Alcoa, the US Environmental Protection Agency (EPA), the New York Department of Environmental Conservation (DEC) and others have been evaluating alternatives to address elevated levels of polychlorinated biphenyls (PCBs) in fish in the lower Grasse River for more than 15 years.
The Record of Decision (ROD) on the remediation of the Grasse River is consistent with the Proposed Remedial Action Plan issued in October last year.
PCBs are probable human carcinogens that build up in the fat of fish and mammals and the primary risk to people is the accumulation of the chemical from eating contaminated fish.
From the 1950's until the mid-1970's, the Alcoa West facility in Massena, New York released waste including PCBs from its aluminium production and fabrication activities, resulting in the sediment in the waters near the facility and seven miles downstream being contaminated.
EPA decision
The ROD requires dredging and capping of contaminated sediments in a 7.2 mile stretch of river. The estimated cost of the remediation is $243m.
The EPA finalized the plan after reviewing and considering comments received during the entitled period, and 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.
It 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 and the remaining five-mile stretch of the main channel will be capped with sand and topsoil mix.
The plan requires long-term monitoring of the capped areas to ensure that the caps remain intact, and monitoring of fish, water and habitat.
Alcoa action
“Alcoa has worked cooperatively with the EPA to address the PCB sediments in the Grasse River, and we are pleased to see this final step in the remediation decision process completed,” said Kevin Anton, Alcoa vice president and chief sustainability officer.
“Based on 15 years of scientific research, Alcoa believes the remedy is both protective of human health and the environment and effective over the long term.”
The firm added that it can now move forward with the next phase of the Massena Modernization Project.
It includes $52m for work that will begin in June 2013, including $10m toward economic development in the North Country.