USA: EPA Finalizes Grasse River Dredging Plan

EPA Finalizes Grasse River Dredging Plan

The U.S. Environmental Protection Agency has finalized its plan to clean up contaminated river sediment at the Grasse River Superfund site in Massena, New York.

Past industrial activities have contaminated the river sediment with polychlorinated biphenyls. PCBs are probable human carcinogens that build up in the fat of fish and mammals, increasing in concentration as they move up the food chain. The primary risk to people is the accumulation of PCBs in the body from eating contaminated fish. The EPA has been engaged in the cleanup of the Grasse River for several decades. In 1989, the EPA issued an administrative order that requires Alcoa to investigate the extent of contamination in a portion of the river, to evaluate cleanup options, and to design and implement a cleanup plan to be selected by the EPA. The EPA expects that Alcoa will perform the $243 million cleanup announced last week.

The plan requires dredging and capping of contaminated sediment in a 7.2 mile stretch of the river. Approximately 109,000 cubic yards of contaminated sediment will be dredged from near-shore areas of the river, which will then be filled in with clean material. Dredged sediment will be disposed of at an on-site permitted, secure landfill. In the river’s main channel, approximately 59 acres of contaminated sediment will be covered with an armored cap and another approximately 225 acres of contaminated sediment will be capped with a mix of clean sand and topsoil to isolate the contamination from the surrounding environment.

The EPA received public comments on the cleanup plan when it was proposed in September 2012. To encourage public participation, the EPA held formal public meetings and informal information sessions in Massena, N.Y. and on the Akwesasne Reservation to discuss its plan. The EPA finalized the plan after reviewing and considering all comments received during the 60-day public comment period, and after consultation with the New York State Department of Environmental Conservation and the St. Regis Mohawk Tribe.

The details of the plan include dredging and filling in the near-shore portion of the Grasse River with clean material. In addition, the plan calls for the placement of a thick armored cap in the upper two miles of the river’s main channel, where the sediment is susceptible to ice scouring during severe weather. The remaining five-mile stretch of the main channel will be capped with sand and topsoil mix. Habitat that is impacted by the cleanup will be reconstructed. The plan requires long-term monitoring of the capped areas to ensure that the caps remain intact, and monitoring of fish, water and habitat. Details of this work will be defined during the estimated two-year design phase of the project, and will include plans for worker and community health and safety. A cultural resources survey will also be conducted prior to the start of in-river work. Based on current estimates, dredging, filling, and capping will take approximately four years to complete and will cost approximately $243 million. The fish consumption advisories established by the New York State Department of Health will remain in effect until PCB concentrations in fish are reduced to the point where they can be relaxed or lifted by the state.

From the 1950’s until the mid-1970’s, the Alcoa West facility in Massena, NY released waste including PCBs from its aluminum production and fabrication activities, onto the facility property and into the Grasse River. As a result, sediment in the waters near the Alcoa West facility and extending approximately seven miles downstream has been contaminated.

In 1995, Alcoa dredged about 3,000 cubic yards of highly contaminated sediment from an area near the Alcoa facility. Since that time, a number of studies have been conducted by Alcoa to evaluate cleanup options for the site. In 2001, Alcoa tested a variety of materials to be used as a cap over the contaminated sediments and also a variety of methods of placing a cap over the sediment. This testing took place in a 7-acre area of the Grasse River. Subsequent monitoring in 2003 showed that part of the cap placed during the study was lost and some underlying river sediment had eroded as a result of hydraulic scouring caused by ice. As a result, the EPA directed Alcoa to re-evaluate cleanup options for the site to account for scouring caused by future severe ice events, as well as other options to address the sediment contamination. The results of the studies were carefully examined and were used to develop the cleanup plan.

Superfund is the federal cleanup program established by Congress in 1980 to investigate and clean up the country’s most hazardous sites. The Superfund program operates on the principle that polluters should pay for cleanups, rather than passing the cost to taxpayers. The EPA looks for parties responsible for the contamination at Superfund sites and requires them to pay for the cleanups.

The cleanup of the contamination at the Alcoa West facility property and upland areas is being conducted by Alcoa with oversight by the New York State Department of Environmental Conservation under state hazardous waste laws. The cleanup of the river will be conducted by Alcoa under the 1989 Superfund administrative order with oversight by the EPA.


Press Release, April 8, 2013