中山高平工业园区周边水体沉积物中重金属污染特征及生态风险评价

Pollution and Ecological Risk Assessment of Heavy Metals in Surface Sediments of Water Bodies Surrounding Gaoping Industrial Park of Zhongshan City

为探讨电镀工业区周边水体沉积物中重金属污染水平及其潜在的生态风险,在广东中山市高平工业园区周边水体采集20个表层沉积物样品,分析Pb、Cd、Cr、As和Hg五种重金属的含量水平及其分布特征,并采用地累积指数法和潜在生态危害指数法初步评价了沉积物中重金属污染状况和潜在生态风险。研究结果表明:中山高平工业园区周边水体存在重金属复合污染,除As外绝大多数沉积物样品中Cr、Pb、Cd、Hg的含量均高于参比值;五种重金属的含量由高到低依次为Cr>Pb>As>Cd>Hg;重金属富集程度处于清洁至偏重污染之间,富集程度强弱顺序为Pb>Cr>Cd>Hg>As;研究区域55%的表层沉积物中重金属污染处于中等生态危害程度,重金属潜在生态风险由强到弱依次为Cd>Hg>Pb>Cr>As。

Heavy metals accumulated in sediments could cause the secondary water pollution.The aim of this study was to investigate pollution of heavy metals in surface sediments of the water bodies surrounding a typical electroplating industrial park and to assess their ecological risks.A total of 20 sediment samples around Gaoping industrial area in Zhongshan City were collected for determining the concentrations of five heavy metals(Pb,Cd,Cr,As and Hg).Geoaccumulation index and Hakanson potential ecological risk index were respectively used to assess the pollution and potential ecological risks of these metals in the sediments.The concentrations of heavy metals in most of the sediment samples were higher than the reference values except As.Their concentrations decreased in order:Cr >Pb >As >Cd >Hg.The geoaccumulation index indicated that pollution degree of heavy metals in the sediments ranged from high to light levels,with Pb>Cr>Cd>Hg>As.A significant positive correlation(P<0.05) was present between Cr and Hg,Cd and Hg,and As and Hg.The potential ecological risks of heavy metals were low to moderate,with 55% of the sediments at moderate levels.For individual metals,the potential ecological risk was in the following decreasing order:Cd>Hg>Pb>Cr>As.