Parameters of mathematical models for vertical migration of heavy metals in soils in the area of lead and antimony plant

The data on distribution of heavy metals in the soil profile (Yuan et al., 2017) of the province Guangxi in southern China in the zone influenced by lead and antimony plant were analyzed. The soil is sod-calcareous and rich in humus. The averaged over the years and depth (“apparent”) parameters of diffusion and convective-diffusion models of migration in the area of combined soil pollution (only soil aerogenic pollution and in combination with the sewage waters) are estimated. The largest values of the diffusion parameters were obtained for Zn and Cd (n∙10-7 сm2/sec), the smallest values were obtained for Pb and Sb (n∙10-8 сm2/sec). When soil was flooded by waste waters, a reliable convective component of migration for Zn and Sb was noted. At the same time the peak of Zn concentration moved to the depth of 40-60 cm. Under these conditions there was no clear inverse correlation between the migration mobility and the amount of sorption of elements by the soil.