NEW YORK — The U.S. Environmental Protection Agency (EPA) finalized a plan to clean up the Gowanus Canal Superfund site in Brooklyn, N.Y., one of the nation’s most seriously contaminated bodies of water. The final plan will require the removal of contaminated sediment and the capping of dredged areas. The plan also includes controls to reduce sewage overflows and other land-based sources of contamination from compromising the cleanup. With community input, EPA decided on the option in the proposed plan that will require the disposal of the least contaminated sediment at a facility out of the area rather than building a disposal facility in the water near Red Hook. The cost of the cleanup plan is currently estimated to be $506 million.
“More than 150 years of industrial waste, storm water runoff and sewer overflows turned the Gowanus Canal into one of the most extensively contaminated water bodies in the nation, threatening people’s health and the quality of their daily lives,” said Judith A. Enck, EPA Regional Administrator. “The cleanup plan announced today by EPA will reverse the legacy of water pollution in the Gowanus. The plan is a comprehensive, scientifically-sound roadmap to turn this urban waterway into a community asset once more.”
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 of being cancer-causing and PCBs can have neurological effects as well. To this day, people can still be found fishing in the Gowanus despite advisories about eating fish from the canal.
Completed in the mid-1800s, the Gowanus Canal was once a major industrial transportation route. Manufactured gas plants, tanneries and chemical and dye plants are among the many facilities that operated along the canal. As a result of decades of discharges, stormwater runoff, 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 divided the Gowanus Canal cleanup 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 the 3rd Street Bridge, and the second 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 in the other segments.
For the first and second segments of the canal, the EPA plan requires dredging of approximately 307,000 cubic yards of highly contaminated sediment. In addition, in areas of the deep sediment that are contaminated with liquid coal tar, which bubbles up toward the surface, the sediment will be stabilized by mixing it with cement or similar binding materials. The stabilized areas will then be covered with multiple layers of clean material, including an “active” layer made of a specific type of absorbent material 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 will be placed on top of the “armor” layer to restore the canal bottom as a habitat.
For the third segment of the canal, the EPA requires the dredging of approximately 280,000 cubic yards of contaminated sediment and capping of the area with active, isolation and armor layers and a layer of sand to help restore habitat. The plan also requires removing contaminated material placed in the 1st Street turning basin of the canal decades ago and restoring approximately 475 feet of the former basin. In addition, the EPA is requiring the excavation and restoration of the portion of the 5th Street turning basin beginning underneath the 3rd Street Bridge and extending approximately 25 feet to the east of the bridge.
The final plan includes various methods for managing the contaminated sediment after dredging, depending on the levels of contamination. The methods include transporting the dredged sediment that is highly impacted by liquid coal tar away from the area to a facility where it will be thermally treated for the removal of the organic contaminants and then put to beneficial reuse such as a landfill cover, if possible. For the less contaminated sediment, treatment includes stabilization of the sediment at a facility out of the area, followed by beneficial reuse.
In addition, the final EPA plan requires controls to significantly reduce the flow of contaminated sewage solids from combined sewer overflows into the upper canal. These overflows are not being addressed by current New York City upgrades to the sewer system. Without these controls, contaminated sewage solid discharges would recontaminate the canal after its cleanup. The EPA is requiring that combined sewer overflow discharges from two major outfalls in the upper portion of the canal be outfitted with retention tanks to reduce the volume of contaminated sewage solid discharges. It is estimated that a reduction of 58 percent to 74 percent of these discharges will be needed to maintain the effectiveness of the cleanup. The final locations of these tanks will be determined during the design phase of the project. The EPA will continue its long-standing commitment to working closely with the community on this project, particularly regarding ways to minimize temporary project impacts during the work. The EPA applauds New York City’s commitment to utilizing green infrastructure, which is part of the city’s ongoing work to address CSO pollution.
Contaminated land sites along the canal, including three former manufactured gas plants, are being addressed by the New York State Department of Environmental Conservation, in coordination with the EPA. 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.
The Superfund program operates on the principle that those legally responsible for the pollution should perform or pay for investigations and cleanups, rather than passing the costs to taxpayers. After sites are placed on the Superfund list of the most contaminated waste sites, the EPA searches for parties responsible for the contamination and holds them accountable. The EPA has identified numerous parties that are potentially responsible for the contamination, including National Grid, the city of New York and other private and federal government entities. The agency is continuing its efforts to identify additional potentially responsible parties.
The EPA accepted public comments on the proposed cleanup plan for 120 days and considered public input before finalizing its decision. The EPA held public meetings in January 2013 to explain the plan and formally receive comments. In addition, from February 2013 to the end of the public comment period on April 27, 2013, the EPA participated in six more meetings with the public to discuss in more detail the specifics of the plan and to answer additional questions from the community. The EPA received more than 1,800 emails, letters, postcards and petitions containing comments. The EPA reviewed these comments and has prepared detailed responses to them, which can be found in the EPA’s Responsiveness Summary at www.epa.gov/region2/superfund/npl/gowanus/additionaldocs.html.
To read the EPA’s Record of Decision for the Gowanus Canal or for more information on the canal, go to www.epa.gov/region02/superfund/npl/gowanus or visit EPA’s document repository located at the Carroll Gardens Library at 396 Clinton St. in Brooklyn, New York.