Key facts
- The Environment Agency said PFOS concentrations in English rivers fell 30% and PFOA 29% over ten years.
- Levels of the two chemicals in fresh-water fish fell 49%, the regulator's figures showed.
- The Environment Agency said uncertainty remains about the toxicity of many of the roughly 15,000 other PFAS.
- The regulator said its findings reinforce the need to regulate all PFAS rather than one by one.
- The chemicals industry has argued there is no or limited evidence other PFAS are toxic and some have vital uses.
- The Environment Agency said overall amounts in the environment are likely unchanged, as the chemicals were diluted and washed to sea.
Concentrations of the two most toxic "forever" chemicals in England's rivers have fallen by nearly a third over the last decade, according to figures the Environment Agency published on November 12, 2026. The regulator said PFOS concentrations fell 30% and PFOA 29% over the ten years, and levels of the chemicals in fresh-water fish fell 49%.
The decline was put down to stricter restrictions on the chemicals' use after increasing evidence emerged of their impact on human health and the environment. PFOS was all but banned in the UK in 2010 and PFOA in 2020.
"It's brilliant to see how far we have come in the last 10 years," said Dr David Megson, reader in environmental forensics at Manchester Metropolitan University. He added: "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."
PFAS were first developed in the 1930s in the US and became popular with companies making products such as frying pans and firefighting foam because of their oil-resistant, water-resistant and electrical properties. They are called forever chemicals because their natural resistance means they take a very long time to break down.
There are thought to be around 15,000 other PFAS, although only around 200 are frequently used. The Environment Agency said that despite increasing research into these compounds, "uncertainty remains regarding the toxicity of many PFAS", and that its findings "reinforces the need" for regulating all PFAS rather than one by one.
The chemicals industry has long opposed such an approach, arguing that there is currently no, or limited, evidence to suggest that other PFAS are toxic and that some have vital uses such as in life-saving medical equipment.
The report acknowledged that while concentration levels have fallen, the overall amount still in the environment is likely to have remained unchanged because the chemicals take so long to break down; they have been diluted and washed into the sea. One of the few ways to permanently destroy PFAS is high-temperature incineration, and there are just two such suitable sites in the country currently.