Pfas in fish and shellfish, there is an alarm: here are the most contaminated species
New research, conducted by experts at the Geisel School of Medicine at Dartmouth College in the US, reveals an often underestimated source of Pfas. These are foods that come from the sea, apparently safe but which in reality can hide an invisible threat, namely contamination by the now well-known and omnipresent perfluoroalkyl substances.
We are referring in particular to seafood and fish which the study, published in the journal Exposure and Health, found to be a significant source of exposure to Pfas, especially in coastal regions such as New England (study sample). Naturally, this finding raises fundamental food safety and public health concerns, suggesting the need for new, more stringent guidelines on fish consumption.
According to Professor Megan Romano, lead author of the study, the research highlighted a significant gap in understanding human exposure to Pfas. While much research focuses on Pfas levels in freshwater (undoubtedly fundamental and worth knowing), the new study analyzed the concentrations of these substances in the fish and seafood that we also consume with a certain regularity (especially if we live near the sea). Experts measured levels of 26 Pfas in several marine species, including cod, haddock, lobster, salmon, scallops, shrimp and tuna. The results showed that it is above all some species that record particularly high concentrations of Pfas.
According to what was discovered, shrimp and lobsters have higher concentrations of Pfas, recording averages of up to 1.74 and 3.30 nanograms per gram of meat respectively. In contrast, concentrations of individual Pfas in other varieties of fish and seafood have generally been less than one nanogram per gram. Why some species are more contaminated with Pfas still remains to be clarified. Currently, it is not known precisely how these chemicals enter the marine food chain and where specifically they accumulate. Probably, some molluscs are particularly susceptible to the accumulation of Pfas in their meat due to their eating habits and their life on the seabed. This vulnerability may be accentuated by the proximity of molluscs to sources of Pfas near the coast. Furthermore, larger marine species could accumulate Pfas by ingesting smaller species, such as molluscs.
Concern about exposure to these substances is well founded, they have in fact been associated with a number of serious health problems, including cancer, fetal abnormalities, high cholesterol, and thyroid, liver, and reproductive disorders. Considering that Pfas are almost omnipresent in the environment, their presence in seafood represents an additional problem, especially for people living along the coasts where fish consumption is more widespread and frequent. However, despite the relevance of this discovery, there are currently no guidelines for the safe consumption of seafood in relation to Pfas and this worries scholars, particularly for the most vulnerable population groups such as pregnant women and children.
To address this challenge, experts recommend implementing safety guidelines for seafood consumption, similar to those already existing for mercury and other contaminants. These guidelines would help protect people who are particularly sensitive to pollutants. As Celia Chen, study co-author and research professor in Dartmouth's Department of Biological Sciences, said: Major predator species such as tuna and sharks are known to contain high concentrations of mercury, so we can use this knowledge to limit exposure. But it's less clear for PFAS, especially if you start looking at how different compounds behave in the environment.
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