BIOACCUMULATION OF MERCURY IN OYSTER (Plicatula Gmelin) EXPOSED TO WASTE SEAWATER DISCHARGED FROM A COAL-FIRED POWER PLANT WITH SEAWATER FLUE-GAS DESULFURIZATION:A FIELD STUDY

摘要

A field experiment was conducted to study Hg bioaccumulation in oyster exposed to waste seawater discharged from a coal-fired power plant with seawater flue-gas desulfurization (FGD) technique. Young oysters were placed in the outfall of the power plant and control site, respectively. The total Hg (THg) concentrations of seawater in the outfall and control sites were determined as 120.4±55.2 and 2.6±1.1 ng/L, respectively, while the methyl Hg (MeHg) 0.98±0.12 and 0.10±0.02 ng/L, respectively. The THg in oyster from the study site increased dramatically from 154.5±23.5 ng/gto 3011.9±289.9 ng/g in 7 d, and kept high between 2535.5 ng/g and 4489.6 ng/g for the next 34 d. During the 41 d, the THg in oyster in the control site kept low between 60.7 ng/g and 137.5 ng/g. The MeHg in oyster from the study site showed no significant change, ranging from 59.0 ng/g to 62.0±9.5 ng/g, and from the control site showed slight decrease to 15.6 ng/g, after 41 d exposure. The study showed that Hg species in the waste seawater was mainly inorganic, and there was no evidence of bio-transformation from inorganic Hg to MeHg in oyster.