PFAS: The Forever Chemicals That Are Everywhere

Per- and polyfluoroalkyl substances (PFAS) represent one of the most pervasive and persistent contamination challenges in environmental science. These synthetic chemicals - engineered to be extraordinarily resistant to degradation - have spread throughout the global environment, contaminating water supplies, agricultural land, and human bodies across every continent on Earth.

What Are PFAS?

PFAS (Perfluoroalkyl and Polyfluoroalkyl substances) are a class of more than 12,000 synthetic organic chemicals characterized by chains of carbon atoms bonded to fluorine atoms. The carbon-fluorine bond is one of the strongest in organic chemistry, making these compounds extraordinarily resistant to heat, chemical degradation, and biological breakdown - hence the term 'forever chemicals.'

PFAS have been manufactured since the 1940s and used in an extraordinary range of consumer and industrial applications:

• Nonstick cookware coatings (PTFE/Teflon)
• Stain and water repellents for textiles, carpeting, and upholstery
• Food packaging with grease-resistant coatings (microwave popcorn bags, fast food wrappers, pizza boxes)
• Firefighting foam (aqueous film-forming foam/AFFF), historically used at military installations and airports - a major source of groundwater contamination
• Industrial processes including semiconductor manufacturing, electroplating, and chemical production
• Personal care products including dental floss, some cosmetics, and shampoos

Environmental Persistence and Bioaccumulation

The same chemical stability that makes PFAS useful in consumer products makes them extraordinarily persistent in the environment. Once released, PFAS do not break down under normal environmental conditions. They migrate through soil into groundwater, accumulate in surface water, and are taken up by aquatic organisms and plants. PFAS bioaccumulate in food chains - concentrations increase at each successive trophic level - and have been detected in Arctic polar bears, deep-sea fish, and Antarctic penguins, far from any industrial source.

Human Health Impacts

When humans consume PFAS-contaminated food or water, or are exposed through direct contact with PFAS-containing products, these chemicals are absorbed and accumulate in the body - particularly in the liver, kidneys, blood, and protein-rich tissues. The half-life of certain PFAS compounds in the human body can range from 3 to 9 years, meaning elimination is extremely slow.

The weight of scientific evidence links PFAS exposure to a range of adverse health outcomes:

• Certain cancers: Kidney, testicular, and thyroid cancer risk increases have been associated with PFAS exposure in epidemiological studies and occupational cohort research.
• Immune system suppression: PFAS reduce vaccine efficacy and impair immune response, a finding of particular concern for children. The National Toxicology Program has concluded that PFAS are immune hazards.
• Thyroid disruption: PFAS interfere with thyroid hormone regulation, affecting metabolism, growth, and development.
• Reproductive effects: PFAS are linked to reduced fertility, altered menstrual cycle function, and adverse pregnancy outcomes including preeclampsia.
• Cholesterol elevation: PFAS exposure is associated with higher total and LDL cholesterol levels.

Regulatory Status and Drinking Water

In April 2024, the U.S. EPA finalized the first-ever National Primary Drinking Water Regulations for PFAS, setting Maximum Contaminant Levels (MCLs) for six PFAS compounds including PFOA and PFOS at 4 parts per trillion (ppt) - among the most stringent drinking water standards ever established. Public water systems have five years to comply. Private well owners, who are not subject to these federal standards, should test their wells independently if they live near military bases, industrial sites, airports, or agricultural areas where PFAS-containing products have been used.

Reducing Your PFAS Exposure

• Filter your drinking water: Reverse osmosis and activated carbon block filters (at point of use) are effective at reducing PFAS in drinking water. Standard pitcher filters (including Brita) offer limited PFAS reduction.
• Avoid PFAS-containing products: Choose stainless steel or cast iron cookware instead of nonstick. Look for PFAS-free labels on food packaging, textiles, and personal care products.
• Reduce food sources: PFAS contamination in food is widespread through agricultural water use and food contact materials. Fish from PFAS-contaminated water bodies is a significant dietary exposure pathway.
• Test your water: EWG's PFAS contamination mapping tool and state environmental agencies can identify known contamination sites near your location. Home testing is widely available.