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 over 12,000 gallons of sodium permanganate solution (various concentrations) into the treatment area to date. Ongoing ground water monitoring indicates that the permanganate reagent has been delivered throughout much of the treatment cell. The most recent injection event, conducted May 20-22, 2008, focused on an area of lower permeability soils within the cell and included pressure injections into existing injection wells and targeted injections via direct-push soil borings.
On July 16, 2008 EPA met with Olympia's cleanup contractor to review the effectiveness of the most recent injection event and to plan for the next phase of work.
On August 21, 2008, Olympia submited a work plan for the next round of injection and monitoring activities slated for October 2008. EPA reviewed this plan and provided comments to Olympia on September 17, 2008.
Planned removal activities include continued monitoring to ensure compliance with cleanup standards established in the Record of Decision (ROD). Future injections will be conducted on an as-needed basis to achieve the cleanup standards.
Olympia plans to revise the work plan based upon EPA's comments by October 1, 2008 and conduct the next injection event during mid-October. In addition to injecting inside the treatment cell, this fall's activities will include limited injection of treatment reagent to address TCE contamination in the area between the cell and the Aberjona River.
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