Scientists are just beginning to understand that the answer is yes.
By Natalie Nix
It’s in the air, it’s in our water, and we’re just learning that it may also be in our food. The nonstick and anti-grease properties of the “forever chemicals” known as PFAS made them champions for lining food containers and wrappers. That melted cheese from your hamburger will peel right off of a PFAS-laden wrapper. But now, PFAS are beginning to appear in the food itself from environmental contamination: from the water that livestock drinks to the soil where crops grow.
“Most of the attention previously has been on food wraps; microwave popcorn was one of our poster child products for showing how widespread PFAS was,” said Phil Brown, a professor of sociology and health science who co-directs the PFAS Project Lab in the Social Science Environmental Health Research Institute at Northeastern University. “But we’re just now starting to look at food — not just from the food wrapping, but from the actual growing of food. There’s just not been enough research.”
The chemical stability that allows PFAS to withstand high temperatures in the likes of firefighting foam is what also allows them to accumulate in our bodies and the environment. Over time they made their way from foams and resins into consumer products: first in the production of Teflon, then later in stain and water repellant clothing and carpeting, and eventually into non-stick food packaging. Though production of a number of specific compounds was banned in 2006, new chemicals with similar properties – and adverse health effects – quickly filled the void.
PFAS in agriculture is a relatively new area of research, but the chemicals have already had ramifications for farmers such as Fred Stone in Maine. In 2016, milk from his cows showed PFAS levels at 1,420 parts per trillion — over 20 times the highest level that the Environmental Protection Agency considers “safe” for drinking water.
While the EPA advisory level is 70 parts per trillion, some states have passed legislation to require even lower levels — in New York it’s 10. Even after investing in water filtration systems, introducing new cows to the herd, and finding new sources of hay, PFAS still found its way into the cows’ milk. The forever chemicals put Stone and his century-old family farm out of business.
Dairy farmer Art Schaap in Clovis, New Mexico, faced a similar fate. PFAS contamination from firefighting foam used on a nearby Air Force base forced Schaap to dump between 12,000 and 15,000 gallons of milk a day. Residents near an air base in Australia were warned against eating eggs and meat from livestock, or fish from local rivers and streams, due to PFAS contamination.
Earlier this month researchers in Colorado alerted consumers that PFAS could reach them by way of crops watered by irrigation contaminated with PFAS. New research suggests that some plants do uptake PFAS from the soil, and that it can accumulate in parts of plants that we eat. A review published by the University of Padova in Italy concluded that uptake of PFAS varied by plant and the size of the specific molecule, showing low levels of PFAS in potatoes and some grains, and higher concentrations of shorter chain length PFAS in leafy greens. This fall, Jinan University in China published a paper on how different varieties of lettuce can absorb PFAS.
In the United States, heavy focus and criticism have been placed on farms’ use of sludge, or biosolids from sewage treatment plants, that farmers across the country and in many parts of Florida commonly use as fertilizer. The sludge has been linked to toxic algae blooms. But Purdue University agronomy professor Linda S. Lee points out that biosolids have been spread across land for a long time without evidence of building up PFAS. “After the big scare [on Fred Stone’s farm] in Maine, other people have looked and they’re not seeing problems. It gets back to supporting the fact that in most scenarios the biosolids that are applied are not causing a long-term trickle effect in terms of PFAS loads getting to ground water or getting into plants that get fed to animals.”
Because biosolids are already subject to regulation, Lee is much more concerned with land applications that come from paper mill waste — another common practice. The Maine site had been spread with biosolids for twenty years, but one year, paper mill waste was also applied. “I have to question whether the PFAS that were long term in that soil profile — how much was really from the land application from biosolids versus that one, high level, application from paper mill waste,” she said.
Lee has spent the past 15 years studying PFAS. She looks at how they behave, degrade and mobilize in soils, their uptake by plants and crops, as well as ways to break down PFAS into safe component parts — perhaps the sword in the stone of the PFAS problem. There are effective solutions for removing PFAS from drinking water, but then the question becomes: What do we do with the filter?
“That has to be dealt with,” explains Lee. “Either landfill, incinerated — which there’s lots of question marks on incineration — or some treatment process. None of them work sufficiently well.” Disposal into landfills risks the chance that the chemicals will leach their way back into the soil and the water, and there’s plenty of evidence that suggests incinerating PFAS not only fails to degrade the compound, but also disperses it into the air.
This past fall, Lee, along with researchers Heather Preisendanz at Penn State and Kurt Pennell at Brown, received a grant from the Environmental Protection Agency to evaluate PFAS in rural water supplies and agricultural operations to inform management strategies. The team plans to look at application of biosolids to fields to see how they contribute to drinking-water contamination.
Lee says she’s operating under the hypothesis that current research supports: biosolids do not carry high loads of PFAS unless they’ve been in direct contact with fire-fighting foam or highly impacted by industry waste. If the researchers find otherwise, they’ll have to reassess if, where, and how to apply biosolids to land. “The fundamental truth is it’s easy to say, ‘stop applying biosolids,’” she says. “But that actually is not easy to do, nor is it a sustainable approach to dealing with our human waste. There are a lot of unintended consequences to making such regulations.”
Just like the problem of how to dispose of PFAS-filled water filters, if biosolids can’t be spread on land, how do we dispose of sewage byproucts? Lee says at this point there are more questions than answers: “Leave them in a landfill for our future generations? And how much landfill are we going to need for the billions of tons that we generate in the United States alone? Are we going to send them to an incinerator? We don’t even know yet what happens to PFASs in an incinerator. We know they’re very hard to break down even under high heat. We could be spewing out a whole other subclass of PFAS we have zero understanding about.”
Greenhouse gas emissions generated by landfills is another factor in our warming world. Over time, organic compounds including biosolids break down in landfills. The process gives off byproducts including carbon dioxide and methane — two greenhouse gases, the latter even more of a heat trap. Plowing biosolids onto fields and into the dirt has the opposite effect.
Water, plants, and soil are the three main parts of nature that absorb carbon and lower the concentration of greenhouse gas in the atmosphere. Years of deforestation and intense farming leached the carbon stores from the soil. But research over the past decade shows promise that the interplay among plants, microbes, and the organic matter from biosolids could recapture a significant amount of the CO2 warming the Earth.
This is where her work on biosolids intersects with the challenge of climate change. “It’s back to looking at a life cycle,” Lee says, “and not just focusing on one place in the life cycle.”
To be sure, these chemicals are ubiquitous, and on many levels the problem is out of any single individual’s control. But Preisendanz, the Penn state researcher, says her group has had some success reframing these huge problems in terms of personal solutions. She likens it to the decrease in sales of exfoliating personal hygiene products containing microplastics before they were banned. “Stuff is getting into the water because we’re using it,” she says. “If you can help people understand what the impact of every decision is on water quality, then maybe people can make a difference in their own household.”
Read Next: Part 4 – Solutions