网湖流域不同类型土壤重金属含量及风险评价

Heavy Metal Content and Risk Assessment of Different Types of Soil in Wanghu Watershed

以网湖流域稻田、林地0~15 cm土壤为研究对象,运用原子吸收光谱仪测定土壤中Cu、Zn、Ni、Cr、Cd重金属含量,基于ArcGIS软件及内梅罗指数法分别分析了土壤重金属元素的空间分布特征和污染状况。结果表明,研究区土壤Cu、Zn、Ni、Cr、Cd的平均值为64.17、118.81、40.67、41.05和3.88 mg/kg。其中Cd含量是背景值的22.82倍;Cr、Cu、Zn和Ni的单因子污染指数均小于1,属于清洁;Cd的单因子污染指数大于3,属于严重超标。通过地累积污染指数的分析表明,Cu为1级轻度污染,Cd为偏重污染;土壤重金属含量变化与湖心距离远近没有明显相关性;Ni与Cr含量呈现较明显的相似性变化特点。

The heavy metal contents of Cu,Zn,Ni,Cr,Cd in the soil of 0~15 cm in paddy field and forest land of Wanghu watershed were determined by atomic absorption spectrometer.The spatial distribution characteristics and pollution status of heavy metals in the soil were analyzed based on ArcGIS software and Nemero index method.The results showed that the average values of Cu,Zn,Ni,Cr and Cd were 64.17,118.81,40.67,41.05 and 3.88 mg/kg respectively.The content of Cd was 22.82 times of the background value,and the single factor pollution indexes of Cr,Cu,Zn and Ni were all lower than 1,belonging to the clean level while the single factor pollution index of Cd was more than 3,which seriously exceeded the standards.The analysis for the accumulative pollution indexes indicated that Cu was the first level mild contamination while Cd belonged to relatively serious pollution.The change of heavy metal content in the soil had no obvious correlation with the distance from the lake center,and the contents of heavy metal elements Ni and Cr presented obvious similarity in changes.