'Forever chemicals' in Great Lakes fish more risky than PFAS in drinking water, study says
Laura SchulteMADISON - The levels of "forever chemicals" found in fish harvested from the Great Lakes are much higher than in commercially raised fish, according to a new study.
The peer-reviewed study, published in the Environmental Research journal, found that consuming freshwater fish harvested from urban areas 12 times per year could more than triple the level of PFOS — one of the most well-known and researched PFAS compounds — in residents of the U.S.
One serving of locally caught freshwater fish could be equivalent to drinking water with PFOS at 48 parts per trillion for a month, researchers said. Last summer, the Environmental Protection Agency released guidance that humans shouldn't consume more than 0.02 parts per trillion of the compounds.
"Finding contaminants in fish isn't new, but talking about PFAS, not a lot of attention has been paid to that," said Tasha Stoiber, one of the researchers from the Environmental Working Group.
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The research, she said, points to the vulnerability of surface waters to PFAS pollution and shows how the compounds found in humans aren't just coming from drinking water, but their diet as well.
"It's a bit shocking and hard to digest this information," she said. "But the contamination is widespread and it's important to talk about that."
The study shows that consuming fish harvested from freshwater must now be thought about differently.
"People who consume freshwater fish, especially those who catch and eat fish regularly, are at risk of alarming levels of PFAS in their bodies," David Andrews, an EWG scientist and one of the lead authors of the study, said in a release. "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 study was published along with a map showing the locations where the fish in the study were harvested. In Lake Michigan near Milwaukee, a Coho salmon harvested in 2010 showed 19,000 parts per trillion of PFOS, while a lake trout harvested the same year from Lake Superior near Superior showed 21,000 parts per trillion of PFOS.
The results analyzed in the study show a trend that's being tracked by the Wisconsin Department of Natural Resources — that PFAS are showing up in a number of fish. The Wisconsin agency has issued advisories warning anglers to reduce the amounts of certain fish harvested from certain bodies of water over the last few years, including fish caught in many of the lakes in Madison.
PFAS — or per- and polyfluoroalkyl substances — are a family of man-made chemicals used for their water- and stain-resistant qualities in products like clothing and carpet, nonstick cookware, packaging and firefighting foam. The family includes 5,000 compounds, which are persistent, remaining both in the environment and the human body over time.
The chemicals have been linked to types of kidney and testicular cancers, lower birth weights, harm to immune and reproductive systems, altered hormone regulation and altered thyroid hormones as well as high blood pressure. The chemicals enter the human body largely through drinking water.
The researchers from Duke University and the Environmental Working Group analyzed more than 500 samples of fish filets harvested from across the United States between 2013 and 2015 by the Environmental Protection Agency during routine monitoring programs.
Fish with PFAS were found in all 48 continental states. All of the 152 fish samples harvested from the Great Lakes had detectable levels of the compounds — raising concerns for the millions of people in the U.S. and Canada that rely on the lakes for drinking water, in addition to harvesting fish.
"These results highlight that PFAS contamination may be of particular concern for the Great Lakes ecosystem and the health of people who depend on fishing on the Great Lakes for sustenance and cultural practices," the report said.
The authors highlighted the particular risk to those who routinely rely on fish they catch from local waters as a major source of protein in their diet.
"Self-caught fish are an important source of subsistence for many individuals, indicating that advisories for PFAS will disproportionately affect these individuals who cannot afford to replace self-caught fish with purchased fish," the report says.
But, the report noted, there is a lack of guidance on how fish can be safely consumed to protect consumers from PFAS. To remedy that, the EPA should begin issuing advisories and educating the public.
"The extent that PFAS has contaminated fish is staggering," said Nadia Barbo, a Duke University graduate student and lead researcher on the study, in a press release. "There should be a single health protective fish consumption advisory for freshwater fish across the country."
The EPA should also collect more data on PFAS in fish, Stoiber said. For example, though a variety of fish were sampled in the data analyzed for the study, there wasn't enough to draw conclusions on which types of fish might be more susceptible to contamination.
"We need more data, and more data released on a quicker basis," she said.
But there was encouraging news found in the data, too, Stoiber said.
Compared to older fish sampling, the levels of PFOS were actually lower in the 2013 to 2015 data collected for the current study. That decrease is likely the result of industry stopping the use of PFOS and PFOA.
But finding PFAS in fish today is still concerning Stoiber said, especially because there still isn't an efficient way to remove the compounds from the environment.
"What's needed is a reduction of discharges to the environment, as well as curtailing non-essential uses of PFAS," she said. "There's no practical way to clean surface waters or watershed. We need to reduce the input so that the contamination isn't made worse."
Laura Schulte can be reached at leschulte@jrn.com and on Twitter at @SchulteLaura.