Eating just one serving of freshwater fish per year may have the same effect as drinking highly polluted water containing so-called “forever” chemicals for an entire month, according to a new study.
The equivalent monthly amount of water would be contaminated at levels 2,400 times higher than recommended by the Environmental Protection Agency (EPA), according to the study published on Tuesday (17) in Environmental Research.
The research added that locally caught freshwater fish are polluted with perfluoroalkyl substances (PFAS) – “forever” or “eternal” chemicals named for their ability to persist in the body and the environment.
PFAS are key components in aviation fuel firefighting foam, industrial discharge, and many household products, including certain types of food packaging. For decades, they have infiltrated the drinking water supply while also contaminating irrigated crops and fish inhabiting local waterways.
Researchers first identified this contamination in catfish inhabiting the Tennessee River in 1979.
But the study published this Tuesday is the first to link fish consumption in the U.S. to blood levels of PFAS, while comparing PFAS levels in freshwater fish to those in commercial seafood samples, the authors explain.
The researchers assessed the presence of different types of PFAS in 501 fish fillet samples collected in the U.S. from 2013 to 2015.
The average total PFAS level in river and stream fish was 9,500 nanograms per kilogram, while the average in the Great Lakes was 11,800 nanograms per kilogram, according to the study. These levels indicate that consuming this type of fish “is potentially a significant source of exposure” to PFAS, the authors determined.
Although the samples included many types of forever chemicals – of which there are thousands – the largest contributor to the total PFAS levels was the compound known as PFOS, responsible for about 74% of the total, researchers found.
PFOS is so potent that consuming just one serving of freshwater fish would be equivalent to drinking a month’s worth of water contaminated with PFOS at levels of 48 parts per trillion, according to the study.
Farmed fish may be less contaminated because they are raised in controlled aquaculture environments. And large-scale ocean fishing typically occurs farther from shore, where PFAS pollution is more diluted.
The contamination of this food source “particularly threatens those who cannot afford commercially available seafood,” the study authors emphasized.