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EPA Says Coakley Landfill 'Impacted' Some Nearby Wells; PFAS Chemicals Found In Superfund's Cap

Annie Ropeik / NHPR

Federal officials say they’ve definitively linked three contaminated water wells in Greenland to the Seacoast’s Coakley Landfill Superfund site.

The Environmental Protection Agency gave a public update on the site Wednesday night, for the first time since 2019.

The agency says it now knows that Coakley has impacted the well water of three nearby homes. Two are above state limits on two harmful chemicals – PFOA, which is a common kind of PFAS, and 1,4 dioxane. They say these two homes have effective point-of-use filters.

The agency says they'll continue testing area water supplies for chemicals indefinitely. They’ve found some levels of PFAS in all of the two dozen nearby wells they've sampled. They say they still can't be sure it's all from Coakley, though neighbors remain skeptical.

PFAS are industrial compounds that were once common in a range of household and commercial products. They were found in and around Coakley in 2016, after it had been dormant as a capped Superfund site since the 1990s.

"To date, our studies do not suggest any significant contaminant migration further away from the landfill, so EPA believes the studies have addressed public concerns on this issue and should be good news for those living in the areas surrounding the landfill," said EPA spokesman Dave Deegan after this week's meeting. "Ongoing investigations and the continued sampling of private wells will further confirm the findings of these studies." 

The state, in the past couple of years, has since imposed new regulations on some kinds of PFAS. While they're an increasing concern at Superfund sites around the country, they’re not subject to any federal laws.

State Sen. Tom Sherman, at Wednesday's meeting, urged the EPA to list PFAS as a hazardous substance to hasten those cleanups and get more funding from polluters. It's one of the actions that the agency has considered under President Trump and, now President Biden, along with setting drinking water limits on PFAS.

Meanwhile, the EPA has been analyzing the groundwater deep beneath Coakley by drilling bedrock wells, hoping to better understand how contamination is spreading. That project is set to wrap up this year.

Credit EPA
Contractors have been testing surface water treatment methods for contamination in Berry's Brook, adjacent to the landfill, under a 2019 state law.

Officials have also been piloting ways to clean up PFAS in surface water around the landfill, in response to a 2019 mandate from Gov. Chris Sununu and the state legislature.

Contractor Chris Buckman said they had mixed results from an attempt to remove contamination from nearby Berry’s Brook with “pillows and blankets” full of an “absorbent media” similar to granular activated carbon, a common filtration method for PFAS.

“It’s important to mention that the widespread treatment of surface water for PFAS isn’t common,” Buckman said. “This is sort of – I’m not going to use the term ‘groundbreaking,’ but it’s still the early stages industry-wide of evaluating treatment of surface water.”

The state and EPA have also confirmed that multiple layers of Coakley’s protective cap contain PFAS, making it a potential contributor to contaminated stormwater runoff. They’re waiting for a major rainstorm to get more data on that, after delays due to last year’s drought.

The EPA says the cap contains several layers of soil, sand and compost, as well as plastic-based fabric. All of those layers except one of the sand sections were found to contain PFAS, with the highest levels in the compost-soil mixture.

"At Coakley, more sampling of the stormwater runoff from the landfill is planned in order to provide additional data to better characterize the extent of contaminant loading that stormwater runoff may contribute," said EPA spokeswoman Mikayla Rumph in a statement. "We can then determine if that loading is significant enough to pose an unacceptable risk." 

Links between the landfill cap and contaminated runoff could have major implications for scores of other capped toxic waste sites across the state and country. Rumph said the Coakley cap is a standard design, though the composition of the layers and the sourcing of their materials can vary from site to site.

"Regionally, we are testing fill at new capping projects to ensure it does not contain unacceptable levels of PFAS," Rumph said.

This year, the EPA will also conduct a routine five-year review of the Coakley site -- the fifth such report, conducted at all post-cleanup Superfund sites, since the cap was installed.

CORRECTION: An earlier version of this story incorrectly stated that three wells linked to Coakley are above state limits on PFAS and 1,4 dioxane. In fact, only two of the wells considered impacted by Coakley exceed state limits. This post has been updated to correct that error and include statements from the EPA on the well contamination and analysis of Coakley's cap. 

Annie has covered the environment, energy, climate change and the Seacoast region for NHPR since 2017. She leads the newsroom's climate reporting project, By Degrees.
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