Spatial structure and distribution of heavy metals in agricultural soils of peri-urban area in pudong of shanghai, china

The contents of heavy metals (Cu, Zn, Pb, Cd, Cr, Hg and As) in agricultural surface soils of Peri-Urban Area in Pudong of Shanghai were analyzed to investigate the heavy metal contents and spatial distribution. Different evaluation methods and assessment standards were also used for comparison. In addition, Kriging method based on GIS was also applied to study the spatial variability of heavy metal pollution. The result showed that mean concentrations of heavy metals were all higher than the natural-background values of them, respectively, except for Pb and As. Based on the national soil quality standard, Cu, Zn, Cd and Hg were determined in some regions, with the ratios of 3.8%, 2.1%, 9.2% and 0.8%, respectively. However, the contents of Pb, Cr and As were much lower than the values of national soil quality standard. The analysis of spatial distribution showed that the soil quality was influenced by different heavy metals at different levels. Cu, Zn, Cd and Hg were the dominant elements, causing soil heavy metal pollution in the area. Additionally, the regional differentiation of soil pollution was also obvious.