EPA Update on the Coakley Landfill Site
EPA has completed the fifth Five-Year Review (FYR) for the Coakley Landfill Superfund Site and a report was issued on September 24, 2021. EPA’s five-year review process requires the periodic review of the effectiveness of the remedial actions implemented at a Superfund site. The FYR included interviews with community officials, residents living near the Site, and other stakeholders. The FYR report summarizes the actions taken at the Site and details the data collected since the last five-year review (2016). The FYR report also provides an assessment of the protectiveness of the current remedy at the Site of human health and the environment, and provides recommendations for making sure the remedy remains protective in the long-term.
Based on a thorough review of the actions being taken and the data collected at the Site, the FYR concluded that the remedy being implemented at the Site currently protects human health and the environment because remediation has addressed the contaminant source and institutional controls and access controls are in place that prevent exposure to site sources and downgradient groundwater. In addition, access to surface water that exceeds risk-based screening levels for PFAS compounds is limited by property access, site conditions and warning signs. And, a risk evaluation of surface water data that exceeds screening levels found that the human health risk estimates for PFOA and PFOS were below the EPA acceptable hazard quotient of 1.0, and that there are currently no unacceptable risks to a recreator through exposure to surface water.
The FYR also made recommendations for the remedy to remain protective of human health and the environment in the long-term, including the following:
- Complete the deep-bedrock investigations to delineate the extent of contamination in bedrock groundwater, as well as, fate and transport of PFAS compounds and site COCs in groundwater and determine if further action is warranted.
- Design and implement a background study, including sampling and analysis, as necessary, to determine if the concentrations of arsenic and manganese are reflective of background conditions or rather are the result of mobilization due to the reducing conditions created by the landfill. Results from the background study will be used to assess natural attenuation and time to cleanup for arsenic and manganese.
- Continued sampling of on-site monitoring wells and private wells, surface water, sediment, and stormwater runoff, and analysis for PFAS compounds to identify trends and continue to compare against current screening levels and standards.
- Continue to evaluate the need for institutional and access controls for areas outside of the current groundwater management zone (GMZ), based on plume delineation and future land use.
The Coakley Landfill Group continues to be responsible for the implementation of the remedy and the recommendation from the FYR, with oversight by EPA and NHDES.
