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 are acting 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 completed the initial 8 rounds of permanganate injection in December 2005. A total of 8,464 gallons of sodium permanganate solution has been injected to date. Monitoring data collected since that time indicates that the permanganate reagent has been effectively delivered throughout much of the treatment cell. However, several areas within the cell may need additional reagent. In addition, two areas outside and adjacent to the cell require additional assessment and possible treatment.
During the week of May 14-18, 2007, Olympia collected 5 discrete ground water sample profiles, advanced 14 soil borings, and installed 2 new peizometers in order to better assess areas which may require injection of additional reagent. Based on the information obtained from these borings and peizometers, Olympia installed 8 new injections wells within the treatment area.
On June 18, 2007, Olympia conducted a focused ground water sampling event to specifically evaluate the area between the southeast corner of the treatment cell and the sewer line right-of-way. Results of this sampling event are pending.
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 is currently preparing a project memorandum to summarize all the data collected during the 3 spring sampling events and to plan for additional injection of reagent utilizing the new injection wells. This project memo is due in August 2007.
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