Stopping PFAS in Its Tracks

UMN researchers Matt Simcik and William Arnold trap harmful chemicals before they can pass through the environment to our drinking water

by Caroline Frischmon

When you turn on the faucet, you probably trust the water in your glass will be safe to drink. For Minnesotans living in the eastern Twin Cities, this trust evaporated when toxic PFAS chemicals (or per and poly-fluoroalkyl substances) infiltrated their groundwater. PFAS are found in many products, ranging from nonstick cookware and food packaging to waterproof clothing. Despite their ubiquity, scientists suspect high concentrations of the chemicals lead to cancer, obesity, and other health problems. 3M formerly manufactured PFAS at its Cottage Grove facility, which caused the east metro contamination. Now the chemicals are threatening drinking water for Minnesotans across the state.

“This is an issue everywhere,” says Matt Simcik, a University of Minnesota Environmental Health Science professor who has studied PFAS for nearly 20 years. He explains that contamination is widespread because landfills throughout the state can also leak the chemicals.

When we throw away PFAS-coated products like raincoats and upholstery, the compounds leach into the water that passes through the landfill. Operators either pump this water (called landfill leachate) to a settling pond or truck it to a wastewater treatment facility. Neither option effectively filters PFAS before discharging the contaminated leachate into the environment. Plants absorb some of the released PFAS, but the rest can percolate into groundwater. With the help of a MnDRIVE Environment seed grant, Simcik and his colleague William Arnold in the Department of Civil Engineering, are developing a solution to prevent the release of landfill PFAS.

Known as forever chemicals, PFAS can persist indefinitely in the environment. We don’t have an effective way to break them down, so Simcik plans to trap the compounds instead. He and Arnold previously developed a groundwater treatment technology that uses a coagulant or clumping agent. These big molecules bind to PFAS to make the chemicals stick together and become entangled in the soil — where they can’t travel to our faucets. While it has shown great promise in the laboratory, they are now field testing this method. Depositing the coagulant within a landfill could immobilize the chemicals in layers of waste even as the leachate flows through the site. Simcik’s plan would effectively turn landfills into PFAS storage containers, and prevent contamination from spreading further in the environment.

While this sounds promising, applying the groundwater technique to landfills is more complicated than simply identifying the best location to bury the coagulant. Groundwater is relatively clean, but landfill leachate can pick up contaminants other than PFAS as it passes through layers of waste, which reduces the coagulant’s effectiveness. Before testing the treatment method in a landfill, the MnDRIVE project will investigate how to maintain performance even as the leachate composition varies.

Simcik must also confirm that the treatment is long-lasting. If the chemicals can leak out of their trap, the coagulation method would just delay the problem rather than solve it. The lab will monitor the longevity of the coagulants, but Simcik anticipates the solution will be long term.
Forever chemicals require a lasting solution because they can endure many years in the environment. 3M phased out production of the two most prevalent types of PFAS (called PFOS and PFOA) in the early 2000s after they were detected in animal bloodstreams worldwide. Over a decade later, the chemicals still linger in the environment near the 3M facility. After 3M phased out PFOS and PFOA, other manufacturers introduced new PFAS chemicals as replacements without proof they were any less toxic.

Ongoing research on the substitute PFAS compounds now points to similar health hazards as the originals, so companies may someday end up replacing these “replacement” chemicals. As this toxic cycle repeats itself, Simcik hopes to at least keep PFAS, both old and new, locked away in landfills and out of our bloodstreams. “Hopefully, we can prevent future contamination. That’s our goal,” he says.

Caroline Frischmon is a writing intern in the Science Communications Lab, majoring in Bioproducts and Biosystems Engineering. She can be reached at frisc109@umn.edu