Risk Assessment of Total Mercury (T-Hg) in Commercial Seafood Marketed in Bangkok, Thailand

Abstract

Seafood is recognized as the high protein source of human consumption. However, it is hampered by mercury contamination. The objectives of this study are to determine total mercury (T-Hg) levels in edible portions of commercial seafood available in Bangkok’s supermarkets, and to evaluate the potential risks from mercury through seafood consumption. Total 32 species, including 22 fish, 4 cephalopod and 6 shellfish, were purchased from super-markets. Fish samples were dissected in 3 parts comprised of flesh, gill and viscera. While, cephalopod and shellfish were separated for edible tissues. The samples were digested in hot acid and were determined using cold-vapor atomic absorption spectrometry technique. The results revealed that T-Hg contained in the fish flesh > cephalopod > shellfish. In addition, T-Hg was accumulated in flesh > viscera > gill. Statistical analysis suggested that T-Hg accumulated in flesh was related positively with species, feeding habit, and habitat (p < 0.05). For risk analysis, estimated daily intake (EDI) of flesh ranged from 0.01 to 0.42 µg kg^-1 bodyweight d^-1, the lowest and highest EDI values were in salmon and yellowfin tuna, res-pectively. Yellowfin tuna, narrow-barred Spanish mackerel, fourfinger threadfin, and silver sillago were the 4 species that having the EDI values of T-Hg higher than the FAO/WHO recommended provisional tolerable daily intake (PTDI) of 0.23 µg kg^-1 bodyweight d^-1. Thus, the frequent consumption of these seafood are not recommended. In addition, the daily consumption of seafood should not exceed the maximum safe daily intake (MSDC). The MSDC of seafood in this study ranged from 15.5 (yellowfin tuna) to 474 (salmon) g d^-1.