Study: freshwater fish full of forever chemicals

Just a single serving of freshwater fish per year could result in the same exposure to the “forever chemical” perfluorooctane sulfonate as drinking a month’s worth of water laced with the chemical, according to a study published Tuesday in the journal Environmental Research.

Perfluorooctane sulfonate, or PFOS, is part of a group of thousands of industrial chemicals, known collectively as PFAS, that have been used for decades in a variety of consumer products. They have been linked to a range of health problems, including decreased fertility, some types of cancer and developmental issues in children.

“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, a senior scientist at the Environmental Working Group (EWG) and a lead author of the study. “Growing up, I went fishing every week and ate those fish. But now when I see fish, all I think about is PFAS contamination.”

The forever chemical found at greatest concentrations in freshwater fish was PFOS, formerly an ingredient in 3M’s Scotchgard, averaging nearly three in four of total PFAS detections. The company recently announced that it would stop making PFAS by 2025. 

The researchers analyzed data from more than 500 samples of fish fillets collected in the U.S. from 2013 to 2015 under monitoring programs by the EPA, the National Rivers and Streams Assessment and the Great Lakes Human Health Fish Fillet Tissue Study. The median level of PFAS in the fillets was 9,500 nanograms per kilogram, and fish from the Great Lakes had a median level of 11,800 nanograms per kilogram. 

EWG has long called for strict regulation of PFAS, in addition to more tests of foods such as fish, since diet is thought to be a major source of PFAS exposure for Americans. Maine has passed the most restrictive PFAS regulations, which are set to take effect in 2030, after PFAS were found on farmland. The chemicals can get into the soil when agricultural waste is spread on fields as fertilizer, and also through contaminated irrigation water. Other states have passed less expansive regulations. Meanwhile, the EPA has proposed a new rule to regulate two common PFAS chemicals under the Superfund law.

The study found the median amounts of PFAS in freshwater fish were 280 times greater than forever chemicals detected in some commercially caught fish. Yet EWG scientists said not everyone can afford to purchase commercial seafood, and communities that depend on fishing for sustenance and for traditional cultural practices may be inordinately harmed by consuming the more PFAS-laden fresh fish.  

“PFAS contaminate fish across the U.S., with higher levels in the Great Lakes and fish caught in urban areas,” said Tasha Stoiber, another EWG senior scientist and an author on the study “PFAS do not disappear when products are thrown or flushed away. Our research shows that the most common disposal methods may end up leading to further environmental pollution.”