Per- and poly-fluoroalkyl substances, also known as PFAS, are a class of chemicals used for their waterproofing and stain-resistant properties. They have been linked to certain cancers, reproductive problems and developmental issues, and are known as “forever chemicals” since they don’t break down in the environment.
Perfluoroalkyl and polyfluoroalkyl chemicals are typically used to create non-stick coatings, improve consistency and shine, repel oil and liquids and create waterproofness in products as diverse as Teflon, Scotchguard, firefighting foam, cosmetics, tooth floss, stain-resistant carpets, furniture, ski wax, rainproof coats, sporting gear and non-stick cookware. High levels of PFAS are also found in food packaging like pizza boxes, microwave popcorn bags and fast-food wrappers in order to keep food from sticking to the containers.
PFASs were designed by companies to be very stable; but that beneficial feature becomes a flaw when the products become waste. PSASs are conserved in the environment for decades (if not centuries). When buried in landfill, PFAS leach into the surrounding environment, contaminating soil and groundwater, threatening the health of people, wildlife and the wider environment. Tests have revealed dangerous levels of PFAS in all sorts of everyday contexts: rain, food and sewage sludge that farmers spread on cropland as fertilizer. Research suggests that nearly every source of surface water is contaminated by PFAS. PFAS can be removed from water with special treatments, but afterwards disposing of these chemicals has proved challenging.
PFAS have been linked to a range of health concerns, including cancers, particularly increased risks of kidney and testicular cancer, liver damage, autoimmune disorders, thyroid problems, low birth weight, compromised immune systems, ulcerative colitis and a host of other health problems.
Because of how PFAS are constructed—using a chain of carbon and fluorine atoms, which is one of the strongest bonds in organic chemistry—they do not break down in the natural environment, thus earning the nickname of "forever chemicals."
Methods to dispose of PFASs typically rely on expensive and harsh treatments, some of which require high pressures and temperatures above 1,000 °C. However, there is evidence that incinerating products containing PFASs can lead to the spread of these compounds into the environment. The average household water filter isn’t capable of removing PFAS from the tap.
PFAS chemicals came on the market around the same time as PCBs, beginning in the 1930s and 1940s. but unlike PCBs, they were never comprehensively banned and to this day have minimal regulations. PFOA and PFOS are the most notorious PFASs. Before they were phased out by the US Environmental Protection Agency (EPA), they were recognized as global pollutants and linked to several toxic injury chemical cases against DuPont (one of the largest PSAF producers and polluters). Opinion is that the financial, medical and environmental costs to address PFAS will almost certainly dwarf those related to lingering PCB contamination.
In May 2015, 200 scientists from 38 countries signed the Madrid Statement on PFASs which warns about the harms of all PFAS chemicals, both old and new. According to the Madrid Statement, health effects associated with the older, long-chain PFAS's such as PFOA, include: Liver toxicity; Disruption of lipid metabolism, and the immune- and endocrine systems; Adverse neurobehavioral effects; Neonatal toxicity and death; Tumors in multiple organ systems; Testicular and kidney cancers; Liver malfunction; Hypothyroidism; High cholesterol; Ulcerative colitis; Reduced birth weight and size; Obesity; Decreased immune response to vaccines; Reduced hormone levels and delayed puberty.
The US EPA estimates that the class of PFAS-related compounds constitutes more than 12,000, with an estimated 1,000 still in use. As the location of production for decades, there is a vast amount of PFAS contamination in the USA. The Environmental Working Group (EWG) has mapped more than 2,800 contaminated sites and identified nearly 30,000 additional potential sites. High PFAS levels exist in drinking water in 34 U.S. cities; for tap water samples taken from 44 places in 31 states in 1998, only one location had no detectable PFAS with Miami, Philadelphia, New Orleans and the northern New Jersey suburbs having the highest levels. The data suggested that roughly 110 million Americans could be contaminated by PFAS and that the substances are present in 99 percent of Americans’ blood.
PFAS are used in toilet paper manufacturing. In a 2023 study, researchers tested PFAS levels toilet paper from around the world and found concentrations of PFAS in all 21 samples. One type of PFAS, called 6:2 diPAP, was most common, being 91% of the average concentrations; there was not much difference between the toilet paper samples, or between recycled and regular toilet paper. Wastewater and its by-products are frequently spread on agricultural fields to help grow crops. According to one 2018 study, toilet paper makes up about 72% of the solid material in wastewater and consistently found PFASs in wastewater sludge. Byproducts of wastewater sludge are processed and sold as agricultural additives, sometimes called biosolids. A 2022 analysis by the Environmental Working Group estimated that 5% of agricultural fields in the U.S. — making up nearly 20 million acres — use sewage sludge as fertilizer. 44 samples of sewage sludge tested by the Maine Department of Environmental Protection in 2019 all contained at least one PFAS chemical, and in all but two of the samples, the chemicals exceeded safety thresholds for sludge that Maine set the previous year.
Another recent source of environmental contamination is PFAS-treated food wrappers and containers, like moulded bowls made from sugarcane fibre which have a surface treatment with PFAS that prevents the fiber bowls from falling apart when filled with hot, wet or greasy food. Using toxic nondegradable chemicals in a biodegradable product makes them unsuitable for composting. Samples taken in 2019 of nine commercial compost stations and one backyard compost pile were tested for 17 different PFAS. Compost in which food packaging was included had a toxic load of PFAS ranging from 28.7 micrograms per kilo to 75.9 mcg/kg. Compost samples that did not include food packaging had a PFOA contamination level ranging between 2.38 and 7.6 mcg/kg.
Recent peer-reviewed research has found that PFAS chemicals have more than 200 categories of use. Just as we are working to mitigate the effects of climate change on future generations, we must do the same to save future generations from the chemicals in use today that will outlive us.