Concentrations of two of the most hazardous "forever" chemicals in England's rivers have fallen by nearly a third over the past ten years, according to new data released by the Environment Agency. The decline in PFOS and PFOA—chemicals that resist breakdown in the environment—reflects stricter product restrictions introduced after mounting evidence of their harm to human health and ecosystems. According to BBC News, the regulator's latest assessment, published on 12 November 2026, shows PFOS concentrations have dropped 30% and PFOA by 29% over the decade, with freshwater fish showing even steeper declines of 49%.
The reduction follows decades of scientific evidence linking these chemicals to serious health effects. PFOS was effectively banned in the UK in 2010, and PFOA restrictions came into force in 2020. However, the Environment Agency has warned that thousands of other forever chemicals—officially known as PFAS—remain in widespread use, and the regulator emphasised the need for comprehensive monitoring and regulation of all such compounds rather than a piecemeal approach.
PFAS were first synthesised in the 1930s in the United States and became commercially valuable because of their resistance to oil, water and electrical damage. Manufacturers incorporated them into products ranging from non-stick cookware to aqueous film-forming foams used in firefighting. Their very durability—the property that makes them useful—also means they persist in the environment indefinitely, accumulating in soil, water and living organisms.
The earliest compounds in this family, PFOS and PFOA, were the first to raise alarm among researchers. Two decades ago, scientists began documenting links between exposure and tissue damage in animals, alongside elevated incidence of conditions including testicular cancer and other serious illnesses in humans. This evidence prompted regulatory action across multiple countries.
How widespread is contamination across England?
Despite the encouraging decline in legacy chemicals, contamination remains pervasive. Earlier Environment Agency data showed that every English surface water body failed chemical status assessments, with PFOS among the principal contaminants alongside mercury and other persistent pollutants. Old landfill sites and former industrial facilities have been identified as major ongoing sources of these chemicals in waterways including the Mersey.
The Environment Agency is now regularly testing for 60 additional PFAS compounds to build a comprehensive picture of contamination across the country. According to New Scientist, the agency's 12 November 2026 assessment reveals that short-chain PFAS and fluorotelomer compounds used as replacements for legacy chemicals are now detectable in the environment, suggesting that substitution of banned chemicals may be creating new contamination pathways.
Why are replacement chemicals a concern?
The shift away from PFOS and PFOA has led manufacturers to adopt alternative PFAS compounds. According to the Environment Agency's government response, short-chain PFAS now dominate water samples, while long-chain PFAS accumulate in living organisms, and local exceedances of safe levels persist despite the overall decline in legacy chemicals. This pattern suggests that simply restricting individual compounds may drive substitution with alternatives whose long-term safety remains uncertain.
The chemical industry has consistently opposed blanket regulation of all PFAS, contending that insufficient evidence exists to classify most compounds as toxic and that some serve critical functions in life-saving medical equipment and other essential applications. The regulator acknowledged this tension, noting that "uncertainty remains regarding the toxicity of many PFAS" but arguing that the precautionary principle demands stronger oversight.
What does the decline actually mean for the environment?
The Environment Agency's report contains a sobering caveat: although measured concentrations have fallen, the total amount of these chemicals remaining in the environment has likely stayed constant. The chemicals have been diluted and washed into the sea rather than destroyed. This distinction matters because PFAS do not naturally degrade—they simply redistribute across environmental compartments. One of the few methods capable of permanently destroying PFAS is high-temperature incineration, and the UK currently has only two facilities suitable for this purpose.
Dr David Megson, reader in environmental forensics at Manchester Metropolitan University, welcomed the progress but stressed the scale of remaining work.
It's brilliant to see how far we have come in the last 10 years,he said, adding that
there is a lot to do, and this report provides an essential foundation to support investigations to make the polluters pay for any damage they have caused.
What health risks do these chemicals pose?
PFAS exposure has been linked to multiple adverse health outcomes in human populations. Testing of residents near a Lancashire chemical factory revealed elevated PFOA levels, though health officials cautioned that blood tests alone cannot predict individual health outcomes. The government has now taken steps to measure population exposure more systematically. Earlier this month, the government announced it would begin monitoring PFAS levels in people's bodies as part of a broader public health surveillance effort.
The UK Health Security Agency has launched its first nationwide study into forever chemicals in the population, collecting blood and urine samples to measure PFAS exposure and establish baseline levels, with initial results expected next year. This initiative reflects growing concern about cumulative exposure through drinking water, food and consumer products.
Where is contamination most severe?
Certain locations have emerged as particular hotspots of PFAS contamination. Testing at a former RAF base earmarked for 9,000 homes revealed the UK's worst PFAS contamination, with dangerously elevated levels of forever chemicals and concerns raised about existing homes and a planned primary school. Such discoveries underscore the legacy of industrial and military activities in creating persistent environmental hazards.
What regulatory changes are underway?
The Environment Agency's assessment builds on its 2021 report and incorporates advances in monitoring and analytical methods developed over the past five years. The regulator has established a combined fish threshold of 77 ng/kg for PFOS, PFOA, PFHxS and PFNA, though PFOS remains the only PFAS with a statutory environmental quality standard in England. This patchwork of standards reflects the ongoing challenge of regulating a vast family of chemicals with varying properties and risks.
The government published its first national PFAS Plan on 3 February 2026, setting out a coordinated approach to reducing exposure and improving management of PFAS risks across multiple sectors and regulatory bodies.
What happens next?
The government plans a comprehensive multi-year assessment of PFAS in England's estuaries and coastal waters by February 2028, extending monitoring beyond freshwater systems to understand contamination in marine environments. This expanded surveillance will provide crucial data for future regulatory decisions and remediation efforts. The Environment Agency's findings reinforce the case for regulating all PFAS rather than addressing them individually, a position that will likely intensify debate with industry stakeholders over the coming months.
