some of the drifters lingered in Cape Cod Bay, water would not collect in the same manner since it is incompressible [drifters accumulate at convergences but water does not].

OMSAP: are the northeasterly wind conditions which appear to be favorable for Alexandrium blooms, also favorable for transport towards Cape Cod Bay?

R. Geyer: northeasterly winds are favorable for transport of Alexandrium blooms towards Cape Cod Bay. These winds cause higher concentration of cells, not necessarily more cells, since the cells are packed closer to the coast where there is sampling.

OMSAP: what kind of study would resolve the question of whether low dissolved oxygen is the result of advection from the Gulf of Maine or a local phenomenon effect?

R. Geyer: the first step would be a more detailed statistical analysis of the data that has already been collected. It would be useful to look at whether there is a high correlation between the dissolved oxygen concentrations in bottom waters at the outfall site and in Stellwagen Basin (though I am not sure we have a long enough time series to distinguish this). Water mass characteristics can also be examined but the time series is still too short for evaluating interannual variability. We could also run the Bays Eutrophication Model. We should also keep monitoring currents and make drifter measurements. Interannual questions such as this are difficult to answer because it takes a long time to collect enough data to attain statistical significance.

OMSAP: to what extent are extreme, but rare, meteorological events (e.g. tropical storms) responsible for a large fraction of the transport processes? To what extent are these events actually dominating the annual transport or biological processes as opposed to the day-to-day transport?

R. Geyer: day-to-day processes influence the water column the most. The mean wind stress correlates with an annual progression of temperature, which correlates with dissolved oxygen. This simple linear connection implies a day-to-day influence not associated with any kind of extreme event. However, sediment and particle-bound contaminant transport relies more on resuspension events such as large storms and will be discussed by B. Butman.

OMSAP: is there any correlation between the "upwelling index" and chlorophyll or primary production values?

R. Geyer: this "upwelling index" is a new variable which has not been compared to the biology yet.

B. Beardsley: the slight decreasing trend in salinity measured by this program over the past few years has been observed on Georges Bank over approximately the same time frame. One of the things that this long time series will allow you to do is compare with other long time series in the Gulf of Maine. The decrease in salinity on Georges Bank seems to be due to a change in the upstream sources of water entering the Gulf of Maine from the Scotian Shelf. This emphasizes the point that R. Geyer made about the connection between Massachusetts Bay and the rest of the Gulf of Maine.

R. Geyer: as we collect a longer time series of data, we can begin to discern locally driven verses more regionally forced processes.

Audience: is there any data within those straight lines between sampling seasons? [Annual Salinity Cycle figure]

R. Geyer: no because the monitoring program does not have any surveys between early December and early February. The scope of the monitoring program is to look for ecological responses and not to generate a long time series of salinity measurements.

Water Quality

Audience: does MWRA make baseline measurements of trash in the surface water (e.g. as plastics or tar balls)? Because if people find trash after outfall goes on-line, they may blame the outfall.

C. Hunt: MWRA makes a note of trash on surveys but does not record amounts. However, the plume tracking survey will be sampling for plastics which may be related to the discharge and the DITP measures amounts of captured floatables. Obviously plastics in Massachusetts Bay come from many sources such as poor waste management on boats.

J. Fitzpatrick: the DITP removes much of the plastics in primary screening. Combined sewer overflows (CSOs) are another source of floatables and the outfall will increase the ability of the DITP to reduce CSOs.

Audience: why do silicate and dissolved inorganic nitrogen behave differently from one another?

C. Hunt: it depends on the dominant phytoplankton species and whether they are silicate-users (e.g. diatoms) or other species.

A. Giblin added that the silicate behavior tends to be temperature and pH driven. Warmer temperatures tend to re-solubilize silicate faster. This abiotic dissolution process tends to offset silicate from nitrogen, which is more biologically driven.

Audience: is there a relationship between the amount of carbon production and how long the dissolved oxygen decreases based on direct loading of carbon? Has the actual sediment-oxygen demand (SOD) been measured?

C. Hunt: we have not looked at that relationship, but others have. We now have the data and can study this linkage. A. Giblin will discuss the SOD when she presents results from the benthic flux program.

OMSAP: will the freshwater effluent discharge at the new outfall site increase stratification during the summer which would in turn further decrease dissolved oxygen by "sealing" off more of the bottom waters?

J. Fitzpatrick: there does not seem to be an intensification of stratification in the vicinity of the outfall based on preliminary hydrodynamic calculations.

C. Hunt added that the plume tracking survey will measure stratification after the outfall goes on-line.

M. Mickelson pointed out that adding freshwater at the sea floor may even tend to destabilize/destratify the water column.

OMSAP: is the diatom abundance, on a carbon basis, equal to or less than the microflagellate abundance?

C. Hunt: the draft data suggests that diatoms have the dominant carbon abundance, but this needs to be examined further.

OMSAP: how is it possible to have a 1999 standard deviation of 55,381 for zooplankton abundance on the draft threshold [zooplankton species figure]?

[This was a typographical error, corrected in the figures on this CD.]

A. Solow: OMSAP will discuss this threshold further at its next meeting.

OMSAP: how will you use this zooplankton threshold information?

C. Hunt: this threshold was developed to observe if there is a major shift in the zooplankton abundance of key species which may be food resources to the right whales during the late winter and early spring. We can debate whether we should use the 50th or the 95th percentiles, however, no one has determined what numbers of these zooplankton species are ecologically significant.

OMSAP: so there will be concern if the monitoring program measures a lower number than this threshold, but operations at the DITP would not be changed, correct?

C. Hunt: a lower abundance of these zooplankton species would not be healthy for a part of the ecosystem and so if this happens, we have to evaluate why the decrease in abundance has occurred.

Audience: if long-term zooplankton mean abundance steadily increases, then the variance will also increase. Would the threshold still be valid?

C. Hunt: we need to examine that.

OMSAP: there could be appreciable change that is not meaningful. Any thought on meaningful verses appreciable change?

C. Hunt: our state of thinking has not advanced enough to truly say what is meaningful change [relative to the zooplankton] for this system.

Audience: do the nearfield data provide any link to the farfield patches that are important feeding sources for whales? Is there any information that could be added to Stormy Mayo's [Center for Coastal Studies] feeding threshold?

M. Mickelson: we will work on this issue with OMSAP.

Audience: the physical data seems to be relatively reproducible from year to year, but the chemical and biological data are less predictable, proving the complexity of the system. How much is due to the sampling scheme? Or is it a modeling issue (grid cell sizes)? I have an uneasy feeling about the variability.

C. Hunt: we sample zooplankton using a net tow from the surface to 25 m. Even though the zooplankton data uses information integrated for 0-25m, there is still spatial variability.

OMSAP: is the spatial and temporal variability of the zooplankton understood with confidence?

C. Hunt: temporal variability is roughly two weeks. Spatially, the statistics comparing different regions such as nearfield and coastal still need to be calculated.

OMSAP: if sampling was done over only a small area but at high resolution, would that miss the big picture?

C. Hunt: probably. When MWRA added the two new zooplankton sampling stations in Cape Cod Bay, the range of zooplankton abundance increased so we knew that we had not been sampling the full variability. There have been some high resolution studies in 1998 and 1999 which address some of the spatial scale issues.

OMSAP: one fear is that because there is so much variability in so many of these biological parameters, if we use a statistical model to calculate a percentile, we could have meaningful change which is not statistically appreciable because of the variability.

C. Hunt: I agree. MWRA and the Outfall Monitoring Task Force (OMTF) chose to calculate mean values so that thresholds are not triggered either too often or not often enough. I would like people to lay out these statistical questions so that we can address them in a very systematic manner. MWRA/OMTF have spent the last six years trying to determine meaningful change.

J. Fitzpatrick agreed that choosing a middle value for a threshold is probably the best approach so that thresholds are not triggered by false alarms.

Audience: chlorophyll concentrations in the nearfield area just offshore from Boston Harbor seem to be the highest. When analyzing the data, have you tried to divide the nearfield into sections? In other words are we looking at the right spatial, and/or temporal detail?

C. Hunt: we do not parse out the nearfield. We examine the nearfield as a whole since it is the area of concern. The projections state that this area will not shift, and that there will be a gradient. The nearfield "box" was determined based on projections of where the plume would be located.

Audience: I am not suggesting changing the sampling locations, only to calculate the average of a different area "box" to see if the mean calculated is the same. There seems to be an optimal area just west of the nearfield where phytoplankton are the least light limited but still have the most nutrients available from the harbor. These chlorophyll concentrations seem to have been enhanced due to the diversion of the Nut Island flows to the DITP.

C. Hunt: that area of enhancement seems to be encompassing the western third to half of the nearfield and runs to the south along the coast which is included in the coastal sampling transect.

Audience: is there any evidence that the high chlorophyll measured near the outfall site is due to mixing events when the wind changes?

M. Mickelson: this was observed in July 1995 when we measured increased productivity in response to a mixing event.

Audience: in terms of reproducibility of the biological data, are the trends in production and respiration more consistent as compared to phytoplankton and zooplankton data?

C. Hunt: I can partially answer that. The productivity data vary quite a bit, but the respiration data are somewhat more consistent because the results integrate a larger set of processes.

Audience: will here be a hydroacoustic study to examine fish movements when the new outfall goes on-line?

MWRA: there are no plans for that type of study.

D. Tomey: I suggest customizing the zooplankton thresholds to right whale feeding behavior. The food web model is coming together conceptually, but I think relative to the monitoring, we need to compare the nearfield verses the farfield, and decide what thresholds are useful so that we may determine meaningful change.

M. Mickelson: there are two different approaches in developing the zooplankton threshold. Should we focus on effects of the outfall ["bottom-up" on the food web] or factors that affect whales ["top-down" on the food web]?

D. Tomey: we need to determine if changes in the nearfield reflect changes in the farfield. [Physical water] convergences dominate zooplankton patch formation in Cape Cod Bay. I suggest examining whether there are enough stations in Cape Cod Bay for us to be able to make any decisions. We should also examine results of a recently funded NSF grant which will examine zooplankton patch formation in Cape Cod Bay. Additional high-resolution information could also be gathered.

C. Hunt: there were two high-resolution Video Plankton Recorder surveys in 1998 and 1999. The 1999 results will provide very useful information.

M. Moore: right whales are more successful at finding patches than scientists. Keep this in mind when developing thresholds.

OMSAP: we need to take a broader view with this zooplankton issue. This is an ecosystem/zoological problem, not a number, and we can not collect zooplankton in any kind of a meaningful way at the present time. Thus no zooplankton threshold can be considered meaningful and so we need to find some other way. I think we should look at some of the other work that has been in other places in terms of how they evaluate ecosystems and try to apply that here. To some extent, zooplankton dynamics seem to be beyond our control. If we develop a threshold that does not take that into account, we would be doing ourselves a disservice.

J. Turner: I agree that there is too much emphasis on numbers, and am also concerned about the taxa included in the new zooplankton threshold. If the emphasis is to be on right whales in the late winter/early spring, then the species establishing the threshold should be important to right whales. Data from Stormy Mayo shows that Oithona is too small and will screen through baleen, yet the vast majority of zooplankton captured by the sampling program and considered in threshold calculations is Oithona. The zooplankton threshold was originally developed as part of the eutrophication thresholds, has that emphasis shifted to whales?

Audience: are there any new findings presented at this workshop that would change our thinking over the last few years?

S. Testaverde: a recent right whale study [Caswell H, Fujiwara M, Brault S. 1999. Declining survival probability threatens the North Atlantic right whale. PNAS 96: 3308-3313] concluded that the right whales will go extinct in 191 years.

OMSAP: but that does not change our way of thinking about the effects of the outfall on right whales.

S. Testaverde: it does in terms of the number of stations in Cape Cod Bay. There is not enough sensitivity to determine if MWRA is having an effect on right whales. The extinction calculation is a new piece of information that the federal government should be concerned about.

M. Moore: right whale feeding has a lot to do with physical oceanography [which affects patch formation]. Climate change also affects patch formation.

OMSAP: we often talk about the importance physical oceanography. Part of the reason why the stations in Cape Cod Bay may be sufficient is that it is difficult to describe a process by which the relocation will affect the physical oceanography in Cape Cod Bay. We have some scientific understanding of these processes and we need to use that in allocating the scarce resources we have to monitoring.

S. Testaverde: I am only suggesting additional monitoring when right whales are in this area (March-April).

OMSAP: we should revisit this.

Modeling in Support of Monitoring

Audience: how does the model reproduce changes in water quality with the transfer of sewage from Nut Island to Deer Island?

J. Fitzpatrick: we have only run the model for 1992-4 but may do additional runs in the future.

OMSAP: one of the issues early on in the monitoring program is that spring blooms are often missed in terms of the sampling cycle. To what extent do those spring blooms contribute to carbon loading, which in turn affects bottom dissolved oxygen concentrations in the summer? What about the fall Asterionellopsis bloom in 1993 and its contribution to the low dissolved oxygen event in 1994?

J. Fitzpatrick: the model captured the 1994 summer particulate organic carbon and chlorophyll relatively well and the results do not suggest that there was unusual primary production in 1994. Increases in bottom temperature, as well as what appears to be influxes of low bottom dissolved oxygen from the Gulf of Maine, may have been responsible for the low bottom water dissolved oxygen.

OMSAP: do you have time series of the dissolved oxygen at the boundaries, and if so, any idea of what kind of variability there is?

J. Fitzpatrick: 1994 boundary data suggest that much of the low dissolved oxygen values entering from the Gulf of Maine were about 7 mg/L. The model calculated an additional 1 mg/L drop due to oxygen consumption, deposition of organic matter, and increase in bottom temperature. 1995 also was a low dissolved oxygen year, 1996 and 1997 were higher and these years would be worth examining further. However, there are only two cruises during the late summer and the time series is relatively short. It might be useful to increase boundary sampling for better definition, at least with respect to dissolved oxygen.

OMSAP: how many zooplankton species are included in the model?

J. Fitzpatrick: none. Predation pressure in the model takes temperature into account, i.e. warmer temperatures, more predation.

OMSAP: is it a parameterized grazing pressure?

J. Fitzpatrick: yes.

Audience: does the model catch upwelling?

J. Fitzpatrick: yes, reasonably well.

Audience: should there be additional model runs using data after 1994?

K. Keay: as recommended by the Outfall Monitoring Task Force several years ago, MWRA/HydroQual ran the model for the additional years of 1993 and 1994 to see how it captured some of the events that were noted in the monitoring program. MWRA is requesting guidance in terms of whether to proceed with the model as it is currently formulated and run additional years and so the OMSAP agreed to form a model evaluation group (MEG). Some questions we would like to ask are: Should additional baseline years be run, and if so, which years? Is the model evaluation adequate, or should additional model development be looked at before running the model again?

B. Beardsley asked that people submit any questions about the model, model data, model revisions or ideas about whether the model should be run in the future.

OMSAP: the model zooplankton grazing rate and benthic community interactions do not use real data. How important is it to use real data, or can parameterization be used for some of these issues?

A. Solow: the model does parameterize zooplankton grazing.

K. Keay: the model does have sediment regeneration as temperature-dependent functions, also in relation to loadings.

J. Fitzpatrick: yes, it is parameterized in terms of the particle mixing which attempts to represent the benthic fauna. Grazing is basically 10% constant temperature-corrected.

OMSAP: is that sufficient enough, or do you need to add real data?

J. Fitzpatrick: there is a limitation using zooplankton data because the variability measured at the monitoring stations cannot be extended over the entire bay.

OMSAP: can you use any of the data being collected to test the parameterization?

J. Fitzpatrick: yes, at least to find out grazing percentages.

Audience: one of the real strengths of the model for which you may be able to use it in the future is to look at processes which are going on once the outfall goes on-line. Which are the boundary conditions that would make the model easy to run in real time in the future? What would it take to make the model easier to run in the future?

M. Mickelson: [We have been using the BEM model for long-term hindcasting rather than in real-time mode. Real-time modeling (e.g. http://robinson.seas.harvard.edu/PAPERS/AMS_NO.html) has different objectives and requires adaptive sampling.]

B. Beardsley: I think the present monitoring program probably does not do a good enough job monitoring the boundary conditions. MEG will address this.

C. Hunt: in 1998-1999 more ammonia was measured in the harbor after the transfer of flows from Nut Island to Deer Island. Would BEM predict the observed response? Though this is not an outer boundary issue, it is a testable event.

B. Butman: models seem to have been used to date as "climatological" tools, but we have not used them to examine particular events. There may be several events that have occurred during the baseline period that you could apply the model to.

C. Hunt: we have used the model to examine things such as the effect of changes in total nitrogen loading.

B. Beardsley: during the summer when the water is stratified, there are a lot of short, spatial phenomena occurring, and the model was able to reproduce the "climate" correctly, but not the "weather". However, during the winter, the water column is more homogeneous and the physics are simpler, so the model does better predicting the "weather". The model could be used to examine winter storm events in greater detail.

Sediment Transport and Topography

OMSAP: what is the tidal excursion at the outfall site?

B. Butman: about 2-3 km.

Audience: is that slide enhanced? [backscatter picture showing the diffusers]

B. Butman: the patterns on either side of the new outfall line are artifacts that could be cleaned up, but the pattern along the outfall is the true image.

Audience: how deep did the sediment core sample? [silver data figure]

B. Butman: roughly a 50cm core was sampled. The results shown are just the upper half centimeter.

Audience: are these results [lead in surface sediments] from the top half centimeter of core?

M. Bothner: possibly the top 1 cm.

OMSAP: is burial in these areas important?

B. Butman: it could be a combination of burial and mixing. Profiles of cores show a subsurface maximum concentration decreasing towards the surface. This implies that newer, cleaner material is being deposited.

Audience: is anyone using a core to reconstruct the history of contamination?

B. Butman: yes, we are in the process of doing that. The pre-industrial levels occur at 50-100 cm below the surface in most of areas. Using lead-210 and cesium dating one can examine the depositional histories of these areas. However, sediment profiles can be complicated by mixing/bioturbation so a mixing model needs to be used to take that into account.

M. Bothner: we have a good core from one location in Boston Harbor where the cesium and lead-210 agree and the lead profile mirrors what has been found in a pond in Central Park in New York City. The lead seems to be more controlled by the practice of incineration in the 1940's rather than the use of lead in gasoline.

Audience: are methylated and bioavailable forms differentiated from total sediment inorganic contaminants?

M. Bothner: we look at total metals but the next phase of this study will use new techniques developed at WHOI to examine speciation (but may not measure methylated forms).

OMSAP: any idea of the relative sources of fine-grained sediments – are they land-based verses relict mud deposits on the shelf?

B. Butman: silver was our first attempt at a mass balance, and we have not calculated a mass balance for fine-grained sediments. However, the sources of natural sediments are pretty small. Existing sediments are mainly moved around and input from rivers is not large.

OMSAP: is the outfall sufficiently offshore and away from the wave resuspension zone?

B. Butman: the outfall is 30m deep, in the midrange of the wave resuspension zone. At 30m, large waves from the northeast will resuspend and move bottom sediments.

OMSAP: are some of these storms strong enough to resuspend sediments even in Stellwagen Basin? Especially in the area containing dredge spoil?

B. Butman: on occasion, but only with very long, low period swell or large amplitude internal waves that occur in the summer. Winter storms cause resuspension in the shallow inner shelf but in the deeper basin, it appears to be summer internal waves that cause resuspension.

OMSAP: is there active dredging in Boston Harbor? If so, where is the dredge spoil disposal site relative to areas of resuspension?

B. Butman: currently, there is dredging in the inner harbor and some dredge spoil is being deposited in the Massachusetts Bay disposal site in 85m of water, out of the wave resuspension zone. This does not appear to be a major source of sediments to the system.

T. Fredette: material from the current deepening project in Boston Harbor is primarily Boston blue clay. Contaminated material is stored within the harbor in sub-channel disposal pits. The entire project is moving about three million cubic yards of material.

OMSAP: is there any possibility that the relocation of the outfall site outside of the harbor will facilitate the transport of contaminated sediments into Cape Cod Bay by wave resuspension and southerly transport?

B. Butman: it was estimated that greater than 75% of particles entering the system were exported from Boston Harbor with the present outfall situation, thus approximately 25% were sequestered in Boston Harbor. I believe that almost anything discharged from the outfall will not be sequestered locally. However, total particle and contaminant loading will be reduced by a factor of 3 o 4.

Audience: with regard to the silver mass balance, nice work, but it might be a little premature to say that all of the silver is from Boston Harbor since there quite a bit of industrialization along the entire coast. Two examples of industrialized areas include Plymouth (outfall present and no sampling station) and the Merrimack River (manufacturing) which could be sources of contaminants in Cape Cod Bay.

M. Bothner: the authors of the study would agree completely and have the same concerns about sources. However silver correlates very well with Clostridium perfringens which is an anaerobic bacteria spore present in sewage. Since Boston is the biggest local source of Clostridium, it makes us believe that most silver in Massachusetts Bay could be coming from Boston Harbor.

B. Butman: we have not made measurements at Plymouth, but we could. However, in terms of sludge and contaminants, Boston is the largest source by about 1-2 orders of magnitude. Another possible source of silver is a glass blowing plant in Sandwich but M. Bothner sampled in nearby marshes and did not find high concentrations of silver.

Benthic Communities

Audience: are all benthic samples taken at the same time of year?

K. Keay: yes, MWRA has conducted soft-sediment sampling mid-summer throughout the baseline period.

OMSAP: are the data rarefied? Do you correct for the number of individuals? [species diversity data]

K. Keay: the graph of "increased Harbor species richness" shows the average species per grab. It is the average number of species collected in the sampled region. Three samples are collected per station at 8 sites and this is the average of the 24 samples. This measure is blind to differences in species composition.

Audience: are units in milligrams of carbon? [HydroQual model results "Bay outfall with secondary treatment"]

K. Keay: correct.

Audience: how deep is the sediment profile? [sediment profile image on page 17]

K. Keay: the entire view is 20 cm and the sediment is 12-14 cm deep.

OMSAP: please define "pollution-tolerant" species?

K. Keay: we examine enrichment-tolerance as opposed to contaminant-tolerance for benthic communities.

Audience: with regard to the community parameters for Massachusetts Bay, you indicated that [evenness] was significantly statistically different in 1998 compared to all the previous years.

K. Keay: that was a one-way ANOVA with two groups. All 1992-1997 replicates were in one group, and 1998 replicates were in the other.

Audience: were you calculating that station by station or averages for each station? Is there any pattern?

K. Keay: individual replicates. In the nearfield, a fraction of the stations have replication whereas a larger number of them only have a single sample. In terms of how best to treat those in analyses, using them as individual replicates is the best we can do. The changes in diversity and evenness are occurring primarily at the sand and silt sites. Stations characterized mostly by medium sands like NF17, have little trend in diversity, richness, and evenness through time. It is mostly the softer sediment stations which drive the pattern. Between 1992 and 1993, we went through a major redesign of the nearfield sampling design and went back again to a design similar to 1992 for 1994 on. Looking at the western Massachusetts Bay farfield sites (FF10, FF12, FF13), the pattern of richness matches the entire western Massachusetts Bay.

Audience: is 1993 is a sampling artifact?

K. Keay: our data review did not indicate that.

OMSAP: are you suggesting that the decreasing trend in species is due to re-setting of the sediment by storms?

K. Keay: the decreasing species diversity trend in 1992-3 was restricted in the nearfield. The farfield sediments outside of western Massachusetts Bay do not show the same pattern. The increase over the last 3-4 years is an exciting finding that we do not have an explanation for but it is similar to some of the cyclical patterns that have been seen in fauna in the Gulf of St. Lawrence as well as the West Coast. Thus this pattern is difficult to ascribe to any sort of recovery due to sediment transport because we did not see large changes in the community from 1993-4 except for a few sites which were highly influenced by storms. Similar fauna were found in the muddy sites in 1993 as 1992 and 1995. So there is increasing species richness. There are additional relatively rare species showing up which appears to be a physical disturbance/recovery from a storm event. This pattern here [showed figure] might be a response to regional Gulf of Maine-scale events. We do not see a trend in, for example, chlorophyll that might suggest some response to the eutrophication on a Bays-wide scale and there is no corresponding trend in the hydrographic data.

OMSAP: could this be natural variability on longer time scales?

K. Keay: I suspect we may have caught part of a long-term cycle. It may be simple variability but seeing it in both in the nearfield and farfield suggests it is variability on a large scale.

Audience: would there be a difference if you separated the mud stations from the sand stations in that average?

K. Keay: most of the muddy sites sampled in the nearfield would show this pattern of increasing richness through time but not the sandy sites.

B. Diaz: it appears that by looking at the images from nearfield and Boston Harbor that 1999 will probably be another "high species year". Ampelisca continues to decline in the harbor which makes sense since species richness is increasing as the community succession advances. Biological processes are dominating in the nearfield and there are practically no bedforms remaining at our sandy sites (have been reworked from 1998-1999).

OMSAP: the coastal area near U. Mass Boston is highly contaminated. Do you see the import of sandy material from outside the harbor into the harbor with high storm surge, i.e. what happens in the harbor in terms of transport during large storms?

K. Keay: northeast winds blow from Deer Island flats across Dorchester Bay near U. Mass Boston. Nearby, material in the highly polluted Savin Hill Cove site is resuspended and settles out. Research by Gordon Wallace on lead-210 and other tracers suggests that the deposition rates are approximately 4-6 cm per year. Is the harbor a net importer or exporter of sediments?

M. Bothner: the harbor could be both an importer and an exporter.

B. Beardsley added that there also could be a lot of resuspension and movement of sediments which remains within the harbor.

OMSAP: the Ampelisca mats have the potential of greatly changing the chemistry of the sediments. Has anyone looked at the sediment contaminant levels at these sites, versus sites that were not colonized for any changes? Is there at least enough data to take a preliminary look?

K. Keay: the Combined Sewer Overflow (CSO) sampling surveys have sampled a lot of sites in Dorchester Bay in 1990, 1994 and 1998. Several of those sites are the same as or close to sediment camera and/or bottom sampling stations. Dorchester Bay is one site where there was a large expansion of Ampelisca mats between 1991-1994. Thus there might be data to examine this.

Audience: does commercial dragging impact areas sampled by this program?

K. Keay: commercial dragging does not occur in Boston Harbor. Dragging does occur in Massachusetts Bay and in the western nearfield, especially in an area called Rosie's Hole. Trawling effects on benthic communities have not been very well studied, however it certainly is a tremendous disturbance. Many of the nearfield depositional sites sampled are too small to be dragged by fishermen (i.e. surrounded by boulders). However, dragging could be affecting the farfield stations that coincide with fishing grounds.

Nutrient Fluxes in the Harbor

Audience: is there any sediment chlorophyll data from Massachusetts Bay sites to suggest enrichment in May 1999?

A. Giblin: we have the data, but it has not been analyzed yet.

Audience: the sediment oxygen demand data in Massachusetts Bay increases throughout the summer and remains high even in October, whereas in Boston Harbor the data peaked in July and then decreased. What is causing this decrease in Boston Harbor, are animals running out of a food source, or is there a decrease in temperature?

A. Giblin: the sediment oxygen demand follows temperature relatively closely in Massachusetts Bay and the temperature continues to increase until the fall overturn. This relationship is not as evident in Boston Harbor because of the biological influence of amphipod mats. Without the mats, the sediment oxygen demand would correlate with the seasonal cycle of temperature.

OMSAP: within Boston Harbor, it looks as though the sediments are an important source of nutrients to the water column, mostly near the sewage outfall. With the outfall relocation, will there be enough of a reservoir of nitrogen such that sediment fluxes will be driving some of the nutrient productivity dynamics in the harbor?

A. Giblin: I suspect that it will take somewhere between 1-2 years for the system to re-equilibrate, after which we should see a typical coastal environment. Long-term productivity will be driven by new inputs from the outside and the sediments will provide a buffer. In systems with limited tidal exchange it is possible to recycle nutrients many times. But this will not play a large role in Boston Harbor because of the large tidal fluxes and short water residence time.

OMSAP: do you think the presence of toxic contaminants in sediments are having some effects on the regeneration dynamics and if so, will some of those dynamics change as the sediments become cleaner?

A. Giblin: given the high respiration rates, there is no indication that the microbes are having any problems. In 1992 the Savin Hill Cove station was so polluted that hydrocarbons were leaching out of the sediment and yet the respiration rates were still very high, although no macrofauna were visible. Based upon the high densities of animals measured at the other stations, there do not appear to be any acute toxic effects.

Audience: did you make any attempt to separate macrofaunal from bacterial respiration?

A. Giblin: no because we try not to kill any of the animals and keep the whole system as intact as possible so that we simulate the entire community's respiration which is the oxygen demand for the water column. However, it would be interesting to undertake this.

Audience: regarding your statement about Boston Harbor sediments having the ability to provide 35% of the nitrogen given the published net primary production, is that on an annual basis?

A. Giblin: yes.

Audience: does the work here relate to J. Fitzpatrick's nitrogen mass balance?

A. Giblin: the model estimates a 15% nitrogen loss for denitrification. Inputs are entered into the model and there is a small error term in the model. The remaining nitrogen is assumed exported. I actually measure the loss of nitrogen gas. J. Fitzpatrick models the same nitrogen loss based on parameters of carbon deposition and nitrogen remineralization and both the model and the data agree.

J. Fitzpatrick added that there is a more accurate value specific to Boston Harbor.

Audience: what is the amount of nitrogen being exported from Boston Harbor based on?

A. Giblin: this is a mass balance argument based upon the fact that the harbor stations are not responsible for a large amount of nitrogen removal. Therefore, if it is not being removed in the harbor through burial or denitrification, it must be exported.

Hardbottom Community

OMSAP: would these hardbottom communities survive after a large storm such as a hurricane?

B. Hecker: most of these communities would probably survive.

OMSAP: the northeastern part of Georges Bank has cobble areas which are the preferred substrate for cod and haddock larvae. Are similar nursery habitats found near the new outfall?

B. Hecker: larvae are too small to be seen in the video and photographs.

OMSAP: is there any indication of rocks turned over due to dragging/trawling?

B. Hecker: I have not seen any indication of dragging but do see lobster gear. We could tell if there was dragging because it would cause damage to the upright algae.

Audience: what if sea urchins proliferate near the outfall after it goes on-line and consume Lithothamnion, would the loss of Lithothamnion be blamed on the outfall?

B. Hecker: this would not occur because green urchins prefer high relief on the tops of the drumlins away from the diffusers.

Audience: can you give us a sense, in a semi-quantitative way, what kind of confidence you have in how your observations represent a particular station?

B. Hecker: variance measures of pictures within stations generally show that Lithothamnion was the most variable species with a coefficient of variation of 175% per picture. Other species had coefficients of variation of several hundred per picture but this is to be expected from any epifaunal study since you have to pool over a number of pictures or larger areas because of patchiness. However, I am very confident that we can revisit stations since landmarks such as boulders remain stationary.

OMSAP: how good is your navigation, is it plus or minus 5 m?

B. Hecker: yes, on the surface, then the ROV and tether must to be taken into account.

OMSAP: is that accomplished acoustically?

B. Hecker: it is an electronic ranging system. We can use it successfully to find a specific rock or even diffuser 44, but it takes us about four times longer to search and we can not do that for every station.

Audience: do you sample in the summer?

B. Hecker: we sample in June (in 1996 sampling occurred in July).

Audience: I would have thought that the sediment drape would be blown away in the winter, and that the shallow stations would be the cleanest.

B. Hecker: not true because stations found at similar depths have been found to have completely different thicknesses of drape. Most likely, sediment drape is carried away in the winter, and redeposited during the warmer months, but that this process is not stable throughout the year.

Audience: what is the light requirement of Lithothamnion?

B. Hecker: Gulf of Maine Lithothamnion peaked at 40m, and was found down to 63m. In terms of its actual light requirements, kelp is approximately 1% of surface light in terms of extinction depth, the red algae is 0.1%, and the coralline [Lithothamnion] is 0.01% of surface illumination.

Audience: would an increase in turbidity due to the outfall affect Lithothamnion?

B. Hecker: yes, if the increase in turbidity decreased light transmission, I would expect to see a decrease in the percent cover of Lithothamnion. Another negative effect could be particulates settling out of the effluent increasing sediment drape which is detrimental to Lithothamnion.

Audience: do you have any idea how the hardbottom communities around Deer Island may recover? Would Lithothamnion colonize the area?

B. Hecker: a type of coralline algae, possibly Lithothamnion, has been observed around Deer Island.

B. Beardsley: B. Hecker is monitoring communities within one tidal cycle of the outfall pipe at a depth below the thermocline. There might be an increase of particles from the new outfall which affect Lithothamnion.

B. Butman: the suspended solid concentrations in the effluent are about 30 mg/l. Dilution past the zone of initial dilution is 100:1 to 300:1 diluting the suspended solids concentrations to 0.03 - 0.3 mg/l. Background concentrations of suspended solids are about 1 mg/l.

B. Hecker: I am more interested in changes in productivity that might affect light transmission and increase particle deposition thus negatively affecting Lithothamnion. There has not been any work done on how long Lithothamnion can survive buried.

B. Butman: there are no measurements in this monitoring program of the flux of sediments to the hard bottom because of the difficulty in obtaining measurements.

Mussels and Bioaccumulation

Audience: are the mussels from Sandwich high in organic contaminants?

L. Lefkovitz: they are relatively high in DDT, but not at dangerous levels.

Audience: are these units in wet weight?

L. Lefkovitz: yes, units on all of our tissue thresholds are calculated using wet weight so that we can compare to FDA limits.

OMSAP: is your outfall station in the zone of initial dilution?

C. Hunt: it is near to that. It was set near Buoy B for every baseline year except 1998 when we tried to move it closer to the outfall. However, we had some problems with recovery due to dragging and other fishing activities in that area so we are still working on how to protect deployments. When the outfall goes on-line, we will try to deploy as close as we can to the diffusers.

M. Hall: the intent is to get within the zone of initial dilution that is 60m on either side of the outfall diffusers.

OMSAP: the caution levels are quite close to what is already being measured yet the Massachusetts Bay mussels are not showing nearly as much bioaccumulation as the harbor mussels. If the mussels are within the zone if initial dilution, the original EPA Environmental Impact Statement would allow for some degradation. Isn't the threshold overly conservative?

D. Tomey: yes and we have a mixing zone established. We had discussed using the edge of the mixing zone.

C. Hunt: I do not expect us to see changes that would exceed the threshold.

OMSAP: what are we aiming for with the caution level shown on the graphs of contaminants versus years?

M. Mickelson: the caution level is the doubling of the mean baseline; the warning level is 80% of the FDA advisory level.

OMSAP: but within the zone if initial dilution, you might expect an impact. I think the caution level should apply to samples from the edge of that zone of initial dilution (60m).

C. Hunt: so the physical location of the mooring should be just outside the edge of the ZID (about 60m to the north or south). The caution number here is based on twice the baseline so it is very conservative. The 70:1 dilution of the modeling was met approximately 60m off of the diffuser line.

OMSAP: is that over a tidal cycle?

M. Mickelson: [70:1 was the lowest dilution, which occurs at slack water. Currents perpendicular to the line of diffusers increase the dilution.]

C. Hunt: in the outfall siting studies, we measured water column metals and organics at several stations and Massachusetts Bay water column contaminants are fairly constant and very low, unlike contaminants in the sediments. We can sample anywhere in that area pre-outfall and obtain a representative number. However, when the outfall goes on-line, we have to measure any bioaccumulation within the zone of initial dilution where we meet the permit requirements.

OMSAP: will there be another mussel deployment location further downstream?

C. Hunt: there will be one in Cape Cod Bay.

OMSAP: nothing in between?

C. Hunt: nothing between right now.

K. Keay: we set the baseline caution level at twice the baseline mean as a result of discussions with the Outfall Monitoring Task Force in late 1997 in terms of tissue residues of PCBs. We apply this approach to the entire fish and shellfish program which looks at appreciable change so that we have a consistent approach in setting caution levels. We set the warning level thresholds at 80% the FDA levels for compounds that have FDA consumption advisories. I would be surprised if we see a doubling of the current levels on the edge of the zone of initial dilution.

C. Hunt: we have looked at significant change and based on the baseline data and variability, we should be able to see significant change before we hit that caution level so we can detect change before we get to that level. Thus the detectability is powerful.

Audience: is it the average that is compared to the caution level?

C. Hunt: it is the mean. In the water column thresholds, using the upper confidence interval could trigger a threshold too early and using the lower confidence interval could trigger a threshold too late so using the mean is more conservative.

M. Moore suggested adding an additional mussel deployment once the outfall goes on-line to provide greater spatial coverage.

B. Beardsley: agreed that this would help initially and might answer some of the spatial questions.

L. Lefkovitz: that is possible but it is difficult to successfully deploy caged mussels.

Audience: why does 1996 seem to have more variation than some of the other years?

L. Lefkovitz: we have not identified any particular reasons for that.

Audience: are results lipid normalized for organic contaminants?

L. Lefkovitz: we found that lipid normalizing the data did not reduce any variability or provide additional information or trends. We still examine lipid concentrations but we do not normalize the results.

Audience: have similar studies been done elsewhere which look at interannual variability?

L. Lefkovitz: caged mussels are used routinely for monitoring in other areas.

C. Krahforst: GulfWatch is an ongoing regional program with 6 years of data (using native and caged mussels).

L. Lefkovitz: there are also mussel studies in Boston Harbor.

C. Hunt asked to look at the GulfWatch data.

M. Hall added that MWRA detection limits are lower than GulfWatch.

OMSAP: are there problems when different population of mussels are used from year to year?

L. Lefkovitz: we always collect mussels from the same place every year. Early on, all mussels used were from Gloucester, and we found that the pre-deployment metals values were higher than Sandwich mussels.

OMSAP: what if different strains of mussels are used which have different bioaccumulation potentials or what if there is a diseased population one year which has a different bioaccumulation potential, would that confound the results?

L. Lefkovitz: we try to assess the health of the pre-deployed mussels as soon as we collect them. We collect a certain size class (60-70mm) from the same locations.

OMSAP: would you ever want to use SPMDs (Semi-Permeable Membrane Devices)? A SPMD is a polyethylene bag with a hollow tube pressed flat containing a thin film of synthetic lipid. This device mimics living membrane such as gills, fish skin, or mussels and bioaccumulates organics.

L. Lefkovitz: we may use them in the future, however SPMDs do not accumulate metals. In my opinion, they would be good to use because they are very consistent, and animal health is not an issue. Though the mussels generally survive quite well, there are definitely confounding factors whenever animals are used in monitoring.

Audience: how are PCBs calculated?

L. Lefkovitz: we use a sum of the 20 NOAA congeners but do not multiply by two for comparison to the FDA limits. Results do not come close to the FDA limits.

Audience: it may be useful to measure silver, which is a potentially good tracer of effluent, to assess the impacts of bioaccumulation.

C. Hunt: in general, metals do not bioaccumulate. After they reach some level, they do not continue to increase as with the organic contaminants, and thus are not a good measure of bioaccumulation.

Flounder Histology and Tissue Chemistry

OMSAP: how old are the flounder which are studied?

M. Moore: they average about 4 years of age and the average age has not changed very much over the duration of this study.

OMSAP: What is the cause for the original decrease [in tumors]?

M. Moore: it precedes much of the MWRA Boston Harbor Project considering that the latency period of tumor development is 5 years. It may be due to the recession in the 1980's during which a lot of the dirty industries in the Boston watershed area were shut down. Certainly the later trend is significantly associated with source reduction and better MWRA effluent quality. USGS has a data series of Deer Island Flats sediment concentration trends over the last 10-15 years that I would like to examine. Organic contaminant data is important since organics drive flounder disease much more than the inorganic contaminants.

OMSAP: what if flounder migratory patterns change, could you see an effect and mistakenly blame the outfall? [i.e. if Boston Harbor flounder migrate to Cape Cod Bay]

M. Moore: that is a problem since there is no genetic distinction between the flounder.

OMSAP: can you tag flounder to study their migration?

M. Moore: yes, there is tagging data from the mid-1970's which we still use to base assumptions on migration today. However, one of the authors expressed reservation about the significance of the data due to bias with regards to fishermen inside the harbor returning more tags than fishermen outside the harbor. It would be useful to conduct acoustic tagging studies.

OMSAP: percent prevalence of centrotubular hydropic vacuolation (CHV) of Cape Cod Bay flounder liver seems to be increasing over time, is this significant?

M. Moore: I do not think so.

OMSAP: what kinds of values would be measured further out?

M. Moore: Georges Bank flounder have zero percent CHV and the entire liver structure is far less complicated.

OMSAP: what kinds of values would be measured east of Stellwagen Bank or the western Gulf of Maine?

M. Moore: I have not looked but suspect results would be more similar to inshore flounder as opposed to Georges Bank.

OMSAP: can you use commercially obtained fish?

M. Moore: if you have accurate information as to where they were fished. I always capture the flounder which I analyze.

Audience: have you examined other species of bottom fish for tumors?

M. Moore: I have not, but there have been no reports of tumors [in this area].

Audience: do you catch other fish?

M. Moore: mainly yellowtail flounder, winter flounder, and many small skates.

Audience: would a decrease in size distribution be a compounding factor when examining trends in CHV over time?

M. Moore: we have age data from NMFS from 1991 onwards and we have not seen a significant reduction in age, but this can be revisited.

OMSAP: assuming tumors have a latency period of five years, if tumors begin to be measured in a population, does that mean that the stress happened five years ago?

M. Moore: yes, for tumors. Vacuolated cells can develop in 2-3 years, and so this is not an acute response indicator.

OMSAP: what happens if you remove the stress at year four, does that mean that you will not see elevated tumors?

M. Moore: it depends on the nature of the tumor, genetic change, and chemical compound causing the stress. If we consider the growth of a pre-existing condition, then removing the stress of the outfall will not change anything. If the stress that is still promoting the growth of that tumor is removed or reduced, the time before the tumor becomes evident is prolonged. However, hydropic lesions are much more sensitive and are predictive of tumor risk. If there is a persistent impact of toxics at the Massachusetts Bay outfall site over three years, it can be measured in about three years.

OMSAP: it was found that fish exposed to contaminated sediments formed lesions, and that the lesions disappeared when the fish were placed in clean sediments.

M. Moore: it depends on the severity of the lesion and the type of fish since various species have different disease processes. The CHV is present in winter flounder, starry flounder, and croaker but not English sole. We do not know whether CHV is reversible since no one has successfully done those kinds of experiments in winter flounder.

Audience: do you have any idea why the metals in flounder fillet are so different from the organics? Results, in particular silver, show higher levels in flounder from the outfall and lower levels in flounder from Boston Harbor and Cape Cod Bay.

M. Moore: it is not clear what the metals data indicate.

J. Fitzpatrick: it is possible that the sediments in Boston Harbor are very reduced producing a lot of sulfides which bind metals and make them not bioavailable but I am not sure if this same process is occurring in Cape Cod Bay.

Audience: any idea of what percentage of these compounds have a strong atmospheric component? Now that we will soon have full secondary, are we still looking at one major source?

M. Moore: if there was a strong atmospheric component, then the consistent between site variability would not be so high.

ATTENDANCE

WEDNESDAY, SEPTEMBER 22

NAME AFFILIATION Membership
Carl Albro Battelle Ocean Sciences  
Robert Beardsley Woods Hole Oceanographic Institution OMSAP
Dave Borkman U Rhode Island/U. Mass Dartmouth  
Brad Butman United States Geological Survey  
Sally Carroll Massachusetts Water Resources Authority  
Cathy Coniaris New England Interstate OMSAP staff
  Water Pollution Control Commission  
Kelly Coughlin MWRA  
Deridre Dahlen Battelle  
Patty Daley Cape Cod Commission PIAC
Bob Diaz Diaz & Daughters  
Jennifer Daquioag MWRA  
Targuin Dorrington URI  
Dave Dow National Marine Fisheries Service IAAC alternate
Brian Ellis Technology Planning & Mgmt Corp  
Marianne Farrington New England Aquarium PIAC
Jim Fitzpatrick HydroQual  
Tom Fredette US Army Corps of Engineers IAAC
Rocky Geyer WHOI  
Anne Giblin Marine Biological Laboratory  
Gillian Grossman Save the Harbor/Save the Bay PIAC
Maury Hall MWRA  
Barbara Hecker Hecker Environmental  
Doug Hersh MWRA  
Carlton Hunt Battelle  
Russ Isaac MA Dept of Environmental Protection IAAC
Bruce Keafer WHOI  
Ken Keay MWRA  
Aimee Keller URI  
Bob Kenney URI OMSAP
Christian Krahforst MA Coastal Zone Management IAAC
Roy Kropp Battelle  
Lisa Lefkovitz Battelle  
Wendy Leo MWRA  
Scott Libby Battelle  
Matt Liebman Environmental Protection Agency IAAC
Steve Lipman MADEP IAAC alternate
Joe Lobuglio MWRA  
Mary Lydon MWRA  
Nancy Maciolek ENSR  
Ron Manfredonia EPA  
Rich Masters Normandeau Associates  
Mike Mickelson MWRA  
Scott Mitchell Association for the Preservation Cape Cod PIAC
D. Monsiett MWRA  
Scott Nixon URI OMSAP
Arleen O'Donnell MADEP  
Candace Oviatt URI  
Judy Pederson MIT OMSAP
Jerry Pesch EPA  
Susan Redlich Wastewater Advisory Committee PIAC
Ginny Renick MWRA  
Andrea Rex MWRA  
Steve Rhode MWRA  
Amy Salditos U Mass Dartmouth  
Larry Schafer retired  
Jack Schwartz MA Division of Marine Fisheries IAAC
Dillon Scott MWRA  
Michael Shiaris U Mass Boston OMSAP
Jim Shine Harvard School of Public Health OMSAP
Andy Solow WHOI OMSAP
Dave Taylor MWRA  
Sal Testaverde NMFS IAAC
Dave Tomey EPA IAAC alternate
Tara Toolan MWRA  
Heather Trulli Battelle  
Wayne Trulli Battelle  
Steve Tucker CCC  
Jane Tucker MBL  
Jeff Turner U Mass Dartmouth  
Grace Vitale MWRA  
Christine Werme consultant  

THURSDAY, SEPTEMBER 23

NAME AFFILIATION Membership
Carl Albro Battelle  
Robert Beardsley WHOI OMSAP
Mike Bothner USGS IAAC
Brad Butman USGS  
Jim Campbell TPMC  
Sally Carroll MWRA  
Anthony Chatwin Conservation Law Foundation  
Cathy Coniaris NEIWPCC OMSAP staff
Diane Cowan Lobster Conservancy  
Deridre Dahlen Battelle  
Mike Delaney MWRA  
Bob Diaz Diaz & Daughters  
Jennifer Daquioag MWRA  
Dave Dow NMFS IAAC alternate
Brian Ellis TPMC  
Marianne Farrington NEAq PIAC
Jim Fitzpatrick HydroQual  
Tom Fredette USACE IAAC
Anne Giblin MBL  
Gillian Grossman SH/SB PIAC
Maury Hall MWRA  
Barbara Hecker Hecker Environmental  
Doug Hersh MWRA  
Carlton Hunt Battelle  
Tamah Hunt Boston University  
Russ Isaac MADEP IAAC
Bruce Keafer WHOI  
Ken Keay MWRA  
Bob Kenney URI OMSAP
Christian Krahforst MCZM IAAC
Roy Kropp Battelle  
Lisa Lefkovitz Battelle  
Wendy Leo MWRA  
Scott Libby Battelle  
Matt Liebman EPA IAAC
Joe Lobuglio MWRA  
Nancy Maciolek ENSR  
Ellen Mecray USGS  
Mike Mickelson MWRA  
Mike Moore WHOI  
Scott Nixon URI OMSAP
Judy Pederson MIT OMSAP
Jerry Pesch EPA  
Susan Redlich WAC PIAC
Ginny Renick MWRA  
Andrea Rex MWRA  
Steve Rhode MWRA  
Larry Schafer retired  
Jack Schwartz MADMF IAAC
Dillon Scott MWRA  
Michael Shiaris UMB OMSAP
Jim Shine HSPH OMSAP
Andy Solow WHOI OMSAP
Dave Taylor MWRA  
Sal Testaverde NMFS IAAC
Dave Tomey EPA IAAC alternate
Tara Toolan MWRA  
Heather Trulli Battelle  
Wayne Trulli Battelle  
Alex Tsukeruik HSPH  
Steve Tucker CCC  
Jane Tucker MBL  
Jeff Turner U Mass Dartmouth  
Katrina Vandine Stellwagen Bank National Marine Sanctuary  
Amy Vinturella HSPH  
Christine Werme consultant  

OMSAP Abstracts, September 22 and 23, 1999
9:00 AM – 5:00 PM
THE BOSTON HARBOR PROJECT PROGRESS TO DATE

Major Milestones of the Boston Harbor Project
Andrea Rex
Massachusetts Water Resources Authority, Boston MA

Brief re-cap of the major milestones of the Boston Harbor Project.

Effluent Quality
Steve Rhode
Massachusetts Water Resources Authority, Boston MA

This presentation will review historical trends in DITP effluent quality from the opening of the new treatment plant in 1995 to date. Historical data for annual metals and solids loadings, coliform levels and effluent concentration data for TSS, BOD and total PCBs will be presented. The correlation between the plant performance and effluent PCB loadings will be described. The composition of the detected PCBs and evidence for possible seasonal effects on effluent PCB concentrations will be discussed.

MWRA efforts to control PCB loading through the TRAC program will be reviewed, and the limitations of approved EPA testing methods relative to this effort will be described. Method issues associated with the total PCB monitoring requirement in the NPDES permit will be described and preliminary performance data for MWRA's proposed method will be presented.

Changes in Harbor Water Quality in Response to Transfer of Nut Island Flows
David Taylor
Massachusetts Water Resources Authority, Boston MA

In July 1998, flows of wastewater from Nut Island WWTF were transferred through Deer Island WWTF. The transfer ended more than four decades of wastewater discharges from Nut Island WWTF to the South Harbor, and increased flows from Deer Island WWTF to the North Harbor by one half. Analysis of long-term water quality data collected in the Harbor indicates that significant changes in water quality have occurred in the Harbor since transfer. The changes in the North Harbor and South Harbor have been quite different, and not necessarily the opposite of each other.

Comparison of average secchi depths before and after transfer indicates an increase in water clarity in the South Harbor, with no measurable decrease in water clarity in the North Harbor. In the South Harbor, the increase was greatest at the previous sites of the Nut Island outfalls, where average secchi depths increased 1 m, from 2 to 3 m's. Further afield in the South Harbor, the increase has been confined to winter, when average secchi depths have also increased 1 m from 3 to 4 m's. No decrease in clarity was observed at the Deer Island outfalls in the North Harbor, presumably because of the improved secondary treatment of wastewater at the Deer Island facility.

Unlike for water clarity, where changes have been confined to the South Harbor, concentrations of dissolved inorganic nutrients in both regions have shown changes. Twelve-month average concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) have decreased in the South Harbor, and increased in the North Harbor, especially at the previous or current outfall sites. At the previous Nut Island outfalls, concentrations of DIN have decreased from 61 to 8 umol L-1. By comparison, concentrations at the Deer Island outfalls have increased from 55 to 72 umol L-1. Further afield in the South Harbor, concentrations decreased from between 10 or 11 umol L-1 to 6 or 7 umol L-1. In the North Harbor, the increases were in the same order as the decreases in the South Harbor, and from 9 to 12 umol L-1.

The effects of the transfer on phytoplankton biomass (measured as concentrations of chlorophyll a) have been complex. In the South Harbor, the responses differed among stations. At the Inner Quincy Bay station, average summer concentrations of chlorophyll decreased from 10 to 7 ug L-1, presumably in response to the decreased DIN loadings from Nut Island WWTF. At the outer Nantasket Roads station, the concentrations increased from 4 to 7.5 ug L-1, presumably in response to the increase in clarity that occurred at this station. In the North Harbor, no significant change in concentrations of chlorophyll could be detected, presumably because of light limitation of phytoplankton growth in this region.

Why the outfall?
Andrea Rex
Massachusetts Water Resources Authority, Boston MA

The outfall is the second of three important components in the protection of the Massachusetts Bay/Boston Harbor ecosystem. (1) cleaner effluent through source reduction and secondary treatment, (2) better dilution, and (3) constant monitoring and contingency planning. Because of the obvious improvements in Boston Harbor, some are questioning the need to use the new outfall/diffuser system. Others wonder if the outfall is not just transferring pollution from the Harbor "away." The outfall location was chosen after a four-year long process including oceanographic and engineering studies, regulatory review, and extensive public participation. The location and structure of the diffuser is designed to maximize dilution and mixing, which will minimize the effects of the major wastewater components, nutrients, remaining in secondary effluent. The greater dilution available also minimizes any risks in the unlikely event of treatment plant upsets. Modeling studies show that the outfall not only decreases the concentration of effluent in the Harbor, but also greatly reduces areas of lowest dilution along the coastline and into Massachusetts Bay. The outfall is designed to trap effluent below the pycnocline in the warmer months, so that nutrients will not be as available to promote surface algal blooms as at present. The length of the outfall affords a long contact time with chlorine disinfectant, which will enable MWRA to effectively disinfect the effluent with a minimum amount of chlorine, significantly less than is used at present. Finally, the outfall is necessary to achieve the maximum hydraulic flow through the treatment plant; and is an essential component in reducing combined sewer overflows.

Monitoring Plan
Mike Mickelson and Ken Keay
Massachusetts Water Resources Authority, Boston MA

As an important part of the Boston Harbor Project, the outfall for treated sewage effluent will soon be relocated from the Harbor to 9.5 miles offshore in Massachusetts Bay. Scientific evidence indicates that relocation will improve the Harbor without harming the Bay. Nevertheless, concerns about potential impacts have been raised. Over the last 8 years, MWRA has developed and implemented a comprehensive outfall monitoring program. Development of the program was guided by the Outfall Monitoring Task Force, which was succeeded by the Outfall Monitoring Science Advisory Panel.

The monitoring program incorporated the newest federal guidelines and received wide technical and public review. It focuses on important ecosystem components likely to be useful as indicators of outfall effects, and consists of four project areas: effluent, fish and shellfish, water column, and benthos.

The monitoring began in 1992 to provide a baseline for comparison to conditions after the outfall is relocated. The 8-year baseline has increased our understanding of the system, allowing MWRA and the oversight committee to translate the stated concerns about the Bay outfall into a set of thresholds which express expectations for the quality of the Bay. Two additional components render the thresholds an effective management tool: a commitment to rapid notification of threshold exceedances, and an up-front consideration of possible responses to those exceedances.

The monitoring program has been incorporated into the new discharge permit for the Bay outfall, ensuring MWRA's commitment to comprehensive monitoring with expert oversight, rapid reporting of monitoring results including threshold exceedances, and responsiveness to concerns.

MONITORING RESULTS

The Physical Environment:
Circulation and Water Properties in Massachusetts Bay
Rocky Geyer
Woods Hole Oceanographic Institution, Woods Hole, MA

Massachusetts Bay is part of the larger circulation regime of the Gulf of Maine. As such, its currents, water properties, and biology are strongly influenced by the conditions in the Gulf of Maine. This interconnection applies to the outfall site as well as Mass Bay as a whole. The dominant characteristic of the water properties of Massachusetts Bay is the large seasonal variation in stratification, from well-mixed conditions in the winter to strong stratification in the summer. There are interannual variations in bottom water temperature and dissolved oxygen at the outfall site that appear to be related to wind forcing. Persistent southerly winds during the summer lead to colder bottom temperatures and higher DO. Weaker southerly winds lead to warmer bottom waters and lower DO. The USGS circulation model indicates that the main influence of the new outfall will be a reduction of the impacts of the effluent in Boston Harbor. The far-field will not be significantly altered.

Water Quality Monitoring Program and Baseline Results
Carlton Hunt and Scott Libby
Battelle, Duxbury, MA

The Massachusetts Water Resources Authority (MWRA) has collected water quality data in Massachusetts and Cape Cod Bays for the Harbor and Outfall Monitoring (HOM) Program since 1992. This monitoring is in support of the HOM assessment of the environmental responses that may result from the relocation of effluent discharge from Boston Harbor to Massachusetts Bay. The data are being collected to establish baseline water quality conditions and ultimately to provide the means to detect significant departure from that baseline. The surveys have been designed to evaluate water quality on both a high-frequency basis for a limited area in the vicinity of the outfall site (nearfield surveys) and a low-frequency basis over an extended area throughout Boston Harbor, Massachusetts Bay, and Cape Cod Bay (farfield). The water column monitoring includes parameters that respond to nutrient loading as well as measurement of anthropogenic viruses, fecal coliform bacterial, and other potential water borne measures of system response such as paralytic shellfish poisoning (PSP). This presentation considers the baseline nutrient related monitoring results.

The water quality monitoring program includes continuous vertical profiles of in situ temperature, salinity, dissolved oxygen, chlorophyll fluorescence, beam attenuation (particle fields), and irradiance, from the water surface to within 5 m of the bottom at each station. Discrete samples from 3 or 5 depths (depending on water column depth) are collected for nutrient analyses (all forms), total suspended solids, chlorophyll a, and dissolved oxygen. Samples are also collected for phytoplankton and zooplankton species enumeration at representative stations throughout the Massachusetts Bay.

Eight years of baseline data show that there is substantial variability throughout the system, both with depth in the water column as well as gradients extending seaward from Boston Harbor. The exchange of Boston Harbor waters, which contain high nutrient levels, with nearfield and coastal waters produces a plume of Harbor water that extends into the western nearfield area and southward along the coast of western Massachusetts Bay. This feature is persistent throughout the year and across all years. These horizontal gradients extending from Massachusetts Bay are less distinct in the bottom waters, partially as a result of water column stratification that occurs from the late spring through the late fall. MWRA's effluent discharge at the mouth of Boston Harbor provides a localized source of nutrients which feeds this coastal plume.

The seasonal nutrient cycle in the Bay is well described and follows conventional wisdom regarding nutrient uptake and control of primary production, phytoplankton and zooplankton species composition, chlorophyll biomass, and dissolved oxygen cycle. Chlorophyll, a measure of the phytoplankton biomass, is one of the water quality measurements and a key indicator in the water quality-monitoring program. Temporal and regional concentrations are variable within the system. Primary producers undergo nutrient limitation in the surface waters in the summer and light limitation in the winter. This results in a seasonal chlorophyll cycle that progresses through a winter spring bloom dominated by diatoms through a period of lower concentration in the summer that is dominated by microflagellates. Maximum chlorophyll levels are generally found in the pycnocline during the stratified period, although the Harbor plume influences distribution in the western parts of the Bay. Chlorophyll levels then progress through a fall bloom, often related to overturn of the stratified water column. This bloom is often dominated by diatoms. During any given season, near monospecific blooms of diatoms or other species such as Phaeocystis can bloom to high levels. The latter species can cause undesirable ecological affects. Of note in the system is a consistent fall bloom that is often larger and more sustained than the classical winter-spring bloom in temperate coastal systems. The largest sustained bloom of the baseline period occurred from the late winter of 1998 through late April of 1999.

Bottom water dissolved oxygen, another key indicator of ecosystem health, also follows a well-defined seasonal cycle. In winter the water column is well mixed and the DO is saturated with respect to atmospheric conditions. As stratification sets up, the DO levels in the bottom waters begin to decline. The rate of decline is relatively constant among years. The DO concentrations at the on-set of stratification, the amount of carbon deposited in the sediments during the fall and winter, and the bottom water temperatures reached in the late fall, all affect the bottom concentrations reached prior to water column turnover. During October 1994 during the baseline period, the mean nearfield bottom water DO decreased to less than 6.5 mg/L (the caution level established under MWRA monitoring program). The DO caution level was approached in early September 1999, possibly in response to the large winter bloom in 1999, and the extended drought and high air temperature experienced since mid-1998.

Phytoplankton and zooplankton community composition generally is consistent within the system and across seasons. Subregions of Massachusetts Bay have similar species composition, although the timing of bloom events may differ. Total numerical abundance varies greatly among samples, surveys, seasons, and regions. Although the variability within surveys is high, distinct temporal patterns are evident in the data. Numerically, diatoms and microflagellates are the major plankton groups within the phytoplankton community. Carbon based abundance is dominated by diatoms. Alexandrium tamarense bloom events have not occurred since 1993. The zooplankton community in Massachusetts Bay is similar to that of the Gulf of Maine and Buzzards although abundance varies among samples, survey, season, and regions.

Because the new outfall relocates the current discharge and discharges at a depth below the photic zone, the effluent will be more diluted than currently achieved, and surface production of phytoplankton biomass is expected to be less than under the current discharge. Thus, the net ecological results are likely to be small and limited to the nearfield. In addition, nutrient fields in the outer Harbor are expected to decrease in concentration and extent, as will the surface chlorophyll levels. Nutrient fields in Massachusetts Bay are not expected to change appreciably in the vicinity of the outfall, although am slight increase in ammonium concentrations against the lower offshore background level may be observed. The coastal plume is also expected to be less distinct and less intense and chlorophyll levels will decrease in surface waters of the western nearfield. Moreover, bottom water DO values in the Bays are not expected to changes substantially relative to the current baseline history.

Changes in the phytoplankton and zooplankton species abundance and composition are not expected to change in the Bays as a result of the transfer of effluent from the Harbor mouth into Massachusetts Bay.

Utility of the Bays Eutrophication Model (BEM)
in the Harbor Outfall Monitoring (HOM) Program
James Fitzpatrick and Richard Isleib, P.E.
HydroQual, Inc., Mahwah, NJ

A coupled hydrodynamic/water quality model has been developed for the Massachusetts Bays system. This model known as the Bays Eutrophication Model (BEM) was developed for the Massachusetts Water Resources Authority (MWRA) to help understand the relationship between circulation, nutrients, and primary productivity in the Massachusetts Bays system. The model was also developed to provide MWRA and other water quality managers with a tool for projecting water quality in Massachusetts and Cape Cod Bays in response to various nutrient management alternatives. The BEM can also be used to assist in the development of additional water quality monitoring needs and field and laboratory research efforts.

The BEM has been recently applied to a three-year HOM data set collected between 1992 and 1994. The data set contains a number of interesting water quality features, including a bloom of the diatom species Asterionellopsis glacialis in the fall of 1993 and very low dissolved oxygen concentrations in the fall of 1994. This presentation will focus on the ability of the model to reproduce these water quality data features, as well as to explore some model limitations.

The presentation will also provide an overview of the utility of the model in developing a system-wide nutrient budget and in assisting in the evaluation of the spatial and temporal distribution of various nutrient inputs within the Massachusetts Bays system.

Predicting the fate of sediments and associated contaminants in Massachusetts Coastal Waters
Bradford Butman, Michael H. Bothner, Harley J. Knebel, Frank Manheim, Marilyn Buchholtz ten Brink, and Richard P. Signell
U.S. Geological Survey, Woods Hole Field Center, Woods Hole, MA

Many contaminants introduced to the coastal ocean are associated with particles. After repeated cycles of transport, deposition, resuspension, and biological and chemical interactions, contaminants on particles eventually may be buried in bottom sediments. The U.S. Geological Survey and the Massachusetts Water Resources Authority are collaborating in a 12-year study designed to provide an understanding of how sediments and associated contaminants are transported and where they accumulate in the Massachusetts Bays system. The overall objective is to provide a predictive capability and understanding of the fate of contaminants associated with fine-grained sediments. The multi-disciplinary project has focused on four questions of interest to scientists and to managers at MWRA and other regulatory agencies.

  1. What are the best locations for monitoring changes in sediment contaminants on a regional basis? Sea-floor mapping, utilizing side scan sonar, high-resolution seismic reflection profiling, multibeam bathymetry, sampling, video and bottom photography, has shown that the sediment texture and other bottom features in Massachusetts Bay are patchy and that major changes occur over a wide variety of spatial scales. The variability is due to the irregular bottom topography, past and present sources of sediment, and the processes causing transport. Maps show the location and extent of erosional and depositional environments and provide a regional context for the interpretation of bottom samples and benthic observations. Fine-grained sediments typically indicate areas of sediment accumulation; coarse-grained sediments or boulders define areas where sediments are scoured and winnowed by currents. Regional maps of sedimentary environments have provided a framework for designing a cost-effective monitoring program and for selection of the new outfall site. The USGS, in cooperation with the MWRA, has established sediment monitoring stations at two depositional sites in the vicinity of the new ocean outfall. These stations are part of the 20 near field stations that MWRA samples annually. Samples have been taken at these USGS sites three times each year since 1989 to document seasonal and inter-annual variability in contaminant concentrations, and to provide a baseline against which to measure future change. In addition, samples have been obtained at representative stations in Massachusetts and Cape Cod Bay in 1992 and 1998. In general, concentrations of metals in the surface sediments decrease with distance from Boston Harbor and are below the ERM guidelines of Long and others (1995).
  2. How are nutrients, sediments, contaminants, and other water-borne material transported regionally in Massachusetts and Cape Cod Bays, and locally around the new and old outfalls? Hydrodynamic modeling of the ocean circulation provides a framework for understanding the regional flow and mixing, and the basis for simulations of water quality. With the existing outfall locations, high effluent concentrations are found within Boston Harbor and along the coastline immediately south. With the new outfall location, high concentrations of effluent are found only within a few kilometers of the outfall, concentrations are dramatically lower in Boston Harbor, and concentrations in most of Massachusetts Bay (including the region near Stellwagen Bank) are not significantly changed from their existing low levels. At the new outfall location in summer, effluent is trapped at mid-depth beneath the warm surface layer, while effluent from the existing outfalls remains near the surface. Because nutrients from the new outfall are trapped in waters that are already nutrient rich and where phytoplankton growth is light-limited, the impact of sewage-borne nutrients is decreased. Computer simulations also indicate that water-quality standards could be met with a secondary treatment capacity 25% smaller than originally planned. This design change saved taxpayers approximately $160 million in construction costs.

    While the effluent concentration simulations show that greater dilution at the new outfall site can decrease the impact of pollutants effects in the water column, contaminants that settle to the bottom can accumulate in the sediments over the long-term. For this reason, the implementation of secondary treatment will greatly reduce the levels of particles and contaminants entering the system.

    Boston Harbor, Stellwagen Basin and Cape Cod Bay are the long-term sinks for fine-grained sediments. The transport and accumulation of sediments in the Massachusetts Bays is determined principally by the residual circulation, major storms, the bathymetry, and the geometry of the semi-enclosed basin. The mean current, driven principally by the along-shore coastal current in the western Gulf of Maine, proceeds in a counterclockwise direction around Massachusetts Bay. Superimposed on this residual flow pattern are tidal, density, and wind-driven currents that can alter the direction and speed of residual flow on a daily basis. Northeast storms generate large swell that propagate into Massachusetts Bay from the Gulf of Maine. The oscillatory currents associated with these waves cause resuspension of bottom sediments in water depths less than about 50 m over areas exposed to the northeast, principally along the western shore of Massachusetts Bay. The near-bottom currents associated with the northeast winds are to the south and offshore and carry the resuspended material southward toward Cape Cod Bay and offshore into Stellwagen Basin. Most of Cape Cod is sheltered from the large swell associated with northeasters, and in deep Stellwagen Basin, the waves are rarely large enough to resuspend the sediments. Sediments that are transported to these two areas from the western side of Massachusetts Bay, by the residual circulation or the storm-driven currents, are less likely to be resuspended again, and thus these areas are long-term sinks for fine sediments and associated contaminants. This conceptual model is supported by direct observations of currents and sediment resuspension during storms, wave and 3D current modeling, by the observed accumulation of fine grained sediments in Cape Cod Bay and Stellwagen Basin, and by the lack of fine sediment along the western shore of Massachusetts Bay. The model is also consistent with the distribution of silver and Clostridium perfringens spores, most likely input to the Massachusetts Bays from Boston's sewage system. Recent observations of internal waves in Stellwagen Basin in the summer suggest that these waves may also play a role in the transport of sediments from the nearshore into the deeper basins.

  3. What are the concentrations of pollutants in sediments of western Massachusetts Bay and how have they changed with time? Geochemical determinations indicate that metal concentrations in bottom sediments near the future outfall are presently below the ERM toxicity guidelines of Long and others (1995). The time-series observations at a monitoring site near the new outfall showed a more than 2-fold increase in the concentrations of silver following a major storm in December of 1992. Similar changes were measured in other variables such as Clostridium perfringens spore counts, inventories of natural radioisotopes, and sediment texture. These changes are evidence for storm-induced resuspension and transport of fine sediments and associated contaminants from shallower inshore areas to deeper depositional areas offshore. The characterization of natural variability, particularly related to high energy events such as storms, provides a critical framework for understanding the cause of future changes.
  4. What is the distribution of contaminants in harbor sediments, and are the concentrations decreasing with time in response to MWRA's harbor cleanup program? Establishment of a contaminated-sediment data base that includes contaminant information from a wide variety of sources, and continuing geochemical observations have revealed areas of the harbor, particularly the inner harbor, where some metal concentrations are above toxicity guidelines. However, a time-series of collection and analysis of surface sediments at monitoring locations indicates that concentrations of lead and other metals in the surficial sediments have decreased by about 50% over the last 20 years. Boston Harbor is getting cleaner.

    Geologic mapping, physical oceanography, biology, geochemistry, and hydrodynamic modeling have all contributed to developing an understanding of the transport and fate of sediments in the Massachusetts Bay system. The research has been enhanced by cooperation among research partners from the academic community and from state and federal agencies. In addition, the project benefited from a continuing, long-term commitment by all partners, a multi-disciplinary approach, a regional system-wide perspective, stable long-term funding, and interactions between management and science. The project provides a framework for assessing the effects of the new ocean outfall on Massachusetts coastal waters and is a model for studies of similar systems elsewhere.

    Massachusetts Bay is a complex coastal oceanographic system affected by both natural processes and past and present anthropogenic activities. The Bay is partially separated from the Gulf of Maine by Stellwagen Bank, which rises to about 30 m of the sea surface. The seafloor environment in the Bay varies from mud in the depositional basins to coarse sand, gravel, and bedrock on the topographic highs. The region immediately surrounding the outfall site consists of a series of ridges and valleys.

    Boston Harbor, Stellwagen Basin, and Cape Cod Bay are areas of sediment accumulation. In general, fine sediments do not accumulate in the region surrounding the outfall, except in a few isolated locations. Sediments and associated contaminants are transported to the south and offshore by the mean flow and storms in the Gulf of Maine. A baseline has been established for contaminants in depositional sites. Inventories of silver show that Boston Harbor, Stellwagen Basin, and Cape Cod Bay are long-term sinks for contaminants. Concentrations of lead and other heavy metals in the surficial sediments of Boston Harbor have decreased by about 50% between 1997 and 1994.

Soft-bottom Benthic Community Monitoring in the Boston Harbor- Massachusetts Bays System
Kenneth E. Keay
Massachusetts Water Resources Authority, Boston, MA
Roy K. Kropp
Battelle, Duxbury, MA
Eugene D. Gallagher
University of Massachusetts, Boston, MA
Robert J. Diaz
R. J. Diaz and Daughters, Ware Neck, VA

Soft-bottom benthic monitoring carried out by MWRA in the past decade in the Boston Harbor-Massachusetts Bay system constitutes the best long-term dataset available in this region for investigating the complex interactions of physical, ecological, and anthropogenic factors that influence these sensitive indicators of environmental health. This presentation summarizes some of the characteristic community types determined by the monitoring and briefly details the more important findings of the monitoring to date.

Boston Harbor: Studies from the late 1970s through the late 1980s found that many soft-sediment Harbor areas, especially in northern sections of Boston Harbor, contained assemblages dominated by pollution-indicating polychaete worms such as Capitella spp., Polydora cornuta, and Streblospio benedicti. Less impacted communities, dominated by the crustacean amphipod Ampelisca vadorum and other animals less indicative of polluted habitats were found in southern parts of the Harbor and sporadically in the North Harbor.

MWRA's long-term Harbor benthic monitoring began in September 1991, and early results were similar to those of historic studies. Following the December 1991 cessation of sludge discharge to the Harbor, (these changes were probably also influenced by the fall 1991 "Halloween" Nor'easter), diversity throughout Boston Harbor increased, and by the mid-1990s stabilized at a higher level than in the past. This was associated with a rapid increase in the distribution of Ampelisca and other amphipod-dominated communities throughout the harbor, from being present at fewer than 25% of the stations sampled in 1989-90 to >60% in the mid-1990s. Severely degraded communities are now found only at a very few stations where fine sediments rapidly accumulate, such as portions of the Inner Harbor or in Savin Hill Cove next to U/Mass Boston, which are near combined sewer overflows and other sources of wastewater

Massachusetts Bays: Soft-bottom benthic communities in the vicinity of the future outfall inhabit a spatially and temporally variable environment. Areas dominated by depositional fine sands and muds, in which organic carbon and/or contaminants might accumulate are distributed primarily to the west of the outfall. Sediments with a substantial proportion of fine sand and mud contain a polychaete dominated community characterized by moderate abundances of one or more of the polychaetes Spio limicola, Prionospio steenstrupi and Mediomastus californiensis though the relative abundance of these species changes from year to year. The few stations with primarily medium-coarse sand and gravel usually contain an assemblage dominated by amphipods such as Crassicorophium crassicorne and by sand-dwelling polychaetes like Polygordius sp. A. Major sediment transport events like those documented by USGS in winter 1992-93 have caused complete changes in sediment character in some areas (for example, one site changed from >80% mud in 1992 to 99% sand and gravel in 1993).

The nearfield fine sand/mud community is very similar to that found in two farfield reference areas, south of Gloucester and about 5 nautical miles southeast of the nearfield. Reference stations deeper than about 50 meters ranging from east of Cape Anne south through Stellwagen Basin have a relatively distinct community, which shares some species with the shallow-water sand/mud community but also has dominant species not found in other regions. Communities at two slightly shallower stations in Cape Cod Bay are normally more similar to each other than to other stations (however, this pattern did not hold in 1998 samples). These Cape Cod Bay stations show affinities to both the offshore assemblages and to the western Massachusetts Bay fine sand/mud communities.

Samples from the Bays routinely contain about twice as many different species as do Boston Harbor samples (they exhibit high species richness) and species evenness is much higher than in Harbor samples (in which 70%+ of the animals present are often from only 1-3 species).

Analyses of the long-term outfall monitoring benthic data document striking changes in diversity. The average number of species per grab in near-field samples decreased about 25% between 1992 and 1993, and then steadily increased each year until leveling off in 1997 and 1998; diversity was substantially higher than in 1992. A similar pattern is evident in the data from the rest of the Bays as well. The cause or causes of this change are currently unclear; possibilities include a region-wide response to sediment transport from 1992-1993 winter storms or to some other large-scale event.

Benthic Nutrient Cycling in Boston Harbor and Massachusetts Bay
Anne Giblin, Charles Hopkinson, and Jane Tucker
The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA, 02543

Monitoring of benthic respiration, benthic nutrient release, and denitrification was begun in 1992 at selected stations in Boston Harbor and Massachusetts Bay and is still continuing. The goal of the monitoring is to determine the role of the sediments in nutrient cycling and oxygen dynamics. Measurements have been made 2-5 times a year. Several new stations were added in the Harbor in 1995.

From 1992-1995, oxygen uptake rates from Harbor sediments were quite high and very variable. Interannual oxygen uptake rates continue to be variable at most Harbor stations, however, the extremely high rates observed in the early part of the study (1993-1995) have not been repeated. Highest oxygen uptake rates are usually associated with a dense cover of tube building amphipods. Although the amphipods continue to be present, the lower rates now observed near the Long Island sludge disposal site suggest some "mining" of sediments organic stores may have taken place.

Harbor sediments are also an active site of denitrification and more than half of the nitrogen mineralized in the sediments is subsequently denitrified and lost from the ecosystem. Although the proportion of nitrogen lost from the sediments is high, it is typical of marine sediments. However, because most of the nitrogen entering Boston Harbor is not cycled through the sediments, only a relatively minor percentage of the N inputs to Boston Harbor from sewage and other sources is lost by denitrification. Hence, moving the outfall should not have a large effect on the N budget of Massachusetts Bay as a whole.

Sediment fluxes were not measured in Massachusetts Bay during 1998. Previous measurements had shown that benthic respiration rates exhibited low interannual variability, less than 20%. This suggested there would be a high power to detect any change due to the outfall relocation. Benthic respiration rates measured in 1999 have been higher than average, and may reflect greater carbon loading to the sediments from an unusually large diatom bloom in early 1999, and warmer than usual bottom water temperatures. However, the October rates will be needed to determine if this year's rates would have fallen outside what was considered normal based upon the 1992-1997 data.

Nearfield Hard-bottom Communities Near the Massachusetts Bay Outfall
Barbara Hecker
Hecker Environmental Consulting, Falmouth, MA

Benthic communities inhabiting hard-bottom habitats (drumlins - rock covered topographic highs) near the Massachusetts Bay outfall have been surveyed annually since 1995. The surveys were conducted using a Benthos Mini Rover ROV to collect video images and color slides at selected sites (waypoints) near the outfall and at reference sites further away. The number of waypoints surveyed has expanded from 19 waypoints (17 near the outfall and 2 reference) in 1995 to 23 waypoints (16 near the outfall, 6 reference, and diffuser head #44) in 1997. Diffuser #44 will not discharge effluent, and was added to the survey because it affords a worst-case example in the extreme nearfield. The major emphasis of the hard-bottom survey was shifted from video images to color slides since 1996, because of the greater resolution afforded by still images. Approximately 20 minutes of video footage and 30 color slides were collected at each waypoint. The video images were used primarily to qualitatively evaluate sea floor characteristics (habitat relief, substratum size class, degree of sediment drape, and habitat heterogeneity) and the occurrence of sparse larger organisms. The still photographs were used to semi-quantitatively assess the relative proportion of benthic inhabitants at each waypoint.

The sea floor on the drumlin tops consisted typically of a mix of boulders and cobbles. Habitat relief in these areas varied from high (predominantly boulders) to moderate (cobbles with occasional boulders). Sediment drape on the drumlin tops was usually light to moderate, but was occasionally heavy at locations that supported a high abundance of upright algae. The sea floor on the flanks of the drumlins usually consisted of a cobble pavement interrupted by occasional patches of gravel, sand or boulders. Habitat relief in these areas usually ranged from low to moderate, depending on the number of boulders present. Sediment drape in the drumlin flank areas usually ranged from moderate to heavy. While some areas were homogeneous with regard to sea floor characteristics, many areas were quite heterogeneous, such that slight lateral shifts in position resulted in markedly different habitats. This spatial heterogeneity was frequently most pronounced on the flanks of the drumlins.

The benthic communities inhabiting the drumlins appeared to be controlled by a combination of location on the drumlin (concurrent with depth), substratum size class and associated habitat relief, and degree of sediment drape. Algae usually dominated the benthic communities inhabiting the tops of drumlins, while invertebrates (mostly encrusting or attached forms) frequently dominated the communities on the flanks. The encrusting coralline alga Lithothamnion spp. dominated in drumlin top areas that had little sediment drape. In contrast, upright algae (Asparagopsis hamifera, dulse and shot-gun kelp) dominated in areas of high relief. The holdfasts of the upright algae appeared to trap sediment, resulting in a reduction of Lithothamnion. Other taxa commonly encountered were the horse mussel Modiolus modiolus, the northern sea star Asterias spp., the sea pork tunicate Aplidium spp., and the cunner Tautogolabrus adspersus. Sediment areas tended to be depauperate, while the diffuser heads typically supported dense aggregations of the frilly anemone Metridium senile and numerous Asterias spp.

The benthic communities were temporally quite stable over the 1995 to 1998 time period. Within-site changes in the percent cover of Lithothamnion spp. and in-community composition between sampling periods frequently reflected slight lateral shifts in sampling location. This temporal stability enhances the likelihood of detecting large changes in the composition of the hard-bottom communities during discharge monitoring. Of all species encountered during this study, Lithothamnion spp. was the least variable and most predictable. As a result, Lithothamnion appears to hold the most promise as an "indicator" of habitat health during monitoring of the outfall discharge. It is abundant, widely distributed, predictable in terms of habitat requirements, and appears to be sensitive to particulate loading.

Caged Mussel Bioaccumulation Monitoring in Massachusetts and Cape Cod Bays
Lisa Lefkovitz and Carlton Hunt
Battelle, Duxbury, MA
Maury Hall
Massachusetts Water Resources Authority, Boston, MA

Caged mussels have been deployed since 1991 as part of the NPDES permit requirement to address bioaccumulatable contaminants and human health exposure associated with the Massachusetts Bay Outfall. This assessment is conducted by deployment of caged blue mussels near the effluent discharge location and at reference areas. Mussels were collected at two locations: Gloucester and Sandwich, for deployment at a number of locations in Boston Harbor and Massachusetts Bay. Mussel composites from each deployment location, as well as pre-deployment mussels, were analyzed for selected organics and metals. To date, chemical concentrations for both organics, such as PCBs and chlorinated pesticides, and mercury, have been highest in caged mussels deployed at Boston Inner Harbor (BIH) and lowest at the Outfall site. A new location in Cape Cod Bay, added in 1998, shows even lower concentrations than the Outfall location. Concentrations measured in 1998 were among the lowest observed since 1991, especially at BIH and Deer Island (DI). Lead and mercury concentrations have been much more variable among the sites over time. Post discharge results will be compared to the baseline period to determine if discharge from the Outfall results in appreciable change to baseline values. Concentrations measured at the Massachusetts Bay Outfall site in 1998 were well below the MWRA Threshold levels, indicating no health risk.

Flounder Histology and Tissue Chemistry
Michael Moore
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA

Contaminant-associated liver tumors and hydropic vacuolation were first described in winter flounder from near the Deer Island outfall in 1985. The prevalence of these lesions had decreased substantially by the early 90's. Today tumors are very uncommon. Hydropic vacuolation is now found in 30-40% of the adult fish examined. Since 1991, Deer Island and four other stations have been annually sampled as part of the harbor and outfall monitoring program. Comparable prevalences to Deer Island have been detected at the Broad Sound site, with lower levels at the Massachusetts Bay Outfall site and off Nantasket Beach. The lowest prevalence has been consistently observed in flounder from a station in Eastern Cape Cod Bay. A suite of organic and inorganic chemical contaminants have also been measured annually in liver and fillet samples. Comparable between-station trends have been seen for most of the organic compounds. Less obvious patterns have been discernible for inorganic compounds. A gradual decrease in chemical exposure and effect at each station is the most likely outcome after activation of the offshore outfall, as source reduction efforts continue.

POSTERS

Transport Of Toxic Alexandrium Populations into Massachusetts Bay
Donald M. Anderson and Bruce A. Keafer
Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA

Toxic or harmful algal blooms (commonly called "red tides") are a serious economic and public health problem throughout the US and the world. In the New England region, the most serious problem in this context is that of paralytic shellfish poisoning (PSP), a potentially fatal neurological disorder caused by human ingestion of shellfish that accumulate toxins as they feed on dinoflagellates of the genus Alexandrium. Past research on these phenomena has led to the hypothesis that toxic Alexandrium cells are introduced to the Massachusetts and Cape Cod Bays via a coastal current formed from the outflow of rivers in southern Maine. When this coastal current enters Massachusetts Bay, it sometimes passes over or close to the new MWRA outfall site. This leads to concern that nutrient inputs from the outfall might stimulate the growth of red tide algae, worsening the PSP problem. This issue is especially relevant to South Shore and Cape Cod communities "downstream" from the outfall, given the typical north-to-south mesoscale circulation of the Bays. Recent public controversy over these possible effects have highlighted how little is known about the PSP phenomenon within the Bay itself or about the manner in which the PSP toxins move through the food chain to zooplankton, fish, and marine mammals. The general objective of this poster is to provide an overview of our understanding of the dynamics of Alexandrium within Massachusetts Bay, focusing on field data during one year (1993) when cells were abundant within the Bay and one year (1994) when they were not. A general conceptual model of how blooms and toxicity develop within the bay will be presented and discussed in the context of the Massachusetts Bay outfall.

Sediment Contaminant Monitoring in Massachusetts and Cape Cod Bays
Deirdre Dahlen, Lisa Lefkovitz and Carlton Hunt
Battelle Duxbury Operations, Duxbury, Massachusetts

Monitoring of toxic contaminants in sediments is one of three main concerns addressed by the Benthic (Sea-Floor) Monitoring component of the MWRA Harbor and Outfall Monitoring (HOM) program. Benthic monitoring collects data on the benthic macrofauna and flora, and the physical properties and levels of organic matter, nutrients, sewage indicators, and contaminants in the sediments in which the macrofauna reside. Measurements are made over a wide geographic area influenced by many natural and anthropogenic factors including effluents from MWRA wastewater outfall. Outfall monitoring includes nearfield and farfield sampling but is focused most intensely on the nearfield area (<8 km from outfall) where changes in water and sediment quality following initiation of the discharge is most likely to be detected, if they occur. Farfield locations (>8 km from the outfall) serve primarily as reference areas for the nearfield or as monitoring stations if the discharge affects sites distant from the diffuser. In addition, a Special Contaminant Study is performed three times a year at stations NF08, NF22, NF24, and FF10 to address possible short-term transport and impact.

The objectives of sediment contaminant monitoring component of the HOM program are to

  • Determine changes in the physical characteristics, organic matter content, chemical contaminant concentrations in sediments near the diffuser;
  • Collect physiochemical data to understand interrelations among these parameters and the benthic communities;
  • Establish baselines in Massachusetts and Cape Cod Bays;
  • Detect change in system after discharge; and
  • Evaluate contaminant levels against the monitoring thresholds

Concentrations of organic and metal contaminants are generally low and highly variable. Variability is related to grain size and TOC, which are variable also. Nearfield average concentrations of organic and metal contaminants are well below levels of ecological concern and are similar over time.

Long-term Trends in Productivity
Aimee Keller, Candace Oviatt , Tarquin Dorrington, Gywnne Holcombe, and Laura Reed
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI

Primary productivity represents the autotrophic fixation of carbon dioxide by phytoplankton during photosynthesis. Since phytoplankton form the base of the marine food web, primary production is the key process that brings food into a marine system. Changes in the rate of primary production are essential to measure since they affect not only the concentration of plant biomass but also the organisms that eat them. Phytoplankton productivity is also important since it is closely tied to the cycling of nutrients and the concentration of oxygen. The major goal during the baseline monitoring of productivity was to establish the range and variability in annual productivity at two sites: near the site of the Massachusetts Bay outfall (Stations N04, N16 or N18) and near the entrance of Boston Harbor (Station F23).

Annual productivity ranged from a low of 141 g C m-2 y-1 at station N04 to a high of 787 g C m-2 y-1 at Station F23 from 1992 -1998. Mean annual productivity was higher (mean 494 g C m-2 y-1) and more variable near the Harbor entrance (Station F23) than at the nearfield sites (Stations N04, N16 and N18). At station F23 productivity varied greater than 5-fold over the 7-year sampling period. Average annual productivity and variability around the means were considerably lower at Stations N04 (mean 285 g C m-2 y-1) and Station N16-18 (mean 396 g C m-2 y-1). Annual productivity in 1998 was unusually low at all three sites (<160 g C m-2 y-1) due to the failure of the winter-spring phytoplankton bloom. The absence of the 1998 bloom was linked to warmer winter temperature and increased grazing by zooplankton during the bloom period.

The seasonal cycle of areal primary productivity (mg C m-2 d-1) at the nearfield stations (N04, N16, N18) was generally characterized by a well-developed winter-spring bloom of several weeks duration, high production during the summer and a less prominent fall bloom. The majority of production (mg C m-2 d-1) typically occurred in the upper 20 m of the water column at the nearfield sites. At the Boston Harbor station (F23) a gradual pattern of increasing areal production from winter through summer was more typical with the majority of production occurring in the upper 5-10 m of the water column.

If nutrient concentrations increase in the euphotic zone as a result of the relocated outfall primary production may increase perhaps leading to greater phytoplankton biomass or increased secondary productivity.

Juvenile Lobsters at the New Outfall Site:
Comparisons With Inshore an Population and Discussion of Potential Outfall Impacts on Lobster Populations Kari L. Lavalli
Southwest Texas State University, San Marcos, TX
Roy K. Kropp
Battelle Duxbury Operations, Duxbury, MA
Kenneth E. Keay
MWRA, Boston, MA

In late May 1998, the Massachusetts Water Resources Authority (MWRA) was directed by the Outfall Monitoring Task Force to design and execute a study in the cobble-boulder habitats of the new outfall nearfield region to sample early benthic phase lobsters ("EBPs", 5 to 40 mm carapace length (CL)), particularly that of new recruits ("young-of-the-year", <12 mm CL) and yearling lobsters (shelter-restricted, <20 mm CL). Both of these life history phases are thought to be relatively nonmobile, obligate shelter-dwellers. MWRA was also required to determine if the numbers of these life history stages were comparable to those of nearby inshore habitats. This mandate resulted from serious concerns about the effects that the new outfall might have on juvenile lobsters and, thus, the future of the economically important lobster fishery.

MWRA responded to this mandate by proposing a survey plan that was developed from examination of videotapes from a remotely-operated vehicle survey conducted in September, 1994, and previous data on lobster density from hard bottom surveys to determine suitable locations for sampling. A mathematical calculation was used to determine an appropriate minimum sample size for the collection of species occurring only rarely in a region. These tactics were designed to maximize the chances of locating young-of-the-year and shelter-restricted lobsters at the outfall vicinity. In early September 1998, EBP-density sampling was undertaken by the foremost experts in airlifting for lobsters underwater at both the vicinity of the outfall and two nearby inshore stations. The data collected showed significantly lower densities of young-of-the-year, yearling lobsters, and larger EBP lobsters at the outfall compared to the inshore sites. Measures of the proportion of non-zero observations (which is another measure of frequency) for each size class also showed significantly fewer non-zero observations at the outfall. Taken together, these data demonstrate that while the cobble habitat at the vicinity of the outfall is suitable for settlement, it does not represent a major settlement site and thus there is no indication that the outfall will have any appreciable impact on these life stages of the American lobster.

Benthic Habitats of Boston Harbor and Nearshore Massachusetts Bay as Characterized by Sediment Profile Imaging
Robert Diaz
R. J. Diaz and Daughters, Ware Neck, VA

Long-term trends and status of benthic habitats in Boston Harbor and Nearshore Massachusetts Bay was characterized using sediment profile imaging. In 1992, annual surveys started in Boston Harbor and in 1997 in the Nearfield area, initial SPI surveys in these areas were conducted in 1989 and 1992 respectively. Sediment profile imaging provided a means of assessing benthic habitat quality by collecting visual data on dominant physical and biological processes that structure benthic communities. Key indicators of habitat quality (amphipod tube mats, Redox Potential Discontinuity layer depth and Organism Sediment Index) in the Harbor declined in 1998 relative to previous years, however, major changes in habitat quality appeared to have occurred prior to 1992. Current habitat quality has developed in response to major disturbance events in 1991, a severe storm in October and sewage discharge abatement in December. Stations with poorest habitat quality in 1992 continued to have poor quality in 1998 (T04, R43). The decline in amphipod tube mats may represent a negative rebound of Ampelisca spp. populations that continually increased from 1992 to 1996. This amphipod is an important indicator that occurs in high abundance in areas trending from poor to good habitat quality. When habitat quality improves to a certain point, a decline in amphipod tube mats is to be expected. Trends in Nearfield habitat quality appeared to be related to the physically dynamics of the area. Bottom instability maintains a patchy mosaic of habitat quality. In 1998 and 1999, biological processes dominated surface sediments at almost all stations with an increase in the degree of bioturbation.

Predicted changes in benthic habitat quality with the operation of the Nearfield discharge are:
Boston Harbor:

  • Decline in Amphipod tube mats
  • Transition to a Stage III benthic community
  • Improved benthic habitat quality for inner harbor

Nearfield:

  • Physical dynamics will control biological communities
  • Periodic appearance of Amphipod tube mats
  • Increase in epifauna

Lobster Contaminant Monitoring in Massachusetts and Cape Cod Bays
Lisa Lefkovitz and Carlton Hunt
Battelle Duxbury Operations, Duxbury, MA

Lobsters have been collected from Deer Island, the Massachusetts Bay Outfall Site and Eastern Cape Cod Bay since 1992 to evaluate general health and contaminant levels. Edible meat and hepatopancreas tissues have been analyzed for selected organics and metals. Results from these analyses are used to evaluate the potential human health exposure. Post-discharge results will be compared to the baseline period to determine if discharge from the outfall results in appreciable change from baseline values and to compare to the fish and shellfish monitoring thresholds. To date, chemical concentrations in edible meat for organics, such as PCBs and chlorinated pesticides, and mercury, have been highest in lobsters trapped near the present Deer Island outfall. The lowest concentrations are consistently found at the eastern Cape Cod Bay monitoring site. Hepatopancreas concentrations for organics show a similar trend. However, metals concentrations appear highest at the Outfall Site in Massachusetts Bay. Concentrations of most contaminants appear to have decreased since 1992 in both meat and hepatopancreas. The exceptions to this trend include silver in hepatopancreas tissue and PCBs and DDTs in both meat and hepatopancreas tissue at all locations. Metals concentrations have been much more variable than the organic contaminants among the sites over time. Concentrations measured throughout the baseline period were well below the monitoring threshold levels and human health consumption action limits.

Phytoplankton and Zooplankton of Boston Harbor, Massachusetts and Cape Cod Bays, 1992-1999, Within a Regional Context
Jefferson T. Turner, David G. Borkman, & Jean A. Lincoln
Center For Marine Sciences and Technology, Biology Department, University Of Massachusetts Dartmouth, Dartmouth, MA

Phytoplankton and zooplankton have been sampled in Massachusetts and Cape Cod Bays and Boston Harbor since 1992. Patterns of community composition, abundance and seasonality of phytoplankton and zooplankton in Massachusetts and Cape Cod Bays are variable in time, on scales from daily (within a survey), to monthly (between surveys), to interannual. Spatial patterns of community composition are generally similar within a given survey for areas outside Boston Harbor, but the Harbor is usually distinct from adjacent offshore areas. Plankton patterns both within Boston Harbor, and offshore in Massachusetts and Cape Cod Bays are generally similar to those in contiguous areas such as the upstream Gulf of Maine, and adjacent areas to the south such as Buzzards Bay, New Bedford Harbor, and Georges Bank.

Initial Effluent Dilution Verification and Plume Tracking Plan
By Carl Albro, Elizabeth Bruce, and Carlton Hunt
Battelle Duxbury Operations, Duxbury, MA
Rocky Geyer
Woods Hole Oceanographic Institution, Woods Hole, MA
Michael Mickelson
Massachusetts Water Resources Authority

This poster describes the proposed plume tracking surveys to determine that initial dilution characteristics of the outfall meet NPDES permit requirements, and track the longer-term location and mixing dynamics of the outfall plume to verify that the plume continues to disperse and does not travel intact to resource areas.

Assessing Temporal Changes in Highly Variable Fecal Coliform and Enterococcus Data in Boston Harbor and Its Tributaries by Randomized Block Factorial ANOVA
G. Gong and J. Lieberman,
ENSR, Inc., Acton, MA
D. McLaughlin
Massachusetts Institute of Technology, Cambridge, MA
A. Rex
Massachusetts Water Resources Authority, Boston, MA

The "Boston Harbor clean-up" is a multi-billion dollar public investment in major public works projects, including addressing wet weather pollution from combined sewer overflows (CSOs). Since 1989, MWRA has monitored fecal coliform and Enterococcus counts in Boston Harbor and its tributaries. Water quality is poorest during wet weather; CSOs and stormwater are the major sources of bacteria. If CSO controls are effective, then bacteria counts in wet weather will be lower than counts before CSO controls were implemented. Tracking environmental effects of pollution control projects is complicated by high variability in the data which make it difficult to interpret changes in bacteria counts over time. Rainfall, geographic location, season, salinity, temperature, and tide are all sources of variation. The purpose of this study was to develop and use a statistical method to answer the question, "Have fecal coliform and Enterococcus counts in these waters changed significantly over time?" Fecal coliform and Enterococcus counts from more than 8,000 water samples at 130 locations were included in the analysis. Preliminary regression analyses failed to detect statistically significant changes in the relationship between bacteria counts and rainfall over time. Factorial ANOVA with randomized blocking to partition the data and control for factors (location, tide, season) not contained in the ANOVA treatments (time and rain) detected significantly lower counts in the study area as a whole after some CSO controls were implemented. Decreases were significant for fecal coliform, but not Enterococcus.

OMSAP Meeting, Monday, March 22, 1999
10:00 AM - 2:00 PM
MADEP Boston
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Robert Beardsley, WHOI; Robert Chen, UMB; Robert Kenney, URI; Judy Pederson, MIT/Sea Grant; Bill Robinson, UMB; and Jim Shine, Harvard School of Public Health.

Observers: Grace Bigornia-Vitale, MWRA; Elizabeth Bruce, Battelle; Cathy Coniaris, OMSAP Assistant; Kelly Coughlin, MWRA; Patty Daley, Cape Cod Commission; Mike Delaney, MWRA; Cate Doherty, Save the Harbor/Save the Bay; Marianne Farrington, New England Aquarium; Pamela Harvey, MADEP; Carlton Hunt, Battelle; Russell Isaac, MADEP; Ken Keay, MWRA; Kristyn Lemieux, ENSR; Matt Liebman, EPA; Steve Lipman, MADEP; Ron Manfredonia, EPA; Mike Mickelson, MWRA; Arleen O'Donnell, MADEP; Cornelia Potter, MWRA Advisory Board; Susan Redlich, WAC; Virginia Renick, MWRA; Andrea Rex, MWRA; Jack Schwartz, MADMF; Dave Taylor, MWRA; Dave Tomey, EPA; and Heather Trulli, Battelle.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets]. All such comments have been inserted for clarification only. They do not, nor are they intended to, suggest that such insertions were part of the live meeting components and have been expressly set-off so as to avoid such inference.

SUMMARY OF ACTION ITEMS & RECOMMENDATIONS

  1. OMSAP agreed to review the upcoming report on Bays Eutrophication Model runs for 1993 and 1994. The Panel will also contact the original Model Evaluation Group (MEG) as well as additional scientists to request that they review the report. A MEG may be convened this summer with B. Beardsley as chair.
  2. OMSAP agreed to host a public monitoring workshop this summer. MWRA will develop a proposed agenda for OMSAP/PIAC/IAAC review. A subcommittee will meet to plan for this workshop. Suggestions for meeting format and content are welcome and should be sent to: [email protected].
  3. OMSAP will review the hypotheses in the Outfall Monitoring Plan phase 1 to see if the current monitoring program is addressing them.
  4. OMSAP postponed decision on the draft food web model scope of work presented by the MWRA at the December 18, 1998 OMSAP meeting pending additional information from the Cape Cod Commission by April 23, 1999. [Update: the CCC has postponed this date.]

FINAL MINUTES

December 18, 1998 OMSAP minutes were approved as amended.

REVIEW OF DRAFT OMSAP/PIAC/IAAC PROTOCOL
Comments to the draft protocol should be sent to C. Coniaris. The group had a brief discussion regarding meeting scheduling of the three groups. C. Doherty pointed out that the PIAC has requested that the OMSAP not vote on an issue until the PIAC has had a chance to discuss it. She said one suggestion was to have PIAC meet right after OMSAP and then meet once again before the next OMSAP meeting. OMSAP/PIAC/IAAC may eventually decide to meet on the same day. OMSAP would meet in the morning and PIAC and IAAC would meet separately in the afternoon to discuss OMSAP's proceedings as well as other issues.

REPORT FROM THE PUBLIC INTEREST ADVISORY COMMITTEE
C. Doherty summarized the proceedings of the second PIAC meeting held on March 2, 1999 [minutes available]. It was decided to keep the membership open for the next two PIAC meetings with the understanding that the PIAC will not allow membership to get so large that the group becomes inefficient. They approved new membership: Anthony Chatwin from the Conservation Law Foundation and Mary Loebig from Stop the Outfall Pipe. PIAC also discussed the MWRA Water Works and Sewerage lab consolidation. MWRA assured PIAC that the consolidation of the labs would not affect the communication of monitoring results from the Harbor Studies and NPDES departments. The PIAC accepted the assurance that this would not become an issue of concern but would like to be kept informed of any new developments on this issue. PIAC decided to request that OMSAP postpone any decisions regarding the draft food web model scope of work presented by the MWRA at the December 18, 1998 OMSAP meeting pending further information from the Cape Cod Commission. The PIAC reviewed and commented on the draft protocol. PIAC agreed that if an individual organization has a concern, they should first discuss it with PIAC so that the entire group can learn about it and potentially form a collective opinion. Finally, there were two informational presentations on plume tracking and endocrine disrupters.

REPORT FROM THE INTER-AGENCY ADVISORY COMMITTEE M. Liebman summarized the proceedings of the first IAAC meeting held on February 24, 1999 [minutes available]. The group discussed the draft protocol and decided to form a subcommittee consisting of Sal Testaverde, Leigh Bridges and Matt Liebman to discuss the mission of the group, protocol, OMSAP charter, as well as the Cape Cod Commission's request to leave PIAC and join the IAAC. At the IAAC meeting, M. Liebman gave an informational presentation on endocrine disrupters and EDSTAC (Endocrine Disruptor Screening and Testing Advisory Committee). EDSTAC is a committee with members from EPA, other agencies, and industries and its purpose is to develop a process to screen the ~87,000 potential endocrine disruptors. IAAC then briefly discussed PCBs and elected S. Testaverde as chair of IAAC.

PLUME TRACKING M. Mickelson presented the draft plume tracking design. The outfall is scheduled to go on-line around September 1999 and MWRA is planning for a plume tracking survey this December. The draft NPDES permit requires plume tracking since it will measure dilution which is used in calculating effluent limits. Details are in appendix N of the draft permit. The draft permit requires:

  • Acoustical technology: MWRA will utilize John Proni's acoustic tracking technique as well as an Acoustic Doppler Current Profiler (ADCP).
  • To understand the dilution available for the discharge.
  • To field test and certify whether the outfall's minimum dilution is equal to, or greater than, the predicted minimum dilution specified by Roberts and Snyder (1993b). This report was provided to OMSAP and is available to others. During lunch, a video of the Roberts and Snyder physical scale model was viewed which showed dye being released from diffuser models under various discharge and current velocities.
  • Completion of study within 180 days of issuance of the permit. MWRA's proposed study design, with surveys in both fall/winter 1999 (unstratified conditions) and early summer 2000 (stratified water column) can be only partially completed within that requirement. MWRA will propose a reasonable timeframe for study completion to EPA/MADEP.

The main goal of the plume tracking study is to measure dilution accurately. A secondary goal is to demonstrate that the diluted plume does not travel intact to resource areas. Flow from the diffuser is a two step process: vertical turbulent motion due to buoyancy and momentum of the discharge followed by much slower horizontal travelling of the diluted plume. Much of the dilution occurs during the vertical mixing step. There are three definitions of dilution but the one preferred by EPA is "flux averaged dilution" where the concentration at any point is weighted by the horizontal velocity. The zone of initial dilution (ZID) is considered to be 60m (the water depth multiplied by two) on either side of the line of diffusers.

M. Mickelson pointed out patterns in the Roberts and Snyder model results. Dilution decreases (i.e. becomes less effective) with higher effluent flow, with strong water stratification, and with slower currents. To examine the effects on dilution with varying combinations of these conditions, Roberts and Snyder developed a model which can calculate dilution. MWRA will run this model using field information (flow, current, and stratification) to test if the same results are obtained in the field as the model. It is expected that flow will vary over the course of the day as well as annually so there will be about 25 hours of dye addition and the study will be repeated in winter and summer.

D. Tomey asked how the Roberts and Snyder model compares to the ULINE model. M. Mickelson replied that Roberts and Snyder consider ULINE obsolete because it considers buoyancy but not momentum, and only simple linear stratification. D. Tomey suggested comparing the Roberts and Snyder model to ULINE since that model was used in the Environmental Impact Statement and outfall-siting studies. B. Beardsley pointed out that ULINE would be more conservative since it does not consider momentum of the flow.

OMSAP members then commented on the study design. B. Chen asked about flow and turbulence and if there is any possibility that the flow is not high enough to mix particles and oil causing higher concentrations to discharge from the first riser. K. Keay replied that the connections of the risers to the outfall tunnel are near the floor of the tunnel to purge trapped salt water, except for the last riser which has a ceiling-connection to purge trapped air. M. Mickelson added that the tunnel has a venturi near the start of the diffuser section to increase turbulent mixing to prevent seawater intrusion through the full length of the tunnel. C. Hunt added that measurements such as total suspended solids and metals will track how well mixed the effluent is.

J. Shine asked about dye smearing in the tunnel. If the effluent is not well mixed, then there will be some parcels of water without dye (but containing particles) and this could possibly overestimate dilution. M. Mickelson pointed out that MWRA is considering adding the dye at the end of the disinfection basin and mixing in the tunnel is good. B. Beardsley added that if the flow is very turbulent, then the dye will travel as a "slug". J. Shine pointed out that one needs to make sure that the concentration of dye in the tunnel is uniform all of the time (i.e. little or no smearing). M. Mickelson stated that the dye will mix and smear but the dye will build up quickly in the tunnel and MWRA will measure smearing. B. Beardsley thinks that there will be a diurnal change in discharge and so he asked if the dye will be added according to flow rates. M. Mickelson replied yes, dye addition will be proportional to effluent flow.

C. Hunt stated that there will be a survey before the plume tracking to sample the apparent dye background. B. Chen asked if the models give a residence time in the ZID. M. Mickelson replied that the rising plume takes about three minutes to reach the ZID and hours to days to for subsequent horizontal mixing. The initial dilution can be from 60:1 to as high as 600:1 in extreme conditions and he expects to see 250:1 in the winter. The permit assumes that the re-entraining (diluted effluent which re-enters the plume) water has a dilution of 364:1. Re-entrained water will be examined by measuring salinity and optical characteristics.

B. Beardsley pointed out that there will be less dilution with rotary tides and asked how this will be measured. M. Mickelson replied that moored USGS current meters describe the water column at two or more different depths, and horizontal velocity of the waste field will be measured using a shipboard Acoustic Doppler Current Profiler (ADCP). He pointed out that concern that the effluent might travel intact without dilution in a layer without any further mixing will be addressed by using John Proni's acoustical techniques for imaging turbulent swirls in the water, salinity differences, and suspended solids. J. Pederson suggested sending the Proni (1996) report to OMSAP. M. Mickelson recalled that the Proni (1996) report showed layers and internal waves. B. Beardsley pointed out that Mass Bay has a lot of internal waves, especially in the summer, which are generated by Stellwagen Bank and it is routine to use acoustics to measure them. He is not sure what is in the effluent which would cause additional scattering with acoustics. It would be interesting to see some of those results. D. Tomey will provide copies of the report to OMSAP. D. Tomey added that acoustics track the backscattering from solids which can show layering but as B. Beardsley pointed out, it is unclear what all of those particles represent. M. Mickelson stated that J. Proni said that acoustics can detect salinity discontinuities (e.g. the Schlieren effect visible when sugar and water are mixed together). Those "little swirly things" echo sound and can be detected more easily than solids for which the load is lower with secondary treatment. D. Tomey added that there are also better sampling techniques available now.

B. Chen asked if the BOSS (Battelle Ocean Sampling System) can sample any lower than 3 m off the bottom. C. Hunt replied that it can sample 2 m off the bottom if the ship is stationary and the towyo can reach 3-5 m off the bottom. Battelle plans to sample as low as possible to see if there is any unusual layering. The USGS mooring 1 km southeast from the outfall has sediment traps. B. Chen added that the 1m-above-bottom sediment trap has captured a layer of flowing particles near the bottom in Mass Bay and that layer could possibly be a significant transport mode. B. Beardsley asked if the number of diffusers is variable in the Roberts and Snyder model. M. Mickelson replied yes. C. Hunt requested that any additional comments on the draft study design be forwarded to MWRA as soon as possible.

[UPDATE: Here is a clarification of the ZID definition provided by Dave Tomey. The permit had a different definition of the mixing zone than the outfall EIR/EIS. The size of the mixing zone for the permit was not determined based on a simple depth factor, as used in the Section 301 (h) definition and implied in the March 1999 OMSAP minutes. The Fact Sheet of the MWRA permit stated: "The draft permit limitations are based on the most restrictive type of mixing zone, the area of hydraulic initial dilution, called the zone of initial dilution. For the draft permit, that area is expected to occur at approximately 60 meters (197 feet) away from the diffuser outfall, and that determination incorporated only the most conservative (i.e., 'worst case') conditions of the receiving water and discharge flow." (Note: this applies to the final permit as well as the draft). The MWRA Facilities Plan/EIR and the EPA EIS, which predated the permit, assumed a dynamic mixing zone. Both agencies agreed to define the mixing zone as a dynamic edge of hydraulic mixing, which, in reality, would vary with flow and ambient currents. The permit, on the other hand, needed a more definable area for developing a practical compliance strategy. Worst case conditions and the results of Roberts' modeling were used to delineate the permit mixing zone with the dimensions of 52.5 m in any horizontal direction from diffuser axis. (This was expanded to be about 60 m which happens to be about 2 times the depth.)

Although this distinction is not major issue, it is important to clarify the mixing zone in the context of the proposed plume tracking study. The primary objective of the study is to verify the dilution and immediate dispersion of the effluent plume as modeled in the EIR/EIS and subsequent analyses under the conditions present during the study. It will be important to find the dynamic hydraulic mixing zone first to verify the modeled dilution at that point. Then the study will follow the advection of the plume in the farfield to about 500:1 dilution after semi-steady state conditions are achieved. Whether the zone is completely encompassed within the 60 m box is only of secondary concern since the study is only a snapshot of mixing under the particular conditions of flow, ambient current and wind at the time of the study.]

FORMATION OF A MODEL REPORT EVALUATION FOCUS GROUP
The original Model Evaluation Group convened by the Outfall Monitoring Task Force assisted in the development of the Bays Eutrophication Model (BEM) model and reviewed the 1992 model runs. One of the recommendations from the group was for MWRA to run the model for 1993 (large phytoplankton bloom) and 1994 (lowest nearfield DO in the bottom waters on record for the baseline period) to see how well the model captures those features. MWRA suggested that OMSAP form a model evaluation focus group to evaluate these model runs. J. Pederson added that the outside review helped the model become more efficient and understandable. K. Keay stated that a draft of the report will be ready in the next 6-8 weeks. B. Beardsley said based on that time frame, he thinks the group could complete the review by July or August 1999.

J. Pederson suggested that the issue of model ownership be addressed by the group. A home for the model needs to be found so that it can be maintained, updated, and used for other outfalls. MIT and U Mass have showed interest in the past if additional state/federal support was made available.

ACTION: OMSAP agreed to review the upcoming report on Bays Eutrophication Model runs for 1993 and 1994. The Panel will also contact the original Model Evaluation Group (MEG) as well as additional scientists to request that they review the report. A MEG may be convened this summer with B. Beardsley as chair.

1999 OMSAP MONITORING WORKSHOP
The OMSAP charter states that the OMSAP shall have a public meeting once a year "to explain findings, to explain their significance and to hear and respond to concerns from the public". MWRA is willing to support this effort by presenting monitoring results. C. Doherty requested that the Public Interest Advisory Committee be involved in the planning. She hopes that a user-friendly document comes out of the meeting. OMSAP agreed to host a public monitoring workshop this summer.

The group then had a discussion about public outreach. B. Chen thinks it is very important, yet challenging, to get information to the public. He hopes that the results of the workshop can be brought to the public in a short and glossy report, which is widely distributed. It may be costly but the impact on public perception would be valuable. C. Doherty hopes that the PIAC will further discuss how to get information out to the public and in what format. J. Pederson feels that the purpose of the workshop needs to be determined -- whether it is to review the science or brief the public. B. Beardsley pointed out that GLOBEC (Global Ocean and Ecosystems Dynamics Research Program) invites science writers to meetings and surveys to help get the information to the public. B. Chen said that the Boston Globe has covered engineering for the Boston Harbor Project. C. Coniaris suggested another insert in the Boston Sunday Globe. J. Pederson pointed out that there are several science writers at MIT who could possibly help. B. Beardsley added that the Japanese prepared a cartoon book describing the sewer system in Tokyo and it was very popular.

ACTION: OMSAP agreed to host a public monitoring workshop this summer. MWRA will develop a proposed agenda for OMSAP/PIAC/IAAC review. A subcommittee will meet to plan for this workshop. Suggestions for meeting format and content are welcome.

PLANKTON MONITORING AND THRESHOLD OVERVIEW
M. Mickelson presented an overview of the phytoplankton (PP) and zooplankton (ZP) MWRA monitoring. There is a map of station locations in his information briefing. M. Mickelson described the concerns raised about plankton:

  • Will nutrients increase, causing more plant biomass and/or higher plankton productivity leading to a dissolved oxygen (DO) depression in bottom waters.
  • Will nutrients increase or will nutrient ratios change causing more nuisance algae which may affect human health and/or the health of higher marine trophic levels.
  • Will nutrients increase or will nutrient ratios change causing a change in the PP community and possibly change the ZP community and possibly change the food web.
  • Will the changed location of effluent discharge cause: an increase in the duration of the spring bloom, abundant growth at depth, and enrichment of Alexandrium entering from the Gulf of Maine.

M. Mickelson then described how monitoring addresses these questions. He showed Bays Eutrophication Model (BEM) predictions for relocation and secondary treatment which show significant decreases of DIN in Boston Harbor and not much change in Mass Bay. There is a decrease in chlorophyll for all locations, especially in the Harbor and at surface depths. The flux of particulate organic carbon (POC) can affect bottom DO and the benthic community. POC model predictions show an improvement in Boston Harbor and no change in Mass Bay, except for a localized increase at the new outfall site. It is not likely in the framework of this model that there would be a disastrous effect. The model has different winter and summer PP communities which have different temperature and silica requirements. B. Robinson asked why POC is presented as a flux and not as a concentration. K. Keay replied that it is a flux to the bottom from the lowest model grid to the sediments to model the effects to the benthic communities in terms of inorganic carbon loading.

M. Mickelson pointed out that the OMP's plankton-related measurements are: nutrients (nitrogen, phosphorus, silica, and carbon) (dissolved, particulate, inorganic, organic), PP (chlorophyll, primary production, microscope counts), ZP (microscopic counts), DO, temperature, salinity, and light. MWRA monitoring is inadequate for properly measuring Alexandrium since it can cause shellfish toxicity even at very low levels. It is best measured by Don Anderson at WHOI (MWRA special studies, Sea Grant) and the MADMF shellfish monitoring program. Zooplankton patches are studied by Cabell Davis, Stormy Mayo and others.

M. Mickelson described general patterns in the plankton results. Overall, there is variability with region, season, and year. The spring bloom is triggered when light conditions are favorable and terminated primarily by nitrogen depletion (secondarily by silica depletion). Chlorophyll and nitrogen are inversely related (i.e. more chlorophyll, more PP, nitrogen depletion). Silica is depleted if diatoms are dominant, especially centric diatoms. Spring blooms may end before completely depleting nutrients (this will be further examined). Nuisance algae have been observed including Phaeocystis and Pseudo-nitzschia. Organic matter from the spring bloom settles and is remineralized by bacteria, releasing nutrients to bottom waters during the summer. Storm-induced mixing events cause small-scale summer blooms due to the mixing of these deep nutrients. Plankton numeric abundances peak during the summer. The fall bloom is triggered by the overturn of the water column which brings nutrient-rich bottom waters to the surface. Bottom water DO is lowest in the fall. The pennate diatom Asterionellopsis often dominates in the fall and the fall bloom is usually larger than the spring bloom (this is an unexpected finding of the OMP).

He described exceptions to the general patterns described above for Boston Harbor (BH). BH has relatively high nutrients and chlorophyll and this signal extends into Mass Bay (MB) surface water. BH has high primary productivity and chlorophyll peaks in the summer (not fall). BH has a similar PP community to MB but has a different ZP community than MB. The BH ZP community is similar to the one found in Cape Cod Bay (CCB).

He then described exceptions to the general patterns described above for CCB. The spring bloom begins earlier in CCB than MB since it is shallower and light can penetrate to the bottom. The spring bloom may be bigger than the fall bloom and may be silica limited. CCB has less summer chlorophyll and ZP abundance. The PP includes more microflagellates and dinoflagellates and the ZP community is similar to coastal MB.

There are three nuisance species of concern. Alexandrium tamarense can cause paralytic shellfish poisoning (PSP). Problem abundances are ~1,000 cells per liter and may bloom from April to June. Pseudo-nitzschia multiseries can cause amnesic shellfish poisoning. Problem abundances are ~100,000 cells per liter and blooms may appear from November to March. Phaeocystis pouchetii blooms produce gelatinous polysaccharide and acrylic acid and may cause the clogging of whale baleen. Problem abundances are ~1,000,000 cells per liter and blooms may appear from February to April. M. Mickelson then described the caution levels for nuisance algae [see handouts], for occurrence of paralytic shellfish poisoning, and for zooplankton community structure in the nearfield. Related thresholds include nitrogen loading, chlorophyll, and dissolved oxygen. PP are sampled using bottle samples at the surface and mid-depth at 13 stations (nearfield 17 times a year and farfield 6 times a year). ZP are sampled using vertical oblique net tows (102 um) through the entire water column at the same stations and frequency as for PP but there are also two additional ZP stations located in CCB, which are measured three times a year during the winter. MADMF has been sampling PSP in shellfish since 1972, and in 1993 there was a large Alexandrium bloom. B. Beardsley pointed out that transport mechanisms are important for Alexandrium.

B. Robinson asked what would happen if a caution level is exceeded. M. Mickelson replied that the first step will be to notify OMSAP and the regulators. J. Pederson stated that there was a lot of discussion initially about the number of plankton samples needed to see a difference and she asked if MWRA takes enough measurements to be able to detect a change given that there is a certain amount of variability to begin with. C. Hunt stated that Battelle is working through the steps to apply a 95th percentile above the mean threshold level. M. Mickelson added that they are first attempting this with simpler measurements such as chlorophyll.

R. Manfredonia asked if there is anything in the plankton record which is surprising. He also asked if there is anything in the baseline record which shows evidence that a change in bloom size will occur with the relocation of the outfall. M. Mickelson replied that it would be surprising if the "textbook" patterns did not occur. One surprise was that the fall bloom was larger than the spring bloom. Another observation is the BH nutrient and chlorophyll signal extending into MB. The similarity of the PP communities in the harbor verses the Bay is important because even with the current nutrient enrichment in BH, manifested by a 3x greater chlorophyll, a marked change in PP community is not seen which suggests that the PP community is not sensitive to nutrient enrichment. MWRA has been comparing each year's results with thresholds in the Outfall Monitoring Overview.

A. Solow asked if a consistent low level of change seen over time, which is not large enough to exceed a threshold, would be a concern. M. Mickelson replied that the threshold formulation is based on the requirement of urgent reporting, and are not expressed in terms of long term effects. K. Keay added that MWRA is currently evaluating what are considered small or large effects and this is something the OMSAP will be asked to review in upcoming meetings. A. Solow feels that it is necessary to be clear about what the purposes of these thresholds are.

J. Pederson stated that one of the problems with looking at subtle changes is that it is difficult to attribute them to the outfall. B. Beardsley and R. Manfredonia feel that MWRA should look at changes other than those which have thresholds and explain them as best as possible. M. Mickelson added that there are certain parameters which are expected to change from the baseline observations and modeling. MWRA should test those as well as possible using future monitoring results. J. Shine feels that everyone needs to make sure that they think about how sampling captures variability over space and time. A. Solow pointed out that the true pre-discharge distribution of parameters is not known.

B. Beardsley gave the example of Georges Bank and how things may be happening over larger time scales than the baseline period. Over the years, there has been a gradual decrease in salinity by about 1.5 psu and it is thought to be due to a larger influx of northern waters. If this is also occurring in MB, it could change plume dynamics over time. A. Solow added that plankton community could also change.

G. Renick gave a brief overview of the history of the thresholds and Contingency Plan (CP). The CP came out of the conservation recommendations attached to the 1993 Biological Opinion (BO) issued by NMFS as a part of the Endangered Species Act consultation. The BO stated that there will be "no jeopardy" to the existence of endangered species but also recognized that there are a number of areas of uncertainty. The CP was developed as a way of trying to identify when significant unpredicted events occur and when they do occur, the outfall should be examined for causality. C. Hunt added that MWRA is trying to set thresholds so there will not be many "false alarms". G. Renick pointed out that it is difficult to determine when something is due to the outfall. B. Robinson agreed with C. Hunt but feels that it is difficult to determine if the nuisance species and shift in ZP community thresholds are liberal or conservative. C. Hunt pointed out that those numbers are based on expert opinions and now MWRA is trying to put data behind those numbers to back them up. Information will be ready on this around June. R. Manfredonia strongly supports looking at the database to gain a better understanding of the system. He feels that the OMSAP should become familiar with the thresholds and raise questions now.

FOOD WEB MODEL SCOPE OF WORK (FWMSOW) STATUS REPORT
A. Solow updated the group on the food web model scope of work. He hopes everyone can come to agreement on this issue. The FWMSOW is required by the draft permit but unfortunately the permit is not very specific. One could infer that the two goals of a FWM, should it ever be constructed, are to enhance our ability to make predictions about the effects of certain changes associated by the outfall on the whales, and detect an effect that could be attributed to the operation of the outfall after the effect had begun to manifest itself. Everyone now agrees that a truly quantitative and predictive FWM is not feasible at this time, but there are other types if FWMs out there. A FWM could be a qualitative description of the food web in the Bays as a way of integrating the results of the monitoring and connecting the results of the monitoring to answer useful questions, e.g. about whales. In thinking about it in those terms, the question then arises, is the OMP missing any important components. Another question is whether the draft scope of work is broad enough to encompass that kind of model. The final point raised is whether the stopping points in the draft FWMSOW, make it too easy to just "start by stopping". A. Solow emphasized that it is not that simple. When a stopping point is reached, missing information is collected and re-evaluation occurs. He pointed out that the PIAC and CCC have requested that the OMSAP postpone any decisions on the FWMSOW so that the CCC can provide OMSAP with a written proposal by April 23 [Update: the CCC has postponed this date].

P. Daley agreed with A. Solow's summary and stated that since the last OMSAP meeting, the CCC had a FWM meeting and came to the conclusion that maybe there is a misunderstanding about what is meant by a FWMSOW. The Cape Cod Commission is not requesting a quantitative food web model or a brand new monitoring program, but rather a different way of looking at the existing data to see if anything is missing. They are considering a qualitative model as a way of integrating the results of the monitoring. The CCC is focusing on the monitoring stations (frequency and timing of sampling) as mentioned by Ted Smayda at the December OMSAP meeting. She will communicate MWRA's plankton presentation back to the group and see if they can formulate a specific recommendation to OMSAP.

M. Delaney commented that what MWRA has done so far is falling in line with the direction from EPA. M. Liebman stated that he had said that the food web model being scoped out did not have to be predictive, but there are differences of opinion in what "predictive" means. EPA would like to see a model which looks at "what if" scenarios. He did not consider this predictive, whereas other people did. J. Pederson pointed out that there is a matrix included in the appendix of the phase 1 OMP which describes these "what if" scenarios. She suggested that the OMSAP review this to see if the current OMP can address these scenarios. This can be considered a type of conceptual FWM, but not with the traditional boxes and arrows. She pointed out that a lot of thought went into determining station locations and there was an awareness that the plankton stations would never be able to give the statistical validity that people are looking for but there were trade-offs such as increased nutrient monitoring. She also suggested reviewing the NRC book, "Managing Troubled Waters".

R. Manfredonia stated that the draft permit did not prescribe any one approach over another as to what kind of model should be developed. EPA understands that MB is a complex ecosystem but EPA does not want to miss any long-term chronic impacts. B. Beardsley pointed out that OMSAP felt that a predictive food web model was not possible at this time but that MWRA could work towards a better understanding of the ecosystem by developing some sort of conceptual food web model.

ACTION: OMSAP postponed a decision on the draft food web model scope of work presented by the MWRA at the December 18, 1998 OMSAP meeting pending additional information from the Cape Cod Commission. OMSAP agreed to review the "Sources of perturbation and resources at risk" matrix on page A-5 of the Outfall Monitoring Plan phase 1 to see if the hypotheses are being addressed with the current monitoring plan.

ADJOURN

OMSAP Meeting, Friday, December 18, 1998
11:00am to 3:00pm
EPA Boston
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow, WHOI (chair); Robert Beardsley, WHOI; Robert Chen, UMB; Robert Kenney, URI; Scott Nixon, URI; Judy Pederson, MIT/Sea Grant; Bill Robinson, UMB; and Jim Shine, Harvard School of Public Health.

Observers: Peg Brady, MCZM; Leigh Bridges, MADMF; Cathy Coniaris, OMSAP Assistant; Patty Daley, Cape Cod Commission; Mike Delaney, MWRA; Jim Fitzpatrick, HydroQual; Maury Hall, MWRA; Carlton Hunt, Battelle Ocean Sciences; Russell Isaac, MADEP; Ken Keay, MWRA; Christian Krahforst, MCZM; Kristyn Lemieux, ENSR; Matt Liebman, EPA; Steve Lipman, MADEP; Ron Manfredonia, EPA; Robert Michener, BU; Mike Mickelson, MWRA; Joseph Montoya, Georgia Tech; Jim F. O'Connell, Cape Cod Commission; Arleen O'Donnell, MADEP; Cornelia Potter, MWRA Advisory Board; Susan Redlich, WAC; Virginia Renick, MWRA; Andrea Rex, MWRA; Larry Schafer, retired; Jack Schwartz, MADMF; Rich Signell, USGS; Ted Smayda, URI; Dave Taylor, MWRA; Heather Trulli, Battelle Ocean Sciences; and Salvatore Testaverde, NMFS.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets].

SUMMARY OF ACTION ITEMS

  1. C. Coniaris is drafting a protocol which will describe the procedures of OMSAP, PIAC, and IAAC. [A draft will be sent to OMSAP, PIAC, IAAC, EPA, MADEP, and other interested parties for comment.]
  2. OMSAP members will draft a statement describing why they approve of the Food Web Model Scope of Work outlined by MWRA and why they believe that the development of a food web model would not be feasible at this time due to the present gaps in knowledge of certain processes in Massachusetts and Cape Cod Bays. This statement paper will be distributed before the next meeting, discussed, and voted upon at the March OMSAP meeting. [Update: the OMSAP have postponed completion of their statement paper until after additional discussion and presentation of the current MWRA phytoplankton/zooplankton monitoring program at the March 22, 1999 OMSAP meeting.]
  3. OMSAP agreed to review the results of the nitrogen-15 stable isotope sampling study when it is completed.

SUMMARY OF MEETING

Members were asked to meet after the meeting to discuss potential new membership. C. Coniaris is drafting a protocol that will describe the procedures of OMSAP, IAAC, and PIAC.

APPROVAL OF THE OCTOBER 1998 OMSAP MINUTES
B. Beardsley requested his statement about N15 be deleted since he did not actually make the comment. Members approved the minutes as amended.

MWRA UPDATE
M. Mickelson gave brief monitoring update. Battelle has completed all of the 1998 sampling. A right whale and two humpbacks were observed feeding during the December water quality survey. C. Hunt stated that fewer stations were sampled in the nearfield during the December survey so that more samples could be collected along the Cape Cod Bay boundary.

M. Mickelson then showed model results which included a transect from the Boston Harbor to Stellwagen Bank and Provincetown, as requested at the October OMSAP meeting. J. Shine asked why the areas under the curves are not the same. R. Signell replied that the areas are not identical (isotropic), however integration shows that they are very similar.

PUBLIC INTEREST ADVISORY COMMITTEE UPDATE
C. Coniaris gave a brief summary of the December 15 PIAC meeting [summary available]. PIAC advises OMSAP on important public concerns so that they are aware of those issues as they review scientific information. PIAC is also responsible for bringing OMSAP's decisions back to their constituencies. At the PIAC meeting, everyone introduced themselves and described their respective organizations. The group then spent most of the meeting discussing PIAC's roles and how it will function. The group agreed that it will attempt to work to consensus but since there are such varying interests in the group, any opposing opinions will be reflected in the minutes. The citizens' issues will first be discussed at PIAC and then brought to OMSAP. The group agreed to meet 4-6 times a year, about a month before OMSAP meets so that there is enough time to discuss issues and present them to the OMSAP. PIAC also agreed to meet if an important issue arises. PIAC agreed that their first item of business is to compile a list of issues to address and place them on a time line. PIAC agreed that they will review the OMSAP minutes as well as the other materials made available to the OMSAP so that they can discuss any issues that they feel are important. Cate Doherty will report to OMSAP on PIAC proceedings. Several PIAC members agreed to try to attend OMSAP meetings so that they can report back to PIAC. PIAC will have email discussions, as needed, as a way of communicating, and they requested that MWRA notify them whenever they are close to exceeding a threshold. PIAC also agreed that flexibility should be maintained as the functions of all three groups are determined. PIAC only had time to briefly discuss the food web model scope of work, however, they did not forward any recommendations to the OMSAP.

S. Redlich (PIAC member) added that PIAC members were also very interested in the opportunity that PIAC afforded in terms of exchanging information among the groups. In addition, PIAC is a conduit for a larger audience - the public - and needs to be aware of what questions and issues are out there. She also added that some of the members need to understand the role of the OMSAP better since they are new to this outfall monitoring process. By attending OMSAP meetings, PIAC members can get a better understanding of how things function. P. Daley (PIAC member), who also attended the meeting, approved of the summary.

INTER-AGENCY ADVISORY COMMITTEE UPDATE
S. Testaverde, interim IAAC chair, gave a brief update. The IAAC has a tentative agenda and will set up a meeting in February [Wednesday, February 24, 1999 1:00-3:30 PM at EPA Boston, summary available]. The IAAC will explore in depth what its charge/mission is. C. Coniaris listed IAAC membership and stated that IAAC is charged with advising OMSAP on the varying agency perspectives on scientific issues.

DRAFT FOOD WEB MODEL SCOPE OF WORK (FWMSOW)
M. Delaney described MWRA's perspective on this issue. MWRA has spent approximately 20 million dollars since 1991 on outfall monitoring, modeling, and reports. MWRA is spending about 3 million a year on the current monitoring. Joe Favaloro [director, MWRA Advisory Board] had asked him why MWRA is working on the FWMSOW since the permit is still a draft. M. Delaney had responded that MWRA expects that the final permit will include the FWMSOW and MWRA would like guidance from the OMSAP on the approach which they are considering. M. Delaney then read from Doug MacDonald's [executive director, MWRA] May 4, 1998 comments on the draft permit to EPA/MADEP: "MWRA should not be asked to do things more appropriately undertaken by other agencies. We are particularly concerned about the scope and extent of the reporting requirements in this permit." MWRA strongly feels that the science should not be allowed to fall behind by trying to attempt something which is not feasible. MWRA would like OMSAP's input on the approach presented today.

C. Hunt then provided background information, presented the approach mentioned by M. Delaney, presented results of a nutrient sensitivity analysis (i.e. response due to outfall) using the Bays Eutrophication Model, further defined what the FWM issues/focus are, and requested guidance from the OMSAP on the next steps. A scope of work defines necessary work but is not a work plan by which one does the work. There are issues of uncertainty which need to be addressed in terms of developing a defensible model: (1) feasibility of developing a predictive model; (2) appropriate goal and approach; (3) level of nutrient change in the receiving waters required to impart a change in the prey of right whales; (4) a modeling exercise of this type is open-ended; (5) and factors other than the outfall that may be affecting the right whale and/or its prey in the Bay.

The MWRA is focusing on the development process of a food web model by using a flow diagram with several levels. The first level is the review of any previous assessments for conclusions and assumptions, update that and validate those assumptions with the seven years of baseline data, conceptualize a FWM (conducted by Kelly, et al. 1998), and perform a sensitivity analysis of MWRA loading using the Bays Eutrophication Model (BEM). C. Hunt showed some of these results later in the presentation.

Once this information is gathered, the following question will be asked: "will the environmental conditions be worse than predicted?" New information will help answer this. If the answer is no, then monitoring should be continued and the same question will be revisited annually. If the answer is uncertain, then there may be other research which could be conducted to address specific issues and questions in terms of uncertainty. If the answer is yes, then MWRA would have to go to the next level: "is such a change likely to harm whales?" Again, there would be a similar cycle. C. Hunt went on to explain the rest of the flow chart.

C. Hunt then described the conclusions of the review of assessments. EPA's 1988 Supplemental Environmental Impact Statement (SEIS) and EPA's 1993 Biological Assessment determined that there would be some impacts to the environment by the effluent but that they would be localized. The 1993 NOAA Biological Opinion (BO) stated that there will be "no jeopardy" to the existence of right whales. The BO examined three pathways: (1) increased nutrient loading to the Bays due to outfall relocation from Boston Harbor into Massachusetts Bay; (2) increased nutrient dispersal/transport to farfield areas of the Bays due to direct discharge of effluent at the proposed site in Massachusetts Bay; and (3) nearfield generated impacts and the outfall as a nuisance attraction for endangered species and/or prey of endangered species. C. Hunt presented information which supported this conclusion. "No jeopardy" means that there may be some effects on the environment but that there is no jeopardy to endangered species. Recent data has indicated that the assumptions in these assessments were conservative.

The effluent will be cleaner than predicted in the assessments since the assessments considered primary and not secondary treated effluent. Higher loads were used in the impact assessments compared to November 1998 MWRA data. Some of the predictions state that there may be lower phytoplankton and biomass in the area of the outfall which may mean that there will be less zooplankton for the whales to feed on. There are also major forcing functions on the total whale food web that are external and will likely override local effects.

Since the original assessments, R. Signell has developed a dilution transport model (1996) which has become more sophisticated over time with the addition of stratification and better advective terms. MWRA has also examined a number of other reports and data analyses. C. Hunt discussed the dilution transport model, nutrient loading, and recent sensitivity analyses.

C. Hunt then described a mass balance based on the 1992 BEM model results. Using the 1992 calibrated BEM model, MWRA examined the flux of nutrients across all of the boundaries, including MWRA, atmosphere, non-point, other wastewater treatment plants, and riverine inputs. He showed both dissolved inorganic (DIN) and organic nitrogen (ORGN) inputs. MWRA also examined the import at the boundary by Cape Ann and the export that exits by Cape Cod. The total input from the MWRA effluent is about 3% of the total nitrogen entering into the Mass Bay system. 5% is from non-MWRA sources and 92% from the boundary. R. Signell pointed out that the Cape Cod Commission information briefing states that MWRA is the largest point source in the system compared to the other sources. This is not inconsistent with the data which have been presented, but one must realize that there is already a large nutrient pool out there.

C. Hunt then presented recent model nutrient loading sensitivity analyses. MWRA put together six scenarios. "COL" is the current outfall location. "0x" is perfect nutrient removal from Deer Island, but not other treatment plants. "1x" is SEIS level predicted input with primary treated effluent. "2x" is the doubled nutrient concentrations using the same water flow. The responses of DIN, TIN, total nitrogen, chlorophyll and oxygen were modeled in the system, both at the current outfall and future outfall locations. All runs used the same coefficients and the same modeling format using primary treated effluent. M. Liebman suggested to repeat this exercise using current data in order to tie together the 1988 predictions and the current predictions. K. Keay replied that MWRA plans to work with HydroQual to produce additional model runs with more baseline data.

C. Hunt then showed the results of the sensitivity analysis for nitrogen, silica, phosphorus, carbon, and chlorophyll in the effluent for April 18, which is at the end of the winter/spring bloom and the period of most concern to the whales. T. Smayda asked if the model includes uptake, or just dilution and dispersion. J. Fitzpatrick stated that it includes phytoplankton uptake, remineralization of organic/detrital matter, and a first-order reaction rate for the effect of zooplankton predation. C. Hunt added that a full benthic cycle is also included. There was a brief discussion on model parameters. C. Hunt then presented the bottom dissolved oxygen model results for October 20. This day was chosen since it is the time of year when bottom dissolved oxygen levels are the lowest. Values ranged from 5 to 9 mg/l.

T. Smayda asked if vertical profiles of nutrients at depth were produced for this exercise so that thin layers, dispersion, entrapment of nutrients, subsurface plumes, and vertical distribution could be seen. C. Hunt stated that a high-resolution profile has been done which includes transmissometry, DO, salinity, chlorophyll, and temperature. T. Smayda asked if BEM will not be able to model nutrient build-up downstream at depth. J. Fitzpatrick replied that the concentration changes seen in the model results in Cape Cod reflect this. Phytoplankton biomass and productivity were examined during the critical summer period in the nearfield since there will be an introduction of increased nutrient concentrations in the immediate vicinity of the future outfall. Increases in primary production were seen, primarily due to the fact that there are nutrients at depth with some light penetration. Changes in productivity were not seen in Cape Cod Bay. Some of the bottom nutrients would gradually bleed up into the surface in shallower sections of Cape Cod Bay. T. Smayda added that they could also be bioconvected. R. Signell pointed out that since the plume is trapped in the lower layer during the summer, it is more likely to follow the topography and travel parallel to the coast. When there is less stratification, the plume will tend to wander out into the bay. C. Hunt added that the outfall monitoring program will include plume tracking during four different times of the year in order to define dilution and other processes. The plume tracking will include high resolution measurements using a towyo [apparatus which is towed up and down off the side of a research vessel on which various instruments can be attached].

C. Hunt believes that there is a lack of fundamental knowledge of many key processes. The development of a rigorous, predictive food web model can not be developed without better understanding of fundamental ecological processes, prey-whale energetics, and whale foraging decision making. There are a lot of relevant fundamental research areas which have been identified which would give us a better understanding of the effects humans have on the endangered right whale. The area is "ripe" for fundamental/basic research and selected modeling efforts linked to research could prove useful when looking at the local Mass Bay effect on endangered species. He pointed out that MWRA's monitoring program is the most comprehensive marine ecological outfall monitoring program in the world with almost every compartment in the system examined. The question is, where does MWRA responsibility end and others agencies' responsibilities begin?

J. Shine asked how the model addresses transport across the pycnocline. J. Fitzpatrick replied that given the diffuser structure, most nutrients will remain trapped below the pycnocline during the summer months, and essentially will not break through. A relatively small quantity of nutrients do diffuse through that layer, with local impacts on the primary productivity in the nearfield, and there may be a small localized increase in phytoplankton biomass at depth.

B. Chen asked how good the model is at predicting chlorophyll (i.e. how do predicted vs. observed compare). J. Fitzpatrick gave the example that models do relatively well in predicting the climate but do not do a very good job at predicting the weather. The model picks up some of the major features seen in the Mass and Cape Cod Bay system such as the fact that blooms begin earlier in Cape Cod Bay and with a higher magnitude. The blooms pulse and then decrease to less than one ug/l for most of the rest of the summer. Boston Harbor usually has a 2-3-fold higher chlorophyll concentration with respect to Mass Bay. The model predicts the nutrient dynamics correct in the sense that silica limitation is observed first in Cape Cod Bay and is followed by nitrogen limitation. It approximately gets correct the N:P ratios in terms of resolving inorganic and organic phosphorus. However, the model does not discern unique blooms. It will not predict Phaeocystis because no one understands enough of the algal physiology to be able to build that into a model. It also does not necessarily do well with all blooms of unique species that come and go over a week or couple of week basis. But it usually does well with average seasonal conditions.

R. Signell pointed out that the box calculation for the boundary might be a little misleading because it considers the whole source. What is relevant is the signal of the local outfall above the background. The term "source" from the offshore boundary would only be the current background. J. Fitzpatrick added that it is important to note that the system, even in the absence of MWRA, would have an input of nutrients and would support some level of primary productivity. C. Hunt added that this analysis looked at the inputs and some response factor in the Bays. There is a visible response to the additional nutrients in the effluent, however, the detectability of response in Cape Cod Bay is relatively low.

Request for Scope of Work -- Concerns
T. Smayda pointed out that Mass and Cape Cod Bays are nitrogen-sensitive, nutrient-enhanced, and regionally coherent. He is concerned that MWRA has focused on the dose-yield relationship between nutrients and phytoplankton and not enough on the ecological status, i.e. the relationship between nutrient loading and trophic response. He would like to see a monitoring program implemented which would examine the community response and be able to model in a helpful manner. He feels that while there has been a lot of data collection, there has not been enough hypothesis formulation and hypothesis-testing. He also believes that there is an intrinsic bias in much of the data collection (e.g. phytoplankton) with the habitat-status or dose-yield approach. The hypothesis which should be the basis of the model: "In nutrient-enhanced systems, associated changes in phytoplankton blooms, community structure and species succession are not a response to nutrient modification, but to changes in grazing pressure, i.e., failure of normal grazing processes". Two levels of hypotheses should be regarded as an intrinsic part of the model and scope of model. The first level relates to abundance and composition of zooplankton in Mass and Cape Cod Bays. The second level is patchiness. The hypothesis related to whales states that there is or has been a significant change in the extent of copepod patches acceptable to right whales. The focus should be on grazing and secondarily on nutrients.

He believes that there is a very low level of frequency of sampling in Cape Cod Bay both temporally and regionally. He then showed seasonal data from Narragansett Bay which shows that the winter-spring bloom can occur anywhere from November to February. This time variability must be considered since this area is at a sensitive biogeographical jump from boreal and temporal/boreal. Because of this, sampling needs to be as quantitative as possible, not only in terms of procedure but in modeling because this variability. If there is ever a catastrophic die-off, the cause should be discerned -- MWRA or other reasons. The scope of a model is necessary and should be able to quantify as closely as possible what is occurring in order to be able to make quantitative and cost-effective decisions (e.g. retrofit Deer Island, if necessary).

T. Smayda believes that it is reasonable to request that a model of suitable scope be incorporated which would then allow for quantification. This will not be perfect, but it is defensible. Perhaps the new outfall will not impact the right whale. But a right whale based model will also address to engineering, public health, and red tide issues. It has the potential of possibly discerning particular factors involved. He encouraged that the model have sufficient scope to allow for these kinds of decisions and that the monitoring program also be expanded.

Discussion
B. Robinson asked if T. Smayda felt that there was enough baseline data being collected. T. Smayda replied that there is adequate baseline data for particular times but not a lot of information is collected to learn about certain important things, for example, examining the microbial loop. He believes that we should use baseline conditions (and not "pristine" conditions) as our "start" position and to somehow use that as an index of change. B. Robinson believes that the biggest issue is potential change in community structure of phytoplankton/zooplankton. He asked if there is enough baseline data to really understand what the natural variability is over a 10-20 year period for the new outfall site. T. Smayda replied that the natural variability is not known. There is significant information available but he believes that the OMP sampling frequency and distribution is inadequate.

J. Shine asked if there is a good understanding of variability on a basic science level, not just in Massachusetts Bay. T. Smayda replied that this is currently under considerable debate. What is known is that blooms last longer and bloom species tend to be less diverse, and eventually become monospecific. J. Shine asked if T. Smayda expects MWRA to take on these basic research questions and incorporate them into a model. T. Smayda replied that monitoring only allows one to be reflexive when something has happened, but does not allow one to be reactive. To get around that kind of a problem, there needs to be process-oriented modeling and monitoring to examine key concerns.

B. Beardsley asked for some examples of what should be measured. T. Smayda suggested zooplankton grazing and phytoplankton uptake of nutrients over time. A. Solow requested that T. Smayda provide a specific list of suggestions about how the monitoring program could perhaps be modified or changed. S. Nixon does not see how OMSAP can endorse a scope for a project which may or may not be desirable. A. Solow suggested that one way is to have this scope of work available and if in the future, the question of implementation arises, a decision will have to be made as to whether that work should be done. B. Robinson asked about phytoplankton/zooplankton monitoring. M. Mickelson replied that MWRA has been monitoring and enumerating phytoplankton/zooplankton species since 1992. The program will continue and any cutbacks in the program will occur only with the approval of OMSAP. B. Robinson would like to see some of the results. M. Mickelson stated that MWRA would be glad to revisit this. [Update: the MWRA will present an overview of the phytoplankton/zooplankton monitoring at the March 22, 1999 OMSAP meeting.] MWRA has drafted a zooplankton retrospective, phytoplankton issues review, and other reports which specifically deal with these aspects. There are also seven years of baseline data. C. Hunt briefly described the phytoplankton/zooplankton monitoring program. M. Mickelson showed a map of zooplankton/phytoplankton stations at which biomass and species are measured.

B. Beardsley asked T. Smayda if he could elaborate more on the time period in which he does not expect much change. T. Smayda replied that the timing is driven by the right whales and summer red tide outbreaks. He briefly described the pre- and post-discharge sampling scheme recommended by the Barnstable Science Advisory Panel. He feels that there is no sense doing any kind of modeling if the right monitoring is not being done. B. Robinson does not think that the second row in the flow chart "will environmental issues be worse than predicted?" is useful. When looking at the phytoplankton/zooplankton community structure, one can not determine "yes", "no", or "uncertain". M. Delaney responded that this is based on examining changes since 1993, when the original determinations were made.

B. Chen pointed out that there is a lot of unknown between nutrient/phytoplankton dynamics and right whales dynamics and there is an ongoing need for research studies. He believes that at the present time, one can not show the potential effects of MWRA on right whales. The debate now is whether MWRA should set up a model which incorporates new findings, however, the model may never become useful. B. Kenney believes that the nature of the linkages and how to quantify them is unknown at the present time. No advances will be made by forcing something to happen before the data are available.

A. Solow believes that there are two ways to approach this. One is to recommend that the FWMSOW requirement be changed in the permit. The second would be to approve the scope of work, even if it involves a model that OMSAP agrees will not come to fruition (negative reaction from members). J. Pederson feels that it is risky because if the scope of work is inclusive and becomes a part of the response to the permit, then it becomes law. S. Nixon agreed with T. Smayda in that there is no point to have a model if there is not adequate data to verify it with. The state of the art does not allow for the construction of a credible, useful and dependable model. He stated that it would be wonderful if we had such a model but we do not and there seems to be no prospect of having one in the near term or median term future. Therefore to require MWRA to go forward and attempt to develop this would be more misleading than useful.

B. Kenney believes that this presentation satisfies the scope of work permit requirement. J. Shine pointed out that it will be impossible to reach "model development" on the flow chart. J. Pederson is concerned about what the responsibility of MWRA is verses others who support research. Developing a food web model is a research, not a monitoring, question. The Gulf of Maine Regional Marine Research Program discussed the issue of zooplankton grazing and determined that there is not a lot known, existing data are fairly inconsistent from area to area, and it is not clear that funding one more study will add to that. She suggested to at least do a literature search to examine what is known and not known. B. Kenney pointed out that OMSAP believes that a model would be desirable. However, a model is not feasible at this point. A. Solow added that it seems that it is not just feasible because of a lack of data, but models of nature are complicated. Even if there were much better measurements of many of the vital rates, it still may not be enough to build a predictive model. B. Robinson suggested that OMSAP accept this as a scope of work but that implementation is not possible at this time. J. Shine suggested asking MWRA to outline what is known and not known about the food web. B. Chen suggested leaving "a door open" so that as new knowledge becomes available, MWRA can add to the monitoring program in order to augment the understanding of the system. He would like to allow for potential model development in the future.

J. Pederson and B. Robinson pointed out that there are different types of models, both qualitative and quantitative. B. Kenney added that the point of a model is to predict where, when, and how many right whales will be found, for example, if a red tide bloom occurs. Crucial information, such as what causes those red tides or what forms the zooplankton patches the right whales feed on is not well understood.

M. Mickelson pointed out that any time the OMSAP requests that MWRA look into new information about modeling, it will be done. A permit requirement should not be required for that. This permit requirement sounds like MWRA has to take full responsibility for the departing of right whales. MWRA has countered with the following approach: first show MWRA has changed the environment in some significant way and then show that the change would harm the whales before considering whether there is enough information for a food web model. P. Daley believes that the monitoring program should spend more effort in examining the variability in the system. M. Delaney argued that MWRA does look for variability and will continue to do so. If there is a change, MWRA will detect it. The previous Task Force debated the form of the monitoring program, and MWRA is always receptive to improvements to the program. K. Lemieux thinks that MWRA has been very supportive. ENSR has prepared for MWRA several special issues reports and are currently preparing one on Phaeocystis which examines naturally occurring correlations and environmental variables. ENSR has also worked on a retrospective which looks at variability among other available data sets in order to augment the baseline data and get a handle on that spatial and temporal variability.

J. Pederson asked if one of the regulatory agencies could comment on this. M. Liebman stated that the permit will not be ready until after December 31, 1998, but the December 31st deadline was not going to change [update: the deadline has been extended]. The draft permit did contain a requirement that MWRA submit a scope of a food web model. This scope of work is a just plan and not a program and EPA/MADEP will rely on OMSAP's comments. A. O'Donnell added that EPA/MADEP would like feedback from the OMSAP on the scope of work and whether it should be implemented. G. Renick pointed out that it is really up to EPA/MADEP to show that by issuing the permit that no harm will result.

A. Solow suggested a motion that OMSAP accept the scope of work, that that a FWM is desirable but that OMSAP does not favor implementation at this time because the scientific knowledge needed is not available at the present time. J. Shine added that there should be hypothesis-driven data collection. B. Beardsley asked if OMSAP will summarize details of any motion in a statement paper and if there will be extended commentary as a way of having agreement in principle. A. O'Donnell suggested that OMSAP vote to draft a motion to be included in the minutes and then formally vote on the motion at the next OMSAP meeting. OMSAP approved that statement as a motion and voted in favor of it unanimously [S. Nixon had departed before the vote]. J. Shine pointed out that the draft scope of work includes continued monitoring and annual re-evaluation. A. Solow nominated J. Pederson to draft the statement but she nominated B. Kenney. He accepted. Members agreed to review drafts of the statement via email. [Update: the OMSAP have postponed completion of their statement paper until after additional discussion and presentation of the current MWRA phytoplankton/zooplankton monitoring program at the March 22, 1999 OMSAP meeting.]

OMSAP MEETING FORMAT
A. Solow stated that the OMSAP needs to be able to have free and open discussions of scientific issues. OMSAP meetings are open to the public and this may constrain the willingness or ability of the Panel to talk openly. C. Coniaris is working on the OMSAP protocol and one proposal is that it include that time be set aside at each meeting during which the Panel have their own discussion after which, audience members will be allowed to ask questions. The OMSAP will need this kind of quality time in order to be able to get things done in an effective way. L. Schafer and C. Krahforst believe that open meetings can work, as long as there is tight control in the participation in the audience. J. O'Connell suggested to perhaps have an additional meeting if there was not enough time to absorb the information, discuss, and develop opinions.

NITROGEN ISOTOPE RATIOS AS A TRACER FOR SEWAGE INPUTS TO THE COASTAL ZONE
J. Montoya summarized the method for using isotopes of nitrogen as an effluent tracer. The December 18, 1998 information briefing describes this method. J. Montoya believes that this gives an actual tracer for the nitrogen into the biota and could prove whether nitrogen from the outfall is having any impact. This approach can be useful not just in quantifying the local impact of sewage nitrogen on the biota but actually setting a biogeochemical index limit on nutrients.

Members then asked questions about the method. B. Robinson asked about background concentrations and other inputs to Mass Bay. J. Montoya replied that the sampling strategy should take these concerns into account. Though smaller sources may not be differentiated, the signature in the vicinity of the outfall will be strong. B. Chen asked about the effects of sediment denitrification. J. Montoya replied that sediment denitrification has little net discrimination because it is usually coupled with nitrification making the net effect about zero. C. Hunt pointed out that since this traces all particles, it includes the bacterial signature which creates a lot more variability. Data presented are based on the current discharge location and thus the signature should shrink in area with the new outfall due to greater dilution.

A. Solow asked why this should be monitored on a regular basis, and not just as a "special study". J. Montoya replied that MWRA should be interested in being able to point to a set of data which shows that there is no biogeochemical evidence that the nitrogen from the outfall is having any impact on the biota. He does not know another way to follow the nitrogen into the biota.

M. Liebman asked about variability. J. Montoya replied that one would have the same variability as measured in other biological processes. B. Beardsley can see how this could be useful in the nearfield but asked how one would differentiate "spikes" in Cape Cod Bay due to variability. J. Montoya replied that there will always be variability in synoptic sampling. The best job one could do is to collect good data in order to be able to delineate the spatial extent of this signature. Even though there is this variation in the source, the dominant signal that is expected is a large isotopic effluent signature. J. Shine pointed out that one would not want to get a false positive with a signal from another source. J. Montoya agreed and stated that other sources and variation would also have to be studied.

A. Solow asked if this could be used as part of a food web model. J. Montoya thinks that adding zooplankton N15 measurements could add a quantitative geochemical component to a food web model. D. Taylor added that the N15 method has been used with particulate material but there is now a mechanism to measure it using ammonium and nitrate, which have a larger wastewater background signal. Nikki Sheats' work suggests that secondary treated effluent will have an even larger signal. However, there are some negative aspects to this method as well. One is the sensitivity of the method relative to the increased dilution in Mass Bay and thus detectability. Another is the separation from alternative sources, the Merrimack River, groundwater from Cape Cod Bay, as well as other factors. There is very little DIN N15 baseline data available for both the effluent and Mass Bay and not enough time to collect very much before the outfall goes on-line. There will be cooperation in collecting some baseline data. MWRA has agreed to supply the CCC with samples from the secondary treatment plant (one per month December to July) and Battelle has offered to supply excess water from their farfield surveys for analysis. B. Michener's lab at BU has offered to analyze the samples. A. Solow asked if any samples will be collected "upstream" in order to measure water entering Mass Bay. K. Keay replied yes. M. Mickelson posted the stations locations.

J. O'Connell asked OMSAP if they believe this method can add significant information. He asked that OMSAP review the N15 report when it is completed. OMSAP agreed to review the report. C. Hunt suggested that source terms such as Cape Cod Bay groundwater intrusion be examined. OMSAP members felt that this method could potentially prove to be a valuable monitoring tool. They welcomed future presentations on this topic as more information arises.

ADJOURN

OMSAP Meeting, October 27, 1998
10:00 AM - 3:00 PM
MADEP Boston
FINAL MINUTES

ATTENDANCE

Members Present: Andy Solow (guest chair), WHOI; Robert Beardsley, WHOI; Robert Chen, UMB; Robert Kenney, URI; Norb Jaworski, retired; Judy Pederson, MIT/Sea Grant; Bill Robinson, UMB; and Jim Shine, Harvard School of Public Health.

Observers: Joseph Ayers, Northeastern University Marine Science Center; Polly Bradley, SWIM; Leigh Bridges, MADMF; Cathy Coniaris, OMSAP staff; Kelly Coughlin, MWRA; Patty Daley, Cape Cod Commission; Mike Delaney, MWRA; Cate Doherty, Save the Harbor/Save the Bay; Bruce Estrella, MADMF; Esther Graf, MWRA; Maury Hall, MWRA; Pam Harvey, MADEP; Carlton Hunt, Battelle Ocean Sciences; Russell Isaac, MADEP; Carolyn Jenkins, New England Interstate Water Pollution Control Commission; Ken Keay, MWRA; Roy Kropp, Battelle; Matt Liebman, EPA; Steve Lipman, MADEP; Joseph LoBuglio, MWRA; Ron Manfredonia, EPA; Mike Mickelson, MWRA; Jim F. O'Connell, Cape Cod Commission; Cornelia Potter, MWRA Advisory Board; Susan Redlich, Wastewater Advisory Committee; Virginia Renick, MWRA; Andrea Rex, MWRA; Jerry Schubel, New England Aquarium; Jack Schwartz, MADMF; Dillon Scott, MWRA; Dave Taylor, MWRA; Heather Trulli, Battelle Ocean Sciences; Sal Testaverde, NMFS; and Grace Vitale, MWRA.

Summary prepared by C. Coniaris. Post-meeting comments are included in [brackets].

SUMMARY OF ACTION ITEMS

  1. Panel members will discuss areas of expertise missing from the OMSAP and suggest additional membership to EPA/MADEP.
  2. EPA/MADEP will attempt to have the two OMSAP subcommittees, the Public Interest and the Inter-Agency Advisory Committees, in place by the next OMSAP meeting.
  3. A public announcement describing the OMSAP will be prepared.
  4. OMSAP requested a complete list of all effluent parameters measured by MWRA.
  5. OMSAP requested all speakers provide copies of their overheads to the members at the start of future meetings [one copy should also be provided to the OMSAP assistant].
  6. Members decided to continue to discuss the food web model scope of work via e-mail. M. Mickelson will make all materials discussed at this meeting available to members.
  7. OMSAP members agreed that MWRA has done a commendable job of addressing the concerns raised regarding lobsters and the new outfall. The OMSAP reviewed the results of recent lobster studies and other supporting material and concluded that no further studies were needed.
  8. The next OMSAP meeting will be in December 1998 [update: it has been scheduled for December 18, 1998 11:00 AM to 3:00 PM at EPA 1 Congress St. Boston, conference room 11A].
  9. After the meeting, Panel members officially elected Dr. Andy Solow as chair.

SUMMARY OF MEETING

OPENING REMARKS
R. Manfredonia thanked the members for accepting their appointment to OMSAP. Both EPA and the State appreciate their dedication to outfall monitoring issues. It is important to have sound scientific judgment when examining information produced by the monitoring program as well as by other permit requirements. EPA and MADEP will be asking OMSAP for their advice before making any decisions on monitoring issues. On behalf of EPA and MADEP, he extended his gratitude to Jerry Schubel for his dedication and good work as chair of the preceding committee, the Outfall Monitoring Task Force (OMTF).

LESSONS LEARNED BY THE OMTF AND GUIDANCE TO OMSAP
J. Schubel thanked the people who gave him the opportunity to chair the OMTF. He believes that the Outfall Monitoring Program serves as a model for the rest of the nation in terms of environmental monitoring programs for coastal waters. J. Schubel then discussed a few suggestions to the OMSAP. He respects the MWRA staff and their competence. He suggested that the OMSAP listen carefully to the advice of the agencies and public interest groups and respond to their questions. The OMSAP should develop mechanisms to keep these individuals involved since they can provide valuable information. He also suggested that the OMSAP host a public forum at least once a year in order to update the public and be able to respond to their concerns. Whenever a specific issue arises, OMSAP should form a focus group to bring in expert advice. Independence is important for OMSAP membership. If a member becomes a contractor for MWRA, they should step down. If questions arise which relate to a colleague's work, members should abstain from voting. Members need to do some work between meetings so that discussions can be efficient. As for additional membership, there were some areas that the selection committee felt were not covered by the current membership. It is the responsibility of OMSAP to try to fill critically important areas with additional independent scientists.

OMSAP PURPOSE AND FUNCTION, ADDITIONAL MEMBERSHIP, FORMATION OF THE OMSAP SUBCOMMITTEES
R. Manfredonia gave an overview of OMSAP logistics. Andy Solow has agreed to serve as interim chair until OMSAP has a chance to appoint a permanent chair [after the meeting, the OMSAP members officially elected A. Solow as chair]. The charter should serve as the guiding principles for OMSAP and its supporting subcommittees. This is a dynamic document which will be flexible, but its basic principles will not change.

The OMSAP may recommend to EPA/MADEP individuals for additional membership. The charter lists the following disciplines suggested to EPA/MADEP last year: fisheries, phytoplankton, zooplankton, marine mammals, biostatistics, public health, aquatic toxicology, modeling, benthic biology, physical oceanography, nutrient dynamics, microbiology and chemical oceanography. There may be some overlap considering members may have more than one area of expertise. The Panel should decide if this list makes sense and where there are voids in expertise.

The deliberations on science will made by scientists but the public perspectives expressed by the Public Interest Advisory Committee are critical. The Inter-Agency Advisory Committee will be an advisory group based on science but will also provide information about the roles and responsibilities of the agencies. C. Doherty from Save the Harbor/Save the Bay has agreed to serve as interim chair of the PIAC and S. Testaverde from NMFS has agreed to serve as interim chair of IAAC. EPA/MADEP would like to have these organizations in place by the next meeting.

In terms of OMSAP membership, the charter mentions two consecutive terms of two to three years each on a rotating basis so there is a continuum of information and decision-making. It is critical to have momentum, continuity in the discussions, and have this process go on without disruption. OMSAP will meet quarterly, but possibly more often as issues arise. EPA/MADEP will be mindful of the OMSAP members' busy schedules.

Focus group membership will have the same guiding principles as appointment to the OMSAP. As for USGS, they are an independent federal agency on matters of science, thus there would not be a problem seeking their scientific advice in a focus group. However, each member of a focus group should be selected on a case-by-case basis. J. Pederson emphasized that it is very important to maintain flexibility in this process.

R. Manfredonia continued with the issue of independence. It is important that the OMSAP be completely independent, be able to speak candidly on matters of science, and not be affiliated with any one group or agency. B. Beardsley asked if discussing the results of a colleague's MWRA funded research and possibly writing a joint paper would be a conflict of interest. R. Manfredonia replied that it possibly would be but it would depend on the specifics of the situation. M. Mickelson asked if members can use MWRA data to write a paper, or collaborate with a consultant to write a paper, provided that there is no financial transaction. R. Manfredonia replied that EPA/MADEP are not asking members to give up their areas of expertise or present efforts. There would be a problem if research were funded by the MWRA, and possibly EPA or the State. If any member has a question or doubt, please contact EPA/MADEP in order to help clarify the issue.

S. Redlich suggested that OMSAP consider drafting a public announcement to inform the public of this group. The OMSAP agreed to this.

OMSAP TRAVEL REIMBURSEMENT PROCEDURES
C. Jenkins stated that each OMSAP member should have received a packet containing instructions on how to process a travel reimbursement request. For reimbursement, members should send a letter to NEIWPCC stating reimbursement amount, who the check should be made payable to, and to what address it should be sent. The letter should accompany a completed travel voucher request. NEIWPCC will send a reimbursement check within 30 days of receipt of the request. NEIWPCC asks that members submit requests within five weeks of each meeting and attempt to keep travel expenses below 50 dollars, if possible. NEIWPCC reimburses at a rate of 25 cents per mile and requires receipts for lunch, parking, tolls, buses, trains, etc. Gasoline costs, and not mileage, will be reimbursed for the use of a company car.

NPDES PERMIT STATUS
R. Manfredonia stated that EPA/MADEP received over 2,000 comments on the permit. EPA/MADEP are still working through the comments and are taking the response to comments seriously. The permit will be issued shortly. Some of the major concerns raised during the public comment period are: not enough protection for lobsters, introduction of freshwater in Mass Bay, not enough monitoring stations sample for nuisance algae/red tide, nutrients, ability to divert to the old outfalls, and appropriateness of caution and warning levels. EPA/MADEP intend to have a response to comments and a summary fact sheet about the important issues that were raised and how they were addressed. Once the permit is issued, EPA/MADEP will be visiting various groups, including OMSAP, to discuss the final permit.

MONITORING AND CONTINGENCY PLAN OVERVIEW AND CONSTRUCTION UPDATE
M. Delaney gave an update on MWRA construction. He invited the OMSAP to have a future meeting at Deer Island and tour the treatment facilities. In July 1998, the Nut Island treatment plant was shut down and the inter-island tunnel was brought on-line bringing all of the southern MWRA wastewater flows to Deer Island. Most of the wastewater is receiving secondary treatment and the existing outfalls at Deer Island will be in use until next summer. The third battery of secondary treatment will go on-line, July 2000 [correction: December 1999].

The effluent tunnel was to go on-line this November but the date has been moved to July of 1999. The outfall workers are in the process of removing the train system and air supply. There is going to be a separate start-up contract to bring the tunnel on-line which will be a difficult operation. First, the 30-inch diameter steel plugs at the base of each of the 55 risers need to be removed from inside the outfall tunnel. After the tunnel fills with seepage, the caps at the tops of the diffuser nozzles will be removed by divers. Until then, the baseline and harbor monitoring programs will continue.

M. Mickelson gave an update on the MWRA water quality monitoring. The OMTF was involved in helping MWRA develop a monitoring plan to measure a combination of environmental conditions and outfall impacts. MWRA will rely on OMSAP for technical commentary on the results. The Contingency Plan deals with appropriate responses to threshold exceedances. The annual Outfall Monitoring Overview includes a summary of the year's results and a comparison to thresholds. Measurements are being made competently and on time. MWRA has had to learn how to quicken the reporting process, but are on track with keeping up with the very tight NPDES permit schedules. MWRA has nearly completed the 1998 water quality sampling. One interesting point is that NMFS required MWRA to collect samples for pathogen testing (bacteria and viruses) and so MWRA is linking this sampling to the water column surveys.

M. Mickelson then described several monitoring projects. MWRA is involved in planning for a dye study for the future outfall which will track the effluent plume during four different times of the year: maximum stratification, turnover, start of stratification, and well-mixed conditions. There will be a 25-hour addition of rhodamine dye over two tidal cycles, starting at high tide. As the dye spreads, MWRA will follow the pigment using a tow-yo (with a fluorometer and salinometer attached) as far as it can be measured into the farfield. MWRA will also be collecting water samples to measure chlorophyll, silver, ammonium and phosphate. The dye experiment will begin when the outfall goes on-line and the first survey is scheduled for October 1999. NOAA/MWRA will also be conducting acoustic measurements which measure sound reflections, such as discontinuities in density (e.g. turbulence and freshwater), and to some extent particles.

Another source of information for this area is the navy-funded LOOPS group (Littoral Ocean Observing and Predicting System). They collect data with quick turnaround for day-to-day forecasting. They currently measure a number of parameters which they analyze and model as quickly as possible. The LOOPS web site is located at: http://www.deas.harvard.edu/~leslie. They will focus on Calanus patches during the spring of 1999.

MWRA is also collecting samples at ten of their water quality stations for the Cape Cod Commission to examine the use of stable isotope nitrogen-15 as a tracer of the effluent. The theory behind this method is that secondary treated effluent is higher in nitrogen-15 due to ammonia volatilization. But some disagree about its usefulness as a tracer. B. Beardsley pointed out that this is not so much a fluid tracer but rather a particulate tracer along the bottom. M. Hall added that the most recent proposal is one looking at the inorganic nitrogen (ammonium in particular) as a fluid tracer in the water column, and to examine uptake by the phytoplankton. C. Hunt is concerned about the amount of discriminatory power this method may have when dilution and background isotope levels are considered. M. Mickelson pointed out that these exploratory studies will study particulate and dissolved N15. Results will eventually be presented to OMSAP in order for the Panel to examine whether this technique has value.

R. Isaac asked whether an oxygen isotope tracer could be used in this area. Someone replied that it has been successfully used to distinguish most of the bigger rivers in the Gulf of Maine. They supposed that it might work for Massachusetts Bay since there is relatively little freshwater entering the system which does not originate in the Gulf of Maine.

K. Keay gave a brief update on the sediment and the fish and shellfish monitoring. The 1997 benthic sample analyses were finalized in early summer. A comprehensive rectification of species identifications (i.e. making sure species identification is consistent) throughout the program to date (1991-1997) was completed in mid-summer. A synthesis report on 1997 benthic community outfall monitoring including an analysis of all of the data to date, chapters on rocky-seafloor monitoring, and proposed refinement of benthic community monitoring thresholds, is scheduled for completion within six weeks. The 1998 rocky-seafloor monitoring field survey in the nearfield was successfully executed in June. Soft sediment community sampling and sediment profile imaging studies were carried out in August. Analytical turnaround to date on 1998 field samples has been within the substantially tighter schedules required in the draft NPDES permit.

For fish and shellfish monitoring, all of the 1997 analyses were completed in late spring. A synthesis report on 1997 fish and shellfish monitoring is anticipated within 4 weeks. This report will include development of the "appreciable change" tissue PCB threshold required by the OMTF at the December 18, 1997 meeting. It will also contain an evaluation of other contaminant thresholds and will propose modifications similar to the new PCB thresholds to the OMSAP. 1998 flounder sampling was completed in early spring. For the first time in several years, the targeted number (50) of flounder were collected at Deer Island Flats. 1998 adult lobster collections were delayed until mid-September based on reports from commercial lobster fishermen that there was a lack of mobile lobsters at the future outfall site and in eastern Cape Cod Bay. 1998 mussel bioaccumulation deployments were installed in late June. A new outfall monitoring reference site in central Cape Cod Bay was added in 1998, as was a station in Quincy Bay to investigate the effects of the South System flow transfer. 40-day recoveries were successful at all sites. 60-day recoveries were successful only at the Cape Cod Bay, Inner Harbor and Quincy Bay sites; Deer Island and Future Outfall Site arrays could not be recovered. The 1998 fish and shellfish field studies are now complete. Analytical turnaround on 1998 field samples so far has also been within the NPDES schedules.

J. O'Connell asked if the OMSAP would consider adding in the future new parameters to the Outfall Monitoring Program which added important information. The OMSAP agreed that they are to review any proposed additions to the OMP. R. Manfredonia added that all OMSAP recommendations need to be forwarded in writing to EPA/MADEP.

N. Jaworski feels that Ted Loder's (UNH) work on the depletion of the inorganic nutrient surface pool in parallel to the depletion of dissolved oxygen below the thermocline is informative and interesting. He asked if that analysis will be continued [work was presented at the February 1998 MWRA technical water quality workshop]. K. Keay replied that any analysis that the OMSAP considers worthwhile would be undertaken by MWRA. N. Jaworski will provide a written description of T. Loder's approach. N. Jaworski then asked about effluent analyses conducted by MWRA which are not listed in the permit. He would like a complete list of effluent parameters being measured, and if there is a proposal to discontinue any of those measurements, OMSAP should be notified. The other members agreed. [Update: the members have since received the October 1998 MWRA Discharge Monitoring Report and Operational Performance Summary which includes information on all effluent parameters measured.] The OMSAP also requested that all speakers provide copies of their overheads to the members at the start of future meetings [one copy should also be provided to the OMSAP assistant].

FOOD WEB MODEL SCOPE OF WORK

Background of Concerns – Whales
B. Kenney described the three species of endangered whales of local concern: right, humpback and fin. Right whale adults are approximately 50 feet long, black, with no dorsal fin. The white patches on their heads are tiny sessile crustaceans (whale lice), which are used to identify individuals. Most knowledge about right whales is from tracking individuals and birthrates. Distribution: early spring occurrence in Cape Cod Bay, late spring/early summer in the Great South Channel, late summer through fall in the Bay of Fundy and Roseway Basin on the Scotian Shelf. In the winter, some females go to the nearshore waters of Georgia and Florida to give birth and the rest travel to unknown locations. The best guess of the total population size is approximately 325-330, possibly as low as 305. Human-caused mortality is a big concern, primarily, ship-strikes (10-12 individuals killed over the last 15 years) and entanglement in fishing gear.

Humpback whales are approximately 50 feet long and individuals can be identified by the pigment pattern on the surface of the tail. They are distributed along the western margin of the Gulf of Maine (GOM) during the spring, summer, and fall. Humpbacks are more common in the northern GOM when herring are abundant and more common in the southern GOM when sand lance are more abundant. In the winter, most of the population goes to the Caribbean. This is the southern end of a feeding population which extends to Iceland and Norway with an estimated size of around 11,000-13,000 with the GOM feeding population numbering around 700-800. There are entanglement and occasional ship-strike mortalities but at a much lower level, both absolutely and relatively to population size, than with right whales.

Fin whales can reach 70 feet long, making them the second largest living animals. They may be identified by the swirls of color on the right shoulder, but identification is difficult. They have a widespread distribution but they are most concentrated in the same areas as humpbacks since they have similar diets. Fin whales are the most abundant of the large whales. The northeast US has a population of around 5,000-6,000. There are no good estimates for the total Atlantic population, but it may be around 50,000.

All three whales have finely fringed baleen suspended from the upper jaw. Right whales are skim feeders that swim with their mouths open for long periods of time. Water flows into the mouth, between the two racks of baleen which trap their food. Most of their feeding tends to be at depth, except in Cape Cod Bay where surface skim feeding is more common. Right whales preferentially feed on copepod zooplankton. The best food, in terms of filtration efficiency and energy content, is Calanus finmarchicus but they seem to feed on whatever is available in high enough concentrations and large enough to filter. Throughout the North Atlantic, right whales feed on Calanus but in Cape Cod Bay, they feed on Pseudocalanus and Centropages. Krill is a another food source, though it is less preferred.

Humpback and fin whales have broader baleen plates which are shorter and coarser. The fringing hairs on the inner edge of the baleen are wider, thus these whales filter out larger food such as small schooling fish. They are called gulpers since they take their food one mouthful at a time. When feeding, the jaw dislocates at the back of the skull, an elastic ligament in the front stretches, and the tongue rolls inside out. They then close their mouth and squeeze the water out, trapping the food on the inside edges of their baleen. Humpback whales can blow bubble rings or walls or slap their tails to concentrate prey.

The reason for the requirement of a scope of work for the food web model is the concern for whale prey species, particularly right whales. The concern which has been raised is that the effluent will change the amount or the balance of nutrients which could affect phytoplankton production and possibly zooplankton production. One word of caution, there is a similar food web model for Newfoundland which looks at Atlantic codfish, capelin, harp seals and fishermen to predict what the impacts on the cod stock of various management strategies would be. This food web model turned out to be immensely complex [showed diagram]. A food web model for this area would be equally as complex.

Scope of Work Approach
M. Mickelson described MWRA's approach in addressing the food web model scope of work requirement in the draft NPDES permit. The draft permit states that "the MWRA shall: .... by December 31, 1998, develop a scope of work for a food web model to characterize the seasonal abundance for important prey species of endangered species in Massachusetts and Cape Cod Bays. The food web model shall: (a.) include phytoplankton, zooplankton, planktivorous fish and marine mammals, (b.) allow an evaluation of the strength and likelihood of potential stressors that may alter the food web, (c.) be based on results of ongoing monitoring, special studies of plankton (phytoplankton and zooplankton) dynamics and any other current or historical research in Cape Cod Bay, and (d.) be reviewed by the science panel described under section 7d below." M. Mickelson presented three potential pathways for a food web model scope of work and requested guidance on which is most appropriate, as well as any other suggestions from the OMSAP. These pathways are [from "Food Web Model" information briefing dated October 27, 1998]:

  1. Goal: to understand the abundance (population density on a scale of tens of kilometers) of endangered species prey. Approach: the Kelly, et al. (1998) report is a first step toward describing the food web of right whale prey especially in relation to outfall nutrient effects. B. Kenney prepared a commentary on this report and pointed out that such a focus would not predict right whale occurrence or address the importance of zooplankton patchiness.
  2. Goal: to further understanding of the availability (meter-scale population density or patchiness, and age structure) of right whale prey. Approach: develop a model of patch formation. The outfall would be an assumed, minor model component.
  3. Goal: to understand the effect of the outfall on whale prey. Approach: extend the Bays Eutrophication Model to include zooplankton. However, BEM's 9-km scale precludes directly assessing the patches that are most relevant to right whales.

M. Mickelson presented overheads of summer and winter model maximum concentration of effluent at any depth of a 100 km transect from Boston Harbor to Cape Cod. Harbor and Mass Bay outfalls were both modeled. Concentration of effluent from 0 to 2% was plotted on the y-axis and distance from Boston Harbor was plotted on the x-axis. The current outfalls cause the harbor to be high in effluent (~2% winter and 1.5% summer) with the percentage decreasing with distance. Once the new outfall is on-line, the harbor will be much cleaner (~0.2%), there will only be a relatively small area around the future outfall which has increased effluent concentrations (~1.1% winter and 1.3% summer), and there will be no change in the farfield. S. Testaverde believes that if the track was repositioned from Boston Harbor to Provincetown, that the percentage of effluent would be higher in the winter since the major flow moves in that direction during that season. M. Mickelson showed model results which disagreed with S. Testaverde's statement but stated that MWRA will look into this. J. O'Connell feels that nitrogen stable isotope studies would be useful in this case. The stable isotope analysis could examine the nearfield and farfield biogeochemical effects, not just maximum concentrations.

K. Keay pointed out that there are many questions in developing a food web model which most likely can not be answered by referencing the literature. He pointed out that there are two general approaches to this: either a "bottom-up" approach starting with the nutrients or a "top-down" approach of a patch study which considers some assumed effect of the outfall.

P. Daley reminded everyone that the Cape Cod Commission initiated the request for a food web model because of the concern for endangered species. The CCC would like a computer model which could evolve as knowledge improved. The CCC understands that a full food web model does not exist at the present time but would like to see one developed in order to get people to look at trophic connections involving endangered species. M. Liebman added that EPA included the scope of work in the draft permit in response to the public concerns. As mentioned at the April 29, 1998 OMTF meeting, MWRA should narrow the focus to right whales and the abundance of their main prey species since there are less trophic levels involved than the other whales. The relative contribution of the different stressors (i.e. the outfall, fish predation, other potential sources or problems) should be addressed. In order to answer questions about whether the outfall will affect the prey species of the right whale, one also needs to know what other factors affect these prey species. EPA/MADEP are concerned about MWRA's third approach in that it might have an averaging effect and thus may not address the issue of concern. EPA/MADEP recognize that this is a difficult project and that there are no functioning food web models to use for guidance, thus they are looking to the Panel for advice.

J. Pederson suggested that since there is no functioning system model available, the best OMSAP can do is recommend one or two of the best options for MWRA to pursue and list the uncertainties around them as well as the reasons for adopting them. However, none of them will address all of the concerns. R. Isaac and B. Robinson wondered if there are other options out there not outlined by the MWRA. B. Robinson requested that the OMSAP discuss this further before any decisions are made.

B. Chen suggested learning more about right whale feeding behavior as well as examining what nutrients need to change in order to alter that behavior and then comparing the results. J. Shine suggested, as a first step in this exercise, examining the area around the future outfall. A. Solow believes that the question that the scope of work ultimately needs to assess is the potential impact of the outfall on the endangered species. The natural way to begin is "bottom-up", with the potential environmental effects of the outfall and to follow from there in order to save some effort. If it is determined that the changes could not conceivably have a significant effect on the prey species, then the exercise is complete. C. Potter added that as this scope of work is discussed, it is important to keep in mind what the MWRA should be responsible for and what the MWRA should be asking the cities and towns to pay for. She suggested that it may be appropriate to share funding for a project if its scale and scope are determined to go beyond the direct effect of the outfall. [Note that earlier in the day, J. Schubel had mentioned that the New England Aquarium has received some foundation funding which could potentially be put towards a food web model partnership with MWRA.]

B. Kenney feels that none of the three approaches are worthwhile since he believes that there is a complete disconnection between nutrients and prey for right whales in this area. The mechanisms of concentration which develop right whale feeding patches are due to physics, and patches are what the whales are most interested in. Patch formation is also influenced by the background concentration of zooplankton but remember also that the zooplankton may originate from other areas. So to develop a good food web model which predicts how much food is available for right whales on the Wellfleet side of Cape Cod Bay in the wintertime, one would have to model the entire GOM for at least two years and this would be very costly.

OMSAP did not reach a clear decision on a scope of work approach. Members decided to continue discussions via e-mail. M. Mickelson will make all materials discussed at the meeting available to members.

LOBSTERS

Outfall Monitoring Task Force April 29, 1998 Lobster Recommendations
C. Coniaris described the OMTF's lobster recommendations. She stated that the OMTF did not conclude that either the current or the future MWRA discharges are likely to harm lobster populations in Massachusetts coastal waters. However, the OMTF addressed these concerns because of the importance of the lobster fishery to our New England heritage and economy. The OMTF began evaluating these issues in June 1997. Below is a list of the recent recommendations which were approved by the OMTF at their April 29, 1998 meeting. Full recommendations are included in the minutes of that meeting. Under each recommendation is a brief summary of how it has been addressed.
(1) "The Task Force recommends that MWRA conduct a suction sampling survey in the vicinity of the future outfall site during the summer of 1998 to sample shelter-restricted early benthic phase juvenile (EBP) lobsters." How addressed: the MWRA suction sampling survey was conducted on September 8-9, 1998. Results will be described by R. Kropp of Battelle.
(2) "If there are significant numbers of EBP juveniles found in the vicinity of the future outfall site, then the Task Force recommends the development of a RFP for toxicity testing." This recommendation is not applicable since MWRA did not find significant numbers of EBP juveniles in the vicinity of the future outfall site.
(3) "The Task Force recommends that MWRA continue to assist MADMF with the input and analysis of the 1997 lobster monitoring data and complete the literature search on the effects of chlorine on egg-bearing females, as recommended at the 20 March 1998 OMTF meeting." How addressed: MWRA tasked a consultant to assist MADMF with the input and analysis of their 1997 lobster data. MWRA addressed the potential effects of chlorine in a report entitled "Biology of the lobster in Massachusetts Bay". K. Keay of MWRA will describe the main lines of evidence which support the MWRA opinion that toxicity to lobster larvae is not a concern.
(4) "The Task Force, or its successor group OMSAP, should evaluate new unsolicited proposals in terms of their importance in assessing the potential effects of treated effluent on egg-bearing female lobsters and planktonic lobster larvae." How addressed: the OMSAP will always be open to evaluating new proposals in terms of their importance in assessing the potential effects of treated effluent on lobsters.
(5) "The Task Force recommends to MIT Sea Grant that they consider including in a future RFP the development of automated suction sampling technologies for collecting EBP juvenile lobsters." How addressed: OMSAP member J. Pederson has forwarded this recommendation to MIT Sea Grant.
(6) "The Task Force recommends that MADMF adjust their cooperative reporting program with lobstermen to include the area around the future outfall site." How addressed: this recommendation has been forwarded to MADMF.
(7) "The collapse of the lobster fisheries in Lynn, Salem and Boston Harbors, as witnessed by local lobstermen, warrants careful examination of existing data and information and should perhaps be conducted by the academic community as an M.S. or Ph.D. dissertation topic." How addressed: in letters dated October 25, 1998 to directors of eleven New England university marine/environmental programs, R. Manfredonia of EPA emphasized the importance of this concern and encouraged research on this topic.

Sept. '98 MWRA Lobster Survey
R. Kropp summarized the results of the draft MWRA report which was distributed to OMSAP members and others for review: "Abundance of juvenile lobsters at new outfall site: comparisons with inshore abundances and discussion of potential outfall impacts on lobster populations" by Kari Lavalli and Roy Kropp. Comments from members on the draft report are requested within the month.

The MWRA suction sampling survey was conducted September 8-9, 1998. This method was chosen for several reasons: (1) it captures young-of-year (YOY) which do not travel and thus could potentially be affected by the new outfall; (2) the numbers of YOY give an estimate of 1998 recruitment; (3) yearling lobsters are also captured which give an estimate of at least one additional year class; and (4) diver suction sampling is currently being conducted by MADMF in shallow coastal areas, thus there are other data available for comparison. In the April 29, 1998 OMTF recommendation (1), there is a little confusion in terminology. Here is a brief summary of terminology used by MWRA:

"Young-of-year" lobsters, are shelter-restricted with a carapace length (CL) less than 12 mm.
"Yearling" lobsters are 12-20 mm CL and are also called "emergent" since they occasionally venture out of their burrows.
"Vagile juveniles" range from 20 to about 50 mm CL and have short-range movement patterns.
"Early benthic phase" (EBP) lobsters include YOY, yearling, and vagile juveniles, and range from 5-40 mm CL.

The draft report describes the design and results of this survey. To select sites, K. Lavalli and R. Kropp examined videotapes collected in 1994 by ROV which sampled approximately three linear kilometers of bottom in the vicinity of the new outfall as well as other data. The goals of the sampling design were to: find the best habitat, be conservative in the numbers of samples taken, find the best possible scientists to conduct the work, and have outside experts review the draft survey plan and report. MADMF has been sampling using suction sampling for several years in several coastal areas. MWRA decided to sample in the Beverly/Salem harbor area since it had MADMF data available from 1995, 1997, and 1998 which were more years of data that other areas sampled. Unpublished work by K. Lavalli indicates that the peak of settling in this area is late August/September, so MWRA decided to schedule the survey in early September in order to sample past the time when most larvae would have settled. Bob Steneck, Carl Wilson (U. Maine) and Rick Wahle (Bigelow Laboratory) were contracted for this project and are very knowledgeable in the methods of suction sampling for young lobsters. MWRA sampled three transects with 12 (0.5 square meter) samples taken at each transect in the vicinity of the new outfall site and two transects with 18 (0.5 square meter) samples taken at each transect in Beverly/Salem Harbor.

The results of the survey indicate that the habitats sampled at Beverly/Salem and the new outfall are quite similar but the temperatures are quite different. The lobster data were variable. The data were non-random since MWRA purposely chose good lobster settling habitat and the quadrats were not placed randomly at the bottom since large boulders could not be sampled properly. At the new outfall, MWRA found two lobsters: one YOY and one vagile juvenile. Inshore, MWRA found a total of 25 lobsters, 21 of which were EBP. Of these, four were YOY, five were yearlings, and 12 were vagile juveniles. Significance tests showed differences among each of the categories between inshore and offshore sites. Larvae have been shown experimentally in the laboratory to avoid crossing a strong thermal gradient, and there is a strong seasonal thermocline which exists at the new outfall site during the peak time of settling. There are also low bottom water temperatures in the area of the new outfall which can retard growth rates and reduce the survival of postlarvae, most likely by keeping them at the size at which they can be preyed upon for a much longer time. In conclusion, MWRA believes that the area around the outfall is not a significant settling site for postlarval lobsters. MWRA also believes that this area is also not a significant nursery habitat due to the near-absence of juvenile lobsters.

Effects of chlorine on egg-bearing female lobsters and larval lobsters K. Keay stated that MWRA addressed the potential effects of chlorine in the report entitled "Biology of the lobster in Massachusetts Bay". In it MWRA includes a comprehensive review of the literature on the effects of chlorine on lobster larvae. Based on laboratory experiments conducted by Judith Capuzzo McDowell in the 1970s, it appears that chlorine and chloramine toxicity to larval lobsters is strongly dependent on concentration and temperature. Since temperatures in the bottom waters of Massachusetts Bay are relatively low, and the concentrations of free chlorine and chloramine will also be low once initial dilution at the new outfall takes place, K. Lavalli concluded that there will not be a concern for the potential toxicity to lobster larvae.

MWRA also investigated two main lines of evidence that suggest that there are no effects of the chlorinated primary effluent in terms of initial toxicity in Boston Harbor. They were [from MWRA information briefing dated October 27, 1998 "Progress report on lobster studies"]:

Acartia tonsa is a common coastal copepod in northern waters. A. Tonsa was one of the more sensitive species to residual chlorine in toxicity testing studies used by EPA in setting the existing water quality criterion, substantially more sensitive than were larval lobster, for which data were also available. Acartia tonsa is seasonally one of the dominant zooplankton species in samples collected in the vicinity of the existing Deer Island discharge, and is present in abundances equivalent to those found elsewhere in its range.

Monitoring by the MADMF documented a 4-fold increase in the proportion of egg-bearing females in the lobster population in Boston Harbor between the mid-1980s and the mid-1990s. During much of the same time, improvements in chlorination infrastructure led to better disinfection and an increase in average residual chlorine discharged. Since 1996, increased solids and BOD removal have allowed a reduction in the amount of chlorine required in order to disinfect the effluent, leading to a reduction in the mean chlorine residual in the past 2 years.

Further evidence shows that residual chlorine is not causing a "dead zone" near the Deer Island outfalls. MWRA deploys caged blue mussels for 60 days every summer. Mussels are placed in the mixing zone of the existing Deer Island outfalls with an average dilution on the order of 25:1. Data show that mussel survival has been approximately 90-95% since the monitoring began several years ago and is very comparable to the caged mussels from the Mass Bay future outfall site. In addition, the Deer Island mussel deployments are always heavily biofouled with a heavy growth of algae, hydroids, and amphipods. Based on all of this information, MWRA feels that there is no evidence that there would be a deleterious effect to egg-bearing female lobsters or larval lobsters from low level chlorine exposure.

Discussion
J. Ayers believes that if one multiplied the density of shelter-restricted lobster found in the sampling area near the future outfall with the entire area affected by the outfall plume, that this would be a significant resource. He would like to see some time-series data taken over several years with a greater sampling area. He added that R. Wahle also sampled three other sites during the September survey as part of his own research. He found over a five-fold difference in the densities of EBP lobsters between the two sides of Nahant in 20 feet of water. In 70 feet of water off of East Point, he found no EBPs. J. Ayers believes that the sites with little or no EBPs are within influence of the Lynn secondary treatment plant discharge. A. Solow feels that it is not clear whether one can attribute this to the outfall or the physical environment. R. Kropp added that scientists have observed a similar phenomenon in Maine. They found radically different densities of larvae and EBPs on the opposite sides of the island of Damariscove which is only meters across at high tide. They attributed this feature to differing wind and oceanographic conditions on either side of the island.

K. Keay described the analysis in the "Biology of the lobster in Massachusetts Bay" report which indicated that there was no appreciable risk and that any impacts on planktonic or shelter-restricted lobster would be substantially less for the new outfall discharge than for existing outfalls in Boston Harbor. The report conservatively assumed that cobble-containing habitat in the vicinity of the new outfall was of high value to juvenile lobster, equivalent to cobble in the shallow nearshore sites. The September survey proved that this was not the case (as mentioned before, fewer EBPs lobsters were found per square meter in the vicinity of the future outfall site than nearshore), thus the impacts would be even less than those indicated by the evaluation. In this report, dilution contours, as modeled by Rich Signell, were overlain onto rocky-bottom areas in Massachusetts and Cape Cod Bays. Using GIS, MWRA calculated that with the new outfall, a much smaller area will have less than 200:1 average winter dilution, than with the current outfalls (approx. five square kilometers with the future outfall and approx. 84 square kilometers with the current outfalls). [K. Keay then showed a map of the area around the future outfall which included the three sampling areas, cobble-containing areas, diffusers, and the 60 m around the diffusers within which the acute water quality criteria must be met.] He pointed out that cobble-containing areas are well outside of the 60 m area within which water quality criteria must be met.

J. Ayers pointed out that the summer Boston Harbor lobster harvest of East Coast Seafood consisted of 65% soft-shell lobsters. This high percentage was not seen ten years ago and he believes that this is a sign that there has been a change in lobster biology in Boston Harbor. However, B. Estrella believes that this is due to the fact that the pressure on the fishery is so great that lobsters are harvested as fast as they molt into legal size, which explains why such a high percentage of lobsters caught are soft-shelled. L. Bridges feels that it is clear that if one looks at the MADMF survey data and resource assessments that the collapse of the fishery is solely due to overfishing.

J. Ayers finds it a coincidence that lobster fisheries have crashed wherever there are outfalls discharging secondarily treated effluent. K. Keay pointed out that the dead zone which lobstermen claimed to exist in Salem/Beverly harbor was not seen when MWRA sampled in Salem/Beverly Harbor, 800 m from the South Essex Sewerage District diffuser (Coney Island) and a couple of kilometers from the diffuser (Bakers Island). MADMF data from the last few years indicate that Coney and Bakers Islands have had some of the highest abundances in terms of both juvenile settlement and sub-adult populations throughout the sampling region, north of Cape Cod. None of MADMF's diver-observational studies have seen this dead zone. B. Kenney pointed out that conditions should improve when the new MWRA outfall comes on-line due to better treatment, better dilution, and the fact that less EBPs were found in the vicinity of the new outfall than inshore.

After further discussion, OMSAP members agreed that MWRA has done a commendable job of addressing the concerns raised regarding lobsters and the new outfall. After careful review of the results of recent lobster studies, the OMSAP concluded that no further studies were needed. The members agreed that the combination of dechlorination, increased residence time of effluent in the outfall pipe, and increased dilution at the new outfall site, ensure that the chlorine residual will meet permit levels and will be reduced to background levels very quickly. Thus, the OMSAP felt that the concerns about the effects of chlorine on egg-bearing female and larval lobsters were not warranted. In addition, the OMSAP agreed that the sampling effort was sufficient to show that, despite substantial landings of adult lobsters in the vicinity of the new outfall site, recruitment at this site is significantly lower than at nearshore sites and that the new outfall site does not coincide with an important nursery habitat.

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Last updated on September 18, 2024