News release

From: AAAS

Global seafood trade shapes global PFAS exposure risk through fish consumption

A combined analysis of fisheries data and PFAS levels in more than 200 marine fish species reveals that the global seafood trade – particularly European markets, even though fish from Europe don’t exhibit the highest rates of PFAS contamination – plays a substantial role in driving exposure risk to these persistent pollutants worldwide. The findings illustrate the need for stronger international cooperation and stricter policies to reduce human exposure to “forever chemicals” through the marine food system. Per- and polyfluoroalkyl substances (PFAS), often called “forever chemicals,” persist in the environment for decades and have become widespread pollutants through industrial use and consumer products. Because they accumulate in organisms and travel long distances through air and water, PFAS now appear throughout global food webs and are detected in nearly all major food categories. Marine fish are a particularly notable source of human PFAS exposure, and the international seafood market is responsible for redistributing these exposure risks worldwide. However, the scale and pathways of this exposure risk remain unclear.

To address this gap, Wenhui Qiu and colleagues compiled a global dataset on PFAS exposure that combines marine food-web modeling, global fisheries data, and seawater PFAS measurements from 3,126 sites over 20 years. They also created a predictive map of PFAS concentrations in 212 edible fish species covering roughly 99% of global commercial fish production. To validate their modeling of traced exposure pathways through international trade data, Qiu et al. further analyzed PFAS concentrations in 150 marine fish samples from 87 species collected across 14 countries. According to the findings, fish in Asia (i.e., Saudi Arabia and Thailand) and Oceania (i.e., Australia’s eastern coast) showed the highest rates of PFAS contamination in fish relative to the global average while fish from Africa and North America had the lowest. Marine fish species at higher trophic levels consistently contained more PFAS, and freshwater fish generally exhibit PFAS concentrations more than an order of magnitude higher than commercial marine fish. Notably, the authors discovered that international fish trade redistributes PFAS exposure risk from areas of high- to low-contamination regions, with European nations acting as a primary hub for PFAS transport through seafood trade. North America, Oceania, and Europe face the highest daily intake levels of PFAS through fish consumption. Qiu et al. also identified a significant decrease in the global median risk for PFAS exposure following the listing of several PFAS compounds under the Stockholm Convention in 2009 and 2019, demonstrating the substantial impact of international regulatory actions, and illustrating that both regulatory measures and trade-driven consumption patterns shape population-level PFAS exposure. “The findings of Qiu et al. present a promising picture of legacy PFAS exposures from marine fish: Production phase-outs have been globally effective, and existing management structures can play a leading role in mitigating ongoing exposures,” write Jennifer Sun and Elsie Sunderland in a related Perspective. “However, the analysis also shows that it can take decades for measurement capabilities and toxicity evaluations to enable global-scale assessments of exposure risks.”