派河干流表层沉积物重金属分布特征及潜在生态风险评价

Distribution Characteristics of Heavy Metals and Potential Ecological Risk Assessment of the Surface Sediment of Pai River Main Stem

目的:以派河干流表层沉积物为对象,研究Cu、Zn、Ni、Cd、Cr、Pb、Hg、As等八种重金属总量分布,并在此基础上对沉积物中的重金属进行生态风险评价,指出主要污染物。方法:于枯水期利用户外助手软件GPS定位在派河干流上游至入湖口采样点采集土样,土样消解采用HNO3-HF-HClO4分解法,Hg、As利用普析原子荧光光度计检测,Cu、Zn、Ni、Cd、Cr、Pb利用固体原子吸收光谱仪检测。运用Origin软件制图分析重金属总量分布,运用潜在生态危害系数法对重金属进行生态风险评价。结果:派河干流表层沉积物重金属潜在生态风险指数排序为Cd>Hg>Pb>Cu>Ni>Zn> As>Cr,从单种金属风险指数的评价结果来看,As、Cr、Ni、Zn、Cu、Pb属于轻微等级污染,Hg、Cd的评价均值分别为753.86和5 537.3,属于极强等级污染;从综合潜在风险指数的评价结果来看,各点位均属于极强等级污染,其中,Hg的贡献率为11.89%,Cd的贡献率达到87.42%。结论:派河是巢湖Cd和Hg污染的主要输送支流之一,对派河流域重金属污染进行治理,应主抓Cd和Hg污染,降低派河以及巢湖Cd和Hg的生态风险。

Objective：As the surface sediments of the Pai-river main stem,the heavy metals＇ distribution of Cu、Zn、Ni、Cd、Cr、Pb、Hg and As were investigated.And on this basis,the ecological risk of heavy metals were evaluated in sediment.The main pollutant was pointed out.Methods：During the dry water period,the outdoor assistant software GPS used to locate the soil samples upstream to the Hukou samplingpoint,and the soil sample was dissolved by HNO3-HF-HClO4 decomposition method.Hg and As were detected by the universal atomic fluorescence photometer,and Cu,Zn,Ni,Cd,Cr,Pb were measured by solid atomic absorption spectrometer.Origin software was applied to analyze the total distribution of heavy metals,and the potential ecological hazard coefficient method was applitd to evaluate the ecological risk of heavy metals.Results：The potential ecological risk index of heavy metals in the surface sediment of the river is Cd〉Hg〉Pb〉Cu〉Ni〉Zn〉As〉Cr.From the point of the evaluation results of single metal risk index,As,Cr,Ni,Zn,Cu,Pb belong to slight pollution grade,Hg,Cd,the evaluation of mean value was 753.86 and 5 537.3,respectively,belong to the strong level of pollution;According to the comprehensive evaluation results of the potential risk index,all points are highly rated pollution,among which,the contribution rate of Hg was 11.89%,and Cd was 87.42%.Conclusion：Pai-river was one of the main transport Chaohu Lake of Cd and Hg pollution,Pai-river basin in heavy metal pollution treatment should focus on Cd and Hg pollution,reduce Pai River and Chaohu ecological risk of Cd and Hg.