兰州市主城区大气降尘和表层土壤重金属污染特征与评价  

Special heavy metal pollution features in atmospheric dust-fall and top soil in main urban districts of Lanzhou

作　　者：李颖泉[1,2] 赵保卫 牛武江[3] 董波 蔡觉先[1,2,3] LI Ying-quan;ZHAO Bao-wei;NIU Wu-jiang;DONG Bo;CAI Jue-xian(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Dust Suppression for Transportation and Storage Engineering Rescarch Center Gansu Province,L anzhou 730070,China;Gansu Province Environmental Monitoring Center,Lanzhou 730020,China)

机构地区：[1]兰州交通大学环境与市政工程学院,兰州730070 [2]甘肃省交通储运扬尘治理工程技术研究中心,兰州730070 [3]甘肃省环境监测中心站,兰州730020

出　　处：《安全与环境学报》2020年第4期1440-1448,共9页Journal of Safety and Environment

基　　金：科技部重大专项(2016YFC0206003);兰州市人才创新创业项目(2018-RC-84);兰州交通大学青年科学基金项目(2018033)。

摘　　要：同一区域大气降尘和表层土壤中重金属的污染特征能够反映出重金属污染物在大气-土壤系统中的迁移、传输和扩散规律。在兰州市主城区设置10个采样点,分别采集大气降尘及附近表层土壤样本,分析大气降尘和表层土壤中6种重金属(Cu、Pb、Zn、Cr、Cd和Ni)质量比、来源等污染特征,并对其污染水平和潜在生态危害进行评价。结果表明,大气降尘中6种重金属元素平均质量比由大到小为Zn(379.84 mg/kg)、Pb(133.78 mg/kg)、Cr(95.61 mg/kg)、Cu(84.25 mg/kg)、Ni(43.13 mg/kg)、Cd(3.89 mg/kg),表层土壤中6种重金属元素平均质量比由大到小为Zn(136.07mg/kg)、Cr(85.25 mg/kg)、Pb(55.99 mg/kg)、Cu(42.20mg/kg)、Ni(37.61 mg/kg)、Cd(0.55 mg/kg),在不同功能区6种重金属的平均质量比差异较大。大气降尘和表层土壤中,Cu、Pb、Cd、Zn的变异系数较大。因子分析结果表明,兰州市大气降尘中的重金属主要来源于燃煤、交通运输和工业生产。重金属污染水平评价结果表明,兰州市主城区大气降尘中的Cd已经构成偏严重污染,Pb达到偏重度污染,Cu、Zn为中度污染,Cr、Ni无污染;表层土壤中的Cd达到中度污染,Pb、Zn为轻度污染,Cu、Cr、Ni均为无污染。潜在生态危害评价结果表明,兰州市主城区大气降尘和表层土壤中Cd的潜在生态危害最大,分别达到极强污染水平和强污染水平;Cu、Zn、Cr、Ni均为低潜在生态危害。The present paper is aimed at making an analysis of the atmospheric dustfall situation and the topsoil in the main urban districts of Lanzhou City by collecting the respective dust samples.The analysis we have done over the pollution features of the 6 kinds of heavy metals(known as Cu,Pb,Zn,Cr,Cd and Ni)in the atmospheric dust fall and top soil even in the same district can reflect the gap or difference of the dust migration,transfer and diffusion in the atmospheric dust system.For instance,among the 10 sampling points of the city,the pollution levels and the potential ecological hazards of the 6 heavy metals can be assessed and evaluated in the following situations.For example,the average mass ratios of the 6 heavy metals in topsoil can be found,such as Zn(136.07 mg/kg),Cr(85.25 mg/kg),Pb(55.99 mg/kg),Cu(42.20 mg/kg),Ni(37.61 mg/kg)and Cd(0.55 mg/kg).The average mass ratios of the6 heavy metals in the atmospheric dustfall were Zn(379.84 mg/kg),Pb(133.78 mg/kg),Cr(95.61 mg/kg),Cu(84.25 mg/kg),Ni(43.13 mg/kg)and Cd(3.89 mg/kg).However,the variation coefficients of Cu,Pb,Cd and Zn in the atmospheric dustfall and top soil have been found greater.The detailed factor analysis results indicate that the heavy metal contaminants in the atmospheric dustfall in the city mainly come from the coal burning leftovers,the urban transportation and industrial production.The results of the heavy metal pollution level assessment showed that in the atmospheric dustfall of the city,Cd had been seriously polluted whereas Pb had been heavily polluted,though Cu and Zn were moderately polluted.As to Cr and Ni polluted,it has been found minor.Besides,Cd has been found just moderately polluted,whereas Pb and Zn were very slightly.And Cu,Cr and Ni can be said non-polluted at all.The results of the potential ecological hazard assessment prove that the potential ecological hazards of Cd in the atmospheric dust fall and top soil in the city turn out to be the greatest,up to the extremely serious pollution level and extremely serious contaminan

关 键 词：环境工程学 兰州市 大气降尘 表层土壤 重金属 污染特征 

分 类 号：X51[环境科学与工程—环境工程]