Developed during the 1940s, per- and polyfluorinated alkyl substances, or PFAS, have an enduring chemical structure—the result of a near unbreakable bond between two main ingredients: carbon and fluorine. The combination is considered strongest single bond in organic chemistry as defined in every general chemistry textbook.
By the 1950s, PFAS were widely used in manufacturing and commercial production, according to the Interstate Technology and Regulatory Council. But the compounds’ real claim to fame came when they were used in Teflon, a nonstick coating applied to cookware made with a type of PFAS called polytetrafluoroethylene (PTFE).
By the 1970s, the council noted, studies “found some PFAS in the blood of exposed workers and further studies in the 1990s ... reported detections in the blood of the general human population.“
Today, the Centers for Disease Control and Prevention reports PFAS is likely in the blood of more than 97 percent of Americans. The chemicals’ ubiquitous use and everlasting nature, as well as their ability to migrate off treated materials, and, like other pollutants, dissolve readily into water or turn into aerosols, have resulted in researchers finding the chemicals in some of the most remote places on Earth. Due to their extreme persistence in the environment, PFAS have migrated over decades to the north and south poles, where they have been found in tissue samples of polar bears, minke whales, and ringed seals.
Graham Peaslee, a professor in Notre Dame’s Department of Physics and Astronomy, first learned about PFAS in 2011 while teaching at Hope College in Holland, Michigan.
He had a particular interest in using science to impact society—a considerable ambition for an experimental nuclear physicist. Peaslee developed a novel method to measure the nuclear and atomic content of various materials. The process included particle-induced gamma-ray emission (PIGE) ion beam analysis. PIGE uses a proton beam to bombard the surface of any solid material, causing fluorine nuclei to emit gamma-rays, a type of high-energy light, which can be detected and measured to determine the total fluorine content of the material.
When struck by protons, all light nuclei emit gamma-rays on a variety of wavelengths, but “fluorine has two very distinctive wavelengths, so we know when we see those, that material contains fluorinated substances,” Peaslee said. After measuring the elemental content and distribution within the sample, Peaslee then uses liquid chromatography–mass spectrometry to analyze each sample’s chemical structure, separating the compounds in each sample.
Peaslee knew his method could efficiently and cost-effectively detect fluorine content in consumer goods. Since he joined Notre Dame in 2016, he and his students have published a steady stream of studies detecting PFAS in everything from textiles, child car seats, face masks, and feminine hygiene products, to plastic containers, eye drops, school uniforms, dental floss, artificial turf, and cosmetics.
Virtually every product type tested in Peaslee’s lab has had some samples that contained PFAS.
In 2017, Peaslee’s lab published a study in the journal Environmental Science and Technology Letters that found PFAS in fast-food wrappers, which went viral. The research included more than 400 samples collected from fast-food restaurant chains including McDonald’s, Burger King, Chipotle, Starbucks, Jimmy John’s, Panera, and Chick-fil-A. The publication has been viewed more than 48,000 times, and the research garnered coverage by hundreds of news outlets.
The study would change the trajectory of Peaslee’s career.
Shortly after, Peaslee said, two US senators issued a letter to those fast-food companies who had been using products treated with the perfluorinated chemicals. They wanted to know what steps were being taken to remove those products from use and replace them with PFAS-free alternatives.
The response was relatively swift, with most if not all of those companies switching to PFAS-free wrappers and paperboard containers in the following 18 months.
“The central focus of my research changed after that paper,” Peaslee said. “I saw that I had an obligation to publish this applied science because it had the power to change policy. That was a real eye-opener for me and I thought, ‘I can do this, I can do it successfully.’ Being at Notre Dame, I can do it with a louder voice. We have a social responsibility to tell people about the dangers of these chemicals. That is why there is so much interest in PFAS from graduate students, faculty, and experts alike. We can make a contribution.”
He has been relentless in his pursuit of that mission ever since.
In 2018 Peaslee initiated his first study on PFAS in firefighter turnout and personal protective gear. His lab detected forever chemicals in both the inner and outer layers of jackets and pants. He received emails and gear samples from firefighters across the country and around the world and has been a returning speaker at the International Association of Fire Fighters’ biennial conference, educating the firefighting community about the use and dangers of PFAS, how the chemicals can migrate from the gear, coming in contact with and absorbing through the pores of the skin.
Peaslee said some manufacturers of personal protective equipment made for firefighters have started swapping out gear treated with PFAS for PFAS-free alternatives. “It’s up to individual fire services to buy it—but it’s now being offered everywhere,” Peaslee said. “The big thing that’s changed is the union has switched 180 degrees from its previous stance and they are leading the charge.”
At home, Peaslee has worked closely with Indiana State Rep. Maureen Bauer, supporting her bill to start a biomonitoring program to measure PFAS concentrations in blood samples from current and former firefighters.
In 2021, he published another viral paper on PFAS in cosmetics—viewed more than 128,000 times and covered by more than 400 news outlets.
Then, in 2022, Peaslee came to another turning point. He developed a new method for quick, accurate, and cost-effective screening for the presence of PFAS in drinking water.
There are a number of ways PFAS seep into groundwater systems—through industrial runoff, in contaminated biosolids used as fertilizer, and by slipping through wastewater treatment processes. But the use of PFAS in aqueous film-forming foams (AFFFs), firefighting foams used to put out flammable liquid fires such as jet fuel fires, is one of the most notorious sources of PFAS contamination in the world.
In 2023, the Department of Defense announced a phaseout of all AFFFs containing PFAS, requiring use of PFAS-free foams as of October 2024. While a relief to those who knew the dangers of PFAS, the regulations underscore a bigger problem.
The foams had been used at military installations, airports, and fire departments in every state and city in the country, for more than 60 years in many cases. With every use, be it an actual fire or a training exercise, every spill and every leak resulted in PFAS being absorbed into the pavement and leaching into the ground and into groundwater systems.
“There are 2,300 military installations in the United States,” Peaslee said. “Most of them have been using PFAS on their runways for more than 50 years. Only 637 locations have had their groundwater tested for PFAS so far—and those are military installations only. There are more than 100,000 fire stations where this stuff is either still being used, or has been used. And there are buckets of AFFF sitting around because nobody knows what to do with it.”
Between industrial facilities, major airports, military sites, and wastewater treatment plants, an estimated 57,000 sites are believed to be a source of environmental PFAS contamination.
“It’s the most costly cleanup the EPA has ever faced,” Peaslee said.
Peaslee’s method to detect PFAS in water samples uses activated carbon felt and gravity filtration with PIGE spectroscopy to measure fluorine content in drinking water. He plans to make it mobile.
With funding from the Department of Defense, he has developed a portable PIGE unit for on-site PFAS screening at hotspots and other impacted sites. Each PIGE particle accelerator will rest on a motorized cart housed in a small box truck for easy transport and is designed to run more than 100,000 samples per year quickly and cost-effectively.
The mobile units won’t be limited to military bases. Peaslee is launching his own company to manufacture and offer portable PIGE devices domestically and internationally.
“We don’t know how widespread the contamination is unless we test,” Peaslee said. “Right now, the goal is to manufacture benchtop and mobile units and get them in the hands of companies and local municipalities, and ultimately to see them used to test water supplies everywhere.”
Each mobile PIGE unit can run 24 hours a day, seven days a week, Peaslee said, “and fast.”
But, he added, there’s no easy way to eliminate PFAS from water. Instead, officials must manage concentrations. This involves testing levels on a regular basis and shutting down overly contaminated wells until rainwater has had a chance to dilute concentrations below proposed federal limits.
Nearly 80 years after PFAS were developed, and more than 60 years after animal studies first revealed the forever chemicals to be toxic, the EPA proposed new standards limiting levels of six different PFAS in drinking water.
The new regulatory standards were proposed in March 2023 and were passed into law in April 2024, becoming the EPA’s first-ever national drinking water standard for PFAS.
With PIGE in the hands of people who need it, Peaslee said, “I see an opportunity to make real change.”
Forever chemicals have saturated pavements at military bases, fire stations, and airports, seeping into the surrounding environment and contaminating rivers, lakes, farmland, and backyard gardens.
Change on that kind of scale requires persistence, commitment, creative thinking—and chemistry.
Kyle Doudrick, associate professor in the Department of Civil and Environmental Engineering and Earth Sciences, knows a little something about that.