海州湾养殖四角蛤蜊体内组织中重金属分布差异及安全评价

Distribution and Safety Assessment of Heavy Metals in Body Tissues of Cultured Mactra veneriformis from Haizhou Bay

采用原子吸收法测定海州湾池塘养殖成体四角蛤蜊外套膜、鳃、斧足、闭壳肌、内脏团(含生殖腺、肝、胃、肠、肾等)5个组织干质量中Cd、Cr、Pb、Ni、Cu和Zn6种重金属的含量,并与相关标准进行比较评价。结果显示:5个组织中内脏团是重金属选择性富集的主要器官,含量介于0.353(Cd)～127.633μg/g(Zn)之间,除Cr和Pb相互差异不显著外,其余相互间均差异显著(P<0.05);6种重金属中,Zn在5种组织中含量最高,而Cd在鳃、外套膜和内脏团中含量最低,Cu则在斧足和闭壳肌中的含量最低。用单因子指数法对四角蛤蜊污染状况进行评价,结果表明:5个组织中主要重金属污染物为Ni,污染指数为0.87(斧足)～10.73(内脏团),其次为Pb和Zn,Cd仅在内脏团中呈轻度污染,未受Cr和Cu污染。海州湾养殖四角蛤蜊食用或作为饲料用时应引起一定程度的重视。

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 Halzhou 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 127.633 μg/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 contaminatext 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.