乳山湾水体重金属含量的季节变化与养殖贝类对水体重金属的生物富集效应

Seasonal varieties of heavy metals pollution in seawater of Rushan Bay and heavy metals enrichment in Crassostrea gigas

为了解乳山湾近岸海域重金属污染情况及养殖贝类对重金属富集情况,按春、夏、秋、冬四个航次采集湾内和湾外的表层海水,并于秋季采集湾内养殖的太平洋牡蛎(Crassostrea gigas)分析海水及牡蛎体内Cu、Pb、Zn、Cr、Cd、As、Hg等7种重金属含量,评价海水质量与养殖贝类的食用安全。结果表明:乳山湾湾内湾外海域水质较好,除冬季Zn以及春、秋两季的Hg符合二类海水水质标准,其余点位均符合一类海水水质标准,海水水质为"清洁"。乳山湾湾内和湾外沉积物中各重金属的含量均低于第一类海洋沉积物标准,没有受到明显的污染。乳山湾内养殖牡蛎体内Cd和Zn的浓度远远高于湾内水体中重金属的浓度,表明太平洋牡蛎对重金属具有较强的富集作用,但仍符合二类海洋生物质量标准。

To investigate the pollution of heavy metals and their bioaccumulation by bivalve mollusks in Rushan Bay,four seasonal cruises(spring,summer,autumn and winter)were conducted in the outer and inner mouth of of Rushan Bay to analyze the contents of seven kinds of heavy metals(Cu,Pb,Zn,Cr,Cd,As and Hg)in water.The heavy metal contents in oyster Crassostrea gigas tissues and in sediment were also analyzed.The level of seawater quality and safety of marine aquaculture were evaluated based on the investigation.The research found that the surface water of the investigated area were clean and according with the Grade Ⅰ sea water standard,The concentration of Zn in winter and Hg in spring and autumn were not according with the Grade Ⅰ sea water,but still met Grade Ⅱ.The concentration of heavy metals in marine sediment were lower than the Grade Ⅰ marine sediments standard.So the sediment was not polluted by heavy metals in Rushan Bay.The concentration of Cd and Zn in C.a gigas were much higher than that in the sea water.The result indicated that the Crassostreagigashad stong bioaccumulation capacity of heavy metals.But the concentration of heavy metals met Grade Ⅱ biological quality standards.