Concentrations of total Hg (THg) in muscle tissues were determined for 10 fish species collected from a reservoir adjacent to a chlor-alkali plant which had been operated for 40 years and later abandoned for 22 years in Annan, Tainan city in Taiwan. The concentrations of THg in the fish muscles ranged from 0.082 to 1.377 mg/kg flesh wt. Among 60 samples analyzed, 32% of them exceeded the WHO limit (THg, <0.5 mg/kg flesh wt.). The THg concentrations also showed significant differences among species, with the trend that carnivorous fish (Pelates quadrilineatus, Elops machnata and Gerres filamentosus) had significantly higher Hg concentrations than did omnivorous fish (Nematalosa come, Liza macrolepis and Mugil cephalus) and herbivorous fish (Chanos chanos), revealing a biomagnification effect, except in the case of the tilapia, Orechromis sp. The mean values of the species (0.106-0.748 mg/kg flesh wt.) were 4 to 21 times higher than those of the same species measured at Chigu Lagoon (<0.025-0.068 mg/kg flesh wt.). The lowest and highest ratio difference between the two areas was found for M. cephalus and G. filamentosus, respectively. Based on daily seafood consumption habits in the Taiwan, except for N. come, L. macrolepis, C. chanos and M. cephalus which contained THg concentrations lower than 0.35 mg/kg flesh wt., in the event of consumption of any of the remaining six species of the fish, the amount of THg taken in will exceed the provisional tolerable weekly intake (PTWI) limit and may consequently pose a health threat.
Concentrations of total Hg (THg) in muscle tissues were determined for 10 fish species collected from a reservoir adjacent to a chlor-alkali plant which had been operated for 40 years and later abandoned for 22 years in Annan, Tainan city in Taiwan. The concentrations of THg in the fish muscles ranged from 0.082 to 1.377 mg/kg flesh wt. Among 60 samples analyzed, 32% of them exceeded the WHO limit (THg, <0.5 mg/kg flesh wt.). The THg concentrations also showed significant differences among species, with the trend that carnivorous fish (Pelates quadrilineatus, Elops machnata and Gerres filamentosus) had significantly higher Hg concentrations than did omnivorous fish (Nematalosa come, Liza macrolepis and Mugil cephalus) and herbivorous fish (Chanos chanos), revealing a biomagnification effect, except in the case of the tilapia, Orechromis sp. The mean values of the species (0.106-0.748 mg/kg flesh wt.) were 4 to 21 times higher than those of the same species measured at Chigu Lagoon (<0.025-0.068 mg/kg flesh wt.). The lowest and highest ratio difference between the two areas was found for M. cephalus and G. filamentosus, respectively. Based on daily seafood consumption habits in the Taiwan, except for N. come, L. macrolepis, C. chanos and M. cephalus which contained THg concentrations lower than 0.35 mg/kg flesh wt., in the event of consumption of any of the remaining six species of the fish, the amount of THg taken in will exceed the provisional tolerable weekly intake (PTWI) limit and may consequently pose a health threat.