Mechanism Analysis and Propagation Model of Heavy Metals Contamination in Urban Topsoil

In order to further research on the polluting condition and spreading features of heavy metals in urban surface soil, this study makes statistical analysis on indexes of 8 heavy metal concentrations. Then Are GIS geo- statistical analyst was used for Kriging interpolation of each kind of heavy metal concentration before figuring out the spatial distribution. Firstly, heavy metal contamination was analyzed by single-element pollution evaluation and multi-element pollution evaluation, before rationality analysis. Then, correlation extents between heavy polluting metals were calculated in each region by rationality analysis, leading to the correlations between the heavy metals. Finally, based on propagating features of different heavy metals, propagation models in water and atmosphere were established. Additionally, according to heavy metal distribution map, distribution point of high concentration was searched. With the assumption of the number of pollution source, theoretical concentration of sample point could be figured out, after the superposition of pollution intensity using propagation model based on data of the distribution points. Thus, the optimization model was established for locating the pollution source by minimizing the difference between theoretical value and actual value.