南京市湖泊沉积物中重金属垂直分布及污染状况评价

为了解城市湖泊沉积物中重金属污染概况及其垂直分布规律,文章选取南京市前湖和月牙湖2个小型浅水湖泊为研究对象,应用电感耦合等离子体原子发射光谱法(ICP-AES)对沉积物中Cd、Cr、Cu、Mn、Ni、Pb和Zn 7种重金属在垂向上的分布进行测定,并采用地累积指数法对重金属的污染情况进行评价。结果表明,月牙湖沉积物中重金属污染程度较前湖严重,整体上,沉积物中7种重金属质量分数由大到小的顺序为:Mn>Zn>Ni>Pb>Cu>Cr>Cd。沉积物中重金属垂向分布规律表明,7种重金属质量分数在表层0~10 cm无明显差别,而10~20 cm波动较大。地累积指数法的评价结果显示,重金属元素中Cd累积最严重,其污染程度处于中度到偏重污染水平之间。前湖沉积物中重金属Zn、Pb和Mn也发生明显累积,而污染较为严重的月牙湖7种元素都处于不同程度的污染状态。

Heavy Metals in Sediment of Urban Lakes in Nanjing:Vertical Distribution and Pollution Evaluation

Qianhu Lake and Yueya Lake as urban lakes in Nanjing City were investigated with emphasis on the sediment pollution linked to heavy metals such as Cd,Cr,Cu,Mn,Ni,Pb and Zn.On the basis of analysis of heavy metal concentrations in sediment samples using ICP-AES,vertical distribution of these heavy metals was measured.Furthermore,potential risks were assessed by the geo-accumulation index method,which showed that Cd,among others,had caused most severe pollution in sediment of two lakes;Zn,Pb and Mn were remarkably accumulated in the sediment of Qianhu Lake;and as to Yueya Lake,all the above-mentioned seven heavy metals were detected indicating its more polluted by heavy metal than the former.