By Mara Mellits, Special to the Reporter
The US Environmental Protection Agency (EPA) has finalized its plan to clean hazardous pollutants out of a 3.7-mile stretch of the Neponset River, the landmark waterway that runs 29 miles from Foxborough into Dorchester Bay.
The project will target those parts of the river that are highly polluted with Polychlorinated biphenyls (PCBs) and other hazardous materials that have been discharged or runoff into its waters from manufacturing sites that have dotted its banks since the 1600s.
After years of lobbying by local officials, the EPA designated the river a Superfund Site in March 2022 and with the final plan now in place, the next phase of the cleanup will begin where the river merges with Mother Brook in Hyde Park and then extends downstream through Mattapan and Milton, ending at the Walter Baker Chocolate Dam in Lower Mills.
A Superfund designation is both a mechanism for the federal government to clean up polluted sites and a tool to hold polluters accountable for the cleanup, said Ian Cooke, executive director of the Neponset River Watershed Association.
Last June, the EPA completed its analysis of cleanup alternatives and recommended the plan to address the widespread river contamination, especially PCBs, chemicals used in many manufacturing processes until the EPA banned them in 1979. According to the EPA, they can cause cancers, learning deficits, elevated blood pressure, and immune and reproductive disorders.
While mills and other businesses going back to early colonial times had used the Neponset to power their gunpowder, lumber, textiles, paper, and chocolate operations, from the 1930s to 1970s, many industries operating along the river and its watershed used PCBs, man-made chemicals introduced in the late 1920s, as production applications. According to Tristan Pluta, a remedial project manager with the EPA, the PCB infestation was the result of both direct discharges and runoff into the river.
Andres Ripley, the greenways program director at the Neponset River Watershed Association, said the Superfund designation allows the EPA to fund the cleanup while it looks for the parties that polluted it and potentially hold them responsible for the cost.
The cleanup will include work at the Tileston and Hollingsworth Dam, where workers will excavate all the riverbank soils where PCBs exceed one part per million, EPA’s Pluta said.
The EPA will restore both the riverbed channel and the river’s banks after its cleanup and will then conclude with the removal of the dam, which is seen as a significant hazard, she sais, noting that the design will begin next year, and the cleanup will follow in 2027. It’s anticipated, she added, that the project will be completed in 2031.
“EPA believes that not only will this cleanup abate the immediate risk, it will also achieve the greatest efficacy for our long-term cleanup goals for the entire river,” Pluta said, “and it will give us the greatest likelihood that we won’t have to do a large mobilization in the future to address contamination in this area.”
The EPA accepted public comments about the plan from June 13 through August 1, which included a virtual public hearing on July 9.
Public feedback was instrumental in the process, Cooke said. The EPA received many observations, and a lot were positive, which is unusual at a Superfund site, he noted.
The Lower Neponset River Superfund Site Community Advisory Group, which meets monthly, is a group of interested citizens, residents, and community organizations that is following the cleanup and want to provide input to it.
“They sort of provide a connection point for EPA with the community and other state agencies as the process goes along,” Cooke said.
Jay Paget, a member of the group, has been involved since early 2024. Most of the group members are residents of Hyde Park, Mattapan, Dorchester, and Milton, he said, as well as some advisory members from the Neponset River Watershed Association.
Other participants include members from the state Department of Conservation and Recreation and the Department of Environmental Protection, as well as the EPA.
Paget said that the report that came out in June, in which the members solicited comments from the community, was a “great success in getting the word out, getting folks engaged.
“Our voice in ensuring that the river is clean to the highest standard possible, and our voice on how we would like to access and utilize this beautiful natural resource is important,” he added.
This story is part of a partnership between the Dorchester Reporter and the Boston University Department of Journalism.
