Bass, catfish and perch: Freshwater fish contain 'staggering' levels of toxic forever chemicals

Eating one fish in a year is the same as ingesting water with PFOS at 48 parts per trillion for one month, researchers have warned..
Eating one fish in a year is the same as ingesting water with PFOS at 48 parts per trillion for one month, researchers have warned.. Copyright Canva
By Charlotte Elton
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Dangerous forever chemicals have been linked to increased risk of cancer and reproductive problems. If you want to avoid them, you might want to steer clear of freshwater fish.


A single freshwater bass or catfish contains the same amount of dangerous ‘forever chemicals’ as a month’s worth of drinking water, a new study warns.

So-called forever chemicals - also known as PFAs, or Perfluoroalkyl and Polyfluoroalkyl Substances - are hazardous manmade substances used in everything from cosmetics to frying pans.

According to scientists at the Environmental Working Group - a non-profit research organisation - people who eat freshwater fish are ingesting very high amounts of the toxic chemicals.

Eating one fish serving can be equivalent to drinking water for a month at 48 parts per trillion PFOS.

US authorities advise that drinking water should not contain PFAs at a concentration higher than 0.2 parts per trillion.

The European Commission is currently considering tightening Europe’s water guidelines to 4.4. parts per trillion.

“People who consume freshwater fish, especially those who catch and eat fish regularly, are at risk of alarming levels of PFAS in their bodies,” said David Andrews, Ph.D., one of the study’s lead authors.

“Growing up, I went fishing every week and ate those fish. But now when I see fish, all I think about is PFAS contamination.”

Which fish contain forever chemicals?

Researchers analysed data from more than 500 samples of fish fillets collected in the US from 2013 to 2015.

Fish samples include 44 different species, with channel catfish, smallmouth bass, largemouth bass, yellow perch, and walleye, measured most frequently.

All of these species contained hazardous levels of the toxic substances.

What are forever chemicals?

Forever chemicals stay in the environment for more than 1,000 years. They are formed of linked carbon and fluorine atoms - one of the strongest chemical bonds that exists.

Such substances are virtually inescapable environmentally, but we can control what we eat. A 2021 study found the substances in rainwater in most locations on the planet, while an earlier analysis located the toxic compounds in breast milk.

Scientists have connected the chemicals to fertility problems, increased risk of cancer, and developmental delays in children.

Freshwater bodies of waters like lakes often contain high levels of chemical pollution.Canva

Are PFAs found in all fish?

The study found that freshwater fish contain up to 280 times the level of forever chemicals as commercially caught saltwater fish.

Authors described the results as “breath-taking” and “staggering.”

The high contamination rate is also an environmental justice concern, the researchers warned, as it mostly threatens those who cannot afford to purchase commercial seafood.

“Identifying sources of PFAS exposure is an urgent public health priority,” said Tasha Stoiber, one of the study’s co-authors.


What can we do about PFAs?

The scientists have called for the swift regulation of PFA production.

Safety guidelines for levels of these chemicals have been tightened significantly in the last 20 years as we’ve discovered their toxicity - many are millions of times lower than they were in the early 2000s.

Last year, investors managing nearly €8 trillion in assets called on chemical companies to phase out PFAs. This is because of growing awareness of the risks of toxic chemicals has triggered a surge in lawsuits, which could cost chemicals companies as much as US$30 billion (€28.7 billion).

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