United States Environmental Protection Agency
Region I
POLLUTION REPORT

Subject: 

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 a current owner of the site.  Olympia is performing the removal action under an Administrative Order on Consent (AOC) issued by EPA.  In order to remove TCE contamination from 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.  Olympia conducted a comprehensive quantitative ground water monitoring survey on April 24-26, 2006 and a focused sampling event on August 31, 2006.

EPA and Olympia conducted a site walk and technical meeting on September 20, 2006 to review the effectiveness of the treatment system to date.  Qualitative monitoring conducted to date  appears to indicate relatively good distribution of the injected permanganate reagent in the subsurface within much of the sheet piling containment area.  However, the reagent has not yet reached several of the deeper wells in the center of the containment area.  In addition, two small areas of lower-level contamination outside of the sheet piling containment area have not yet been addressed.

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.

At the September 20, 2006 technical meeting, it was agreed that Olympia will submit a work plan by mid-October for additional characterization as needed to develop an approach to deal with the above-mentioned areas not yet treated with the reagent.