大燕河沉积物重金属污染特征及生态风险分析

为了解大燕河表层沉积物重金属污染特征及潜在生态风险,对大燕河干流和支流沉积物重金属污染物进行了分析,并采用Hakanson生态危害指数法进行评价。结果表明,大燕河干流沉积物重金属含量明显高于支流,重金属含量高于广东省土壤背景值,Cu、Cd、Zn、Pb、Hg超出了土壤环境质量Ⅰ级标准。沉积物中重金属Cu、Cd的富集系数明显高于其他重金属,不同采样点重金属超出背景值的程度具有明显的差异性,呈现干流高于支流,下游高于上游的特征。沉积物中重金属具有极强的生态危害,各种重金属造成的平均生态危害程度由大到小依次为:CdHgCuAsPbZnNiCr,其潜在生态风险应引起足够的重视。

Pollution Characteristics and Potential Ecological Risk Assessment of Heavy Metals in Dayan River Sediment

In order to find out the heavy metals concentrations and their potential ecological risks in the sediments of Dayan River, pollution levels of heavy metals from both the trunk stream and tributaries of Dayan River were analyzed. The Potential Ecological Risk Index were then employed to evaluate the pollution degree of heavy metals in the sediments. The results showed that the heavy metals concentrations in sediments of trunk stream are much higher than that of tributaries of Dayan River, which is higher than soil background value of Guangdong province. The concentrations of Cu, Cd, Zn, Pb, Hg are higher than the first standard of soil environment quality. Enrichment coefficients of Cu and Cd in sediments are much higher than that of other heavy metals. Sediments from different places and the concentrations of different heavy metals are much different. The heavy metals in sediments are very harmful to environment. The descending order of pollution degree of various heavy metals is： Cd 〉 Hg 〉 Cu 〉 As 〉 Pb 〉 Zn 〉 Ni 〉 Cr; Potential ecological risk of heavy metals should arouse the attention of the relevant government departments.