The Wells G & H Superfund Site covers approximately 330 acres in Woburn, Middlesex County, Massachusetts. The Site includes the aquifer and land area located within the zone of contribution to the City of Woburn’s two municipal drinking water wells known as Wells G & H. The Olympia Property is one of the five primary source areas of contamination within the Federal Superfund Site.
At a former drum disposal area at the Site, PCB-contaminated surface soils posed a direct contact threat and TCE-contaminated subsurface soils acted as a continuing source of ground water contamination. See previous polreps for additional background information.
The Olympia Nominee Trust (Olympia) has been identified as a potentially responsible party (PRP) as the owner of the site. Olympia is performing the removal action under an Administrative Order on Consent (AOC) issued by EPA. In order to address TCE contamination in subsurface soils at the Site, Olympia has installed and is now operating an in situ permanganate injection treatment system. See previous polreps for prior activities conducted by Olympia.
Olympia has injected about 20,000 gallons of sodium permanganate solution (various concentrations) to date. Ongoing ground water monitoring indicates that the permanganate reagent has been delivered throughout much of the treatment cell.
EPA approved Olympia's plans for the next phase of injection and monitoring activities on October 3, 2008. In accordance with these plans, Olympia is now conducting injection events at the rate of about 6 per year. These injections will continue to utilize direct push technology to better target the delivery of the permanganate reagent in areas of tighter soils. Olympia conducted two such injection events during this reporting period. The first, a 3700-gallon event conducted during the week of October 14-17, 2008, included targeted injections to an isolated area of contamination between the treatment cell and the Aberjona River. The second, conducted during the week of November 10-14, 2008, delivered 4800 gallons inside the treatment cell.
Planned removal activities include continued monitoring to ensure compliance with cleanup standards established in the Record of Decision (ROD). Future injections will be conducted at the rate of about 6 events per year as needed to achieve the cleanup standards.
Olympia plans to conduct the final injection for this year during the week of December 8-12, 2008. The Site will then be secured until injection activities can resume in the spring of 2009.
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