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EPA Proposes Change in Cleanup Goals for Gilson Road Superfund Site in Nashua

Release Date: 10/09/2002
Contact Information: Alice Kaufman, EPA Community Affairs Office, 617-918-1064 Darryl Luce, EPA Project Manager, 617-918-1336

Boston - The United States Environmental Protection Agency announced today a change to the cleanup goals of two chemicals found in groundwater at the Gilson Road Superfund Site in Nashua, New Hampshire. The chemical compounds identified are 1,1 dichloroethane (DCA) and 1,1,2 trichloroethane (TCA). This change is published in a document called an Explanation of Significant Differences (ESD) and is available for public review.

Finding that the original cleanup goals were too low to be detected using current analytical procedures and standard methodologies, EPA is adjusting the goal for DCA from 1.5 ppb to 81 ppb. The 81 ppb cleanup goal for DCA is the New Hampshire water quality standard level. EPA is also adjusting the goal for TCA from 1.7 ppb to 3 ppb, which is the current level set by the federal Safe Drinking Water Act. These new site cleanup goals reflect the most stringent cleanup levels currently established for these contaminants under federal and state law. The concentrations of DCA and TCA in the groundwater meet the new cleanup goals.

To clean-up the site, EPA and the state of New Hampshire constructed a 20-acre slurry wall and cap to isolate the contaminants in the disposal area. Beginning in 1986, EPA and the state operated a treatment plant that treated over one billion gallons of water in the disposal area and destroyed over 216 tons of contaminants recovered from that ground water. In 1996, when the treatment plant met cleanup goals for all contaminants except DCA and TCA, EPA and the state ceased operating the treatment plant .

A copy of the ESD document, as well as other information on the Gilson Road Superfund Site are available for public review at: the Nashua City Clerk’s Office, 229 Main Street, Nashua, New Hampshire; the New Hampshire Department of Environmental Services at 6 Hazen Drive, Concord, New Hampshire; and EPA’s Record’s Center; One Congress Street, Boston MA 02114.