Three people who are studying “forever chemicals” and removing the toxic compounds from the environment discussed what they want to see happen next to address contamination, at a forum on Tuesday organized by the Bangor Daily News and Maine Farmland Trust.

Rachel Schattman, assistant professor of sustainable agriculture at the University of Maine; Steve Woodard, chief innovation officer at Emerging Compounds Treatment Technologies, known as ECT2; and Dr. Abby Fleisch, a pediatric endocrinologist at MaineHealth and environmental health researcher, discussed what is known and not known about how to remove per- and polyfluoroalkyl substances, or PFAS, from soil, the technologies showing promise to destroy PFAS, and the biggest outstanding questions about how the chemicals affect people’s health. 

Schattman is in the early stages of research on how PFAS chemicals are absorbed by crops. Woodard, who leads research and product development for ECT2, has developed ways to remove the toxic compounds from water and wastewater, and plans to soon apply technology to destroy them in real-world situations. Fleisch researches associations between PFAS exposure and health, especially in children and adolescents.

PFAS are a group of thousands of manmade chemicals that do not naturally break down in the environment due to their extremely stable chemical bonds. As a result they accumulate in the environment, food chain and people’s bodies. For many years in Maine, contaminated sludge from wastewater treatment plants was spread on farm fields, and the chemicals found their way into private wells. The wastewater is also discharged into rivers, which are sometimes used as sources of public drinking water. 

The state’s investigation to locate places with contamination is ongoing.

The chemicals can also be found in firefighting foam, food packaging, coated paper products and cookware, and they have been linked to a number of health problems, such as a decreased response to vaccines and kidney cancer.

Below, read how the panelists answered some questions from the Bangor Daily News, Maine Farmland Trust and the public, or listen to the entire conversation at

more answers to your questions about pfas

Questions about health

What are the biggest outstanding research questions right now about how PFAS is affecting the health of kids and adults?

Abby Fleisch, MaineHealth: “There are data linking PFAS exposure to high cholesterol, but the impact on cardiovascular disease endpoints, so things like stroke or heart attacks, is an important outstanding research question. There’s also a gap in understanding the effects of PFAS among those most highly exposed, so it’s important to study associations of PFAS with health outcomes in communities that have higher levels of exposures like here in Maine.”

What do you think needs to happen better to serve patients who believe they might have been exposed to high levels of PFAS whether through water or other means?

Fleisch: “I think we need to improve lab capacity and insurance coverage. The ability for a provider to order a PFAS test is limited in Maine. And insurance doesn’t always cover the test, so those are the two areas that I think we need to focus on.”

Questions about crops

What PFAS-related experiments are you working on at the University of Maine, and what can we hope to learn from them?

Rachel Schattman, UMaine: “I’d like to give credit to a graduate student named Alexandra Scearce, who’s working in my lab, who’s doing quite a lot of work on reviewing the literature related to crop uptake of PFAS compounds and has really designed the study that I’m about to describe. So what Alex and I are hoping to look at is the uptake rates in several different vegetables that are common both in people’s gardens and in commercial farms in Maine and across the Northeast. These include lettuce and corn, cabbage. …

“What we’re hoping to look at is where in the plants both short- and long-chain molecules, in field and greenhouse settings, accumulate. … We know that plants with bigger leaf surface areas like lettuces or cabbages transpire more, and it’s thought that PFAS accumulates more in those plants. So plants where we eat the leaves we’re mostly concerned about. 

“But the other thing we’re interested in is how planting crops near each other might lead to potentially some competition for PFAS. So if there’s a known amount of PFAS in the soil, and you plant a tomato plant next to a lettuce plant, what is the relative accumulation between these two crops, and where in the crop does it end up? It’s not likely to end up in the tomato fruit. The testing that has been done in tomatoes, for example, has shown very, very low levels of accumulation. But perhaps it will end up more in the leaves, so we’re interested in that dynamic.”

What do we know about how to remove PFAS from the soil so far, either through hemp or through other crops?

Schattman: “PFAS is very difficult to remediate from the soil in general owing to the strong bonds that it forms with other molecules in the soil. … 

“Current research that I have read up on suggests that phyto-management is most useful in soils that are not heavily contaminated to begin with, so using plant materials for that purpose might be better suited for lands that are not super, super contaminated. Studies point to the remediation potential of several different types of species sometimes referred to as hyperaccumulators. These include plants like tall fescue and birch. Then there have been some suggestions that hemp is a hyperaccumulator, although we are still kind of looking for robust data to come out from some ongoing studies like the study that’s going on at the Loring Air Force Base.

“So it’s important to remember also that different plants that might be used for remediation purposes might have an affinity to different types of PFAS molecules. So, for example, plants like amaranth have been found to hyperaccumulate PFOA but they don’t really take up PFOS very much at all. So what species we use in a given location depends on what the particular contaminants are in that location. … 

“There has been a lot of conversation about hemp as a potential hyperaccumulator. The prior studies that I have read have shown that hemp is very good at extracting things like heavy metals from the soils. … There is some logic that says that if hemp is a good hyperaccumulator of heavy metals that it might also be a good hyperaccumulator of PFAS. However we are still waiting for that research to be published.”

What areas do you think the most research is needed and what could help to accelerate that research? 

Schattman: “We have a desperate need for cost-effective remediation plans, and I am particularly interested in those that help keep agricultural lands in agriculture. I think there’s a real threat to farmers’ livelihoods. We have a lot of unknowns in terms of whether or not they’re able to market the products that they grow. …

“I would also say that additional funds for research and non-research testing is needed. We don’t really have a lot of lab capacity out there to run the number of tests that people would like to run. Also the tests are very expensive.”

what you need to know about forever chemicals

Questions about removing, destroying PFAS

Walk us through the basics of what could be the most promising technologies to destroy PFAS in water and wastewater, and how do they work?

Steve Woodard, ECT2: “Supercritical water oxidation, which is also referred to as SCWO, and hydrothermal alkaline treatment, or HALT, are two of the top technologies that are being watched closely today, and there’s a lot of exciting research. They both use really high temperature and pressures to break apart the bonds that hold PFAS molecules together, so these are fairly extreme conditions of temperature and pressure. …

“Both of these technologies can completely destroy or mineralize PFAS compounds, which is a big deal, and they can do it in a short reaction time period, too. Supercritical water oxidation, or SCWO, typically only takes seconds to completely destroy PFAS. The HALT process, hydrothermal alkaline treatment, is more on the order of minutes. 

“The key for both of these technologies is an upfront volume reduction step or a pre-concentration step … because the cost of these destruction technologies is dependent on treatment volume — or the volume that has to be treated.”

What are you seeing on the ground when it comes to local efforts to address PFAS? What are the hurdles to treating and destroying PFAS in real-world scenarios? 

Woodard: “Maine has some of the strictest drinking water standards in the country, and our company, ECT2, has installed several PFAS drinking water systems in Maine, most recently in Fryeburg just prior to the Fryeburg Fair. They wanted to get that system online to clean PFAS from the drinking water well. Many of the problematic drinking water systems in the state have already been addressed. …

“On the wastewater side, we’ve received very few serious inquiries. Most of them actually are coming from out of state, from large chemical companies. … But there are a few of these districts or municipalities in the state of Maine that are quite proactive and are getting ahead of the regulations. The Anson-Madison Sanitary District … [is] working hard to evaluate and implement PFAS treatment, followed by destruction, on their wastewater, which discharges to the Kennebec River. … 

“On-site PFAS destruction, that’s really becoming the holy grail, and we need to work on making on-site PFAS destruction cost effective for Maine communities because right now these technologies are still on the costly side.”

What areas do you think the most research is needed and what could help to accelerate that research? 

Woodard: “We really need real-time data to make good operational decisions. The current analytical methods are expensive. They involve sending [water] samples away to laboratories, and it typically takes two to three weeks to get results at $200 to $300 a sample. Having real-time sensors would enhance not only the treatment effectiveness but also advance the technologies.”

“I can’t emphasize that enough. It’s very difficult to operate a treatment system, take a sample, and then not get a result for two to three weeks. Then it’s a little too late to make an adjustment to your treatment system.”

Maine pfas regulation efforts

Reader, viewer questions

Are PFAS spread in rain or other atmospheric deposition?

Schattman: “There has been some research looking at concentrations of PFAS in rainfall. There was one study … that looked at seven sites across the United States, and they did find trace amounts of PFAS, but not above the EPA’s threshold or a level of concern. I think when we’re talking about routes of exposure, that rainfall is probably not the avenue that we’re most concerned about.”

Woodard: “It has been found in areas where there are factories or chemical plants that have spewed a lot of PFAS up into the atmosphere. It can carry for a fair distance, and then when it rains it brings it back down and enters the water — the surface water, the groundwater.”

Can PFAS be eliminated from the body?

Fleisch: “If there were a way to eliminate it safely from the body that would be fantastic. The studies that have been done have looked at some medicines, such as cholestyramine, which is a medicine for high cholesterol, and probenecid, which is a medicine for gout. Also studies have looked at repeated phlebotomy, so going to have blood taken out frequently over the course of a year or two years.

“Studies have looked at all of these things as ways to reduce the body burden of PFAS, but the studies have been small and limited, and right now there’s insufficient evidence to show that the benefits of these interventions outweigh the potential risks.” 

How concerned should we be about in-home exposures to treated clothing, bedding, carpets and so on?

Fleisch: “I think a big issue is that companies aren’t required to disclose whether there are PFAS in their products, so it makes it really hard for the consumer to discern whether a particular product that they’re using is or isn’t safe, and so that’s part of why that question is so tricky to answer.”

How do negative health impacts from exposure to PFAS compare with other negative health impacts from exposure — for instance secondhand cigarette smoke?

Fleisch: “To my knowledge that hasn’t been officially done, although I think a comparison like that could be very meaningful.”

How can the consumer know whether locally grown vegetables and other foods are safe when sold at markets or grocery stores? 

Schattman: “At this point there is no way that it is being communicated to consumers, and that’s because most of the time farmers don’t know, also. We’re still in such early stages of understanding how far and wide the contamination has been. But I do want to emphasize that most vegetables that have been tested by the Maine CDC have come up with very, very low levels. So we are in the process of trying to figure out which crops are the highest risk.”

Are there replacements for PFAS in products, to limit further contamination?

Woodard: “There certainly is a ton of research being done in that arena. Firefighting foams, for example, those are products that contain some of the highest concentrations of PFAS. [Firefighting training areas] are switching over to fluorine-free foams. They’re not as effective at putting out fires or preventing fires, but things are headed in the right direction there at least. 

“As far as things like Gore-Tex and Scotch Guard and Teflon, basically what a lot of these companies are doing is changing out the formulation to things like GenX and ADONA. … But the jury’s still out on really how much safer these compounds are, and there are a lot of concerns.”

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Erin Rhoda

Erin Rhoda is the editor of Maine Focus, a team that conducts journalism investigations and projects at the Bangor Daily News. She also writes for the newspaper, often centering her work on domestic and...