They’re everywhere, from the sleeves of your raincoat to the soil near an airport. They’re in your kitchen, from popcorn bags in the microwave to frying pans on the stove. They show up in countless industrial applications. The chemicals known as PFAS have many uses, but they also present a sizable suite of health hazards. Now, as the Montpelier City Council advances plans to keep landfill leachate containing PFAS out of its wastewater treatment plant, residents and lawmakers can take steps to prevent PFAS from continuing to reach soils and groundwater moving forward.
For the chemistry-inclined, PFAS stands for perfluoroalkyl and polyfluoralkyl substances. To many Vermonters, PFAS are what polluted Bennington’s groundwater. An umbrella term for a variety of chemicals, PFAS include perfluorooctanoic acid (PFOA), found more often in the vicinity of industrial sites, and perfluorooctanesulfonic acid (PFOS), more frequently associated with firefighting foams, explained geologist Tim Schroeder, Ph.D., and faculty member at Bennington College. Schroeder has been involved in efforts to study a PFOA plume thought to be associated with a North Bennington chemical company. According to its website, the Vermont Department of Environmental Conservation first identified the Bennington/North Bennington contamination in 2016.
The leachate that Montpelier’s wastewater treatment plant accepts from regional landfills also contains PFAS, and PFAS have been identified in both the incoming leachate and outgoing treated water, or effluent, as Montpelier’s deputy director of public works and city engineer Kurt Motyka reported at a city council meeting last month. Motyka noted that although wastewater treatment plants that accept leachate have higher levels of PFAS, all treatment plants have them.
Known broadly as “forever chemicals,” PFAS have chemical qualities that make them last a very long time. In particular, the bond between the carbon and fluorine atoms in PFAS is extremely strong. “In chemistry, this bond is the strongest bond that we know about in that it is indestructible in nature in many capacities,” said Anna Robuck, Ph.D., a research fellow at the Icahn School of Medicine at Mount Sinai in New York City.
And with PFOA and PFOS, “in order to turn them into something else, you have to put a whole bunch of energy in to react them away, so there’s no natural processes that break them down,” Schroeder noted. He observed, “They’re just super-duper thermodynamically stable.”
Even birds in extremely remote areas with no human contact have PFAS in them, Robuck noted. “In the environment there’s very few processes or organisms that are capable of breaking that carbon-fluorine bond, and so that’s why they stick around on what we think are geological timescales,” Robuck noted.
Unfortunately, these long-lived chemicals are also potentially hazardous. The C8 Science Panel, which performed studies from 2005 to 2013 on an Ohio Valley community exposed to PFOA, identified associations between PFAS exposure and many health issues, per its website. The C8 Science Panel noted a “probable link” between PFOA and high cholesterol, ulcerative colitis, thyroid disease, and testicular and kidney cancer.
“There’s just such a growing body of research showing different associations that it’s really vast at this point, what we think are associated with PFAS,” Robuck said. She noted that the negative health impacts can include “a lot of gnarly stuff, a lot of health outcomes that are avoidable and costly, so it’s unfortunate.”
But what makes PFAS so detrimental — their resistance to breakdown in a variety of environments — is also what makes them so appealing to industry and so useful in everyday life. They impart water- or oil-repellency, and many products utilize this feature. “It’s so pervasive in things you wouldn’t even think about,” Robuck said. She noted that “you find it in day-do-day food packaging products” including pizza boxes, as well as water-repellent outdoor gear, ski wax, cookware, water-repellent textiles, rugs, and even cosmetics.
Some PFAS also have many industrial functions, she noted, and are used in metal plating and creating plastics.
Another source of the chemicals is firefighting foam, because of the heat resistance of the substances combined with their capacity to coat surfaces, Schroeder said. “Basically, anyplace you had a bunch of the firefighting foam used is going to be a PFAS source.”
“Firefighters still have it pretty bad in that their gear is still full of PFAS,” Robuck said. “It’s mandated to be in their gear, so they’re exposed through that gear in that it’s water-repellent and heat-resistant.”
Industries have begun to replace some of the older PFAS with different substances that perform the same functional roles but have a different chemical structure. But, said Robuck, these changes may not make much difference from a health perspective. They may not accumulate in the body in the same way that older PFAS did, but they still produce negative health outcomes, she noted.
So what can be done to reduce or eliminate PFAS in the waste stream? “The amount of PFAS that’s going to come off of your coat, or your nonstick fry pan, or something, is really pretty minor,” Schroeder said. The main sources of PFAS are likely to be larger-scale industrial activities. In such activities, Schroeder noted, “there’s literally thousands of replacement chemicals that are being used, that there’s no regulations on yet, and they’re not being tracked.”
A different approach to regulation could help, Schroeder suggested. “What really should be happening is that we should be regulating the PFAS as a class of chemicals, and if you’re using any of them in your process, there should be very, very careful accounting for how you’re using them, and how much you’re using them, and how much is left over at the end of your process. What’s happening to all of them at the end?” In other words, he said, “cradle-to-grave accounting for the chemicals through the whole system.” And the systems, he said, must be closed, rather than allowing PFAS to escape industrial facilities and pervade the surrounding environment.
Another approach could be more research into replacements for PFAS, Robuck said. “There’s been so much reliance on PFAS chemistry across production for so long that I think there’s discussion of, oh, well we use it in so many things, what are we going to do without it?” She adds, “Well, have we really even explored other chemistries that could fill its role? Because frankly we’ve just been pumping out PFAS for 60 or 70 years. I’m not sure if we’ve explored other things that could take that role to maximum extent.”
Keeping PFAS out of wastewater leaving the treatment plant is not going to have a cheap solution, Robuck noted, saying, “… if consumers want it out of the waste effluent, they’ve got to be willing to pay for it.” The means of keeping PFAS out of waterways have associated costs. “Granulated activated carbon needs maintenance. You have to do tests to make sure you’re getting out all of the stuff. You have to renew it periodically depending on how much PFAS is in your waste stream, so it’s a thorny problem in that it’s hard to pull out one thread of intervention without pulling this whole fabric of … so many things to do to get this out of our lives.”
At the end of the day, said Schroeder, it may be difficult to stop using PFAS. “There’s a lot of stuff that we really like that it’s hard to make without the PFAS chemicals,” he said, but regulation may be a better approach. He suggested to “have it be baked into the regulations that if you use PFAS as part of a process in your industry, you have to account for every gram of that in your process … you better show that I purchased this many grams, this is how it was used, and this is how it is being disposed of at the end of my process.” He added, “That’s the kind of waste stream management I feel like we need.”