宝鸡市王家崖水库沉积物重金属含量及潜在生态风险评价

Content Distribution and Potential Ecological Risk Evaluation of Heavy Metal in Sediment of Wangjiaya Reservoir in Baoji City

利用X-Ray荧光光谱仪对宝鸡市王家崖水库表层沉积物中的As,Co,Cr,Cu,Ni,Mn,Pb,V和Zn共9种重金属元素含量进行了测定,分析了这几种元素含量的分布特征,并采用潜在生态风险指数法对重金属生态危害程度进行了评价。测定结果表明,9种重金属的含量平均值均高于陕西省土壤背景值,是陕西省土壤背景值的1.5～1.9倍,其中Cu的累积程度最高,Zn的累积程度最低;各重金属元素具有相似的水平分布特征,高值区位于水库中游,低值区位于水库上游。潜在生态风险评价表明,研究区重金属元素综合生态风险程度属于中度,采样点位5(中游)综合生态风险最高,采样点位8(上游)综合生态风险最低;各元素生态危害程度大小顺序为:As>Cu>Ni>Co>Pb>V>Mn>Cr>Zn,其中As具有中度生态危害,其余各元素均为轻度生态危害。

The heavy metal content in the sediment of Wangjiaya Reservoir in Baoji City were determined by using X-ray fluorescence spectrometry and their ecological risk were assessed by using the potential ecological risk index.The results indicate that the average contents of As,Co,Cr,Cu,Ni,Mn,Pb,V and Zn in the sediment were higher than the soil background values of Shaanxi Province.The accumulation coefficient of Cu was the highest among the studied heavy metals,while Zn was the lowest.The heavy metal element distribution in the sediment had the similar horizontal character,which was high content in the reservoir centre,low values in the reservoir up-reach.The results of potential ecological risk assessment showed that the ecological risk degree of the heavy metal pollutants was moderate,and the highest comprehensive ecological risk was in section 5（in the middle reach） and lowest was in section 8（in the upper reach）.The order of individual potential ecological risk was AsCuNiCoPbVMnCrZn.As had the moderate ecological harm and other heavy metals have lower ecological risk.