The Newark South Groundwater Plume Site is located in southeast Newark, New Castle County, Delaware. The Site is located in a mixed industrial, commercial and residential area. Groundwater in the area has been found to be contaminated with volatile organic compounds (VOCs) including tetrachloroethene (PCE) and trichloroethene (TCE). These chemicals are commonly found in dry cleaning solvents and other industrial solvents and degreasers.
The City of Newark has reported the presence of low levels of the contaminants in the untreated/raw groundwater from several of its public supply wells since 2000. The public drinking water supplied by the City of Newark is treated to remove the contaminants from the untreated/raw water and continues to meet Federal and State Safe Drinking Water Act standards.
Several communities in the area receive their drinking water from SUEZ Delaware Water (formerly United Delaware Water). The water provided by SUEZ draws surface water from the White Clay and Red Clay Creeks and is not affected by the local groundwater contamination. The drinking water supplied by SUEZ meets Federal and State Drinking Water Standards.
Investigations conducted by the Delaware Department of Natural Resources and Environmental Control (DNREC) have identified several potential source areas. The State of Delaware has referred the Site to EPA for further consideration. EPA is considering the Site for potential inclusion on the National Priorities List (NPL). The NPL is a list of sites that are eligible for cleanup financed under the Federal Superfund program.
In the interim, as a precautionary measure, EPA’s Removal Program is evaluating the potential for vapor intrusion at the Site. Vapor intrusion (VI) is the term used to describe the migration of volatile chemicals from subsurface contaminated soils and groundwater into the indoor air spaces of overlying buildings through openings in the building foundation. Common sources of VI include petroleum products, dry cleaning solvents, and other industrial solvents and degreasers including those found at the Site.
In January/February 2017 EPA installed and sampled 9 new groundwater monitoring wells in residential developments located east of South Chapel Street (Route 72). EPA also sampled an existing monitoring well previously installed by DNREC on a commercial property located west of Route 72.
EPA has reviewed the final validated results of the monitoring well sampling. All of the wells sampled had either no detections of VOCs or very low concentrations of VOCs that are below EPA vapor intrusion screening levels. The results of the sampling effort show that VOCs are not present in shallow groundwater at concentrations that would present a vapor intrusion concern to nearby residents and businesses.
Given the results of the groundwater sampling, EPA does not plan to conduct in-home vapor intrusion testing at this time. To confirm the results and evaluate possible changes in VOC concentrations in the groundwater, EPA plans to resample the wells later this year. EPA will re-evaluate the need for additional investigation, including vapor intrusion testing at that time.
EPA will continue to coordinate with DNREC, Delaware’s Division of Public Health Office of Drinking Water, the City of Newark and the Centers for Disease Control and Prevention (CDC) /Agency for Toxic Substances and Disease Registry (ATSDR).
