A new study led by Dartmouth suggests that individuals who have diets high in seafood may be at a higher risk of being exposed to PFAS, which are human-made toxins known as ‘forever chemicals’, than was previously believed. The researchers emphasize the importance of implementing stricter public health guidelines to determine safe levels of seafood consumption in order to limit exposure, especially in coastal regions where seafood is commonly eaten.
A Dartmouth-led study suggests that people who frequently consume seafood may face an increased risk of exposure to PFAS, the family of ubiquitous and resilient human-made toxins known as “forever c.
The study suggests that stricter public health guidelines are necessary to determine safe levels of seafood consumption in order to limit exposure to perfluoroalkyl and polyfluoroalkyl substances. Researchers, writing in the journal Exposure and Health, emphasize the urgency of these guidelines, particularly in coastal areas like New England, where a history of industry and PFAS pollution intersects with a cultural preference for fish.
The authors clarify that their recommendation is not to avoid seafood entirely, as it is a valuable source of lean protein and omega fatty acids. However, they caution that it may also contain potentially harmful chemicals.
Megan Romano, an associate professor of epidemiology at Dartmouth’s Geisel School of Medicine and the study’s corresponding author, emphasized the importance of understanding the potential human exposure to PFAS from seafood. She pointed out that it is crucial for individuals, particularly vulnerable populations like pregnant women and children, to consider the risk-benefit balance of seafood consumption when making dietary choices.
The study involved examining PFAS levels in fresh seafood and analyzing eating habits in New Hampshire through a statewide survey. National data suggests that New Hampshire, as well as all of New England, is one of the highest seafood consumers in the United States.The state of New Hampshire studied the exposure of people to PFAS through seafood. Dr. Romano, an expert in PFAS and other chemicals, noted that existing research focuses on PFAS levels in freshwater species, not in species that people primarily eat. This was seen as a gap in knowledge, especially in a state like New England where seafood is popular. The study also utilized New Hampshire’s data on the sources and effects of PFAS, commonly used in consumer products.Plastics and nonstick coatings are made with PFAS, which are known as forever chemicals due to their molecular stability. These chemicals are nearly indestructible and have been linked to various health issues in humans, including cancer, fetal abnormalities, high cholesterol, and thyroid, liver, and reproductive disorders. They have also accumulated in soil, water, and wildlife, and studies have found that almost all Americans have detectable levels of PFAS in their blood.
According to a study co-author, PFAS are not just found in manufacturing, fire-fighting foams, or municipal waste streams, but are a longstanding global problem.Jonathan Petali, a toxicologist with the New Hampshire Department of Environmental Services, said that New Hampshire was one of the first states to find PFAS in drinking water. He mentioned that the state has a lot of data from years of investigating the effects of PFAS and trying to reduce exposure.
The researchers looked at 26 different types of PFAS in samples of popular seafood like cod, haddock, lobster, salmon, scallop, shrimp, and tuna. They bought the seafood from a market in coastal New Hampshire and it came from different places.
Shrimp and lobster had the highest concentrations, with averages atThe researchers have reported that certain PFAS compounds were found in fish and seafood at concentrations as high as 1.74 and 3.30 nanograms per gram of flesh. In other fish and seafood, the concentrations of individual PFAS measured generally less than one nanogram per gram. The researchers state that the widespread presence of PFAS in the environment makes it challenging to pinpoint exactly where and how the chemicals enter the marine food chain. They suggest that shellfish, in particular, may be at risk of accumulating PFAS in their flesh due to their feeding and living habits on the seafloor and their proximity to PFAS sources near the coast. Larger marine species may also ingest PFAS by consuming smaller organisms.
Larger species, such as shellfish, are prone to the accumulation of these compounds in their systems.
Supporting the research is a survey of 1,829 New Hampshire residents conducted by the researchers to determine the amount of seafood consumed in the state, which turned out to be quite high.
According to the survey, men in New Hampshire consume slightly over one ounce of seafood daily, while women consume just under one ounce. These numbers are higher than those found in the National Health and Nutrition Examination Survey for men and women in the Northeast, and they are more than 1.5 times the national average for both. The daily seafood intake for New Hampshire children aged 2 t…o The average consumption of seafood among 11-year-olds was about 0.2 ounces, which is at the high end of the range for children across the country.
Of the adults surveyed, about 95% reported eating seafood in the past year, and 94% of those individuals had consumed fish or shellfish in the previous month. Additionally, over two-thirds of respondents had seafood within the last week.
However, seafood consumption in New Hampshire is not consistent across the state. More than half of those who had seafood in the week before the survey lived on the state’s coast or near the Massachusetts border. Furthermore, over 60% of people with a household income below $45,000 per year reported consuming seafood at that time.At least once per week, individuals with lower household incomes reported consuming seafood more frequently compared to those with higher incomes. The researchers found that shrimp, haddock, and salmon were the most popular species among adults who ate seafood at least once a month, with over 70% consuming these species. Additionally, over 54% of adults in this group consumed lobster. Children most commonly consumed salmon, canned tuna, shrimp, and haddock. While federal guidelines for safe seafood consumption exist for mercury and other contaminants, there are currently none for PFAS, according to Celia Chen, a co-author of the study and a research professor in the Department of Biological Sciences.
At Dartmouth.
“Predatory species like tuna and sharks are known to have high levels of mercury, so we can use that information to minimize exposure. However, it’s not as clear for PFAS, especially when considering how the different compounds behave in the environment,” explained Chen, who is leading multiple federally funded projects investigating the accumulation of PFAS in aquatic food webs in New Hampshire and Vermont.
Establishing safety guidelines would be beneficial in protecting individuals who are particularly vulnerable to pollutants, according to Kathryn Crawford, the lead author of the study and an assistant professor of environmental studies.The researcher Kathryn A. Crawford conducted a study on seafood consumption advisories at Middlebury College. She found that these advisories often provide more conservative advice for certain individuals compared to the general population. Crawford, who was a postdoctoral researcher in the Romano Lab at Dartmouth, stated that people who consume a balanced diet with moderate amounts of seafood can still enjoy the health benefits without excessive risk of PFAS exposure. The study was referenced in a journal and authored by Kathryn A. Crawford, Lisa G. Gallagher, Nathan G. Giffard, Christine L. Gardiner, Tracy Keirns, Sujan Fernando, and Thomas M. Holsen.M. Holsen, Jonathan M. Petali, Celia Y. Chen, and Megan E. Romano conducted a study titled “Patterns of Seafood Consumption Among New Hampshire Residents Suggest Potential Exposure to Per- and Polyfluoroalkyl Substances” in the journal Exposure and Health in 2024. The DOI for the article is 10.1007/s12403-024-00640-w.