Spatial Variability Characteristics of Soil Heavy M etals due to Industry Development of Typical Regions in Changjiang River Delta of China

The main objective of this study was to evaluate the spatial variability characteristics of soil heavy metals due to industry development of Yixing, an area with intensive industrialization in the Changjiang (Yangtze) River Delta of China. To do that, concentrations of heavy metals in soils with different distances from solid-, liquid-and gas point sources and non-point sources were measured. The results show that 1) different point sources can induce the strong enrichment of different heavy metal elements in soil and the concentration around solid point source is the highest, followed by liquid, and gas is relatively low. Concentrations of heavy metals in soils are significantly decreased with distance. And affected by the prevailing wind, the influenced area due to gas point source is the largest, followed by solid, and liquid is relatively small; 2) compared with point source, the enrichment of heavy metals in soils around non-point source in industrial town is relatively weak, but its element types are complex. There are no significant changes of concentrations of heavy metals in soils with distance, but the influenced area is larger; and 3) affected not only by the prevailing wind direction, but also by industry layout, concentrations of soil heavy metals due to non-point source are of difference in different directions around industrial town. Due to the complexity of the enrichment element’s types of soil heavy metals and their combined effect in non-point source, the spatial variability is more complex. It means that taking effective measures to control non-point source is especially difficult.