湘江(株洲段)沉积物重金属污染现状及生态风险评价

Evaluation of Pollution Situation and Ecological Risk for Heavy Metals in Sediment of Xiangjiang River(Zhuzhou Section)

采集湘江(株洲段)9个断面的底泥样品,和1个柱状样品,对重金属(Cu、Pb、Zn、Cd、Ni、Cr、Hg、As)含量进行了检测;并运用地质积累指数法对底泥中重金属进行了生态风险评价。结果表明,该江段底泥已受到较严重的重金属污染,在霞湾断面达峰值。Cu、Pb、Zn、Cd含量为湘江背景值4.6倍~58.8倍,比该江段20世纪80年代均值增高1.71倍~1.96倍;地质积累指数评价结果表明,该江段未受到Ni、Cr的污染;Cd的污染比其他重金属的污染要严重,污染级别为强-极强、极强;重金属的垂直分布表明:大体上,各重金属元素最高值出现在深度0 cm^50 cm,随深度的变化Ni、Cr的含量变化不大。

Heavy metals（Cu,Pb,Zn,Cd,Ni,Cr,Hg,As） were detected in the samples which were collected in nine cross sections and one vertical section at Xiangjiang River of Zhuzhou.Ecological risk was evaluated by index of geoaccumulation method.The results showed that sediment of Zhuzhou section had polluted seriously and pollutant concentration at Xiawan was the highest among all samples.The concentrations of Cd,Pb,Zn and Cd reached 4.6~58.8 times higher than background values of Xiangjiang river,and 1.71~1.96 times higher than the heavy metal values during the 1980s.There were on evidence of Ni and Cr pollution by evaluation of the geoaccumulation index.Cd was the top pollutant and pollution level had reached high-highest or the highest.The highest values of the heavy metals were found in the vertical section samples between 0 cm and 50 cm except Ni and Cr.