贵州红枫水库沉积物重金属污染评价及来源分析

Evaluation and source analysis of heavy metal pollution in sediments of Hongfeng Reservoir in Guizhou Province,China

为了解红枫水库沉积物重金属污染现状,沿库区采集8个点共计80个沉积物样品,采用原子荧光光谱仪及原子吸收光谱仪对重金属Hg、As、Pb、Cd、Cr、Cu、Zn和Ni含量进行了测定,利用地积累指数(Igeo)和潜在生态风险指数(RI)进行污染评价,同时进行相关性分析并讨论其污染来源。结果表明:红枫水库北湖沉积物重金属含量明显高于南湖,8种重金属Hg、As、Pb、Cd、Cr、Cu、Zn、Ni的平均含量依次为0.56、35.76、43.66、0.50、91.03、89.14、152.44和109.30 mg·kg-1;以贵州省土壤背景值为参比,地积累指数评价结果显示Hg为中等污染,污染顺序为Hg>Ni>Cu>As>Zn>Pb>Cr>Cd,综合潜在生态风险指数评价结果显示红枫水库为中等生态风险;库区沉积物重金属污染来源于三方面:一是工业排放,主要集中在北湖和中湖,重金属包括Pb、Zn、Cd;二是城市排放及周边农药、化肥残留,主要污染区为北湖、中湖,污染物为Cr、Ni、As和Cu;三是矿区开采,污染覆盖全湖区,主要包括Hg和As。

To understand the status of heavy metal pollution in sediments in Hongfeng Reservoir,a total of 80 sediment samples were collected from eight sites. The concentrations of Hg,As,Zn,Pb,Cd,Cr,Cu and Ni were analyzed using atomic fluorescence spectrometer and atomic absorption spectrometer. The pollution status was evaluated by geo-accumulation index( Igeo) and potential ecological risk index( RI). Meanwhile,correlation analysis was carried out and the sources of pollution were discussed. The results showed that the concentrations of heavy metals in the sediments of the North Lake of Hongfeng Reservoir were significantly higher than those in South Lake. The average concentrations of Hg,As,Pb,Cd,Cr,Cu,Zn and Ni were 0.56,35.76,43.66,0.50,91.03,89.14,152.44 and 109.30 mg·kg-1,respectively. Based on the soil background value of Guizhou Province,the results of Igeoevaluation showed that Hg was in a moderate pollution,and the pollution order was Hg>Ni>Cu>As>Zn>Pb>Cr>Cd. The RI evaluation results showed that Hongfeng Reservoir was in a medium ecological risk. There were three sources for the heavy metal pollution of Hongfeng Reservoir. Industrial emissions were the main source of Pb,Zn and Cd for North Lake and Central Lake. Urban emissions and the remaining of pesticides and chemical fertilizers surrounding the reservoir were the main source of Cr,Ni,As and Cu for North Lake. The Hg and As mainly came from mining activity for the whole reservoir.