Even Vermont has its bad days. 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. 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.
Even Vermont has its bad days. 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. 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.
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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 that recommendation in 1998, and the cap was built in 2003 and 2004.
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.
For further information: http://yosemite.epa.gov/opa/admpress.nsf/0/0F15023671BB99CE852578CC0055F839
