MOBILE FORMS OF HEAVY-METALS IN SOILS OF MIDDLE VOLGA FOREST-STEPPE (EXPERIENCE OF MULTIVARIATE REGRESSION-ANALYSIS)

Regional statistical models have been developed, which demonstrate qua ntitative correlations between mobile Mn, Ce, Cu, Pb, Ni, Zn, and majo r soil-geochemical agents. They made possible evaluation of the impact of total metals content, humous content, pH, and redox conditions on the differentiation of heavy metals mobile forms. The paramount import ance of organic matter has been revealed for migrations of Mn, Zn, and partially of Pb. The increase in soil solution pH contributes to Zn a nd Mn mobilization and to the decrease of mobile Pb compounds content. The mobile Cr concentrations are regulated by its total amount and by pH values. The fate of Ni is determined by the combination of all the agents enumerated.