河南省某高校校园表层土壤重金属污染状况与评价

Distribution and evaluation of heavy metals in surface soil in one of universities of Henan province

为了解和评价高校校园不同功能区和新老校区表层土壤重金属污染状况,在河南某校园多个校区采集了91个表层土壤样品,利用BCR(European Community Bureau of Reference)连续提取法提取校园表层土壤中重金属的化学形态,并采用单因子污染指数法和内梅罗污染指数法对其污染状况做出评价.结果表明:校园不同功能区的表层土壤重金属Pb,Zn,Cd和Cu的平均含量分别为116.37、95.08、0.64和39.89mg·kg-1,均高于河南省土壤背景值,4种元素的残渣态均占有较大比例,其中Pb在土壤中除残渣态之外,酸可提取态、可还原态和可氧化态含量在土壤中都占有相当的比例,具有潜在的环境风险;生物有效性分析表明,Cd和Pb易被生物利用的量相对较大,潜在危害性较大,Zn和Cu不易被外界生物所利用;绿化区各重金属元素之间均不存在相关性,Zn-Cd在校门口、教学区和建筑区都呈显著正相关,Pb-Zn在生活区与教学区中呈显著正相关关系,Pb-Cd在实验区呈极显著正相关.内梅罗综合污染平均指数为0.54.高校校园表层土壤重金属含量处于安全级别.

In order to investigate and evaluate the heavy metal pollution of topsoil in different functional areas as well as old and new campus,91 topsoil samples were collected from several campuses of a university in Henan.The chemical forms of heavy metals in the surface soil were extracted by BCR(European Community Bureau of Reference)continuous extraction method.The pollution level of heavy metal was assessed by single pollution index and Nemerow index method.The results showed that the average contents of heavy metals Pb,Zn,Cd and Cu in the different functional areas of the surface soil were116.37,95.08,0.64 and 39.89 mg·kg-1.All of the heavy metals exceeded the soil background values of Henan province.The residual states of the four elements all occupied a large proportion.In addition to residue state,acid extractable state,reducible state and oxidizable state content of Pb in soil account for a considerable proportion in soil,with potential environmental risks.Bioavailability analysis showed that Cd and Pb were relatively easy to be utilized by organisms,indicating a serious potential risk.Zn and Cu were not easily used by outside organisms.There was no correlation among heavy metal elements in greening area.Zn-Cd had a significant positive correlation in the doorway,teaching area and building area.Pb-Zn had a significant positive correlation in living area and teaching area.Pb-Cd had a very significant positive correlation in the experimentation area.The Nemerow comprehensive index was 0.54.The content of heavy metals in the surface soil of university campus was at a safety level.