Wild caught, freshwater fish in the United States are far more contaminated with toxic PFAS “forever chemicals” than those commercially caught in oceans, and the highest levels are found in fish from the Great Lakes, a new analysis of federal data suggests.
The peer-reviewed study by public health advocate Environmental Working Group (EWG) also found eating one serving of US freshwater fish contaminated with median PFAS levels could be equivalent to drinking highly contaminated water every day for a month.
The findings are “breathtaking”, said Scott Faber, senior vice-president for government affairs with EWG.
“Widespread PFAS contamination of freshwater fish in the US is likely a significant source of exposure to PFOS and potentially other [PFAS] for all persons … especially for high frequency freshwater fish consumers,” the study’s authors wrote.
PFAS are a class of about 12,000 compounds, including PFOS, used to make products resist water, stains and heat. They are known as “forever chemicals” because they do not naturally break down, and they have been linked to cancer, high cholesterol, liver disease, kidney disease, fetal complications and other serious health problems.
The new study analyzed data from three studies conducted by the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) at different periods since 2013.
The EPA found all but one of the 501 samples it checked had elevated PFAS levels. Farmed freshwater fish typically had significantly lower levels of PFAS than wild caught, which David Andrews, one of the study’s coauthors, said might be due to farms using groundwater as a source to fill ponds instead of contaminated rivers or lakes.
The highest levels were found in several species of bass and catfish, while the lowest relative levels were found in chinook and coho salmon. Fish caught near urban areas typically had higher levels.
The FDA tested commercially caught fish bought at grocery stores. The median levels of PFAS detected in wild caught fish from streams and rivers were 280 times higher than those sold in grocery stores.
The study’s authors note the issue represents an especially challenging problem for low income residents who cannot afford to buy fish from stores, or groups that fish for cultural practices.
Despite the findings, the EPA and the FDA have not warned consumers or those fishing about the dangers of eating what they catch. Fish advisories are typically issued at the state level and differ across the country, and most are based on outdated EPA health advisories that allow much higher levels of chemicals than do the revised levels issued this year.
The situation is “frustrating because there’s no clear solution” beyond eliminating any further sources of PFAS pollution, Andrews said. Lakes that don’t regularly turn over water could be contaminated for decades, he added.
“I don’t want to tell people not to fish because I love fishing, but I would recommend, if at all possible, to avoid consuming freshwater fish unless you have clear information that it’s not contaminated, because this study indicates nationwide contamination of freshwater fish,” Andrews said.