At the request of the Massachusetts Department of Environmental Protection (MassDEP), the EPA initiated an investigation in October 2008 to identify the source of contamination contributing to vapor intrusion within several buildings located at the Site. EPA collected soil, groundwater, soil gas, indoor air and asbestos samples in December 2008, January 2011, April 2011 and July 2011. Data from these samples confirmed the presence of high levels of volatile organic compounds (VOC) in all media at several locations across the Site. One building was found to contain friable asbestos in its piping insulation.
The 2.08 acre Site was a former cotton and woolen mill which operated from approximately 1739 until the 1960's and used the abutting waters of Beaver Brook to power mill operations. Currently there are thirteen interconnected buildings which were constructed between 1860 and 1952. A former printed corcuit board manufacturer, United Circuits, operated at the site from approximately 1980 to 2000 and is considered to be the source of the VOC contamination.
Based on sampling results, methods for addressing contaminated soil which is suspected to be the source of vapor intrusion into several building will include in-situ chemical oxidation (ISCO) treatment and potential excavation of surface soils. The scope of the area to be treated was determined by the indoor air samples taken by EPA which confirmed potential human exposure to TCE and PCE through vapor intrusion. Based on indoor air samples, Buildings 1 and 4, which are occupied by commercial tenants, has concentrations of TCE and PCE which exceed MassDEP action levels. The area delineated for treatment will encompass these buildings and will be reassessed as the ISCO injections proceed and progress is determined.
