太湖竺山湾沉积物重金属形态分析及风险评价

采用BCR 3步连续提取法研究了太湖竺山湾沉积物中重金属Cr、Ni、Cu、Zn、Cd和Pb在垂直方向上不同形态的分布特征,并利用人类活动系数和重金属形态评价方法对其进行潜在生态风险评价。结果表明,重金属总量大小为:Zn>Pb>Cr>Ni>Cu>Cd,表层沉积物表现出明显的富集效应;重金属总量和可提取态的含量均有从表层至下层逐渐降低的趋势;河流入湖口处5 cm的沉积物重金属总量和可提取态含量显著高于其他区域;AF富集系数评价显示,除Cr外,其余重金属在沉积物中表现出明显出明显的富集效应,特别是Cd和Pb;RSP生态风险评价表明,表层5 cm沉积物生态风险最高,特别是Cd;Cd元素在表层15 cm的沉积物属于重度污染;Zn的表层10 cm属于重度污染;重金属Ni、Cu和Pb在表层5 cm沉积物中基本介于中度污染和重度污染之间,在5～10 cm介于轻度污染和中度污染之间。

Heavy Metals in Sediment of Lake Taihu's Zhushan Bay:Chemical Speciation and Risk Evaluation

Sedimentary cores from Zhushan Bay was analyzed for chemical speciation of heavy metals(incl.Cr,Ni,Cu,Zn,Cd and Pb) by BCR 3-stage sequential extraction method,and meanwhile their vertical distribution characteristics in the sediment were investigated.It was found the top sediment in particular,was typical of enrichment of heavy metals,and top sediment around the river inlets contained much higher heavy metals than in other places,in terms of both total and extractable contents.The human activity factor evaluation(AF) indicated that apart from Cr,heavy metals' enrichment in the sediment was notable,particularly Cd and Pb.Additionally,result of the ecological risk evaluation revealed that top sediment of 15 cm depth had very high level of Cd with greater RSP values;pollution of Zn within 10 cm depth was severe,while the pollution level of Ni,Cu and Pb within 5 cm-depth sediment were from moderate and severe,and in the depth from 5 to 10 cm pollution of heavy metals was at mild or moderate levels.