It’s been described as a slow-moving disaster. That’s a tragically beautiful way to describe an impending catastrophe from the Clean Water Act of 1972. The intent behind the act was to clean up US waterways. Part of that entailed building sewage treatment plants, which led to sludge build-up. Burning and landfilling were expensive, while discharging to waterways was prohibited. Another method gained steam by the late 1970s: spreading treated sludge (aka biosolids or humanure) onto farmland as a fertilizer.
In Maine, thousands of tons of biosolids were spread onto farmland and worked into the soil. Some farmers were repeat customers. Then, in 2017 low levels of PFAS were detected on a farm in southern Maine. Currently, nine farms have tested positive for contamination, while statewide farmers are bracing for the storm.
What are PFAS?
Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are artificial compounds with many uses, from flame retardants to food packaging. Originally developed during the 1930s for nonstick and waterproof applications, PFAS came into their own after the 1960s when the US military created an aqueous film-forming foam to extinguish fires..
In the decades that followed, industry developed new uses for PFAS. Designed to be stable and heat-, water-, and friction-resistant, they made things better. For these reasons, industry exploited their desirable properties to, for example, make clothing stain-resistant, keep food safe and cookware easy to clean, protect homes and offices from fire, and insulate electric wires.
It’s estimated that more than 4,700 PFAS are in use worldwide.
Are PFAS dangerous?
Despite the ubiquitousness of PFAS, only two classes—PFOA and PFOS—have been extensively studied by researchers. Molecularly, PFOA and PFOS are classified as long-chain PFAS because their molecules form chains of eight or more carbon atoms. Highly stable, they are in carpets, ski wax, pesticides, cleaning products, and even microwave popcorn bags. Unsurprisingly, tests show that 98 percent of Americans have PFOA and PFOS in their blood.
Researchers have found solid connections with cancers; kidney, liver, and thyroid problems; hormone suppression; reproductive complications; and low birth weight and developmental delays. Only minute doses are needed to cause health issues, and yet, because of their Teflon-like qualities, they can bioaccumulate in the body.
Taking the forever out of forever chemicals
Because of their molecular structure, PFAS were designed to be indestructible. This explains why they are more widely known as forever chemicals and can be found everywhere, especially in our drinking water.
In 2019 more than 180 countries, including the US, agreed to stop producing PFOA, PFOS, and other kinds of PFAS. This is a good start because it helps limit the source. However, their stability allows them to persist in the environment long after their intended use. We need to find ways to capture them.
Presently, the only capture technology is filtering water with, for example, activated carbon. Some methods reprocess the filtered material for reuse, whereas others incinerate it. Said to be the best method to destroy the tenacious PFAS molecules, temperatures have to exceed 1,000 degrees Celsius. Though efficient, this process comes with a large carbon footprint.
Fortunately, innovators are looking to less energy-intensive methods, like electrochemical, thermal, and ultrasonic processes. Another possibility might involve mushrooms. Scientists are also exploring short-chain PFAS, which may be safer; unfortunately, recent studies find they are just as toxic as their long-chained cousin.
Andrews, Caitlin. “Maine’s PFAS Problem Traces Back to a Landmark Environmental Law.” Bangor Daily News, February 21, 2022.
“History and Use of Per- and Polyfluoroalkyl Substances (PFAS).” Interstate Technology and Regulatory Council, April 2020.
Howell, Mark C., Jr. “PFAS.” ConsumerNotice.org, November 21, 2023.
Jansen, Kerri. “‘Forever Chemicals’ No More? These Technologies Aim to Destroy PFAS in Water.” Chemical & Engineering News, March 25, 2019.
“Per- and Polyfluoroalkyl Substances (PFAS).” U.S. Environmental Protection Agency, November 3, 2021.
“Per- and Polyfluorinated Substances (PFAS) Factsheet.” U.S. Centers for Disease Control and Prevention, February 2, 2022.
Ross, Rachel. “What Are PFAS?” Live Science, April 30, 2019.