Shrimp and Lobster Dishes May Come With Elevated PFAS Risk

Your next lobster thermidor may just come with a side order of “forever chemicals”.

According to a recent study of seafood caught off the New Hampshire coast, lobster and shrimp contained high levels of per- and poly-fluoroalkyl substances (PFAS), the human-made toxins thought to elevate cancer risks.

Based off their findings – published in Exposure and Health – the researchers warn that safety standards for PFAS are urgently needed in seafood.

A different kettle of toxin

PFAS are a growing concern around the world. The group of surfactants were first mass produced in the mid-20^th century to waterproof consumer products like pans, paints and packaging. They’re now known as “forever chemicals” because they have an almost-unbreakable highly-fluorinated alkyl chain backbone that makes them extremely chemically stable, and difficult to degrade naturally.

This hardiness is all the more troubling considering the recent wave of research linking the chemicals to cancers, high cholesterol and low birth weights. Avoiding the chemicals doesn’t seem to be an option, either; most Americans already have some levels of PFAS in their blood, according to the US Department of Health and Human Services.

But some people may still be more exposed to PFAS than others – seafood lovers, for instance. As the chemicals are known to run off into streams and collect in seas, many researchers are concerned that those who regularly eat fish, crustaceans and other marine food might be ingesting a worrying amount of PFAS.

To learn more, researchers from Dartmouth College purchased fresh seafood from a market in coastal New Hampshire (a US state with a notable fishing industry) and tested the samples for 26 varieties of PFAS.

“We saw that as a knowledge gap in the literature, especially for a New England state where we know people love their seafood,” Megan Romano, one of the researchers of the study and an associate professor of epidemiology at Dartmouth’s Geisel School of Medicine, said in a statement.

Romano and her team discovered that shrimp and lobster had the highest PFAS concentrations; averages ranged as high as 1.74 and 3.30 nanograms per gram of flesh, respectively, for certain PFAS compounds.

The researchers say these kinds of shellfish may be especially vulnerable to the buildup of PFAS in their flesh due to their feeding and living on the seafloor, as well as their proximity to coastal sources of PFAS, like rivers and industrial outflows.

Concentrations of individual PFAS in fish and other seafood generally measured less than one nanogram per gram.

Fishy habits

To accompany their findings, the researchers surveyed 1,829 New Hampshire residents on their seafood intake, which turned out to be substantial.

On average, men in the state eat just over 1 ounce (30 grams) of seafood per day, while women eat just under 1 ounce. Both figures are more than 1.5 times the US average for seafood consumption. The daily intake for New Hampshire children aged 2–11 was about 0.2 ounces, the highest end of the range for children nationwide.

Regarding the more concerning species tested, over 70% of adults said they ate shrimp at least once a month (as well as fish like haddock and salmon). Lobster was less popular, eaten by just over 54% of these adults.

Nonetheless, Romano and her colleagues remain concerned about the safety of such crustacean consumption, particularly as there are no current regulations on PFAS limits in seafood. In lieu of such regulations or more comprehensive studies, Romano urges seafood lovers to keep moderation in mind and eat a healthy, balanced diet.

“We do know from studies of the general population in the US that folks who eat more seafood, meat, chicken, and dairy tend to have higher concentrations of PFAS in their blood,” she told Technology Networks. “This really underscores the importance of eating a balanced diet that includes a wide variety of healthy foods so that, for example, no single protein source makes up too great a portion of your overall diet.”

“To me, this also highlights the need for more rigorous regulations around PFAS contamination to prevent it from getting into our food chain in the first place,” she continued.

While PFAS can still seep into the US’ water systems and food chains, the federal government has at least taken one recent, significant step in limiting its presence. On April 10, the Biden Administration announced that it had finalized strict limits on 6 types of PFAS in drinking water – the first national limits of their kind in the US.

Two common types of PFAS (PFOA and PFOS) now cannot exceed 4 parts per trillion in public drinking water, while 3 other PFAS chemicals (PFOS, GenEx Chemicals and PFHxS) will be restricted to 10 parts per trillion.

Megan Romano was speaking to Leo Bear-McGuinness, Science Writer for Technology Networks.

About the interviewee

Dr. Romano is an assistant professor of epidemiology at Dartmouth’s Geisel School of Medicine. Her research primarily explores the influence of exposure to environmental endocrine disrupting chemicals during pregnancy, maternal and infant hormones, breastfeeding, infant feeding behaviors, and early life growth.

Reference: Crawford KA, Gallagher LG, Gifard NG, et al. Patterns of seafood consumption among New Hampshire residents suggest potential exposure to per‐ and polyfuoroalkyl substances. Expos. and Heal. 2024. doi: 10.1007/s12403-024-00640-w