Per- and polyfluoroalkyl substances (PFAS) are a class of more than 12,000 synthetic chemicals that have earned the nickname “forever chemicals” because their carbon-fluorine bonds — among the strongest in organic chemistry — make them virtually indestructible in the environment. Developed since the 1940s for their ability to repel water, oil, and heat, PFAS are found in nonstick cookware, waterproof clothing, food packaging, firefighting foams, and countless industrial applications. Their persistence, combined with growing evidence of health risks, has made PFAS contamination one of the most significant environmental and public health challenges of the 21st century.
What Makes PFAS So Persistent?
The carbon-fluorine bond is the strongest single bond in organic chemistry, with a dissociation energy of approximately 485 kilojoules per mole. This exceptional stability is precisely what makes PFAS useful — they resist degradation by heat, acids, bases, and biological processes — but it also means that once released into the environment, they accumulate indefinitely. PFAS do not break down through natural weathering, microbial action, or photodegradation under normal environmental conditions.
These chemicals migrate through soil into groundwater, travel vast distances in waterways and air currents, and bioaccumulate in living organisms. PFAS have been detected in rainwater on every continent, in Arctic ice, in deep ocean sediments, and in the blood of virtually every person tested worldwide.
Health Concerns
Epidemiological studies have linked PFAS exposure to a growing list of health effects. The most studied compounds — PFOA and PFOS — are associated with elevated cholesterol levels, thyroid disease, immune system suppression (including reduced vaccine effectiveness), kidney and testicular cancer, reproductive problems, and developmental effects in children.
The health impacts of most PFAS compounds remain poorly understood because only a small fraction of the 12,000+ known PFAS have been studied individually. Scientists increasingly warn that assessing PFAS one chemical at a time is inadequate — people are exposed to complex mixtures, and the cumulative effects may be greater than those of individual compounds.
Environmental Contamination
PFAS contamination is widespread and often concentrated near military bases, airports, and industrial facilities where aqueous film-forming foam (AFFF) was used for firefighting training. In Canada, several communities have discovered PFAS contamination in drinking water supplies, particularly near military installations and manufacturing plants. Contaminated sites are extraordinarily difficult and expensive to remediate because the chemicals resist conventional water treatment methods.
Water treatment technologies capable of removing PFAS include granular activated carbon filtration, ion exchange resins, and high-pressure membrane systems such as reverse osmosis and nanofiltration. However, these methods are expensive and generate concentrated waste streams that still contain PFAS, requiring further treatment or secure disposal.
Regulatory Response and Destruction
Governments worldwide are tightening PFAS regulations. The European Union has proposed a near-total ban on PFAS manufacturing and use. The U.S. Environmental Protection Agency established enforceable drinking water limits for several PFAS compounds in 2024. Canada has added certain PFAS to its list of toxic substances and is developing a comprehensive management approach.
Destroying PFAS requires extreme conditions. Incineration at temperatures exceeding 1,000 degrees Celsius can break carbon-fluorine bonds, but concerns about incomplete destruction and toxic byproducts persist. Emerging technologies include supercritical water oxidation, electrochemical treatment, and a promising approach using sodium hydroxide and dimethyl sulphoxide that breaks PFAS apart at relatively low temperatures. Researchers are also engineering bacteria and enzymes capable of cleaving carbon-fluorine bonds — a biological approach to green chemistry that could enable cost-effective remediation at contaminated sites.
Addressing PFAS contamination will require decades of sustained effort across regulation, remediation, and the development of safer chemical alternatives — a defining challenge for environmental science and policy in the coming years.
