The Remediation Ability Of Shellfish To The Contaminated Water

Finding influencing factors was the key of remediation of heavy metals by shellfishes of offshore waters including external and internal factors. Laboratory simulation condition was conducted to investigate the different influencing fators on restoration.Two species of shellfishes were cultivated in laboratory simulation conditions, and Cadmium content was mensured under different conditions and factors to search for the enrichment factors. And the Cadmium content of Mytilus edulis and Conch from Heishijiao coastal area were simultaneously studied to investigate the factor of enrichment ability under natural condition. Using the Bioaccumulation Coefficient and the Absorption Rate Coefficient to evaluate the enrichment ability of shellfish, and using equation for the fitting of absorb isotherms, which can give the fundamental data and technical basis for bioremediation of cadmium-contaminate seawater.The results were shown as follows:Mytilus edulis and Scallops had certain enrichment ability, and the sequence of enrichment ability was Mytilus edulis > Scallops. Mytilus edulis with the characteristic of remediation had more adaptability and affinity than Scallops in the polluted seawater by Cadmium. Different tissues of Scallops'accumulation ability was Gill>Viscus>Muscle, and the Bioaccumulation Coefficient decreased with the increase of Cadmium concentration, the accumulation was up to 61.9 mg·kg-1 under maximum Cadmium concentration.The positive effect of copper ion to the Mytilus edulis and Scallops accumulate Cadmium was observed; there was insignificant correlation between Zinc iron and Cadmium, and the existence of Zinc ion can inhibit Mytilus edulis from absorb Cadmium. Sampling results showed that the sequence of accumulation ability was Mytilus edulis >Conch, and maximum accumulation was observed in April. According to the International Standard, the over standard rate of Cadmium concentration was up to 55.6%. Certain enrichment ability was also observed in the shell of Mytilus edulis and Conch, however, there was no significant change of the enrichment amount with the change of external conditions.The investigation results of three markets in Dalian showed that the Cadmium content of all samples conform to International Standard with the excepton of one item. The average content of Mytilus edulis was higher than others, and the maximum value was determined in May.