PFAS stands for per and polyfluoroalkyl substances, a family of around 10,000 - 12,000 chemicals, which are valued for the non-stick properties and used in a huge range of consumer products and industrial processes. They don’t break down in the body and some PFAS are known to be toxic and to build up the body, particularly two substances – PFOS and PFOA.
The chemicals have been in production since the 1950s and given they don’t degrade, the environmental load is significant and growing – every molecule made since that time is still with us and more are being added every day.
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“The industry is constantly producing and releasing new PFAS compounds,” said Dr Silvia Lacorte, research professor at the Institute of Environmental Assessment and Water Research.
“The most worrying thing about this is that we have no idea about the toxic effects of these compounds…and even less about the effects of complex mixtures.”
PFAS are bad news for humans but they are also bad news for wildlife, whose habitats are contaminated with them – in air, water, soil and sediments. PFAS build up in animals and humans and as a result they biomagnify up the food web, with those at the top of the chain often receiving higher doses from their prey.
The mapping project, undertaken by the US Environmental Working Group (EWG), looked at hundreds of studies that found a huge range of animals to be affected by PFAS, including fish, birds, reptiles, frogs, horses, cats, otters and squirrels.
It’s part of a growing body of research that is slowly revealing the potential damage that could be wreaked by PFAS. The European Food Safety Agency (EFSA) says that the substances’ impacts on animals can include effects on the liver, thyroid, and immune system, as well as affecting reproduction and development, and can be carcinogenic.
Research out of Cardiff University found PFAS in otters across England and Wales, concluding that the PFAS is widespread in British freshwaters, something that is backed up by the Environment Agency that has said PFOS is ubiquitous in the environment and that it will be the reason many rivers fail Water Framework Directive standards beyond the already extended 2027 deadline.
The researchers found that most PFAS in otters were associated with wastewater treatment works or the use of sewage sludge in farming. Speaking at the launch of the study last year, Emily O’Rourke, lead author of the report, said further work is needed to “understand where the highest concentrations are now and any current sources of contaminants.
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“It is deeply concerning that PFAS were introduced into the environment through industrial and farming practices – policy and management action is vital to address this where it remains an issue,” she said.
Further afield, a study of alligators in the Cape Fear River found they had elevated levels of 14 PFAS in the blood serum and appeared to have caused autoimmune effects.
Scott Belcher, associate professor of biology at North Carolina State University, took blood samples and did health evaluations on 49 alligators living along the Cape Fear River between 2018 and 2019 and compared them with alligators living in Lake Waccamaw in the nearby Lumber River basin.
He said there were “clear differences” in the levels and types of PFAS in the animals, and that the Cape Fear alligators had a number of unhealed or infected lesions.
“Alligators rarely suffer from infections,” Belcher said. “They do get wounds, but they normally heal quickly. Seeing infected lesions that weren’t healing properly was concerning and led us to look more closely at the connections between PFAS exposure and changes in the immune systems of the alligators.”
They concluded that PFAS was disrupting the alligators’ immune systems by affecting an immune protein that stimulates immune response.
“Alligators are a sentinel species – harbingers of dangers to human health,” Belcher says. “Seeing these associations between PFAS exposure and disrupted immune function in the Cape Fear River alligators supports connections between adverse human and animal health effects and PFAS exposure.”
Dr Richard Benwell, chief executive of nature coalition Wildlife and Countryside Link, is concerned about what’s in store for wildlife. “Toxic forever chemicals have been found in hundreds of species in every circle of the world. In the UK, they’re present in birds like gannets, mammals like otters, and fish like plaice,” he said.
“We don’t yet know the full extent of harm these chemicals can cause, but they can disrupt immune responses and the endocrine system, as well as affecting reproduction. It’s particularly a risk for top predators like orcas, otters – and us.”
The contaminants move through water systems easily and fish living in polluted water are likely to contain higher levels. Analysis of freshwater fish across the US by the EWG found that eating one contaminated fish could be equivalent to drinking PFAS laced water for a month.
Usually the largest, oldest animals at the top of the food chain have the highest chemical load. But according to the centre for PFAS research at Michigan State University, PFAS doesn’t act like other chemicals. “It’s showing up in the US in Bluegill fish, which is in the middle of the food web so it doesn’t make sense,” says Cheryl Murphy, the director of the centre.
“We don’t really have a handle on how it accumulates in different organisms. Every species does something different.”
MAPPED: The UK sites where PFAS has been detected
There are moves in the EU to tackle PFAS through stricter regulation and the US is expected to announce very low acceptable standards for PFAS in drinking water, but in the UK DEFRA said it is “working at pace across government to assess the levels of PFAS occurring in the environment” and that it will shortly publish further analysis of the risks of PFAS which will also make recommendations to inform future policy - with further details on our approach to be announced later this year.
DEFRA said it also plans to establish an “expert advisory board who will consider a range of international research to help us ensure our drinking water standards and regulations continue to be based on the latest evidence”.
Benwell wants the government to act now to get a grip on the problem. “Once they are in the environment, the PFAS pollution legacy can last hundreds of years. Yet they continue to be used unnecessarily in food packaging, non-stick pans, clothing, cosmetics and furniture. DEFRA has the chance this year to regulate, stop non-essential use, and stop this persistent pollution from getting any worse,” he said.
The challenge is huge, but PFAS can be cleared out of the body if exposure is stopped. “It just depends on the species and the level they’re exposed to,” Murphy said. “In humans it has a half life of five years, so it’ll eventually leave us… Cows take 100 days to clear it. We know it’s everywhere but we need to figure out what it’s doing so we can minimise exposure.”
Rachel Salvidge and Leana Hosea are journalists from not-for-profit investigative journalism organisation Watershed Investigations.