High Levels of PFAS ‘Forever Chemicals’ Found in Fish | Civil Eats

High Levels of PFAS ‘Forever Chemicals’ Found in Fish

Communities that rely on locally caught fish as a key component of their diet and culture may have much higher exposure to PFAS, the industrial pollutants linked to a number of negative health impacts.

Eh Mwee still remembers a fish he received over a decade ago, and—more importantly—where it came from.

Mwee, who is of Karen ethnicity and was born in Burma (now Myanmar), was 29 years old and had just arrived in Syracuse, New York, after spending 25 years in a Thai refugee camp. Food was scarce in the camp. Mwee was accustomed to eating what he could find. So when a fellow Karen refugee offered him a fish from nearby Onondaga Lake, a Superfund site that butts up against several polluting factories, he gladly accepted. “I didn’t believe anything about poison. ‘Come on, a fish is fish,’” he recalls thinking.

But his meal came from waters contaminated with industrial pollutants—including those known as per- and polyfluoroalkyl substances (PFAS) or “forever chemicals,” which have been linked to health conditions, such as cancers and impaired immune function.

Htoo Say prepares to fish in the Oswego River in New York.

PFAS are infamous for contaminating drinking water. But a growing number of studies suggest that we may also consume concerning quantities of these chemicals through food—especially fish.

Earlier this year, New York State Department of Health (NYSDOH) scientists published a study finding that refugees from Burma living in the Syracuse area had elevated PFAS concentrations in their blood. Locally caught fish may be the source.

But the full extent of PFAS contamination in fish—whether from a fishing hole or supermarket counter—is not yet known. U.S. Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) studies are ongoing, and researchers are still working out how best to quantify PFAS in fish, as even exceedingly low levels are now believed to threaten human health.

One concern is clear: Communities that rely on locally caught fish as a key component of their diet and culture may face the greatest risk.

Awash with PFAS

PFAS hit the manufacturing scene in the 1940s as an exciting new tool for making products more water, grease, and stain resistant.

But PFAS molecules contain carbon-fluorine bonds so strong that, once created, these “forever chemicals” do not easily break down in the environment. PFAS are increasingly showing up in food, such as beef in Michigan and produce in Maine, due to soil fertilized with contaminated wastewater sludge.

Fish are also a concern, says Heidi Pickard, a PhD candidate at Harvard University who studies PFAS in aquatic ecosystems. “The same way that [PFAS] can get into the drinking water, they can get into the surface waters and a lot of these chemicals then can accumulate into the fish.”

A 2017 study drawing on data from the Centers for Disease Control and Prevention’s (CDC) National Health and Nutrition Examination Survey showed that Americans who ate more fish and shellfish had greater PFAS concentrations in their blood than those who did not.

“The same way that [PFAS] can get into the drinking water, they can get into the surface waters and a lot of these chemicals then can accumulate into the fish.”

The EPA has been testing for PFAS in fish from select rivers since 2008 and from the Great Lakes since 2010. “In the majority of our studies we have found low levels of perfluorooctane sulfonate (PFOS) in nearly all of the fish tissue tested, and five additional PFAS chemicals that are often found with the PFOS in fish but are less likely to be detected in ambient or drinking water,” said an EPA spokesperson in a statement to Civil Eats.

As part of their Total Diet Study (TDS), the FDA has tested for PFAS in food since 2019—including in fish from supermarket counters. They’ve detected PFAS in fish sticks and canned tuna, as well as tilapia, cod, and shrimp. But their stance is that, “Based on the best available current science, the FDA has no scientific evidence that the levels of PFAS found in the TDS samples tested to date indicate a need to avoid any particular food.”

Elsie Sunderland, an environmental chemist at Harvard University, questions that messaging. “The big issue I have is how that limited set of data has been interpreted and communicated to the public,” she says, noting that standard PFAS analyses only capture a limited number of these chemicals. There are now over 9,000 PFAS; the FDA’s most recent analysis included only 20.

Sunderland also worries that standard analytical tools are not yet sensitive enough to capture PFAS concentrations in food at levels that could potentially impact human health when multiplied by many meals. “Quantifying the concentrations at low levels is hard,” says Sunderland. “But it turns out that that is what we need to do because people eat a lot of certain things.”

Because of their diets, subsistence fishers can be at risk of increased exposure to a range of environmental pollutants. “If someone eats 10 times more fish, they are going to have 10 times more exposure to whatever is in that fish,” says Jeremy FiveCrows, communications director for the Columbia River Inter-Tribal Fish Commission (CRITFC) and a member of the Idaho-based Nez Perce Tribe. In the early 1990s the commission conducted a survey of tribal members’ fish eating habits. The study revealed that they ate 6 to 11 times more fish than the general U.S. population, which at the time ate 6.5 grams per day.

CRITFC uses this data to advocate for cleaner water standards to protect those who eat more fish. The organization is not currently focused on PFAS, as the chemicals have not yet been found in Columbia Basin salmonids, says Dianne Barton, CRITFC water quality coordinator and member of the Bad River Band of the Lake Superior Tribe of Chippewa Indians. But they follow PFAS data as it becomes available.

FiveCrows says he tries to direct tribal members away from fishing in regions where fish consumption advisories are in place because of pesticides, metals, and other contaminants. But simply eating fewer fish is not a solution. FiveCrows says he often hears regional tribal members say, “I’m going to eat salmon because it’s my culture. It’s who I am.”

Meals from New York Waters 

On a warm June afternoon, Mwee sifts through a bait box by the Oswego River, about 15 miles north of where it runs into Onondaga Lake. He holds up a purplish lure—meant to draw walleye and bass, he tells me.

Mwee doesn’t do a lot of fishing, but he’s brought me here to speak with his friend, Htoo Say, who is also Karen, and who visits this or other local fishing haunts with friends and family nearly every weekend.

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Say, who is 23, arrived in Syracuse in 2014 after spending nine years in a Thai refugee camp. He had never fished until his brother-in-law took him to this spot five years ago. He was immediately hooked. “I love fishing,” says Say, noting the fresh air. Whatever he catches, he gives to his sister and father.

For many Karen refugees, fishing is more than a hobby—it’s a rare, accessible source of abundance. “[Burma] is a very poor country. They don’t have enough food,” says Mwee. “The first time we come here, we’re gonna eat everything.”

In 2015 and 2016, scientists from the NYSDOH and the CDC’s Agency for Toxic Substances and Disease Registry began exploring whether regularly eating fish from the waters in and near Onondaga Lake, might be associated with increased levels of PFAS and other environmental pollutants in blood.

“[Burma] is a very poor country. They don’t have enough food. The first time we come here, we’re gonna eat everything.”

“We wanted to understand a baseline level of body burdens of contaminants to better inform public health actions to help reduce exposures for these vulnerable populations,” says study author Sanghamitra Savadatti, assistant director of the Bureau of Environmental and Occupational Epidemiology at NYSDOH.

Over 300 refugees from Myanmar and Bhutan and 89, mostly minority, U.S.-born anglers offered up blood samples and responded to a questionnaire about fish consumption habits in the past year.

More than half of Karen participants said they had eaten 135 fish meals or more from the region’s waters in the previous year. The PFAS results, published earlier this year, also showed that blood from Karen volunteers contained a median PFOS level nearly 10 times greater than the general U.S. population. For another PFAS, known as PFDA, the level was nearly 27 times greater.

Other refugees from Myanmar ate a median of 103 locally caught fish meals a year. And their blood also contained elevated PFAS levels—three times that of the general population for PFOS and over seven times for PFDA.

Other study participants (not from Myanmar) ate relatively fewer fish and did not have elevated PFAS levels in their blood.

Fishing on Onondaga Lake in 2017. (Photo CC-licensed by the New York State Department of Environmental Conservation)

Fishing on Onondaga Lake in 2017. (Photo CC-licensed by the New York State Department of Environmental Conservation)

Earlier this year, this same research team similarly reported that refugees from Myanmar in Buffalo, New York had blood PFOS levels six times that of the general population.

Though these studies suggest a link between local fish and PFAS, it isn’t clear whether fish are truly the exposure source. Overall, the Syracuse study found that refugees from Burma ate more fish and also had higher PFAS levels than the other participants. But within this group, the researchers weren’t able to show a statistically significant correlation between the two. They explained that it’s hard to show PFAS increasing with fish consumption when all participants ate fish in high quantities.

It’s also possible that the elevated PFAS levels stemmed from other factors, including exposures predating time in Syracuse.

The potential health risks of these high exposures are also not entirely known, in part because the toxicology studies are all done on animals, which often excrete PFAS chemicals at different rates than humans. This month, the EPA announced an interim updated drinking water health advisory for PFOS, as well as another PFAS known as PFOA, suggesting that “some negative health effects may occur with concentrations of PFOA or PFOS in water that are near zero.”

The EPA’s decision was based on studies suggesting that exposure to PFOS and PFOA can reduce responsiveness to vaccines in children, though they note other potential health concerns such as decreased birth weight and cancer. EPA scientists are still assessing the toxicity of PFDA.

Mwee suspects that his fellow Karen refugees fish less now than at the time of the survey, since they’ve become more accustomed to a greater variety of accessible food. But many continue to fish simply for enjoyment, and also to supplement their diets.

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More Data Coming

We’ll soon learn more about the threat of PFAS in fish, both to subsistence fishers and the general population. “The TDS results indicated that additional data on PFAS in commercially caught fish and shellfish will help the FDA better understand potential exposure,” the FDA said in a statement to Civil Eats. Scientists there are currently analyzing 80 commercially caught, primarily imported, seafood samples purchased in the Washington, D.C.-area for PFAS.

This summer, the EPA also began testing for PFAS in fish in U.S. lakes as part of their 2022 National Lakes Assessment. According to the agency’s PFAS Strategic Roadmap, the data will “allow EPA to better understand unique impacts on subsistence fishers, who may eat fish from contaminated waterbodies in higher quantities.”

Academics are also working to quantify PFAS in fish, often in collaboration with those who are potentially impacted. In Cape Cod, Massachusetts, Harvard’s Pickard studies PFAS in fish from waters below a military base that historically used aqueous firefighting foam—a common source of PFAS contamination.

Pickard is a member of STEEP (Sources, Transport, Exposure, and Effects of PFASs), a collaboration between Harvard, the University of Rhode Island, and the Silent Spring Institute. “A big part of the STEEP program is doing bidirectional research,” explains Pickard, “asking the communities what their needs are, what their questions are, and then forming our scientific questions around that.”

The team is collaborating with the local Mashpee Wampanoag Tribe to test the fish and shellfish in waters where the tribal members fish.

Further south, endocrine toxicologist Scott Belcher of North Carolina State University’s Center for Environmental and Health Effects of PFAS is studying fish in the Cape Fear River, which was contaminated with PFAS from the Chemours chemical manufacturing plant in Fayetteville.

In 2020, Belcher’s team reported that striped bass living in these waters contain total PFAS levels, on average, 40 times greater than hatchery raised counterparts. There’s a moratorium on catching striped bass in the region because the population is in decline—PFAS, Belcher hypothesizes, could be a contributing factor.

He is now studying PFAS in other fish. “The high levels that we saw in the striped bass really motivated me to look more closely,” he says. He also studies alligators—a charismatic species that he chose, in part, to draw more public attention to the issue. While conducting his striped bass study, Belcher often saw families out fishing and groups having catfish fries on Wednesdays. In 2020, the state awarded over 20,000 subsistence fishing licenses.

As more data comes in, PFAS fish consumption advisories are popping up in states across the country, from Oregon and Wisconsin to Michigan and Maine.

Audrey Van Genechten, a public health specialist in outreach and education with the NYSDOH’s Center for Environmental Health, is working with Karen and Burmese anglers in focus groups across several New York locations, including Syracuse, to develop safe fishing guides geared to their communities. “We’re going through local waters with them and finding out what they call the waters,” she says. “We’re taking it to the community and going through it page by page and they are giving us feedback on what works and what doesn’t.”

Mwee hasn’t been involved with the state’s research. But he doesn’t eat the fish from Onondaga Lake anymore. The Karen community now refers to it as “Noh Ner Au,” he tells me, meaning “Stinky Lake,” because they understand that it’s polluted.

On a broader level, educating communities about fishing risks is critical for keeping people safe. Long term, the goal should be to clean up the water, says FiveCrows of CRITFC, “so [fish] don’t get contaminated in the first place.”

Carolyn Beans is a science writer and editor specializing in food, agriculture, and health. Her writing has appeared in Science News, New Scientist, Slate, PNAS Front Matter, NPR, and other outlets. Read more >

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