Abstract: In this study, the contents of six heavy metals, including Cd，Cr，Pb，Ni，Cu, and Zn, were determined by atomic absorption spectrometer in five dry tissues of mantle, gill, foot, adductor muscle, and visceral mass (gonades，hepatopancreas，gastrointestinal and kidney, etc.) of the adult clam Mactra veneriformis cultured in Haizhou Bay pond. The results indicated that visceral mass of the clam was the major tissue selectively enriched by heavy metal and it content of high metals were ranged from 0.353 for Cd to 127.633μg/g for Zn. There were significant differences (P＜0.05) between different tissues except for Cr and Pb. The content of Zn was highest among the six metals, while Cd was the lowest in gill, mantle and visceral mass and Cu in foot and adductor muscle. The contaminative assessment results for the clam by the single factor index method indicated that the five tissues were contaminated by heavy metal Ni and the contaminative index ranged from 0.87 in foot to 10.73 in visceral mass, while there were lightly contamination by Pb, Zn and Cd in visceral mass, but the other heavy metals were minor. In general, the heavy metal Ni contamination in visceral mass as feed or edibles in Haizhou bay needs attention.

Key words: Mactra veneriformis, tissues, heavy metal, contamination assessment