Reducing Children’s Lead Exposure in Omaha, Nebraska
Published August 13, 2018
For over 125 years, the American Smelting and Refining Company operated a lead refinery in Omaha, Nebraska, only a few blocks west of the Missouri River. Large amounts of lead were emitted into the air, contaminating the surrounding neighborhoods. Between 1998 and December 2015, EPA sampled more than 40,000 residences in the area, and found that about thirty-three percent of the properties had soil in their yards with lead above the cleanup level.
EPA’s Region 7, which encompasses a four-state area including Nebraska, has been working for years to clean up the neighborhoods surrounding the old lead smelter, which is now a Superfund site. A Superfund site is any land in the United States that has been contaminated by hazardous waste and identified by EPA as a candidate for cleanup because it poses a risk to human health and/or the environment. At this particular Superfund site, over 95% of properties with soil found to have lead above the cleanup level have been remediated. This means that the soil has been removed and replaced with new, clean soil. With the cleanup nearing completion, EPA wanted to ensure that the soil remediation was leading to decreasing blood lead levels in the children that lived in the affected neighborhoods and determine whether further remediation was needed.
Lead is particularly dangerous to children because their growing bodies absorb more lead than adults. Lead has been shown to have negative impacts on children’s developing brains and nervous systems. Babies and young children can have higher lead exposure because they often put their hands and other objects into their mouths which can be covered with lead from dust or soil.
Through a collaboration with the Douglas County Health Department, EPA researchers accessed blood lead level data that had been collected from thousands of children living in residences within and bordering the most impacted 27-square mile area in Omaha. EPA combined this data with data on lead in soil and dust inside local homes. Through some analysis, EPA linked the datasets together to create a complete picture of lead exposure in local children, down to the level of exposure that occurred in each home. EPA completed a preliminary analysis of the data, which found that blood-lead levels in local children had dramatically decreased over time.
However, EPA’s work is not done. Because there are many factors that may have influenced the drop in blood lead levels, EPA is now working to tease out the effect of soil remediation on the blood lead level decrease by doing a direct comparison of levels of lead in the soil before and after remediation.
Once this analysis is completed, EPA researcher Ellen Kirrane will create a template for the evaluation of environmental data and community blood lead levels that can be used at other Superfund sites. “This will enable us to share our experiences and methods for collecting and analyzing these data so other communities can benefit from similar evaluations,” says Kirrane.
“This work may also help EPA further evaluate the EPA’s Integrated Exposure Uptake and Biokinetic (IEUBK) model for lead in children at lower blood lead levels than previously evaluated,” said EPA researcher James Brown.
The IEUBK model is used to estimate the probability of exceeding specified blood lead levels given that lead exposure can occur through multiple pathways. Since the late 1970s, blood lead levels in children have dramatically decreased due to changes like the phase out of lead in gasoline. Increasing the accuracy of the model at lower blood lead levels that are now more commonly seen is very important, as health effects can occur even at very low levels of lead exposure.
What EPA is learning in Omaha has the potential to help protect children across the country in areas where not as much data is available.
In addition to protecting public health in Omaha, this research could potentially focus scarce resources on the most important sources of lead exposure in other communities.
Gene Gunn in EPA Region 7 says, “This work will help determine whether additional residential soil cleanup actions will be a cost-effective way to further reduce blood lead levels in young children in Omaha and other lead sites across the country. In Omaha alone, it can cost more than $300 million dollars to achieve lower soil lead levels in yards.”
This work is another example of how EPA’s collaboration with state and local health officials can contribute to a better understanding of Superfund site impacts and decision making that leads to healthier communities.