Studies have shown that regular consumption of seafood may increase the risk of exposure to PFAS

A study led by Dartmouth University suggests that people who regularly consume seafood may be at increased risk of exposure to PFOS, highlighting the need for specific consumption guidelines. The study, which focused on seafood intake in New Hampshire, found high levels of PFOS in commonly eaten marine species such as shrimp and lobster. The study calls for a careful assessment of the benefits and risks of seafood, especially for sensitive populations.

The findings underscore the need for stricter public health guidelines that dictate the amount of seafood people can safely eat to limit their exposure to per- and polyfluoroalkyl substances, the researchers report in the journal Exposure and Health. The need is particularly acute in coastal areas such as New England, where the legacy of industrial and PFF contamination conflicts with people's cultural preferences for fish, the authors write.

Benefits and risks of seafood

"Our advice is not to avoid seafood, which is a great source of lean protein and omega fatty acids. "But seafood is also a potentially underestimated source of human exposure to PFAS," said Megan Romano, corresponding author of the study and associate professor of epidemiology at Dartmouth University Geisel School of Medicine. Understanding this risk-benefit trade-off of seafood consumption is important for people to make dietary decisions, especially for vulnerable groups such as pregnant women and children. "

The study combined an analysis of PFOS concentrations in fresh seafood with a statewide survey of dietary habits in New Hampshire. National data shows that New Hampshire and the entire New England region have one of the highest seafood consumption regions in the country, so the state is great for understanding the extent to which people are exposed to PFAS through fish and shellfish.

"Most of the existing research focuses on the amount of PFAS in freshwater species, and people don't primarily eat freshwater species," says Romano, who studies the effects of PFAS and other endocrine-disrupting chemicals in drinking water on New England communities. "We think it's a knowledge gap in the literature, especially for New England states where we know people love to eat seafood. "

The study also drew on a wealth of data from New Hampshire on the sources and effects of PFOS, a major ingredient in consumer products such as plastics and non-stick coatings, whose molecular stability makes it versatile and also makes it virtually indestructible, hence the term "forever chemical."

In humans, PFAS have been linked to cancer, fetal malformations, high cholesterol, and thyroid, liver, and reproductive disorders. These chemicals accumulate in soil, water, and wildlife, and studies have shown that almost all Americans have measurable amounts in their blood.

Country insights and global challenges

Jonathan Petali, a toxicologist at the New Hampshire Department of Environmental Services and co-author of the study, said: "PFAS are not limited to manufacturing, fire extinguisher foam or municipal waste streams, they are a global challenge that has been going on for decades. New Hampshire was one of the first states to discover PFAS in drinking water. We are a data-rich state as we have been investigating the effects of PFOS for many years and working to reduce exposure."

The researchers measured the levels of 26 PFOS in the most consumed seafood samples, such as cod, haddock, lobster, salmon, scallops, shrimp and tuna. The seafood studied was fresh seafood purchased from a market off the coast of New Hampshire, from different regions.

Researchers reported that shrimp and lobster had the highest concentrations of certain PFOS compounds, averaging up to 1.74 and 3.30 ng, respectively, in each gram of fish meat. Individual PFOS concentrations measured in other fish and seafood are generally less than one nanometer per gram.

The researchers report that because PFOS is ubiquitous in the environment, it is difficult to know exactly where and how these chemicals enter the marine food chain. Some shellfish may be particularly susceptible to PFOS accumulation in their flesh due to their feeding and living on the seafloor and their proximity to PFOS sources near shores. Larger marine species may ingest PFOS by eating smaller species, while smaller species, such as shellfish, can easily accumulate this compound in their bodies.

Seafood consumption in New Hampshire

Researchers surveyed 1,829 New Hampshire residents to find out their residents' seafood intake, and the results showed a high seafood intake.

The survey found that men in New Hampshire eat a little more than an ounce of seafood a day, while women eat less than an ounce a day. Both figures are higher than the National Health and Nutrition Examination Survey of men and women in the Northeast and more than 1.5 times the national average. The daily intake for children ages 2-11 in New Hampshire is about 0.2 ounces, which is the highest in the country.

About 95% of the adults surveyed by the researchers said they had eaten seafood in the past year, and 94% of them had consumed fish or shellfish in the past month. More than two-thirds of respondents have consumed seafood in the past week.

But people in New Hampshire don't have consistent seafood habits. More than half of those who had eaten seafood in the week before the survey lived along the state's coast or on the border with Massachusetts. More than 60% of those with an annual household income of less than $45,000 reported eating seafood at least once a week, while those with higher household incomes reported eating seafood less frequently.

More than 70 percent of the PFAS species tested by the researchers consumed shrimp, haddock and salmon among adults who ate seafood once a month or more. 54% of adults consume lobster. Salmon, canned tuna, shrimp and haddock are the most commonly consumed seafood by children.

The study's co-author, Celia Chen, a research professor in Dartmouth's Department of Biological Sciences, said the US federal government has guidelines for the safe consumption of mercury and other contaminants, but no regulations for PFOS.

Top predator fish such as tuna and sharks are known to contain high concentrations of mercury, so we can use this knowledge to limit mercury exposure. But for PFOS, the picture is less clear, especially when studies begin to be made into how different compounds behave in the environment. Chen says he leads several federally funded projects to study how and where PFOS accumulates in aquatic food webs in New Hampshire and Vermont.

Kathryn Crawford, the study's lead author and assistant professor of environmental studies at Middlebury College, said developing safety guidelines would help protect people who are particularly vulnerable to pollutants.

Crawford, a postdoctoral researcher in Dartmouth's Romano Lab, said: "Seafood consumption recommendations are generally more conservative for these people than for other populations. People who eat a balanced diet with a more typical, moderate intake of seafood should be able to enjoy the health benefits of seafood without being overly exposed to PFAS. "

编译来源：ScitechDaily