A groundbreaking new study has revealed how the international seafood market is acting as a conveyor belt for dangerous 'forever chemicals', transporting them from polluted waters directly to consumers' plates across the globe, including in the UK.
The research, published on Friday 19 December 2025, found that consumption habits and complex trade networks are just as significant as local pollution levels in determining human exposure to per- and polyfluoroalkyl substances (PFAS).
Trade Routes Reshape Chemical Exposure
Scientists analysed levels of PFAS in more than 200 marine fish species, which together account for nearly all global commercial fish production. They discovered that international trade systematically shifts exposure from highly contaminated regions to nations where locally caught fish are cleaner.
Europe has emerged as a pivotal hub in this global flow of exposure, despite not having the most contaminated fish stocks in its own waters. The continent's high volume of imports from across the world reshapes exposure pathways, effectively increasing PFAS intake in areas with relatively lower local pollution.
Dr Julián Campo, a researcher at the Food Safety and Environment Research Group in Valencia, explained the threat. "PFAS are a group of more than 4,700 synthetic chemical compounds," he said. "They are highly toxic and pose a clear potential danger to human health, as they can act as endocrine disruptors, in addition to causing liver damage, thyroid disease, obesity, and being associated with fertility problems and cancer."
Mapping the Global Contamination Hotspots
To build their model, researchers combined global fisheries data, marine food-web simulations, and PFAS measurements from over 3,000 seawater sampling sites. They predicted concentrations in 212 edible marine species and validated their findings with real-world measurements from 150 fish samples collected in 14 countries.
The analysis pinpointed clear geographical trends:
- Fish from parts of Asia and Oceania, including Saudi Arabia, Thailand, and Australia's eastern coast, showed the highest PFAS concentrations relative to the global average.
- Fish from Africa and North America had the lowest levels.
- Species higher up the food chain, like tuna and swordfish, consistently contained more PFAS due to bioaccumulation.
- Freshwater fish were found to harbour far higher levels than their commercial marine counterparts.
Dr Pablo Gago, a senior scientist at Spain's Institute of Environmental Assessment and Water Research, praised the study's scope. "It is of high scientific quality and stands out for its ambition and methodological robustness," he said. "It integrates global data on PFAS contamination, bioaccumulation models, fish consumption, and international trade, covering more than 99 per cent of global marine fish production."
Regulation Works, But Global Gaps Remain
The study delivered both concerning findings and a sign of hope. It confirmed that from a public health perspective, wealthier regions with higher fish consumption and greater trade intensity face elevated dietary exposure.
However, the research also provided clear evidence that regulation can be effective. It found that global exposure risk from two notorious PFAS compounds – PFOS and PFOA – has dropped sharply since they were restricted under the international Stockholm Convention in 2009 and 2019 respectively.
"The results are consistent with previous evidence identifying fish as a relevant source of dietary PFAS exposure, but they add a key element: the international redistribution of risk," Dr Gago noted. "They show that restrictions applied to PFOS have been effective, but also that unregulated long-chain PFAS continue to represent a high risk, especially through food trade."
The authors caution that their study focuses solely on marine fish and does not account for other dietary or environmental sources of PFAS, meaning total human exposure is likely still underestimated. Nevertheless, they argue the findings underscore an urgent need for stronger international coordination on food safety standards and chemical regulation within our globalised food system.
