• Posted April 12, 2024

Seafood Can Pass on PFAS 'Forever Chemicals,' Study Finds

Cancer-linked 'forever chemicals' made news this week, with the Biden Administration vowing to cut levels in the nation's tap water.

New research finds that the chemicals, known as PFAS, can also contaminate the seafood Americans eat.

No one is advising that consumers avoid fish and shellfish, the study's authors stressed. However, their findings point to a need for federal guidelines on PFAS levels in seafood, similar to what happens with mercury.

"People who eat a balanced diet with more typical, moderate amounts of seafood should be able to enjoy the health benefits of seafood without excessive risk of PFAS exposure," said study first author Kathryn Crawford, now an assistant professor of environmental studies at Middlebury College in Vermont. She worked on the study as a postdoctoral researcher at Dartmouth College in Hanover, N.H.

According to the Environmental Protection Agency, exposure to PFAS chemicals leaked from industrial sites and other sources has long been linked to various cancers, liver and heart issues, and immune and developmental damage to infants and children.

"PFAS are not limited to manufacturing, fire-fighting foams or municipal waste streams -- they are a decades-long global challenge," study co-author Jonathan Petali, a toxicologist with the New Hampshire Department of Environmental Services, noted in a Dartmouth news release.

In the research, Petali, Crawford and colleagues analyzed levels of 26 different forms of PFAS in cod, haddock, lobster, salmon, scallop, shrimp, and tuna.

The seafood originated from various regions but was all purchased at a market in coastal New Hampshire.

Shrimp and lobster had the highest concentrations of PFAS, with averages ranging up to 1.74 and 3.30 nanograms per gram of flesh, respectively, for certain PFAS compounds.

Concentrations fell to less than one gram of PFAS per gram for other seafood types.

It's not clear how these sea animals are ingesting PFAS. It's possible that concentrations are higher on the seabed, explaining why shrimp and lobster came out on top, the researchers said.

Some species may also have higher PFAS levels if they live nearer to the coast.

Perhaps unsurprisingly, New Hampshire residents eat more seafood than the average American, with 94% telling the researchers that they had eaten fish or shellfish at least once over the prior month.

"Salmon, canned tuna, shrimp and haddock were the most commonly consumed species among children," according to the Dartmouth news release.

"Our recommendation isn't to not eat seafood -- seafood is a great source of lean protein and omega fatty acids. But it also is a potentially underestimated source of PFAS exposure in humans," said study corresponding author Megan Romano, a professor of epidemiology at Dartmouth.

"Understanding this risk-benefit trade-off for seafood consumption is important for people making decisions about diet, especially for vulnerable populations such as pregnant people and children," Romano said.

According to study co-author Celia Chen, federal guidelines on levels of PFAS in seafood could help folks better understand the risk.

"Top predator species such as tuna and sharks are known to contain high concentrations of mercury, so we can use that knowledge to limit exposure. But it's less clear for PFAS, especially if you start looking at how the different compounds behave in the environment," said Chen, a research professor in biological sciences at Dartmouth.

The study was published April 12 in the journal Exposure and Health.

More information

Find out more about PFAS chemicals at the Environmental Protection Agency.

SOURCE: Dartmouth College, news release, April 12, 2024