Spatial Variability of Soil Heavy Metals Content under the Influence of Urban Expansion

To reveal the spatial variability of soil heavy metals under the influence of urban expansion, Yingxing city of Jiangsu province was selected as study area. Three transects were arranged in the urban-rural ecotone. 24 surface soil samples were collected. And the contents of heavy metals including Hg, Pb, Cu and Zn were measured and analyzed. The results were as follows: (1) Hg contamination and Pb, Cu accumulation phenomenon had taken place in soil of some area of urban-rural ecotone; (2) Urban expansion had more influence on Hg content and Pb content than Cu content and Zn content. Also the formers had more complex spatial distributions; (3) The contents of Hg, Pb and Cu were zonal anisotropic in the space, and that of Zn was geometric anisotropy. The four elements were different significantly in the characteristics of migration and accumulation in different direction of the urban expansion.