All fish caught in Michigan rivers and tested for toxic PFAS contained the chemicals – and at levels that present a health risk for anyone eating them, according to a new study.
Researchers checked 100 fish samples that represented 12 species in the Huron and Rouge rivers.
PFAS are a class of about 12,000 compounds used to make products resistant to 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 and kidney disease, fetal complications and other serious health problems in humans.
The chemicals are thought to be polluting drinking water for more than 200 million people, and the study is the second this year to suggest widespread contamination of freshwater US fish.
The independent studies and research from state and federal regulators have shed light on a potential health threat in Michigan and nationally that public health advocates say needs urgent attention.
The findings are “sad”, said Erica Bloom, one of the study’s co-authors with the Ecology Center, an environmental non-profit that tracks PFAS contamination in the state.
“It just demonstrates how ubiquitous these chemicals are in the environment,” she said.
The levels found in fish sampled from those rivers ranged from about 11,000 parts per trillion (ppt) to 180,000 ppt, and tests revealed 14 different kinds of PFAS compounds.
While no state or federal limits on the amount of PFAS in fish or other food exist, Michigan’s health department issues “do not eat” advisories for fish fillets with levels over 300,000 ppt of PFOS, just one kind of PFAS compound. Fillets typically have lower levels of PFAS than the organs, which were included in Ecology Center’s testing.
However, recent research showed how the nation’s freshwater fish can represent a dangerous exposure route even at levels below the state’s threshold. Eating a fish fillet with 11,800 ppt of PFOS is equivalent to drinking water contaminated with PFOS at 48 ppt every day for a month.
The situation presents not just an environmental safety issue to those who fish in rivers as a hobby but an environmental justice issue as it is lower income residents who most frequently rely on eating fish they catch from freshwater rivers, as well as groups that fish as a cultural practice. The Ecology Center worked with about a dozen local anglers who caught the fish that were sampled.
“Fishing in these rivers is an important way of life, and we’re not out here to tell people to stop fishing – but if you’re fishing, here are some things to look out for,” Bloom said.
She said it is up to state regulators to protect anglers, and the results highlight how agencies are failing to keep pace with new science and regulations around PFAS. Michigan’s 300,000 ppt “do not eat” level for PFOS was based off outdated science from the federal Environmental Protection Agency (EPA).
The EPA last year lowered its health advisory limit on PFOS in drinking water after it found virtually no exposure level is safe. Michigan has yet to adjust its fish advisory accordingly, and doing so would dramatically lower the “do not eat” threshold.
Bloom said it is unclear why state regulators have not updated their advisories, and added that fish consumption levels in Michigan “should be reviewed and lowered”.
“Fish advisories need to be as protective as possible to keep pace with what’s happening with emerging science at the federal level,” Bloom said.
