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Public Radio's Environmental News Magazine (follow us on Google News)

Sewage Sludge Danger

Air Date: Week of

According to a study in the journal Environmental Health, over 40% of the six million dry metric tons of sewage sludge produced annually in the United States is later applied to the land. (Photo: City of Geneva, Flickr, CC BY-NC 2.0)

Millions of acres of cropland in the U.S. may be contaminated from PFAS-tainted sewage sludge spread on fields as fertilizer. These “forever chemicals” are taken up by plants and then consumed by livestock and people, making them sick. Kyla Bennett of Public Employees for Environmental Responsibility (PEER) joins Host Jenni Doering to reveal the invisible threat of PFAS in our food and discuss why she believes EPA has failed its mission to protect the public.


O’NEILL: It’s Living on Earth, I’m Aynsley O’Neill.

DOERING: And I’m Jenni Doering.

If you’ve seen the movie Dark Waters, you may remember the story of [West] Virginia farmer Wilbur Tennant, whose cows mysteriously lost weight, developed tumors and died. His farm was just downstream from a landfill where Teflon manufacturer DuPont illegally dumped thousands of tons of toxic sludge containing PFOA chemicals, poisoning the cows that were drinking from the local stream. That real farmer was one of the first whistle blowers whose persistence in the 1990s lifted the veil on the dangers of PFOA and other PFAS known as “forever chemicals”. But we are now learning that the presence of PFAS on farms is a much more widespread problem. A 2022 study by the Environmental Working Group found that about 20 million acres of cropland in the US may be contaminated from PFAS-tainted sewage sludge spread on fields as fertilizer. In 2022, Maine became the first state to ban the practice of using treated sewage as fertilizer after officials discovered astronomical levels of PFAS in water, crops, cattle, soil and even farmers’ blood. Adam Nordell was owner of Songbird Farm, that had to be shut down.

Aerial photo of the Texas farms showing PFAS levels in soil and water. PFAS is toxic to human health in even tiny amounts. (Photo: Office of the Texas State Chemist)

NORDELL: Discovering PFAS on our farm was incredibly devastating. This directly undermined what we're trying to do on our farm. All farmers that I know work incredibly hard to steward the land, to perhaps pass the farm on to the next generation, and the last thing any farmer wants to see is their land and their water contaminated with forever chemicals. Farmers are also, we’re mission-driven. We're working hard for low pay. And you know, we all want to produce a safe product. We all are working to nourish our customers, to nourish our communities. And the last thing any farmer wants to do is to sell contaminated food.

DOERING: Now watchdog group, Public Employees for Environmental Responsibility, or PEER, and five Texas farmers have filed a petition to take the Environmental Protection Agency to court for allegedly failing to protect the public from the risk of sewage sludge contaminated with PFAS. Joining me now to discuss is Kyla Bennett. She previously worked with the EPA for 10 years and is now PEER’s Director of Science Policy. Welcome back to Living on Earth, Kyla!

BENNETT: Thank you so much for having me.

Smoking piles of biosolids, and one of the Texas ponds that was tested. (Photo: Office of the Texas State Chemist)

DOERING: So how exactly does PFAS, these forever chemicals, end up in biosolid fertilizer used across the United States?

BENNETT: Well biosolids is actually just a euphemism for sewage sludge. So if you think about it, since PFAS is so ubiquitous in consumer products and food and water, anything that we flushed down the toilet or put into the sink and goes into a wastewater treatment system, that will end up going into the biosolids, because the wastewater treatment plants were not designed to remove PFAS. And indeed, they actually create more PFAS than they remove.

DOERING: How are they creating more?

BENNETT: So we don't really know for sure, except that PFAS chemistry is really kind of complex. And what happens is that whatever the treatment is, in the wastewater treatment plant, what it's doing is certain short-chain PFAS or certain compounds are recombining and forming more PFAS. So studies have been done that show the amount of PFAS in the influent going into the wastewater treatment plant is actually less than the PFAS coming out.

Pictured above is a wastewater treatment plant that treats domestic sewage. Part of this output could be used as biosolid fertilizer. (Photo: Montgomery County Planning, Flickr, CC BY-SA 2.0)

DOERING: Wow. So we're not just talking about a matter of concentration here as the sewage gets sort of decomposed at the plant, but it's actually creating more PFAS?

BENNETT: Correct. It's creating all sorts of different kinds, and more.

DOERING: So we're following the path of this PFAS as it goes from the wastewater treatment plant to, you know, spread on the fields, and then it actually can get into plants. How is that happening? How is it actually getting into these plants?

BENNETT: So when PFAS gets into water and soil, that's how plants get their nutrients in their water, they take it up through their roots, and that's the same way the PFAS is getting into the plants. So short-chain PFAS in particular, the ones that have six carbons or less, are readily taken up by plants. And they will just go mostly to the leaves and the stems. So some of the leafy vegetables like kale, rhubarb, things like that tend to have more PFAS than some of the, you know, things like tomatoes or onions, things like that.

One of the dead calves found on the Texas farms tested by PEER for PFAS contamination. (Photo: Office of the Texas State Chemist)

DOERING: So what do we know so far about the impact that agricultural products contaminated with PFAS can have on our health?

BENNETT: Oh, there are so many. In fact, just recently, a study came out that shows that people with high PFAS in their blood serum can be at much higher risk for cardiovascular disease. So certain PFAS are carcinogens, like PFOA and PFOS. EPA said in March of last year that those two PFAS, there's no safe level of them. They will cause kidney cancer, liver cancer, testicular cancer. They've been associated with all sorts of thyroid disease, diabetes, developmental issues in children, obesity and heart disease.

DOERING: These are some of the worst diseases you can get. I mean, you know, cardiovascular disease, cancers, this sounds pretty concerning.

BENNETT: It's very concerning, not just because of how PFAS actually can attack almost every organ in your body, but also how ubiquitous they are. Almost everybody tested, something like 98% of humans, have a certain amount of PFAS in their blood. So it's been found everywhere from the Arctic Circle, everywhere to even remote areas, because it travels through the air, through the water and through our soil.

Kyla Bennett is the Science Policy Director for PEER. (Photo: Courtesy of Kyla Bennett)

DOERING: So this class of chemicals we're talking about is often called "forever chemicals". What is it that makes PFAS so persistent in our environment?

BENNETT: One thing that all PFAS have in common is a backbone of fluorine and carbon atoms. And that carbon fluorine bond is one of the strongest bonds known in organic chemistry. It's almost impossible to break, and that's why they've achieved the nickname “forever chemicals”, because they just don't readily break down.

DOERING: So we're talking about PFAS in this sewage sludge fertilizer. Where in the US is this problem of PFAS in sludge being uncovered?

BENNETT: Right now the states that have the most problems, or at least that we're aware of, are Maine, Michigan, New Mexico and now Texas. But honestly, everywhere biosolids are spread we're going to have this problem, because I have never seen a sample of biosolids that have been tested to not have PFAS. They all have extremely high levels of PFAS, and biosolids are used on many, many conventional farms. They're not allowed to be used on organic farms. But any conventional farm can use biosolids, and those PFAS will get into the soil, the groundwater, the crops and the animals, which can give you PFAS in dairy, in meat and in vegetables and fruits.

DOERING: Now, Kyla, you mentioned Texas, and I understand that you're involved in analyzing samples from two Texas farms that were allegedly contaminated with PFAS and biosolids from a waste management company. What's happening there?

Among the produce grown at Songbird Farm were grains like wheat, rye, and oats, which the farm milled on-site. (Photo: Courtesy of Adam Nordell)

BENNETT: So it's really interesting. We were contacted by an investigator for Johnson County, Texas. She had some, what she calls victims, some farmers who were suffering greatly from not just the smells of biosolids being placed in the farm across the street from them, but they started noticing that their animals were dying, and they themselves were having health impacts. So together with Johnson County, Johnson County paid for a vast array of tests, that we tested soil, we tested surface water, we tested drinking water, and we tested some of the dead animals to find out how much PFAS was in these media, and we found that there were vast amounts of PFAS. One of the stillborn calves, for example—and because it was stillborn remember it never ate grass or drank water on that farm. It was, all the PFAS in this stillborn calf was from its mom through the placenta. We found 610,000 parts per trillion of just PFOS, which is one of the two PFAS that EPA says there's no safe level of. Well people eat calf liver all the time. So just staggering. And the two fish that we tested, one had 54,000 parts per trillion of PFOS, the other one had over 70,000 parts per trillion. So really high levels, dangerous levels. And so right now there are three parallel tracks of enforcement, if you will, going on. Johnson County has an ongoing criminal investigation into what happened. PEER, we did a notice of intent to sue EPA for their failure to regulate PFAS and biosolids. And then finally, there's a private law firm in Austin, Texas, which is suing Synagro, the company that produced the biosolids, for tort, to try to make these farmers whole again.

DOERING: Gosh. So how has this impacted the farmers there? I mean, are they able to even keep farming?

BENNETT: You know, because there's no law in the US about limits of PFAS in food, they could legally just continue to sell their fish and their meat. But because they are so concerned about their friends and neighbors who might be buying these products, they voluntarily stopped selling their products. And so their livelihood is gone. Literally overnight. They are no longer making money from their farm, and they still have these animals that are alive that they have to take care of.

DOERING: Tell me more about how those strategies might help hold companies that sell toxic sludge with PFAS to farmers accountable.

BENNETT: Well I think if the private lawsuit from Austin, Texas is successful, it will severely limit the ability of these companies to provide these PFAS-contaminated biosolids as fertilizer, because if these companies know that they could be held liable and have to pay for the damage that it causes, they're going to not want us to supply it anymore. So that's one possible pathway. And then our suit with EPA, hopefully it will spur EPA to actually start regulating PFAS in biosolids. So this provision of the Clean Water Act, Section 503, came into play in 1987. And EPA was mandated by the statute to every two years identify toxic pollutants in biosolids as step one, and step two, promulgate regulations if there's enough evidence that these toxic chemicals harm human health and the environment. Well, EPA has known for a very, very long time now, decades, that PFAS is harming human health and the environment. They've also known for a very long time that these biosolids contain PFAS. So their failure to identify these PFAS and promulgate regulations is a huge failure on their part to protect human health and the environment, which is EPA's sole mission.

SongBird farm also grew Abenaki Flint Corn (pictured above), a regional, heritage variety traced back to the western Abenaki people of what we now call Northern New England. (Photo: Courtesy of Adam Nordell)

DOERING: So in recent months, Kyla, we've seen EPA unveil some drinking water standards for PFAS. How might those standards help resolve this issue of PFAS ending up in the fertilizer that farmers are using?

BENNETT: It may not, unfortunately. I am all for those drinking water regulations, right now they're in draft form. EPA is very late in finalizing those. We're hoping they come out any day now. But all that's going to do is require public water systems to filter water down below a certain level of just six PFAS. And how that will impact the biosolids, probably not very much unless, what we all are hoping, is that if there are regulations limiting the amount of PFAS in water, one of the only ways to address that is to stop putting PFAS in the consumer product. So what EPA really needs to do is not just force public water systems to filter it out. But what they need to do is regulate PFAS as a broad class rather than this Whac-A-Mole approach of regulating one at a time, because we're talking about a class of 14,000 chemicals. So regulating six is a drop in the bucket, no pun intended there, but honestly, it's really not enough. So they need to regulate them as a class and ban all non-essential uses. And that's the only way that we will ultimately see biosolids be reduced or eliminated, the PFAS levels being reduced or eliminated in biosolids.

DOERING: Now, some folks like yourself say we should really stop producing this stuff, this is toxic, we need to, you know, cut it out entirely. So that's one option. But you know, even if we did that, the fact of the matter is that there is all this PFAS out in the environment, in our water supply, on farms. So what can be done to clean up these so-called forever chemicals once they're already out there?

BENNETT: Not a whole lot. With water, we can filter it, with drinking water, we can filter it, but then you have the problem of what you do with that PFAS-laden filter, which is now hazardous waste. There is some work being done up in Maine on how to clear PFAS out of cattle. And if—it turns out that if you give them clean water and clean food, they can remove it from their body more readily than humans can.

DOERING: They have a superpower?

BENNETT: They do, they have a superpower. So that's a possibility. But another way that people are trying to remediate some of these sites, they're putting in fast-growing plants that will uptake a lot of PFAS. So they're trying to draw it out of the soil and the groundwater using these plants, but then you have the problem of, okay, now you've got tons of this PFAS-laden plant material, what do you do with that? You can't landfill it because the PFAS will get into the leachate which then goes to a wastewater treatment system and we're back to where we started again, you can't incinerate it with a regular incinerator because PFAS can't be destroyed. You need really, really high temperatures to destroy PFAS and traditional incinerators don't really affect it that much. And it can become airborne and travel and then become deposited on the land and water again. So it really is a conundrum. And I often liken, I make the analogy between climate change and PFAS contamination. If we stopped burning fossil fuels tomorrow, we'd still have 425 parts per million of carbon dioxide in our atmosphere for decades, if not hundreds of years before it slowly starts coming down. That's not a reason not to do it, we have to do it. But it's gonna take a while to get back to where we should be. Same thing with PFAS, if we stopped emitting it tomorrow, the amount of PFAS in our water, our soil and our food is going to stay pretty leveled for decades, if not hundreds of years or longer before it starts coming down. Which is why it's important for EPA and the states to act now.

Adam Nordell and Johanna Davis owned and operated Songbird Farm together on a beautiful hilltop farm in Unity, Maine. They were among the 4 farms that were shut down due to dangerous PFAS contamination from biosolids. (Photo: Courtesy of Adam Nordell)

DOERING: This is such a huge issue, Kyla, you know, and it might feel daunting to some of our listeners hearing about just how widespread this problem is. So what can individuals do to limit PFAS in their daily lives?

BENNETT: You can do a lot. I have made a concerted effort in my life for the past five years to get PFAS out of my house. So you know, get rid of your carpets, don't have upholstered furniture that have PFAS in it. Don't buy makeup with PFAS. Don't buy anything in plastic containers, particularly number two plastics because those are the ones that are fluorinated. So I try really hard in my life to eliminate PFAS from our house, but I know that I'm privileged and not everybody has the ability to do that. For example, we have a organic farm that's a mile and a half from our house and we buy our produce from there. We know it's safe, because our town just put in a $10 million filtration plant. So the water is safe. It's an organic farm so there's no biosolids. So I'm pretty positive that the vegetables that I'm buying there are pretty low in PFAS if not PFAS free. And not everybody's able to do that. Unfortunately, it's hard to protect yourself, because you don't know which products contain PFAS. They're not listed as ingredients most of the time. So the only thing you can do is try to self-educate and contact companies and say, "Hey, do you use any fluorinated chemistry in this raincoat,” or in these hiking boots, or in these guitar strings, or whatever it is that you're buying. And it's time consuming. So there is a website that has PFAS-free products. And I often consult with that, that's how I got my rain gear. And so there are scattered lists around of brands that are PFAS free or lower in PFAS, and that's the only thing people can do until our government starts taking control and doing what they're supposed to do.

DOERING: Kyla Bennett is Director of Science Policy at PEER. Thank you so much, Kyla.

BENNETT: Thank you so much for having me.

DOERING: We’ll link to those resources Kyla Bennett mentioned for avoiding PFAS chemicals at the Living on Earth website, loe.org. And we reached out to EPA for a response but did not hear back in time for our broadcast.

Correction: An earlier version of this interview and transcript contained a numerical error regarding the number of Maine farms that had to be shut down.



PEER | “Remove Forever Chemicals from Biosolid Fertilizers”

The New Lede | “Texas Farmers, Watchdog Group Demand EPA Act on PFAS in Farm Fertilizer”

The Guardian | “Maine Plans Removal of PFAS From Sewage Sludge Used as Fertilizer”

Learn more about Kyla Bennett

WBUR | “Maine Nonprofit Buys PFAS-Contaminated Farm to Help ‘Forever Chemicals’ Research”

Learn more about Song Bird Farm

Learn more about PFAS free products

Learn more Defend Our Health, where Adam Nordell now works on issues around PFAS farmland contamination


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