Exposure to PFAS from diets high in seafood may be underestimated, research shows

A Dartmouth-led study suggests that people who regularly consume seafood may be at increased risk of exposure to PFAS, the family of ubiquitous and resilient man-made toxins known as “forever chemicals.”

The findings highlight the need for stricter public health guidelines that determine how much seafood people can safely consume to limit their exposure to perfluoroalkyl and polyfluoroalkyl substances, the researchers report in the journal. Exposure and health. This need is especially urgent for coastal areas like New England, where a legacy of industry and PFAS pollution clashes with a cultural fondness for fish, the authors write.

“Our recommendation is not to avoid eating seafood; seafood is a great source of lean protein and omega fatty acids. But it is also a potentially underestimated source of PFAS exposure in humans,” said Megan Romano, the study’s corresponding author and employee. professor of epidemiology at the Geisel School of Medicine at Dartmouth.

“Understanding this risk-benefit tradeoff for seafood consumption is important for people making dietary decisions, especially for vulnerable populations such as pregnant people and children,” Romano said.

The study combined an analysis of PFAS concentrations in fresh seafood with a statewide survey of eating habits in New Hampshire. National data shows that New Hampshire – along with all of New England – is among the largest consumers of seafood in the country, making the state ideal for understanding the extent of people’s exposure to PFAS through fish and shellfish.

“Most existing research focuses on PFAS levels in freshwater species, which are not what people primarily eat,” says Romano, who studies the effects of PFAS and other endocrine-disrupting chemicals in drinking water on New England communities. “We saw that as a knowledge gap in the literature, especially for a New England state where we know people love their seafood.”

The study also used New Hampshire’s extensive data on the sources and effects of PFAS, a key ingredient in consumer products such as plastics and nonstick coatings. The molecular stability that makes PFAS so versatile also makes them nearly indestructible, earning them the name forever chemicals.

In humans, PFAS are associated with cancer, fetal abnormalities, high cholesterol, and thyroid, liver, and reproductive disorders. The chemicals have built up in soil, water and wildlife, and studies have shown that almost all Americans have measurable levels in their blood.

“PFAS are not limited to manufacturing, firefighting foam or municipal waste streams – they pose a decades-long global challenge,” said co-author Jonathan Petali, a toxicologist with the New Hampshire Department of Environmental Services. “New Hampshire was one of the first states to identify PFAS in drinking water. We are a data-rich state because of the years we have spent researching the impacts of PFAS and trying to reduce exposure.”

The researchers measured the levels of 26 types of PFAS in samples of the most commonly consumed marine species: cod, haddock, lobster, salmon, scallop, shrimp and tuna. The seafood studied was purchased fresh at a market on the New Hampshire coast and came from different regions.

Shrimp and lobster had the highest concentrations, with averages of 1.74 and 3.30 nanograms per gram of meat, respectively, for certain PFAS compounds, the researchers report. Concentrations of individual PFAS in other fish and seafood generally measured less than one nanogram per gram.

The prevalence of PFAS in the environment makes it difficult to know exactly where and how the chemicals enter the marine food chain, the researchers report. Some shellfish may be particularly vulnerable to the accumulation of PFAS in their flesh due to feeding and living on the seabed, as well as their proximity to near-shore sources of PFAS. Larger marine species can ingest PFAS by eating smaller species that, like shellfish, tend to accumulate the compounds in their systems.

The study is supported by a survey of 1,829 New Hampshire residents that the researchers conducted to gauge how much seafood Granite Staters eat – and that’s a lot.

The study found that men in New Hampshire eat just over an ounce of seafood per day and women eat just less than an ounce. Both are higher than what the National Health and Nutrition Examination Survey found for men and women in the Northeast, and more than 1.5 times the national average for both. The daily intake for New Hampshire children ages 2 to 11 was about 0.2 ounces, the highest range for children nationwide.

About 95% of adults the researchers surveyed reported that they had eaten seafood in the past year, and 94% of that group had consumed fish or shellfish in the past month. More than two-thirds of these respondents had eaten seafood in the past week.

But people in New Hampshire don’t eat seafood the same way. More than half of the people who had eaten seafood in the week before the survey lived on the state’s coast or near the Massachusetts border. More than 60% of people with a household income of less than $45,000 per year reported consuming seafood at least once a week, while people with higher household incomes reported eating seafood less often.

Of the species the researchers tested for PFAS, shrimp, haddock and salmon were consumed by more than 70% of adults who ate seafood once a month or more. Lobster was eaten by just over 54% of these adults. Salmon, canned tuna, shrimp and haddock were the most commonly consumed species among children.

Federal guidelines for safe seafood consumption exist for mercury and other contaminants, but there are none for PFAS, says Celia Chen, co-author of the study and research professor in the Department of Biological Sciences at Dartmouth.

“Text predator species such as tuna and sharks are known to contain high levels of mercury, so we can use that knowledge to limit exposure. But for PFAS it is less clear, especially when you look at how the different compounds behave in the environment. said Chen, who leads several projects investigating how and where PFAS accumulate in aquatic food webs in New Hampshire and Vermont.

Establishing safety guidelines would help protect people who are particularly sensitive to pollutants, said Kathryn Crawford, the study’s first author and an assistant professor of environmental studies at Middlebury College.

“Seafood consumption advice often provides advice for those individuals that is more conservative than for the rest of the population,” says Crawford, who started the project as a postdoctoral researcher in the Romano Lab at Dartmouth. “People who eat a balanced diet that includes more typical, moderate amounts of seafood should be able to enjoy the health benefits of seafood without excessive risk of PFAS exposure.”