Comments Sought on Revised Cleanup Plan for Burlington’s Pine Street Canal Superfund Site? (VT)
(Boston, Mass. – July 13, 2011) – This summer, EPA will be continuing its work at the Pine Street Canal Superfund Site in Burlington, Vt., by gathering public input on plans to enhance part of the site’s remedy and by conducting a comprehensive evaluation of the cleanup.
From July 14 to Aug. 15, 2011, EPA will be seeking public input on recommended modifications to the site’s underwater cap. The existing underwater cap is meant to hold contaminated groundwater and coal tar in place to prevent contamination from moving towards Lake Champlain. Groundwater monitoring has been conducted since the remedy was selected in 1998 to ensure that contamination does not migrate beyond the Pine Street Canal site. For nearly ten years, the plume of contaminated groundwater beneath the Site was stable. However, since 2008, increases in benzene concentrations in groundwater samples have been detected, along with the intermittent presence of accumulations of coal tar, in several monitoring wells on the lake side of the canal. These findings indicate that additional containment is necessary.
EPA is proposing to enhance the existing remedy by adding a vertical barrier below the ground surface at the northwestern corner of the Site between the canal and bike path. The vertical barrier will intercept the flow of contaminated groundwater to the lake. Recovery wells will also be installed at strategic locations to allow for the removal of coal tar, as necessary, so that it does not migrate around or below the vertical barrier.
The details of EPA’s recommendation are presented in a document called an “Explanation of Significant Differences” (ESD), which describes the actions EPA and the Vermont Department of Environmental Conservation (VT DEC) believe are necessary to prevent the release of contaminants to Lake Champlain. The draft Explanation of Significant Differences can be found on EPA’s website at http://www.epa.gov/ne/superfund/sites/pinestreet.
Also this summer, EPA will be conducting its second comprehensive evaluation—also called a five-year review—of the cleanup. This review is repeated every five years at sites where a remedy has been implemented but some waste remains and use of the site is restricted. This review process ensures that the remedy, as implemented, continues to protect public health and the environment. As part of the review, EPA will talk with Burlington officials and citizens, including members of the Pine Street Barge Canal Coordinating Council to gain a better understanding of local concerns.
EPA expects to complete the five-year review process later this year, and will issue a report summarizing its findings, including a determination whether the cleanup remains protective of human health and the environment. The first five-year review was conducted in 2006, and the findings resulted in the replacement of part of the original sand with a cap using a reactive core mat in a portion of the canal in 2010.
Site Background: A manufactured gas plant operated at the Pine Street Canal site from 1895 to 1966. Operations at the plant included on-site 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, companies responsible for the contamination conducted additional studies under the oversight of EPA, 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, to address t ecological risks at the site.
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; the imposition of land use restrictions on the site to prevent migration or unacceptable human exposure to contaminants; wetlands restoration; and long term monitoring, including groundwater monitoring.
Construction of the underwater cap was completed in March 2003. In the summer of 2004, the cap was further extended over a portion of the cribbing on the western bank of the canal. After oily sheens and globules of coal tar were observed floating on the surface water at the southern end of the canal in 2005,the parties responsible for the implementation of the cleanup conducted additional studies under the supervision of EPA and VT DEC. These studies concluded that contamination was migrating upwards through the underwater sand cap and into the water in the canal when gas bubbles were released from the peat below the cap during warm weather. In 2009, after a public comment period, EPA issued an ESD requiring the replacement of part of the sand cap with a reactive core map. Construction of the amended cap was completed in 2010.
The draft ESD and additional EPA technical reports and documents are available for public review in the site information repositories located in Burlington at the Fletcher Free Public Library, 235 College Street, and the, Bailey-Howe Library at the University of Vermont. The public may also review information about the site at the EPA Region 1 Records Center, 5 Post Office Square, Boston, MA, 617-918-1440.
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