Total and organic mercury, selenium and α‐tocopherol in some deep‐water fish species

BACKGROUND: Mercury is a well‐known toxic element present in seafood. Nevertheless some antioxidants, like selenium, as an integral component of the enzyme glutathione peroxidase, and α‐tocopherol having a protective role against it, are present as well. The purpose of this study was to evaluate the levels of total mercury (HgT), organic mercury (HgOrg), Se and α‐tocopherol in some adult deep‐water fish species caught off Portuguese waters. RESULTS: Levels of HgT were above EU limits in 6% of Lophius spp. and Aphanopus carbo, 2% of Lepidorhombus spp. and 70% of Helicolenus dactylopterus. HgOrg represented the major fraction (more than 84%) of HgT in all studied muscles. The selenium concentration in muscle was similar in all species (about 0.4 mg kg−1 wet weight) and the highest level of α‐tocopherol (70 mg kg−1 wet weight) was found in Aphanopus carbo. CONCLUSION: The muscle of all species studied is a good source of selenium, but only can give a small contribution of α‐tocopherol. Attending to the provisional tolerable weekly intake established by the WHO/FAO for methylmercury, it appears that the species studied should be consumed sparingly.