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Comments Sought on Revised Cleanup Plan for Burlington’s Pine Street Canal Superfund Site

Release Date: 12/17/2008
Contact Information: David Deegan, (617) 918-1017

(Boston, Mass. – Dec. 17, 2008) – Following a careful review of previous work, EPA is seeking public input on recommended modifications to part of the underwater cap at the Pine Street Canal Superfund Site in Burlington, Vermont.

EPA’s proposed modification is contained in a document called a draft “Explanation of Significant Differences” that proposes steps to repair and augment a leaking portion of the underwater cap installed several years ago. In 2006, EPA performed a “5-Year Review” of previous work at the Burlington site, and found that some portions of the cap are leaking oil and coal tar.

The cleanup of the Pine Street Canal Site, performed in 2003 and 2004, has been largely effective in preventing contamination that exists beneath the canal from moving into the canal, but oily sheens and globules of coal tar have been observed periodically in a 450 foot-long portion of the canal since 2005.

EPA’s recommended modification of the cap will address the ongoing migration of leaking oil and coal tar (collectively referred to as nonaqueous phase liquid, or NAPL). In areas where NAPL is seeping, the cap will be partially replaced and/or augmented with a new cap system that will capture NAPL before it is released into the canal. The NAPL that accumulates will periodically be removed and shipped off site for treatment or disposal in an approved facility.

EPA will accept written public comment on the draft modifications from Dec. 22, 2008 to Jan. 27, 2009.

Site Background: A manufactured gas plant operated at the Pine Street Canal site from 1895 to 1966. Operations at the plant included disposal of wastes from the gasification process, including coal tars. Manufactured gas wastes were placed in and migrated to a canal on the site, which had been built in the mid-1800’s to serve lumber yards in the area.

A remedy to remove coal tar and place excavated contaminated sediments into a disposal facility to be constructed on the site was proposed by EPA in 1992, and withdrawn six months later, due to considerable community opposition to the proposal. From 1994-1998, additional studies were conducted by companies responsible for the contamination under the auspices of EPA, the Vermont Dept. of Environmental Conservation (VT DEC) and the Pine Street Barge Canal Coordinating Council, a citizen’s advisory group. In 1998, the Coordinating Council recommended constructing a cap over contaminated sediments in the canal and nearby wetlands, and restoring the wetlands, so that ecological risks at the site would be addressed.

EPA adopted the recommendation of the Coordinating Council and issued a “Record of Decision” in 1998 that called for capping the contaminated sediment and soil in the canal and adjacent wetlands to address risk to ecological receptors; long term monitoring; and the imposition of land use restrictions on the site to prevent migration or unacceptable human exposure to contaminants.

Construction of the cap was completed in March 2003. In the summer of 2004, the cap was further extended over a portion of the western bank of the canal, after it was discovered that NAPL was migrating along historic cribbing and the root systems of dead trees, and accumulating in pools on the ground and on the surface of the subaqueous cap.

Oily sheens and globules of coal tar were once again observed floating on the surface water at the southern end of the canal in the spring of 2005. In 2006, in a five-year review of the remedial action, EPA made the determination that the remedy was not meeting the performance standard for isolation of contamination in those areas where releases were observed.

Subsequent studies conducted by the parties responsible for the implementation of the cleanup, under the supervision of EPA and VT DEC, concluded that NAPL is migrating upwards through the existing cap, into the water column, primarily when gas bubbles are released from the peat below the cap during warm weather. Since 2005, absorbent booms placed across the canal have prevented the contamination from entering Lake Champlain.

More information:

EPA cleanup activities at the Pine Street Canal Superfund Site (www.epa.gov/ne/superfund/sites/pinestreet)

The draft ESD and additional EPA technical reports and documents are available for public review in the site information repositories located in Burlington, Vermont at the Fletcher Free Public Library, 235 College Street, and the, Bailey-Howe Library at the University of Vermont.