Working together to mitigate forever chemicals

Story by Stacey Mickelbart • Photos by Katherine Jacobson, Joshua Clark, Tom Campbell, Lacy Gehmlich and Rebecca Robiños

PFAS, or per- and polyfluoroalkyl substances, are a group of chemicals used to make consumer products heat, water or stain resistant. Think firefighting foam, nonstick cookware, stain-resistant carpets and fast-food packaging. These “forever chemicals” last in the environment for a long time and are difficult to destroy. They build up in the body and are linked to slowed metabolic rates, reduced fertility and fetal growth, increased cancer risk and suppression of immune responses.

They’re also frequently in the news, because in April 2024, the Environmental Protection Agency (EPA) began regulating levels of six PFAS in drinking water.  That same month, Indiana Attorney General Todd Rokita filed a lawsuit accusing 22 companies of polluting Indiana’s natural resources by continuing to manufacture PFAS.

To facilitate collaboration, Purdue University’s Institute for a Sustainable Future (ISF) has designated a strategic research team (SRT) for PFAS. And the recent launch of the university’s One Health strategic initiative focuses on solving just this type of complex challenge at the intersection of human, animal and plant health.

Researchers in the College of Agriculture work with colleagues across the university to address PFAS, including detection and accurate measurement, impact on human and animal health and mitigation in the environment.

Marisol Sepúlveda, professor of forestry and natural resources, and Jennifer Freeman, professor of health sciences development in the College of Health and Human Sciences (HHS) and assistant vice president for research development in the Office of Research, co-lead the PFAS SRT.

“My component of this whole chain is looking at what PFAS do once they’re released, and mostly what they do in aquatic systems,” Sepúlveda explains. As an ecotoxicologist, she studies how PFAS impact an organism’s life, including physiology, behavior and reproduction.

She often uses small fish as models for their high genetic similarity to humans. The translation from small fish, like zebrafish, to humans is also valuable to Freeman’s work on the neurotoxicity of PFAS, specifically, “things that are happening in the brain during development, either during the exposure or right after the exposure. Primarily we’re looking at embryonic exposures in the first three days of the zebrafish life.”

Freeman and others in the SRT cite the measurements of PFAS in water and tissue samples from Linda Lee’s lab as key to their work. Lee, distinguished professor of agronomy and environmental and ecological engineering and assistant dean of agricultural research and graduate education, uses liquid chromatography–tandem mass spectrometry to detect PFAS in parts per billion or even parts per trillion. She has studied PFAS for nearly 20 years, including how the application of human biosolids used for fertilizer can introduce PFAS into the agricultural landscape — in the soil, taken up by crops or grazing animals, or as runoff into wells and streams.

Freeman is also lending her expertise to studies with Sepúlveda and Tyler Hoskins, research assistant professor in forestry and natural resources. “I like doing science that can help make decisions to make society better,” says Hoskins, who wants to provide evidence-based ways to make rules about PFAS usage.

While he’s worked with Sepúlveda to understand the basic mechanisms of PFAS bioaccumulation and toxicity, he’s especially interested in how to quantify those effects in the real world. Factors like temperature, precipitation, pH, and the presence of other chemicals in the water being tested all mediate the way PFAS behave, and wildlife exposed to PFAS also experience multiple stressors.

Hoskins is currently studying constructed ponds, often added to new housing subdivisions and common on agricultural landscapes, but rarely sampled like rivers, lakes, reservoirs and other public bodies of water.

That could pose a threat to human health, because many of these ponds receive runoff from agricultural lands where biosolids have been applied. Thanks to our regular exposure to PFAS in the environment and products we use, they’re in the blood of 97% of Americans — so we’re excreting them in our waste.

Some of Hoskins’ preliminary, unpublished data showed surprisingly high levels of PFAS in fish tissue exposed to biosolids runoff, so he secured funding to study if those results are representative of constructed ponds in general or simply a hotspot.

With the presence of more than 15,000 different PFAS in our environment, Lee and Hoskins agree that coordination, and not just among researchers, is the key. “We need cooperation across academia, industry and government,” Hoskins says. “Let’s reduce PFAS use where we can, engineer PFAS replacement products that are not toxic as quickly as possible and work together to reduce the release of these chemicals into the environment.”

It’s helpful to think about essential uses of PFAS as a starting point. We may choose to continue using PFAS to manufacture heart valves or the aqueous film-forming foams (AFFF) used to extinguish flammable liquids, for example. However, Lee suggests we should work to clean or pre-treat PFAS as a byproduct of manufacturing, require transparency so that manufacturers can come forward when they find a new problem and encourage the EPA to conduct specific, annual sampling for PFAS.

Lee’s work has expanded to include collaborators like George (Zhi) Zhou, associate professor of civil and construction engineering and environmental and ecological engineering, who works on water quality and treatment.

His research on point-of-use water filtration systems shows that activated carbon filters or reverse osmosis filters installed under your kitchen sink are effective at filtering PFAS from drinking water in your home.

Lee and David Warsinger, assistant professor of mechanical engineering, also work on ReNEW, a National Science Foundation Regional Innovation Engine in the Great Lakes to eliminate PFAS from wastewater. PFAS are filtered via a nanomembrane, and an electric field is used to break them down. ReNEW will allow them to partner with companies who can help scale up the technology more rapidly.

As researchers work to address PFAS in all parts of the environment, “People should not be fearful,” Lee says. “We should just recognize where we are and move forward. Try to be mindful.”  

Zhou recommends purchasing a point-of-use water filter. These systems can range from a more affordable $50 for the simplest activated carbon filter to several hundred dollars for reverse osmosis. 

Freeman recommends avoiding PFAS exposure where possible. Helpful online buying guides share questions consumers should ask and what product labels to look for, including those that indicate no PFAS.