三峡水库小江消落区土壤重金属时空分布与来源初步分析

2010年3-9月对小江流域消落区的5个断面的土壤重金属含量进行监测。结果表明，2010年小江流域消落区土壤Cu、Zn、Pb、Cr、Fe、Mn均值分别为28.90、72.73、23.58、20.70、35.58*103、517.14 mg/kg。土壤综合污染指数为0.73，污染等级处于警戒级。小江消落区土壤重金属含量沿程分布以高阳站点较低，黄石站点较高，且大部分重金属含量随高程升高总体呈现升高的趋势。时间分布上以3、7月各重金属均值含量较高。与2009年相比，2010年消落区土壤重金属Fe、Mn 、Zn含量有所降低，Cu、Pb含量有所增高。利用相关性分析和因子分析对5种重金属的相关性和来源进行解析的结果表明，Fe、Mn与其他重金属相关性显著（P<0.05或P<0.01），而Cu、Pb之间也显著相关（P<0.01）,Cr与Fe、Mn之外的重金属的相关性都较弱，初步推断Fe, Mn, Zn属于“自然因子”类别元素，Cu、Pb属于“污染因子”类别元素。

Temporal and Spatial Distribution and sources analysis of Soil Heavy Metals in Water- level- fluctuation Zone of Xiaojiang Watershed in Three Gorges Reservoir

Soil samples were collected from the surface of five sections in the water-level-fluctuation zone of Xiaojiang River from March to September in 2010.The average concentrations of Cu,Zn,Cd,Pb,Fe and Mn were 28.90,72.73,23.58,20.70,35.58×103 and 517.14 mg/kg.The integrated pollution index of heavy metals in water-level-fluctuation zone of Xiaojiang River was 0.99,and the pollution grade was on the alarm level.Along the Xiaojiang River,the average concentrations of soil heavy metals reduced in Gaoyang section,increased in Huangshi section.The average concentrations of most heavy metals were increased with the increasing of elevation.The average concentrations of soil heavy metals were the highest in March and July.Compared with 2009,the average concentrations of Fe,Mn and Zn were reduced,and those of Cu and Pb were increased in 2010.Further Correlation Analysis and Factor Analysis on Correlation and sources of heavy metals revealed that Fe,Mn and other heavy metals in soils took on positive correlations(P<0.05 or P<0.01),the correlations between Cu and Pb concentrations were significantly positive(P<0.01),Cr had the poor correlations with other heavy metals except Fe and Mn.We deduced that the contaminations of Fe,Mn and Zn in the watershed of Xiaojiang River were caused by natural factors,and those of Cu and Pb were caused by pollution factors.