浙江沿海经济鱼类体内重金属的残留水平

2006年秋季采集浙江沿海主要经济鱼类6种,分析检测了鱼肉组织中重金属铜、铅、锌、镉、铬、汞、砷的质量分数.研究发现6种鱼类样品中重金属质量分数具有锌>铜>砷>铅、汞>铬>镉的分布特征.聚类分析显示,重金属质量分数综合水平为弹涂鱼>鲻鱼>白姑鱼>凤鲚>龙头鱼>菊黄东方鲀.鱼类体内重金属质量分数与海水和沉积物中的质量分数相关,但是在环境中重金属质量分数低的情况下,其自身的生理特性及摄食途径是决定性影响因子.鱼类体内的汞质量分数与水层密切相关,表现为底层>中下层>中上层的分布趋势.通过不同时空的比较,发现鱼体内重金属质量分数的差别总体不超过2个数量级,且质量分数水平有上限,说明鱼类具有主动调节组织器官中重金属质量分数的机制.利用单因子污染指数法对6种经济鱼类体内重金属残留水平进行评价,结果表明鱼类体内砷污染较为严重,其他重金属元素的残留情况基本良好.

Levels of heavy metals in commercial fish species from the near-shore of Zhejiang Province

Six important commercial fish species from the near-shore of Zhejiang Province were collected in the fall of 2006.The contents of copper,lead,zinc,cadmium,chromium,mercury and arsenic in the fish muscle were determined.The result showed that the contents of different heavy metals had the sequences: zinc>copper>arsenic>lead and mercury>chromium>cadmium.The levels of heavy metals in different fishes had the following sequences through cluster analysis: mudskipper>mullet>white croaker>anchovy>bummalo>tawny puffer.The contents of heavy metals in fishes had relationship with those in seawater and sediment.But the physiological character and feeding pathway were more important when the contents of heavy metals in marine environment was relatively low.The content of mercury in fishes was related to the water layer in which they lived,it generally had the tendency that bottom>lower-middle>upper-middle.It was found out through temporal and spatial comparing that the contents of heavy metals in different fish species did not had so much large difference,it generally did not exceed two orders of magnitude.There was upper limit of metal levels which indicated that fishes could actively adjust the content of heavy metals in their bodies.The residual levels of heavy metals in these six fish species were estimated by single factor contaminant index.The result showed that the fishes from the near-shore of Zhejiang Province were seriously polluted by arsenic and the rest heavy metals were basically in good situation.