To deal with PCB (polychlorinated biphenyls) and heavy metal contamination in Massachusetts’ New Bedford Harbor, the U.S. Environmental Protection Agency (EPA) has plans to bury and cap toxic silt at the bottom of the harbor via the deployment of an underwater Confined Aquatic Disposal (CAD) cell. According to the agency, dredging New Bedford Harbor alone would not be enough to rid it of PCBs and other pollutants. The New Bedford Harbor serves the Massachusetts communities of Acushnet, Fairhaven, Dartmouth and New Bedford.
According to an EPA press release, the agency has been trying to clean up PCBs and heavy metals in New Bedford Harbor since 1982. From the 1940s until PCBs were banned by the in the 1970s, two electrical device manufacturing facilities improperly disposed of industrial wastes, which contaminated the harbor bottom for about 6 miles from the Acushnet River into Buzzards Bay. PCBs do not break down naturally, the EPA statement pointed out, and the greatest risk from the harbor has been the buildup of PCBs within the local marine food chain. Since 1979, there have been restrictions on fishing, shellfishing and lobstering in New Bedford Harbor because of the risks associated with PCB-contaminated seafood.
The use of a CAD cell, which will be located between the Route 195 and Route 6 bridges, will greatly expedite the cleanup in the lower reaches of the harbor south of Sawyer Street, according to the EPA. Nationally, the use of CAD cells for contaminated sediment disposal is increasing because it successfully isolates contaminants from further impacting local marine food chains, the agency’s statement said.
The CAD cell is estimated to shorten the cleanup timeframe by up to 14 years, depending on the level of funding, the EPA said. The use of the CAD cell may also save $500 million compared to the current remedy at the usual funding rate of approximately $15 million per year.
“We wouldn’t have put this idea on the table if we didn’t believe fully it could be done in a safe manner,” an EPA spokesperson told South Coast Today. “That is the primary focus of our project. What we felt wasn’t safe was to have the contamination remain in the lower harbor for another decade or so.”
Others, however, are not so sure.
“The EPA hasn’t provided enough information to know whether it’s a safe alternative or not,” Mark Rasmussen, executive director of the Coalition for Buzzards Bay, told South Coast Today. Among the details not yet known are the exact location and size of the CAD Cell, as well as a plan for managing the cell.
“We are asked to accept a significant change in the cleanup strategy without any details of how it’s going to be accomplished, and that’s unfortunate,” Rasmussen continued.
According to Sun Coast Today, the Coalition for Buzzards Bay had hired a professor of oceanography from Stony Brook University in New York who concluded last year a CAD cell could be feasible but there were too few details for him to make a final assessment.