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EPA Proposes Changes to the Silresim Chemical Corporation Clean-up Plan and Opens Public Comment

Release Date: 07/28/2008
Contact Information: Michael Ochs, (617) 918-1066

(Boston, Mass. - July 28, 2008) – The New England Environmental Protection Agency is seeking public comment from July 28, 2008 through August 29, 2008 regarding three changes to the current clean-up plan. The current clean-up plan was issued by EPA in 1991 inclusive of past revisions to the clean-up goals in 2003.
The additional changes to the plan include:

• Identification of an alternative source control technology which will reduce the primary source of volatile organic chemicals. The original clean-up plan called for treatment of soil using soil vapor extraction (SVE). This was implemented for a period of 14 months, but due to site-specific conditions (such as high water table) was terminated. The first change is the identification and subsequent selection of “thermally-enhanced” SVE; one technique that was successfully pilot-tested is electrical resistive heating or “ERH”. ERH utilizes electrical current passed through soil and groundwater to heat the subsurface and liberate more organic vapors. The vapors are then collected and treated in a manner similar to traditional soil vapor extraction.

• The second change is the elimination of potential migration of contaminants to indoor air in EPA’s determination of site clean-up goals. This is based on indoor air sampling results as well as the current industrial usage of abutting properties. This potential exposure pathway will be periodically evaluated and clean-up goal further revised (if necessary) if property use changes substantially (i.e., from industrial to commercial or residential).

• The third significant change is the elimination of the soil stabilization requirement. EPA has determined that an appropriately design and constructed cap will be sufficient to minimize migration of contaminants in soil.

Comments on the proposed changes should be sent to Daniel Keefe, US EPA, 1 Congress Street, Suite 1100, Boston, MA, 02114-2023 or to keefe.daniel@epa.gov. For questions please call Daniel Keefe at 617-918-1327 or Michael Ochs at 617-918-1066.

The site is comprised of approximately 16 acres in an industrial area of Lowell, Massachusetts, just south of the City’s central business district. The 4.5-acre Silresim property was formerly owned and operated by the Silresim Chemical Corporation at 86 Tanner Street, and the groundwater and soil contamination extended to other nearby properties. The site and its surrounding areas have been used for industrial activities since the early 1900s. From 1916 to 1971, several petroleum companies used the Silresim property as an oil and fuel storage depot. From 1971 through 1977, Silresim operated its chemical waste reclamation facility. The site was listed on the National Priorities List in 1983.

An 8-foot high chain link fence surrounds the Silresim property. Most of the land surface within the fence is covered with a clay cap. Crushed stone has been placed on runoff areas along the northern and southern perimeter of the Silresim property to prevent direct contact with runoff from contaminated surface soils. The groundwater treatment plant required by the 1991 Record of Decision occupies the central portion of the Silresim property and commenced operation in November 1995.

Further information is available at the Pollard Memorial Library, 401 Merrimack Street, Lowell (978-970-4120) and EPA’s Boston Record Center, 1 Congress Street, Suite 1100, Boston, MA (617-918-1440) or at the EPA Website on Silresim Chemical Corporation Site (epa.gov/region1/superfund/sites/silresim)