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The Rocky Hill Municipal Well site is located in Somerset County, New Jersey. The 2-acre site consists of two wells put in place in 1936 to supply residents of the borough of Rocky Hill with drinking water. In 1978, the first well was sealed and abandoned because it was contaminated with volatile organic compounds (VOCs), in particular trichloroethylene (TCE). The second well continued to operate until 1979, when it was also closed due to high levels of TCE. The well reopened for a short time when TCE levels declined, only to be closed again in 1982, when contamination levels increased in the groundwater. The borough temporarily used a private water supply until an air stripper could be installed on the municipal well. The air stripper has been operating since 1982 to ensure drinking water standards are met. Long-term groundwater treatment and monitoring are ongoing.

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What Has Been Done to Clean Up the Site?

Following closure of the wells and completion of a remedial investigation and feasibility study, EPA selected a remedy for cleaning the contaminated groundwater plume in 1988. It called for: (1) extracting contaminated groundwater from the primary plume area; (2) treating the groundwater to state and federal cleanup standards using carbon; (3) discharging the treated water to surface water; (4) connecting residences to the public water supply, as needed; (5) sealing private wells within the contaminant plume; and (6) implementing a groundwater sampling program to monitor the contaminant plume and the effectiveness of the cleanup. This cleanup covers not only the site but also the nearby Montgomery Township Housing Development site.

Following successful enforcement negotiations that led to a monetary settlement with a potentially responsible party (PRP), EPA put the site’s groundwater pump-and-treat systems in place in 2004 and 2005.

EPA conducted the site’s second five-year review in 2010. These reviews ensure that the remedies put in place protect public health and the environment, and function as intended by site decision documents. The review concluded that response actions at the site are in accordance with the remedy selected by EPA and that the remedy continues to be protective of human health and the environment in the short term. For the remedy to be protective in the long term, the five-year review indicated the need for the New Jersey Department of Environmental Protection (NJDEP) to establish a Groundwater Classification Exception Area (CEA).

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What Is the Current Site Status?

The site is being addressed in a single long-term remedial phase focused on cleanup of the entire site.

In January 2005 construction of the extraction wells and two groundwater treatment plants were completed. Quarterly groundwater sampling began in 2005 and is ongoing.

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