Role of humus substances in chemical soil pollution during deposit exploitation in Priokhotye and Priamurye

Abstract

Here we analyze how the mining enterprises of Priokhotye and Priamurye affect the state of soils. It is established that during 3–5 years of operation of the ZIF (gold mining factory) there is occurred in the soil an increase in total concentrations of Fe, Mn, Pb, Cu and Zn with respect to the background level. We show that sulfate-containing minerals of mining raw materials and waste play a role in the formation of wastewater composition and chemical contamination of soils. The background-forming elements (Fe and Mn) were found to determine the nature of the distribution of soluble forms of Cu, Pb, Zn and Co in the soil profile, while the content of aggressive fractions of humic acids intensifies their migration activity. The distribution of chemical elements in the soil profile is controlled by the content and quality of organic matter. The degree of activation of geochemical processes in situ in the soils against the background of a low temperature gradient does not prevent the migration of pollutants via the subsurface flow down the slope. The conditions of the migration of the elements and the processes of their concentration in the soils were analyzed. The migration activity of multi-charged cations (Fe3+, Mn7+) was shown to determine the behavior of low-charged cations (Cu(1−2)+, Zn2+, Pb2+). The levels of contamination of the soils characterized by the excess of concentrations of elements over their regional geochemical background were studied. The spatial heterogeneity of chemical element concentrations in soils is considered as a function of migration activity of elements. The mechanisms of chemical contamination of soils that present the risks of soil degradation in the absence of recultivation are described. The basic principles of the regime of natural resources management in the areas of mining activity for the territory of Priokhotye and Priamurye are formulated.We publish fragment of the map, original geochemical studies and a new data, focusing on the different aspects of this case study. We are publishing this for the first time.