东湖沉积物中重金属垂向分布特征及污染评价

为了掌握武汉东湖的水环境状况,以沉积物为研究对象,使用电感耦合等离子体质谱仪(ICP-MS)测定了不同湖域沉积物柱状样中9种重金属(Cd、Zn、As、Cu、Co、Pb、Mn、Cr、Ni)含量,对重金属元素的垂向分布特征进行了研究,并采用地累积指数法对重金属的污染程度进行评价。结果表明:沉积物中9种重金属元素含量排序为MnCrPbZnNiCuCoAsCd;垂向分布特征为Cr、Ni的含量随沉积物深度增加而增加,Cu、As、Cd的含量随沉积物深度增加而减少。地累积指数评价表明,郭郑湖西岸污染最为严重,汤菱湖最轻,累积较为严重的是Cr、Mn、Cd和Pb,其中Cd和Pb达到中度污染程度。

Vertical distribution of heavy metals in sediment of East Lake and pollution evaluation

To master the environmental situation of East Lake in Wuhan City, taking the sediment of the lake as the research object, the concentration of 9 heavy metals ( Cd, Zn, As, Cu, Co, Pb, Mn, Cr and Ni) in the columnar sediment samples of different lake areas was measured with the Inductively Coupled Plasma Mass Spectrometer( ICP-MS) to study the vertical distri-bution of the metals, and the pollution was assessed by using geo-accumulation index. The results indicated that the concentra-tion of 9 heavy metals followed a descending order of Mn, Cr, Pb, Zn, Ni, Cu, Co, As and Cd;with the increase of sediment depth, the concentration of Cr and Ni increased, while the concentration of Cu, As and Cd reduced. Assessment results on the basis of the geo-accumulation index indicated that the pollution status of the west bank area of Guozheng sub-Lake was most seriously while that of Tangling sub-Lake was the lightest;Cr, Mn, Cd and Pb were accumulated more than the other elements, the pollution of elements Cd and Pb reached a moderate level.