临水河表层沉积物中的重金属污染评价

选取临水河底部表层沉积物为研究对象,采用地质累积指数、潜在生态危害指数对其重金属污染进行评价。结果表明:沉积物Cr、Cd、Cu、Pb的含量介于203.971~412.363 mg/kg,浓度由高到低依次为Cr>Cu>Pb>Cd;Cd、Cu、Pb的空间变异系数较大,依次为82.8%、65.1%和43.1%,表明这3种重金属可能存在点源污染;Cr的空间变异系数较小,为28.2%,说明该重金属可能存在面源污染。地质累积指数表明:Cd和Cr的污染等级分别为3~5级和1~2级,为中度污染到极强度污染,Cu和Pb无污染。潜在生态危害指数RI值为280.54~879.27,污染程度为中等污染至很强污染。Cd为河流表层沉积物重金属污染的最大贡献者。

EVALUATION OF HEAVY METAL POLLUTION IN SURFACE SEDIMENTS OF THE LINSHUI RIVER

To analyze the heavy metal contents in surface sediments of Linshui River,evaluations were done by the methods of geological accumulation and potential ecological risk.The results showed that the concentration of Cr,Cd,Cu and Pb in sediments were in the range of 203.971 ～ 412.363 mg/kg,and the order of the concentration was Cr ＞ Cu ＞ Pb ＞ Cd.The coefficient of spatial variability of Cd,Cu and Pb were 82.8％,65.1％ and 43.1％,respectively,indicating that three heavy metals might have point source pollution.The small coefficient of spatial variation of Cr was 28.2％,indicating that the heavy metal may be non-point source pollution.By the geological accumulation index,the pollution degrees of Cd and Cr were 3 ～ 5,2 ～ 3,respectively,while Cu and Pb were ranked as non-polluted.The potential ecological hazard indexes RI ranged from 280.54 to 879.27,with the pollution ranging from moderate to strong.Cd was the largest contributor to heavy metal pollution in the surface sediments.