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Abstract

Ce 3+ is a potential antagonist of Cd 2+ due to their similar ionic radius. Its effect on the bioaccumulation of Cd 2+ in pacific oyster Crassostreagigaswas explored through laboratory experiments. The oysters were exposed to 5, 10 and 25 μmol/LCe(NO 3 ) 3 in the presence of 25 μg/L Cd 2+ (0.22 μmol/L) for 12 days and the concentrations of Cd, Ca, Zn as well as Cu were indicated in the whole soft tissues and separate organs. Ce 3+ in all the three doses significantly inhibited Cd 2+ bioaccumulation in the oysters on day 12 and the inhibition ratios reached 30%, 31% and 41% respectively. Organ-level analysis revealed that Ce 3+ possibly exerted its inhibitory action by delaying the saturated absorption of Cd 2+ in the gill. Ce 3+ in all the three doses antagonized the negative effects of Cd 2+ on Ca concentration and restored the its level to the normal range on day 12, but 25 μmol/L Ce 3+ decreased the Zn and Cu concentrations by up to 27% and 88% respectively. It was concluded that Ce 3+ could markedly inhibitthe Cd 2+ bioaccumulation of Crassostreagigasand the presence of Ce 3+ must be considered in marine pollution assessment by using oysters as the bioindicator.