巢湖市河流表层沉积物重金属污染和风险评价

Heavy Metal Pollution in Surface Sediment of Urban River in Chaohu City and Its Risk Assessment

摘要:

采集巢湖市不同河道9个点位的表层沉积物样品, 检测了7种重金属元素的含量水平, 分析空间分布特征, 并评价了其潜在的生态风险. 结果表明, 巢湖市河道表层沉积物中重金属含量水平相对较高, Hg和As的平均含量已经超过沉积物质量基准上限; 根据地累积指数计算结果, 重金属污染程度大小依次为Ni, Hg, Cu, As, Cr, Zn, Pb, 单项重金属潜在生态风险大小依次为Hg, As, Cu, Pb, Cr, Ni, Zn, 其中Ni污染程度达到极强污染水平, Hg为中污染水平, 但却是最主要的潜在生态风险因子, As表现为较重风险, 其他重金属的潜在生态风险相对较低; Hg单项潜在生态风险区域与综合潜在生态风险区域特征相对一致, 重金属污染可能存在的主要风险区域为西环城河, 相关部门应当足够重视.

Abstract:

Nine surface sediments were collected from urban rivers of Chaohu City, China, for an analysis of 7 heavy metals (Hg, Cu, Pb, Zn, Cr, Ni and As). A comprehensive way was conducted to investigate distribution patterns and assess the potential ecological risks of heavy metals. The results indicate that the sediments are severely contaminated by heavy metals and mean concentrations of Hg and As are above PEL values. The contamination order of the 7 metals is Ni, Hg, Cu, As, Cr, Zn, Pb according to the mean Igeo values, while the single potential ecological risk of heavy metals followes the order Hg, As, Cu, Pb, Cr, Ni, Zn. The element Ni was the main pollutant and Hg was the second most abundant element with the most serious ecological risks. More attention was demanded to the metalloid As in ecological risk assessments. The pollution of the remaining 4 metals was slight with little ecological risk. The distribution pattern of Hg individual potential ecological risk indices was similar to that of the general potential ecological risk indices for all metals. More concern should be focused to West Huancheng River suffering serious ecological risk.