Evaluation of Selected Groundwater Cleanup at NPL Sites

OSRTI will present the findings of a new report that analyzes selected groundwater cleanups at National Priority List sites. The 43 groundwater cleanups in the report have achieved, or made significant progress towards achieving, their remedial action objectives (RAOs). The remedies evaluated include less difficult cleanups involving small dilute groundwater plumes in simple hydrogeologic settings to more difficult cleanups such as large plumes with high concentrations, complex hydrogeologic settings, and dense nonaqueous phase liquids (DNAPLs). The report analyzes key aspects of the groundwater remedies, including progress towards achieving RAOs, the remedial approaches applied, the contaminants addressed, hydrogeology, and the magnitude of the cleanup. Based on the analysis of the remedies in this report, the Superfund program has demonstrated that even challenging sites, such as those with DNAPLs and in fractured rock, can achieve significant reductions in contaminant concentrations and plume size, under a wide range of conditions. The program has also remediated sites to stringent RAOs, including those based on federal and state drinking water standards.