巢湖表层沉积物中重金属污染的时空变化特征及潜在生态风险评价

The Spatial and Temporal Variation Characteristics and Potential Ecological Risk Assessment of Heavy Metal Pollution in Surface Sediments of Chaohu,China

2008年3月至7月连续对巢湖8个采样点的表层沉积物中Zn、Hg、Cr、Pb、Ni和Cu6种重金属含量进行分析,据此探讨巢湖表层沉积物中重金属污染程度及时空分布特征,评价巢湖重金属污染的潜在生态风险并筛选出主要生态风险因子。结果表明:3月至7月期间,全湖范围内表层沉积物中重金属含量逐渐降低,河流入湖区的污染程度高于其他区域,Zn、Cu、Pb的污染程度高于其他重金属,表层12cm沉积物中的重金属含量随深度增加污染情况呈加重趋势;从潜在生态风险角度分析,巢湖表层沉积物总体只具有轻微潜在生态风险,生态风险指数排名前两位的区域是南淝河入湖区和十五里河入湖区,3月至7月期间重金属潜在生态风险级别逐渐降低,巢湖生态安全主要风险因子为Hg,其次是Pb和Cu。

Based on the monitoring of six heavy metal elements（Zn,Hg,Cr,Pb,Ni and Cu）in the surface sediments from eight samples sites of Chaohu from March to July in 2008,temporal and spatial variation characteristics and contamination degree of heavy metal pollution was discussed,and their potential ecological risk and key ecological risk indexes were assessed.The concentrations of heavy metals in the surface sediments of Chaohu reduced gradually during investigation period.The contamination in the inflow lake region was higher than others.Zn,Cu and Pb were the main contaminants compared with other heavy metals.Heavy metal pollution from 12 cm depth surface sediments became aggravated with depth increasing.In addition,the surface sediments from Chaohu appeared slight potential ecological risk,and the first two regions were Nanfei inflow rive area and Shiwuli inflow river area.The potential ecological risk levels of heavy metals reduced gradually from March to July.The result also showed that the main factors influencing ecological safety in Chaohu were Hg,Pb and Cu.