Reacción a "International fish trade increases risk of PFAS exposure worldwide"

Per- and polyfluoroalkyl substances (PFAS) are a group of more than 4,700 synthetic chemical compounds. Due to their properties (they are non-flammable, thermodynamically stable, and highly resistant), they are widely used in a range of industrial and commercial applications, from non-stick cookware to foams used to control and extinguish fires. Because of these characteristics, PFAS are considered extremely persistent in the environment and are also known as “forever chemicals.” These compounds are highly toxic and pose a clear potential danger to human health as they can act as endocrine disruptors, cause liver damage and thyroid disease, lead to obesity, and be linked to fertility problems and cancer.

Once in the environment, PFAS have the potential to bioaccumulate and biomagnify, meaning that their concentration increases progressively as they move up the food chain. In the marine environment, PFAS tend to accumulate in aquatic food webs, from where they can pass to humans through the consumption of fish and other marine species. However, the significance of these products for human exposure remains unclear. To attempt to answer this question, a group of researchers led by Dr. Qiu of the Southern University of Science and Technology in Shenzhen, China, has published an article in the journal Science in which they comprehensively assess the risks of human exposure to PFAS through the consumption of marine fish. The authors conclude that such exposure is generally low and has generally decreased with the phasing out of PFAS production, but they also warn that the international seafood market is responsible for redistributing these exposure risks globally.

Dr. Qiu and his colleagues conducted a combined analysis of fishery data and PFAS levels, mainly PFOA and PFOS, in 212 marine fish species by combining marine food web models, global fishery data, and PFAS measurements in seawater from 3,126 sites over 20 years. The model, which also includes the calculation of risk indices, was validated by measuring PFAS concentrations in 150 samples of marine fish from 87 species collected in 14 countries. According to their results, fish from Asia (Saudi Arabia and Thailand) and Oceania (eastern coast of Australia) had the highest PFAS concentrations compared to the global average. On the other hand, fish from Africa and North America had the lowest concentrations. The authors also demonstrated that marine fish at higher trophic levels contained more PFAS than those at lower levels and that freshwater fish have higher PFAS concentrations than marine fish (up to an order of magnitude). They also point out that international fish trade redistributes the risk of PFAS exposure from highly contaminated areas to regions with low contamination. In Europe, for example, although fish do not have the highest levels, European countries can be considered key points for the distribution of PFAS through the trade in seafood products.

The study concludes that, following the inclusion of several PFAS compounds in the Stockholm Convention in 2009 and 2019, a significant decrease in the global average risk of exposure was observed, demonstrating the need for greater international cooperation and stricter regulatory measures to reduce human exposure to “forever chemicals” through the marine food system.