Eating fish may well be good for you, but it carries a hidden risk of exposure to so-called “forever chemicals.” A new study published in the journal Science has revealed that the global seafood trade is acting as a massive delivery system for per- and polyfluoroalkyl substances (PFAS), industrial pollutants that persist in the environment for decades.
These forever chemicals are used in many products, from nonstick cookware and cosmetics to food packaging and firefighting foams. They are extremely resistant to breaking down in the environment and have been linked to a variety of serious illnesses such as cancer and liver disease.
From oceans to dinner plates
PFAS can travel long distances around the planet in the air and through water. Once they wash into the ocean, they are absorbed by tiny organisms at the bottom of the food chain, such as plankton and algae. Because these chemicals do not break down, they accumulate in their bodies, and when small fish eat them, the toxic substances pass up the food chain. Large predatory fish, the kind that end up on our dinner plates, eat these smaller marine creatures, and as a result, the chemical concentrations build up in their tissues and organs.
In their paper, the researchers set out to map how these chemicals move once they are inside the fish. They built a computer model covering 212 different species to track how toxins accumulate up the food chain and then validated this with lab tests on fish from numerous countries. Then the team combined this data with global trade records to see how the fish and PFAS travel from one country to another.
Imported risk
One of the most significant findings was that the international fish trade acts like a global conveyor belt, redistributing PFAS from contaminated regions to consumers thousands of miles away.
Before this study, it was generally assumed that forever chemicals were a local problem. If your country’s rivers and seas were clean, then so were the fish. However, a nation with clean water can still be exposed to high levels of PFAS through the seafood it imports from other parts of the world. For example, researchers found that Italians buy only 11% of their fish from Sweden, yet this accounts for more than 35% of their PFAS exposure.
Given that this problem doesn’t respect borders, researchers argue that a unified global strategy is needed to protect public health.
“Our study highlights an urgency for strengthening global cooperation and policies to facilitate the minimization of human exposure to PFAS from the consumption of marine fishes, particularly through the advancement of relevant guidelines for the international fish trade and tightened control of long-chain PFAS.”
There is evidence that this approach works. Global efforts to phase out PFOS (perfluorooctanesulfonic acid) have helped reduce the health risk of this forever chemical in marine fish by 72% since 2009.
Written for you by our author Paul Arnold, edited by Lisa Lock, —this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive.
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More information:
Wenhui Qiu et al, Risks of per- and polyfluoroalkyl substance exposure through marine fish consumption, Science (2025). DOI: 10.1126/science.adr0351
Jennifer Sun et al, Reevaluating PFAS exposure risks from marine fish, Science (2025). DOI: 10.1126/science.aed7431
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