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Clean up Decision Made for West Site/Hows Corner

Release Date: 10/01/2002
Contact Information: Alice Kaufman, EPA Press Office, 617-918-1064

Boston - EPA New England announced today an estimated $8.1 million interim groundwater cleanup plan for the West Site/Hows Corner Superfund Site in Plymouth, Maine. The plan calls for:

• Installing a groundwater extraction and treatment system for a two-acre fenced area of the site thought to be the source of contaminated groundwater. This approach would serve to contain highly contaminated groundwater in this area while allowing for natural processes to act to clean the groundwater outside the containment area. This natural process is known as natural attenuation and involves the natural breakdown of materials through dissipation or dilution, for example.
• Monitoring surface water, sediments, and groundwater outside the two-acre area to measure the progress of natural attenuation toward meeting cleanup goals and to ensure that the contaminated groundwater plume is not expanding.
• Imposing groundwater use restrictions to reduce the risk that people are exposed to contaminated groundwater and to reduce the risk of drawing contaminants from the site. Prior to this, the decision calls for monitoring residential drinking water wells near the site and to provide public water should data show unsafe levels of contaminants.

EPA will continue to study the contaminated plume while evaluating the effectiveness of this remedy.

The cleanup is taking place at a former 17-acre waste oil storage and transfer facility, used from 1965 to 1980, affiliated with the Portland/Bangor Waste Oil Company. Waste oil, delivered by the company's tank trucks, was stored on site in 1,000- to 20,000-gallon storage tanks. The company collected, transported, and deposited unknown quantities of waste oil from military bases, auto dealerships, municipalities, local garages, bulk transportation companies, industries, and utility companies.

The lighter oil was eventually sold for fuel and the heavier oils for dust control on dirt roads. In 1980, the waste oil company ceased operations, cut up the tanks on site and sold them to a scrap metal dealer.

An EPA site investigation revealed that groundwater in private drinking water supply wells near the site and in monitoring wells on the site were contaminated with volatile organic compounds (VOCs), including tetrachloroethene, trichloroethene, and dichloroethene. Drinking water contaminated with these chemicals could pose a health threat. EPA has since installed a new water supply system to serve 36 residences whose drinking water was found to be contaminated. However, a number of residents near the site continue to use their own wells and there are a number of undeveloped parcels where a well could be installed at some future time.

Soils on the site were found to be heavily contaminated with polychlorinated biphenyls (PCBs) and volatile organic compounds. Consequently, more than 1800 tons of contaminated soils were removed for disposal off-site as part of previous EPA activities.