三亚市果蔬地重金属空间分布及其污染评价

通过野外调查采样,采用标准对比法和地累积指数法,评价了三亚市果蔬地表层土壤重金属的污染状况。结果表明:土壤中Hg、Cd、Cr、Pb和As5种重金属的积累不显著,其平均值均未超过国家环境质量二级标准(GB15618-1995);但Hg、Cd和Pb的平均值高于海南岛农用地的自然背景值,表明存在区域轻度污染;Cr、Hg、Pb和As4种重金属元素的变异系数均>1,表明土壤中Cr、Hg、Pb和As的分布极不均匀。同时,利用地理信息系统(GIS)Krging插值方法得到了5种重金属的空间分布图,显示出不同重金属元素的空间分异特征,为三亚市果蔬地的可持续开发利用提供指导。

Heavy metals in orchard and vegetable garden soils of Sanya City: Spatial distribution and contamination evaluation

Through field sampling and by using standard comparison and geoaccumulation index methods,the heavy metals contamination status of surface soils in the orchards and vegetable gardens of Sanya City was evaluated.In the test surface soils,the average concentrations of Hg,Cd,Cr,Pb and As were all lower than the Grade Ⅱ of China National Environment Quality Standard(GB 15618-1995),but those of Hg,Cd and Pb were higher than the background values of farmlands in Hainan Island,showing a slight pollution in certain areas.The variation coefficients of the metals were all>1.suggesting their extremely uneven distribution in the soils.The spatial distribution patterns of the five heavy metals obtained by using Kriging algorithm approach displayed spatial heterogeneity of soil heavy metals contamination,which provided guidance for the sustainable development and utilization of orchards and vegetable gardens in Sanya City.