PFAS are often described as “forever chemicals”. The phrase is memorable, but it only tells part of the story. PFAS are not a single substance; they are a large family of synthetic chemicals used in products designed to resist water, grease, oil, stains and heat. Their durability makes them useful in manufacturing—and difficult to remove once they enter the environment.
These chemicals have been detected in drinking water, rivers, soil, food packaging, household dust and human blood. Some exposure is unavoidable, but understanding where PFAS come from and how contact occurs can help households, businesses and communities make more informed decisions.
What are PFAS?
PFAS stands for per- and polyfluoroalkyl substances. The group includes thousands of compounds with chemical structures built around carbon–fluorine bonds. These bonds are among the strongest in organic chemistry, which explains why PFAS can withstand heat, water, oil and chemical reactions.
The same properties that make PFAS valuable also create an environmental problem. Many PFAS break down extremely slowly. They can move through water, persist in soil and accumulate in living organisms. Some can remain in the human body for years before being eliminated.
Not every PFAS behaves in exactly the same way. PFOA and PFOS are two of the best-known examples, and their production has been restricted or phased out in many countries. However, they have not simply disappeared. Older contamination can remain in soil and groundwater, while other PFAS may still be used as replacements or in specialised industrial applications.
It is also important to distinguish between two broad groups:
- Long-chain PFAS: compounds such as PFOA and PFOS, which have been extensively studied and associated with persistence and bioaccumulation.
- Short-chain and newer PFAS: substances that may leave the body more quickly in some cases, but can be highly mobile in water and are often less well studied.
“Short-chain” does not automatically mean “safe”. A chemical that does not accumulate in the same way may still persist in the environment or pose risks that scientists are continuing to investigate.
Where do PFAS come from?
PFAS have been used since the middle of the twentieth century in a wide range of industrial and consumer products. Their presence is not limited to one sector, which is one reason contamination can be difficult to trace.
Industrial manufacturing
PFAS may be used during the production of electronics, textiles, metal plating, medical equipment, paints, plastics and specialised coatings. Industrial facilities can release PFAS through wastewater, air emissions, spills, waste disposal or the handling of contaminated materials.
Manufacturing sites are not the only concern. PFAS can also be present in raw materials, processing aids and equipment used across a supply chain.
Firefighting foams
Aqueous film-forming foams, commonly known as AFFF, have been used to extinguish fuel fires at airports, military sites, oil terminals and industrial facilities. They can be highly effective in emergencies, but historical use has caused significant contamination at some sites.
When firefighting foam is released onto the ground, PFAS can migrate into soil and groundwater. Once contamination reaches an aquifer, it may travel considerable distances and affect private wells or public water supplies.
Food packaging and textiles
PFAS have been used to make food packaging resistant to grease, particularly in some takeaway containers, wrappers, microwave popcorn bags and paper products. They have also been applied to carpets, outdoor clothing, upholstery and other textiles to improve resistance to stains, water and oil.
Regulations and industry practices are changing, but products manufactured in previous years may still be in circulation. Imported goods can also be subject to different requirements from those applying in the UK.
Everyday household products
PFAS may be found in some non-stick cookware, cosmetics, dental floss, polishes, paints and stain-resistant treatments. Not every product in these categories contains PFAS, and labelling is not always clear. Terms such as “waterproof”, “stain-resistant” or “non-stick” describe a performance feature—not necessarily the chemicals used to achieve it.
How do PFAS enter the environment?
PFAS can move from products and industrial processes into air, water and soil. Wastewater treatment plants may reduce some contamination, but conventional treatment is not designed to destroy PFAS. As a result, PFAS can remain in treated effluent, sewage sludge or landfill leachate.
Landfills are another potential source. When PFAS-containing products are discarded, rainwater can pass through waste and produce contaminated liquid known as leachate. If that leachate is not adequately managed, PFAS may reach groundwater or surface water.
PFAS can also travel through the atmosphere attached to particles or in gaseous form. This means contamination is not always confined to the location where a product was manufactured or used. Rivers, groundwater and air currents can all contribute to wider distribution.
How are people exposed to PFAS?
For the general population, exposure most commonly occurs through contaminated food and drinking water. The relative importance of each source varies according to location, diet, occupation and the specific PFAS involved.
- Drinking water: particularly where a supply is affected by industrial activity, airports, military sites, landfill or firefighting foam.
- Food: through contaminated soil, water, food-processing equipment, packaging or bioaccumulation in fish and livestock.
- Household dust: from treated carpets, furniture, textiles and consumer products.
- Consumer products: through skin contact or, more importantly in many cases, accidental ingestion of residues and dust.
- Occupational exposure: among workers in manufacturing, firefighting, waste management, aviation, construction and certain industrial settings.
For most people, swallowing PFAS is considered a more significant exposure route than absorption through intact skin. That does not make skin contact irrelevant, but it helps put risk-reduction steps into perspective. A person does not need to panic because they wore a waterproof jacket once. Repeated exposure from contaminated water or a workplace requires a more focused response.
What does the science say about health effects?
PFAS research is extensive but still developing. Evidence varies between individual chemicals, exposure levels and study populations. Scientists have reported associations between exposure to certain PFAS and changes in cholesterol levels, reduced vaccine response, liver effects, pregnancy-related outcomes and some cancers, particularly kidney and testicular cancer in relation to specific compounds and exposure patterns.
The US Agency for Toxic Substances and Disease Registry, the US Environmental Protection Agency and European public health authorities have all identified PFAS as chemicals requiring careful management. The International Agency for Research on Cancer has classified PFOA as carcinogenic to humans and PFOS as possibly carcinogenic to humans.
These findings do not mean that every person exposed to PFAS will develop illness. Risk depends on factors including the chemical involved, concentration, duration of exposure, age, health status and combined exposure to other substances. However, the persistence and widespread distribution of PFAS make reducing unnecessary exposure a sensible public health measure.
PFAS in drinking water: why treatment matters
Water treatment is technically possible, but standard treatment processes do not reliably remove all PFAS. The most established technologies include granular activated carbon, ion exchange resins and high-pressure membrane systems such as reverse osmosis.
- Granular activated carbon: can be effective, particularly for longer-chain PFAS, but performance depends on the carbon type, water chemistry, contact time and maintenance.
- Ion exchange: uses specialised resins that attract PFAS and can work across a broad range of compounds.
- Reverse osmosis: can remove a high proportion of many PFAS, although it produces a concentrated waste stream and requires energy and regular maintenance.
No filter should be treated as a magic box. A product must be independently tested for PFAS reduction, installed correctly and replaced according to the manufacturer’s schedule. An exhausted carbon filter can lose effectiveness, while an improperly maintained system may create new water-quality problems.
Look for certification or test data that specifically refers to PFAS reduction. General claims such as “purifies water” or “removes chemicals” are too vague. In the United States, NSF/ANSI standards provide one useful reference point, although consumers in the UK should also check the manufacturer’s independent performance data and relevant regulatory guidance.
Practical ways to reduce exposure at home
People cannot eliminate all PFAS from modern life, and attempting to do so would be unrealistic. The more useful approach is to focus on repeated and controllable sources of exposure.
- Check local water information. Contact your water supplier or local authority if you are concerned about PFAS. Private well owners should consider testing where there is a nearby industrial site, airport, landfill or history of firefighting foam use.
- Use an appropriate water filter. Choose a system with evidence of PFAS reduction, and replace cartridges on time. Boiling water does not remove PFAS and may concentrate them as water evaporates.
- Reduce unnecessary stain-resistant treatments. Think carefully before applying treatments to carpets, sofas or clothing, especially when a product is marketed mainly for convenience.
- Choose alternatives to grease-resistant food packaging. Use reusable glass or stainless-steel containers where practical, and avoid heating food in packaging unless it is clearly designed for that purpose.
- Keep dust under control. Regular vacuuming with a well-maintained vacuum cleaner and damp dusting can reduce household dust, including dust containing residues from treated products.
- Follow workplace controls. Workers handling PFAS-containing materials or firefighting foams should use the personal protective equipment, hygiene procedures and monitoring required by their employer.
- Be cautious with product claims. “PFAS-free” is useful only when supported by a credible definition or test method. Some products may contain fluorinated chemicals that are not fully disclosed.
What should businesses and water operators do?
PFAS management begins with identifying possible sources. Businesses should review chemical inventories, product specifications, wastewater discharges, historical site activities and waste contractors. A site that no longer uses PFAS may still have contaminated soil, drainage systems or groundwater.
Water operators need a monitoring strategy that reflects local risks. Testing only for PFOA and PFOS may miss other compounds, precursors or replacement chemicals. Broader analytical methods, including total organic fluorine or extractable organic fluorine measurements, can provide additional insight, although each method has limitations.
Regulation is evolving across the UK and Europe. Restrictions under the UK REACH framework and wider European action are moving towards controlling groups of PFAS rather than regulating one chemical at a time. Drinking-water standards are also developing, with requirements differing between jurisdictions. Operators and property owners should therefore rely on current guidance from the Drinking Water Inspectorate, the Environment Agency, devolved administrations and local water suppliers rather than outdated summaries.
A contaminant problem that requires prevention
PFAS are difficult to manage because contamination is persistent, mobile and often invisible. A clear glass of water can still contain chemicals that require advanced testing to detect. The most effective long-term strategy is not simply to install more filters after contamination occurs. It is to prevent unnecessary releases, phase out non-essential uses, improve product transparency and apply the precautionary principle where evidence is incomplete.
For individuals, the sensible response is informed action rather than alarm: check local information, focus on drinking water where a credible risk exists, choose verified filtration and reduce avoidable contact with treated products. For industry and regulators, the responsibility is broader—identify sources, monitor the full range of PFAS and ensure that pollution prevention keeps pace with scientific knowledge.
PFAS may be persistent, but public awareness, better regulation and improved water-treatment technology can change how much of that persistence reaches people and ecosystems.