Toxic “forever chemicals,” scientifically known as PFAS, have been detected in the tissues and organs of dolphins, otters, porpoises, fish, and birds across the UK, according to an analysis of official data.

PFAS, or per- and polyfluoroalkyl substances, are synthetic chemicals that do not degrade in the environment, earning them the “forever chemicals” label.

Widely used in consumer products and industrial processes, some PFAS are linked to severe health issues in humans and animals, including cancers. These chemicals have been found contaminating water, soil, and are believed to exist in the bloodstream of nearly every human globally.

Data obtained by Watershed Investigations, the Marine Conservation Society, and The Guardian reveals extensive contamination in over 1,000 animals, particularly from PFOS and PFOA, two of the most studied and toxic PFAS variants, both now banned. Despite bans, over 10,000 types of PFAS exist, with limited information on their toxic effects.

Current environmental quality standards for PFOS stipulate that fish should not exceed 9 micrograms per kilogram (9.1μg/kg) in their tissue to protect both top predators and human consumers. However, 12% of fish samples surpass this limit, with flounder and roach reaching 34μg/kg and 41μg/kg, respectively. Applying this threshold to all species reveals nearly half of the sampled animals exceed it.

The EU is considering lowering this limit to 0.077μg/kg, which would classify 92% of the animals as contaminated beyond safe levels.

Watershed’s pollution map highlights alarmingly high PFAS concentrations, especially in top predators. Otters exhibit levels up to 9,962μg/kg, harbour porpoises 2,420μg/kg, grey seals 357μg/kg, and dolphins 78μg/kg. Bird species are also affected, with gannet eggs containing up to 158μg/kg and buzzard livers up to 104μg/kg.

Primary PFAS pollution sources include airports, military sites, and chemical manufacturing plants.

A Cardiff University study identified high PFOA levels in otters near a chemical plant with historical PFOA usage, with contamination decreasing with distance from the site. Further investigations by Watershed in 2023 reported significant PFOA levels in effluents from this location.

Additional PFAS sources are sewage treatment facilities, fire stations, fire training grounds, metal industries, pulp and paper mills, leather and textile manufacturers, energy and industrial sites, and waste disposal areas, including both historical and active landfills. Landfills near rivers and coastal regions are known to leach hazardous substances into surrounding waters. Contaminated sewage sludge used as fertiliser also introduces PFAS into soils and water systems.

An Environment Agency report estimates up to 10,000 PFAS hotspots across the UK.

Despite some of the animal data spanning several decades, PFAS’s persistence means these results remain relevant, as the chemicals do not break down for thousands of years.

Prof Alex Ford from the University of Portsmouth said he “got concerned with PFAS because they … follow the PCB story, which were banned three decades ago and they’re still causing problems now. There are concerns that some killer whale populations might go extinct because the levels are still bioaccumulating through the food chain and get to a threshold where they have adverse health effects.

“I suspect the same thing will happen with PFAS. Long after we’re pushing up daisies, people will look back in decades to come and ask, why didn’t you act sooner?”

Ford wants to see PFAS banned. “Whichever organisms we look in, we find them.” He has found newer types of PFAS in Langstone Harbour in Hampshire alongside the banned ones. “We know that they substituted them on the basis that they thought that they were less toxic. But now there are plenty of studies suggesting that they’re just as toxic, or toxic in different ways, to some of the banned ones.”

Dr Tony Fletcher, at the London School of Hygiene & Tropical Medicine, said that “a number of studies are done on animals because one experiments on animals to get some insight into toxicology. So the fact that similar effects on the endocrine system and immune system have been shown in animal species as in humans, suggests that to some extent you can read across”.

Environmental experts, including Ford and Dr. Fletcher, advocate for stricter PFAS regulations in the UK. They were among 59 scientists who penned a letter to the government last year, outlining their concerns about PFAS contamination and urging immediate action to address the issue.

Dr Francesca Ginley, policy and advocacy manager at the Marine Conservation Society, said: “These chemicals have only been around since the 1950s but have already caused severe harm to wildlife around the world. And now we can see some of the UK’s most iconic wildlife, like otters and harbour porpoises, are also polluted with PFAS. The only way to stop this pollution is to stop it at its source, which is why we’re calling for a ban on the entire group of chemicals. This is the only way we can truly address this problem and prevent it getting worse, before it genuinely is too late.”

Richard Benwell, the CEO of Wildlife and Countryside Link, said: “PFAS pollution is spreading across the map, up and down the food chain, and accumulating over time. We don’t know the full extent of the risks, but the presence of high concentrations of potentially harmful chemicals in such a wide spread of wildlife is a serious warning that we must stop this pollution at source.

“After years of delay, the government should ban PFAS in all but the most vital uses. Restrictions on use should be matched with new financial responsibilities for chemical companies to pay a nature restoration levy to contribute to UK environmental recovery and international nature finance.”

A spokesperson for Department for Environment, Food and Rural Affairs said the government was committed to protecting the environment from the risks posed by chemicals and that it is “rapidly reviewing the environmental improvement plan to deliver on our legally binding targets to save nature, which includes how best manage the risks posed by PFAS”.