Airborne pollution can spread PFAS contamination farther than previously thought, according to a new study by Bennington College researchers.
The study confirms and expands on the researchers’ preliminary findings, presented to the public in 2018, which found that pollution from factories in Bennington was likely the cause of contamination in the nearby Green Mountain National Forest.
Since then, authors Tim Schroeder, David Bond and Janet Foley — all with Bennington College — have expanded their sampling efforts, finding more evidence of contamination in the forest, which is otherwise largely pristine.
In 2016, news broke that pollution from local Teflon-coating factories had caused widespread contamination by PFAS, perfluoroalkyl and polyfluoroalkyl substances. PFAS are used to make products resistant to heat and water, and they cause an array of harmful health effects. The contamination damaged hundreds of residents’ drinking-water wells and prompted several lawsuits against the plastics company Saint-Gobain, which owns the now-defunct factories.
“All of these different interests descended on us at the same time when the crisis unfolded,” Schroeder said. “There was so much information. There was a lot of public mistrust of what was being said by all of the different parties.”
That prompted the team from Bennington College to look for its own answers, which it’s been reporting to the community.
At first, questions circulated about whether ChemFab, the company that owned the factories at the time, mishandled liquid waste that led to the contamination.
“But there was also this possibility that was out there in the scientific literature, that the PFAS could theoretically move through the air and settle on the ground and possibly contaminate soils,” Schroeder said. “And then we wondered, well, can that infiltrate to the groundwater? And on what scale could that happen?”
It’s an important question with big implications, Schroeder said. Knowing how PFAS travel through the environment could influence policy and help communities with contamination understand where to look and how to respond.
The researchers’ results were published in the journal Environmental Impact: Processes & Impacts earlier this year.
When they started the project, the working presumption was that all PFAS emitted into the air “fell right back down to the ground immediately in the vicinity of the factories,” Bond said. When PFAS were discovered farther away, it was easier for the companies involved to shirk responsibility for the problem.
“You needed to put a wide-angle lens on the question of how far this stuff went, and sort of see the great distance that these toxic chemicals were traveling in the air, falling back and contaminating groundwater,” Bond said.
A Green Mountain National Forest wilderness area, located downwind of the polluting factories “where there are no roads and haven’t been since prior to the invention of PFAS,” Schroeder said, provided an ideal laboratory.
“Lo and behold, we found contaminated springs at the top of the mountain, 2,000 vertical feet above the factory, and about 8 miles downwind of the factory, pretty conclusively suggesting that, yes, the air deposition was the source of the contamination,” Schroeder said.
A sample from a spring near the top of the mountain contained 41 parts per trillion of PFOA, and soil at a similar elevation showed 23 parts per billion of the chemical.
PFAS are now ubiquitous in the environment — they have been found in soil, lakes, rivers and oceans in all corners of the globe, including polar regions, according to the study. But by comparing soil samples downwind of the factories with soils in more distant areas, the researchers could connect the contamination to ChemFab.
“There are patterns in the contamination that you can identify and begin to link back in a persuasive way to specific source points — factories,” Bond said.
Both authors said they were shocked when they found relatively high levels of contamination on the far side of the mountain, where they expected low detections.
Bond and Schroeder said contamination in the soil itself poses little risk to the public, but if water percolates through the soil and drains into nearby groundwater, that leaves “potential for more communities to be impacted,” Bond said.
“It’s something we really have to have some vigilance towards — long-term, ongoing monitoring of how these chemicals are moving through the soils of the Green Mountains and into our water systems,” he said.
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