These chemicals were developed in the 1940s to resist water and heat.

They are found in non-stick coatings, textiles or food packaging.

But the indestructible nature of these PFAS, the per- and polyfluoroalkyles, implies that they have accumulated over time in the air, the soil, the waters of lakes and rivers, food and even the human body.

Calls have grown for stricter regulation of the use of PFAS, which are harmful to health, with liver consequences, high cholesterol, reduced immune response and several kinds of cancers.

The researchers wanted to measure the contamination of freshwater fish by analyzing 500 samples taken from American lakes and rivers between 2013 and 2015.

The median contamination rate was 9.5 micrograms per kilogram, according to their study published in Environmental Research.

Of all the contaminated samples, three-quarters were PFOS, one of the most common and harmful contaminants of the thousands that make up PFAS.

Eating a freshwater fish is like drinking water contaminated with 48 parts per billion of PFOS for a month.

Water is considered safe to drink if it contains no more than 0.2 parts of PFOS per trillion, according to the US Environmental Protection Agency (EPA), in its new recommendation.

Levels of PFAS found in wild-caught freshwater fish were found to be 278 times higher than those found in commercially farmed fish.

"I can no longer look at a fish without thinking about its PFAS contamination," David Andrews, a scientist with the NGO Environmental Working Group, who led the study, told AFP and grew up fishing and eating fish. savage.

The finding is "particularly worrying because of the impact suffered by disadvantaged communities who consume fish as a source of protein or for socio-cultural reasons", he continued.

"This research makes me very angry because the companies that were manufacturing and using PFAS have contaminated the globe without taking responsibility."

For Patrick Byrne, an environmental pollution researcher at Britain's John Moores University in Liverpool, PFAS are "probably the greatest chemical threat to mankind in the 21st century".

PFAS are found in non-stick coatings, textiles or food packaging © Karim SAHIB / AFP/Archives

"This study is important because it provides the first evidence of widespread transmission of PFAS directly from fish to humans," he said.

The study is published after the initiative of Denmark, Germany, the Netherlands, Norway and Sweden, which last Friday submitted a proposal to ban the use of PFAS to the Agency European Chemicals.

This proposal extends the finding of the five countries that the use of PFAS was not sufficiently controlled.

© 2023 AFP