Total and Organic Mercury in Fish from Different Geographical Areas in the North Atlantic Ocean and Health Risk Assessment

Fish consumption is considered the main route of exposure to mercury for the human population. In this sense, this study analysed the total and organic mercury content present in the muscle tissue of 38 fish species caught in different geographical areas of the North Atlantic Ocean (included in FAO fishing areas 27 and 31). The potential risk to human health through fish consumption was assessed using the maximum limit for mercury intake of 1.3 μg methylmercury Kg body weight −1 week −1 . The results show that carnivorous species presented higher mercury content (range 0.03–0.88 μg g −1 ) when compared to omnivorous (range 0.003–0.19 μg g −1 ) in all sampling sites. Furthermore, demersal fish exhibited higher mercury levels (range 0.01–0.88 μg g −1 ) than the pelagic species (range 0.003–0.38 μg g −1 ) did. From the 38 species analysed only Zeus faber presented mercury levels (0.68 ± 0.07 μg g −1 ) above the maximum limit (0.5 μg g −1 ) established for human consumption. On the other hand, mercury intake can be higher than the recommended due to the consumption of 13 species from fishing area 27 (Azores archipelago and Northwest Portuguese coast) and one species ( Cynoscion nebulosus ) from fishing area 31 (Southeast Mexican coast). However, only the consumption of Zeus faber and Aphanopus carbo from the fishing area 27 is discouraged. Thus, the fish consumption per capita in a specific area can exceed the limits of mercury ingestion, even when the mercury content in the fish is below the recommended for consumption.