REGIONAL— A new study, based on data from the Environmental Protection Agency, finds that fish caught in lakes and rivers in the U.S. contain dangerously high levels of toxic synthetic chemicals known as PFAS.
PFAS is short for perfluorooctane sulfonic acid, part of a family of synthetic chemicals known to bring a wide range of health concerns. PFAS and other closely related synthetics such as PFOS, are widely known as a “forever chemicals,” known to be persistent indefinitely in the environment. The chemicals appear to concentrate in fish tissue, among other places, and they’ve become increasingly common in the environment since their use in the production of firefighting foam and many other products became more commonplace beginning in the 1950s. EPA testing between 2013-2015 showed that even infrequent consumption of freshwater fish was linked to higher levels of this toxic family of chemicals in human blood.
The median levels of the chemical detected in freshwater fish was 278 times higher than levels found in most commercially harvested fish, which are typically from the ocean. The higher dilution factor in the ocean is believed to be responsible for the lower levels of the chemical found in fish there.
The study found that just a single serving of freshwater fish per year with a typical concentration of the chemical is enough to cause “a significant increase of PFAS in blood serum,” states the study.
The study’s authors state that the situation represents a case of environmental injustice “that especially affects communities that depend on fishing for sustenance and for traditional cultural practices.”
The study cites data that points to food as the primary source of PFAS exposure in humans. The same likely holds true for wildlife, although the study did not explore those impacts. The study cites research that suggests levels of PFAS currently found in most humans may suppress the immune system. “Additionally, exposure to PFAS, has been associated with many health harms, including an increased risk of cancer, high cholesterol, thyroid disease, and reproductive and developmental harms,” note the study’s authors.
The study also cites data that indicates that those who regularly catch and eat fish had levels of these related forever chemicals in their blood ranging from 9.5 to 26.9 times that of the general U.S. public.
“The U.S. EPA recognizes that eating locally caught freshwater fish is a significant source of exposure to PFOS, yet there are no current federal policies or regulations providing guidance on fish consumption specific to PFOS or other PFAS,” states the authors of the study, which was published last week in the journal Environmental Research. “A closer evaluation of PFAS as a source of dietary exposure from fish, specifically freshwater fish, is urgently needed. Towards this goal, the present study provides the first analysis to estimate the relationship between fish consumption and PFAS in serum in the U.S. population and to compare PFAS in freshwater fish with commercial seafood samples in the U.S.”
At least 44 different species of fish were tested by the EPA, with channel catfish, smallmouth bass, largemouth bass, yellow perch, and walleye being the most commonly tested species.
The study found that commercially-caught seafood contains far lower concentrations of PFOS and PFAS, but notes that the cost of those products may put them out of reach for lower-income segments of the population. “Self-caught fish are an important source of subsistence for many individuals who cannot afford to replace self-caught fish with purchased fish,” wrote the authors.
“At the same time, knowing that high levels of PFOS present in freshwater fish could impact serum levels is concerning and should warrant the creation of national consumption advisories and an awareness program.”
Minnesota-based 3M, a major producer of these toxic chemicals, announced last month that it would phase out the production of PFAS from its manufacturing and products by the end of 2025.