Roux Associates is conducting an MCP Comprehensive Site Assessment/RCRA Corrective Action program at a former electroplating facility in North Attleboro, Massachusetts. Post-closure monitoring of groundwater in the vicinity of a closed surface impoundment (formerly used for the clarifying of treated plating wastewaters) revealed the presence of both metals (chiefly nickel) and chlorinated volatile organic compounds (CVOCs) in groundwater. Although subsequent investigations showed that metals impacts were limited in both concentration and extent, CVOC impacts were more significant and more widespread. CVOC concentrations exceeding 100 ppm were detected in deeper bedrock groundwater, prompting the MADEP (delegated oversight responsibility by the USEPA) to require installation of a groundwater pump-and-treat system as a stabilization measure. Roux Associates was retained at this point to assist the client in negotiating its RCRA responsibilities.

Roux Associates presented a conceptual site model to the MADEP and successfully negotiated a risk-based approach to cleanup of the CVOC contamination. The MADEP agreed to defer their earlier demand for immediate installation of a pump-and-treat stabilization measure for deeper bedrock contamination until additional data could be developed to expand the conceptual site model and more fully evaluate the need for (and ramifications of) pumping of deeper bedrock. Through additional investigation and detailed analysis of the groundwater VOC distributions and geochemical "signatures" in the various groundwater zones (overburden, shallow bedrock, and deeper bedrock), Roux Associates was able to demonstrate that the deeper bedrock contamination was limited to a discrete fracture zone, that it was not migrating significantly, and that it posed no risk to receptors. As a result, the MADEP agreed that remediation of the deeper bedrock was not necessary. Roux Associates also successfully demonstrated that portions of the downgradient groundwater plumes in overburden and bedrock are attributable to an off-site source and that migration of CVOCs in shallow groundwater has not resulted in significant impacts to indoor air of buildings on adjacent properties.

As a result of these demonstrations, regulatory attention has shifted mainly to on-site soil and groundwater contamination and their potential effects on future redevelopment of the property. To facilitate on-site treatment and disposal of source-area CVOC soil contamination, Roux Associates has assisted the client in obtaining preliminary designation of RCRA Corrective Action Management Unit. Roux Associates has also successfully brokered an agreement-in-principal between the client, the USEPA, and the MADEP to transition regulatory oversight of the site from the MADEP's RCRA program to the MADEP's Bureau of Waste Site Cleanup (i.e., the MCP). This has facilitated negotiation of a draft Brownfields Covenant Not to Sue, which in turn has made the property more attractive to prospective purchasers. Currently, Roux Associates is completing Phase II Comprehensive Site Assessment activities under the MCP, including human health and ecological risk assessments. Roux Associates is also assisting the client through negotiations with a contract purchaser.