泾河流域农业土壤重金属污染调查与评价

Investigation and Assessment on Heavy Metal Pollution of Farming Soil in the Jinghe River Basin

通过对泾河流域主要农业区土壤样品的采集、监测,依据泾河流域土壤重金属元素背景值和国家《土壤环境质量标准》(GB15618-1995)二级标准作为评价标准,分析了对土壤环境及人体危害较大的Cd,As,Cr,Pb等重金属元素的累积和污染程度。结果表明:以泾河流域土壤重金属元素背景值为评价标准,泾河流域农业土壤重金属累积污染程度具有Pb>As>Cd>Cr的特征;泾河流域农业土壤重金属Pb,As,Cd累积污染程度较高,主要是由于人类长期不合理使用化肥所致。以国家土壤环境质量二级标准为评价指标,泾河流域农业土壤重金属污染程度具有As>Cd>Cr>Pb的特征;泾河流域农业土壤样品重金属单项污染指数Pi和综合污染指数P均小于0.7,土壤环境中的重金属含量现状适宜于无公害农产品和果品基地建设的要求。

After collecting and testing the soil samples from the Jinghe River Basin in the south Loess Plateau, in this study the accumulation degree and the pollution status of soil heavy metals （Cd, As, Cr and Pb） which are harmful to soil environment and human health in the drainage basin are analyzed and assessed by using the singlefactor index and synthetic pollution index methods based on the ＂ Environment Quality Standards for Soils＂ （GB15618-1995 Ⅱ）. The results reveal that the accumulation degree of heavy metals in farming soil in the Jinghe River Basin is in an order of Pb 〉 As 〉 Cd 〉 Cr by regarding the background values of heavy metals in soil as the standards. The accumulation degree of Pb, As and Cd in farming soil are relatively high in the drainage basin, which is mainly caused by the long-term irrational application of chemical fertilizer. The pollution degree of heavy metals in farming soil in the drainage basin is in an order of As 〉 Cd 〉 Cr 〉 Pb by taking the ＂Environment Quality Standards for Soils＂（ GB15618-1995 Ⅱ） as the evaluation standards; the synthetic pollution index and the singlefactor pollution indices of heavy metals in farming soil are all lower than 0. 7, so the soil environment in the drainage basin can satisfy the safety qualification for producing chemical-free farming products and building up fruit production base based on considering the contents of heavy metals in soil.