Testing of “forever chemicals” in wild fish in England has found high levels of an industrial contaminant that, if eaten more than twice a year, exceed recommended EU safety guidelines.
Per- and polyfluoroalkyl substances (PFAS) are a class of nearly 10,000 chemicals used in many household items, such as non-stick cookware, waterproof fabrics, personal care products, and stain-resistant coatings on carpets.
Two specific types, PFOS and PFOA, accumulate in humans and have been linked to health problems, including cancer, liver damage, reduced fertility, and an increased risk of asthma and thyroid disease.
Data obtained by Watershed Investigations – a team of journalists who investigate water issues, and shared with the PA news agency – shows contamination of flounder, dab and plaice in England’s riverine and coastal habitats, with the highest levels in the Thames, Mersey and Wyre.
A sample taken from bone in the Thames at Woolwich showed that it contained 52.1 micrograms per kilogram of PFAS.
An average 75 kg adult who eats a normal portion (170 g) of this fish more than once every five months exceeds the recommended safety margin set by the European Food Safety Authority (EFSA).
There is currently no such set of guidelines in the UK, although a spokesperson for the Department for Environment, Food and Rural Affairs said: “PFAS chemicals are in the environment because they are widely used in products and are extremely persistent.
“Since the 2000s, we have taken action to improve monitoring and support a ban or very limited specific PFAS, both nationally and internationally.
“We continue to work with regulators to better understand the risks of PFAS and implement measures to address them.”
The EFSA assessment is based on four chemicals – PFOS, PFOA, PFNA and PFHxS – although the samples taken from wild fish by the Center for Environment, Fisheries and Aquaculture Science (Cefas) contained around 30 different species.
Dr. David Megson, an environmental chemist at Manchester Metropolitan University, believes there are hundreds of different PFAS in the environment.
He said: “PFAS are a very broad group of chemicals and have different levels of persistence and toxicity.
“At this point, we don’t have enough information to confirm what is safe and what is a problem.
“If you look at most PFAS, you would assume that they are toxic and bioaccumulative. I would prefer that we follow the precautionary principle and only use them if they are proven to be safe and pose no risk to the environment.
“Instead, it seems we assume they are all safe for use and we will have to wait decades before we can confirm that they have caused significant harm to our environment and human health.”
Once in the environment, PFAS are almost impossible to remove and some species are known to bioaccumulate through the food chain, with apex predators such as whales and sharks receiving the highest dosage.
Professor Ian Cousins, an environmental scientist at Stockholm University, said scientific research has focused more on human exposure to PFAS than their effect on ecosystems.
He added: “But you have to worry about consuming the fish and you wouldn’t want to catch and eat the fish if you lived along the Thames on a regular basis, based on what we know about human exposure.”
Not all PFAS are known to be toxic or bioaccumulative, but all are persistent, which has led Prof Cousins to believe that achieving environmental quality standards in urban rivers such as the Thames is “not really possible”.
He said: “The problem is that they are still floating around in the environment and they last for a long time because they are so persistent that they don’t break down at all, which is why they are called a forever chemical. ”
A study last year from Cardiff University on otters found PFAS in every specimen they sampled, with more than 80% of them containing 12 types of PFAS.
The researchers said wastewater treatment or agricultural use of sewage sludge were likely sources.
Currently the UK only regulates PFOA and PFOS, although there are proposals in the EU to regulate PFAS together as one class, which Prof Cousins described as “an idealistic, pragmatic and very sensible approach”.
Dr. Janine Gray, head of science and policy at WildFish, said: “The significant concentrations of PFAS found in fish are of great concern but not surprising, and unfortunately only the tip of the chemical iceberg.
“Today there are more than 350,000 regulated chemicals in use. Our waters and their wildlife are exposed to a large number of these, but our rivers are currently only routinely monitored for 45.
“We must ban all but the most vital uses of PFAS chemicals in perpetuity and policies must take into account the additive/synergistic effects of chemical mixtures on aquatic life.”