Oral bioaccessibility of arsenic, mercury and methylmercury in marine species commercialized in Catalonia (Spain) and health risks for the consumers.

This study was aimed at characterizing the bioaccessibility of arsenic (As), mercury (Hg) and methylmercury (MeHg) in commercial fish and seafood species widely consumed by the population of Catalonia (Spain). An accurate evaluation on how bioaccessibility estimations may affect the outcomes of exposure assessment studies was also conducted. The concentrations of As, Hg, and MeHg in samples of fish and seafood incubated in a 3-compartmental (mouth, stomach, and small intestine) in vitro gastrointestinal model, were quantified and compared with the levels of these elements in cooked samples. Arsenic showed a high bioaccessibility in all the fish and seafood species, ranging from 72% (mackerel) to 89% (sardine). In contrast, the bioaccessibility of Hg was rather lower, being <50% for most species, while MeHg could be only quantified in swordfish and tuna. This study elucidates the potential overestimation of health risks to consumers, when the effects of bioaccessibility and cooking procedures are not taken into account in the risk assessment. Unlike As, whose risk is not generally overestimated, Hg and MeHg showed a lower and variable bioaccessibility in marine species, meaning an overestimation of health risks for the adult population. Further studies should assess the bioaccessibility of mercurial species for children.