EPA Extends Public Comment Period on Gowanus Dredging Plan (USA)

On December 27, 2012, the U.S. Environmental Protection Agency announced a proposed cleanup plan for the Gowanus Canal, which includes removing some of the contaminated sediment and capping dredged areas.

The proposed plan also includes controls to prevent raw sewage overflows and other land-based sources of contamination from compromising the cleanup. The cost of the cleanup plan is expected to be between $467 and $504 million. The EPA is extending the public comment period for the plan to April 27.

The EPA held public meetings on January 23 and 24 to explain the proposed plan. The agency is extending the public comment period, which was set to end on March 28 to a new deadline for public comments of April 27.

On February 11, the Gowanus Canal Community Advisory Group will meet with the EPA regarding the proposed plan from 6:30 pm to 9:00 pm at the P.S. 58 Auditorium, 330 Smith Street, Brooklyn.

On February 13, the EPA will be in the Red Hook community to discuss in more detail the specifics of the proposed plan. That meeting is scheduled to begin at 6:30 PM at P.S. 15, located at 71 Sullivan Street in Red Hook, Brooklyn. The public is welcome.

More than a dozen contaminants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals, including mercury, lead and copper, were found at high levels in the sediment in the Gowanus Canal. PAHs and heavy metals were also found in the canal water. PAHs are a group of chemicals that are formed during the incomplete burning of coal, oil, gas, wood, garbage or other organic substances. PCBs were used as coolants and lubricants in transformers, capacitors and other electrical equipment and their manufacture was banned in 1979. PCBs and PAHs are suspected to be cancer-causing and PCBs can have neurological effects as well. Consumption of fish from the canal continues to this day notwithstanding fish advisories.

Completed in the mid-1800s, the Gowanus Canal was once a major industrial transportation route. Manufactured gas plants, paper mills, tanneries and chemical plants are among the many facilities that operated along the canal. As a result of years of discharges, stormwater runoff, raw sewage overflows from sewer systems that carry sanitary waste from homes and rainwater from storm drains and industrial pollutants, the Gowanus Canal has become one of the nation’s most seriously contaminated water bodies. In 2010, the Gowanus Canal was added to the Superfund list of the nation’s most contaminated hazardous waste sites. The EPA has identified numerous parties that are potentially responsible for the contamination including National Grid and the city of New York.

The evaluation of the alternatives for cleaning up the Gowanus Canal was divided into three segments that correspond to the upper, middle and lower portions of the canal. The first segment, which runs from the top of the canal to 3rd Street, and the 2nd segment, which runs from 3rd Street to just south of the Hamilton Avenue Bridge, contain the most heavily-contaminated sediment. In the third segment, which runs from the Hamilton Avenue Bridge to the mouth of the canal, the sediment is less contaminated than sediment in the other segments.

For the first and second segments of the canal, the EPA is proposing to dredge approximately 307,000 cubic yards of highly contaminated sediment. In some areas where the sediment is contaminated with liquid coal tar, the EPA is proposing to stabilize the sediment by mixing it with concrete or similar materials. The stabilized areas would then be covered with multiple layers of clean material, including an “active” layer made of a specific type of clay that will remove PAH contamination that could well up from below, an “isolation” layer of sand and gravel that will ensure that the contaminants are not exposed, and an “armor” layer of heavier gravel and stone to prevent erosion of the underlying layers from boat traffic and currents. Finally, clean sand would be placed on top of the “armor” layer to restore the canal bottom as a habitat. The plan also calls for removing contaminated material placed in the 1st Street Turning Basin decades ago.

For the third segment, the EPA is proposing to dredge 281,000 cubic yards of contaminated sediment and cap the area with an armor layer and a layer of sand to help restore habitat.

The proposed plan includes various methods for managing the contaminated sediment after dredging, depending on the levels of contamination. The proposed methods include transporting the dredged sediment to an off-site permitted disposal facility, transporting it to a location where the sediment can be treated and the possible beneficial reuse of some of the sediment after treatment.

In addition, the proposed plan calls for additional controls to significantly reduce combined sewer overflows into the canal. The EPA is concerned that such overflows would contribute to the recontamination of the canal after its cleanup. The EPA is proposing that combined sewer overflow discharges from two major outfalls in the upper portion of the canal be outfitted with controls to reduce the total volume of discharges from those outfalls by 58% to 74%.

Contaminated land sites along the canal, including three former manufactured gas plants, are being addressed by the New York State Department of Environmental Conservation. Other potential sources of continuing contaminant discharges to the canal have been referred to the state of New York and will be investigated and addressed as necessary.

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Press Release, February 11, 2013