城市土壤重金属污染多元统计及空间评估

Multi- statistical and Spatial Assessment of Urban Soil Heavy Metal Contamination

为确定徐州市城区土壤重金属的污染情况,对167个城市土壤样品的Mn,Fe,Ni,Cu,Zn,Cd和Pb等7种重金属元素进行多元统计和空间分析。结果表明,7种重金属元素中,Ni,Cu,Zn,Cd,Pb含量均高于背景值。聚类分析和因子分析显示,研究区域土壤中Pb,Cd,Cu,Zn具有相似来源,Ni,Fe,Mn具有相似来源。Pb,Cd,Cu,Zn,Mn,Ni的块基比在0.25~0.75之间,表明变量具有中等程度的空间相关性,其空间变异性同时受土壤母质和人类活动的影响。研究区域土壤中,Zn,Cd,Pb的空间分布基本一致,同时受到交通运输和工业排放的影响;道路交通污染为研究区域Cu的主要来源。Fe和Ni同时受土壤母质和人类活动的影响,徐州钢铁厂附近区域土壤Fe含量整体偏高,在市中心主要交通干道附近表土中,Fe也表现出一定量的富集,Mn主要来自于土壤母质。

In this study,167 soil samples have been collected and multivariate statistical analysis and spatial analysis has been conducted on 7 heavy metal elements（ Mn,Fe,Ni,Cu,Zn,Cd and Pb） to determine the soil heavy metal contamination of Xuzhou urban areas. The results indicate that the concentrations of Ni,Cu,Zn,Cd and Pb are higher than the background values. Cluster analysis and factor analysis shows that Pb,Cd,Cu and Zn have similar sources and Ni,Fe and Mn have similar sources within the study area. The block ratios [C0/（ C0＋ C） ] of Pb,Cd,Cu,Zn,Mn and Ni are all within the range of 0. 25- 0. 75,indicating that Pb,Cd,Cu,Zn,Mn and Ni are moderately spatially dependent and their spatial variability is not only affected by soil parent materials,but also affected by stochastic factors,such as anthropogenic activities. Spatial distributions of Zn,Cd and Pb are consistent within the study area,affected by traffic and vehicles and industrial emission. Road traffic pollution is the primary source of Cu in the study area. Fe and Ni are influenced by soil parent materials and anthropogenic activities,and the levels of Fe around the near areas of Xuzhou steel works are high. Fe also manifestes a certain amount of enrichment in the topsoil around the main traffic artery in the downtown and Mn is basically induced by soil parent materials.