EPA Completes Construction Work at W.R. Grace Superfund site in Acton, Mass.
Boston, Mass. -- EPA has completed construction activity at the W.R. Grace Superfund site in Acton. Completed work includes the Northeast area groundwater treatment system, the Landfill area groundwater treatment system and the dredging and proper off-site disposal of over 11,899 tons of contaminated sediment from the North Lagoon Wetland and Sinking Pond.
During 2011 and 2012, EPA and the Massachusetts Department of Environmental Protection (MassDEP) conducted final inspections at the site to ensure that the construction of the groundwater treatment systems and the sediment excavation and removal were in compliance with and operating in accordance with the remedial design plans. Based on these site inspections, EPA and MassDEP have determined that construction of all the clean up actions at the Grace site is complete.
A preliminary close out report for the site formalizes the construction completion. The following activities will continue in the future to ensure the clean up actions remain protective:
- Conducting Five-Year Reviews;
- Operation & Maintenance (O&M) of the Northeast and Landfill Area Treatment Systems;
- Vegetative monitoring of the restored wetland areas, twice per year for the next five years;
- Implementation of enforceable Institutional Controls;
- Long-Term Groundwater Monitoring; and
- Operation & Maintenance (O&M) of the former caped Industrial Landfill.
The W. R. Grace (Acton Plant) Superfund Site is a former chemical manufacturing facility located off of Independence Road and includes several surface water bodies and various wetlands. The property consists of approximately 260 acres of land located in the Towns of Acton and Concord, Mass.
The site is bounded to the north in part by Fort Pond Brook and to the east and south by the Assabet River. Residential properties border the W. R. Grace site to the northeast, northwest, east and west. Several industrial properties border the site to the south and northeast and industrial parks and a gravel pit border the site to the south.
The site was used for industrial purposes for over one hundred years. The American Cyanamid Company and the Dewey & Almy Chemical Company (D&A) were former occupants of the site. American Cyanamid manufactured explosives, and D&A produced synthetic rubber container sealant products, latex products, plasticizers, and resins. W. R. Grace acquired the property in 1954, and chemical operations continued at the site.
Manufacturing operations at the W. R. Grace facility included the production of materials used to make concrete and organic chemicals, container sealing compounds, latex products, and paper and plastic battery separators. Wastewater and solid industrial wastes from these operations were disposed of in several unlined lagoons and were buried in or placed onto an on-site Industrial Landfill and several other waste areas.
Discharge to all lagoons and other waste areas ceased in 1980. The production of organic chemicals was discontinued in 1982. A small distribution center for concrete additives was moved to another location in September 1996. A second plant for the manufacture of battery separators, known as the Daramic facility, was constructed in 1979, but operations there ceased in 1991. All buildings, with the exception those associated with the remedial action, have been demolished.
Investigations in 1978 indicated that two Acton municipal supply wells, Assabet #1A and Assabet #2A, were contaminated with yinylidene chloride (VDC, also known as 1,1-dichloroethene or 1,1-DCE). Significant levels of vinyl chloride (VC), ethylbenzene and benzene were also detected in these wells at that time. As a result of these findings, the Town took the precautionary action of closing the two wells. As a result of the discovery of the municipal well contamination, W. R. Grace and EPA entered into a Consent Decree regarding cleanup of the site in October 1980. A similar settlement was reached between W. R. Grace and the Commonwealth of Massachusetts. In 1983, the W. R. Grace site was placed on the Superfund National Priorities List.
From 1983 -1997, numerous studies, risk assessments and sampling events were conducted at the site. This work culminated with the removal of over 100,000 cubic yards of contaminated soil and sludge that was excavated from the former lagoons and disposal areas. These excavated materials were then thermally treated, solidified on-site and then placed onto the former Industrial Landfill, which was then properly covered and closed with an impermeable cap.
As an interim measure, Grace operated an Aquifer Restoration System (ARS) that extracted and treated contaminated groundwater on portions of the site from 1983 – 2011. The newly constructed Landfill and Northeast Area treatment systems are currently operational and replaced the ARS.
More information on EPA’s work to cleanup the W.R. Grace Superfund site (http://www.epa.gov/region1/superfund/sites/graceacton ).