Superfund Information Systems: Site Profile

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The Mansfield Trail Dump site (the Site) consists of former waste disposal trenches located on wooded, undeveloped properties and associated groundwater contamination in an adjacent residential neighborhood in Byram Township, Sussex County, New Jersey. It is suspected that the Site was used as a dump for septic and other industrial wastes from the late 1950s through at least the early 1970s. In 2005, TCE was detected in nearby residential supply wells. Trichloroethene (TCE) was found to have migrated in groundwater from the source area to nearby residential supply wells. Cis-1,2-dichloroethene (cis-1,2-DCE) and several other contaminants were also detected in the impacted residential wells. This discovery triggered the Sussex County Health Department (DOH) and New Jersey Department of Environmental Protection (NJDEP) to sample approximately 75 private wells in the area from 2005 through 2006. Based on these results, point-of-entry treatment (POET) systems were installed in 18 residences to provide safe drinking water. Vapor intrusion investigations conducted by NJDEP from 2006 to 2008 in the residential area also led to the installation of sub-slab depressurization systems (SSDS) inside five affected residences. NJDEP continued conducting investigation until 2009 when the former source areas were discovered.

EPA began investigating the source areas and installed additional monitoring wells in 2010. The Site was listed on the National Priorities List in March 2011.





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What Has Been Done to Clean Up the Site?

Initial Actions:

From February to May 2012 EPA completed excavation activites to remove soil contamination from the source area. Concurrently, EPA collected well-water samples, sub-slab and indoor-air samples between 2011 and 2012. From August 2013 to December 2015, EPA’s contractor performed Remedial Investigation activities at this site. The contractor performed site reconnaissance activities and collected environmental data, including samples of overburden and subsurface soil, groundwater, surface water, and sediment. These results are described in the Revised Data Evaluation Summary Report (DESR).


The site is being addressed through initial action and long-term remedial approaches. The first operable unit (OU1) includes the contaminated potable wells as residential properties at the Site.. A focused feasibility study (FFS) was initiated in summer 2016 and in 2017 the Record of Decision for OU1 selected the construction of a water line to address contaminated drinking water at the Site.

A remedial investigation and feasibility study has been completed for OU2 to address the contamination in and around the former waste disposal trenches (dump areas), associated groundwater contamination, downgradient residential areas (properties along Brookwood Road and Ross Road), and downgradient drainage areas (Cowboy Creek and Lubbers Run). A proposed plan is expected to be released in July 2019 and a Record of Decision for OU2 is expected in September 2019.







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What Is the Current Site Status?

Remedial Design for the OU1 remedy, construction of a waterline to connect impacted residential properties to a waterline, is currently in design. A Record of Decision for OU2 is expected in September 2019.

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