Olga A. Sorokina

The article presents the results of studies of the major and trace element composition of alluvial soils in the Amur River valley. Based on analysis of changes in the distribution pattern of trace elements (rare earth elements), as well as geochemical indices (WIP, STI, R, CIA, CIW, PIA, V), it is shown that the formation of alluvial soils proceeded in different segments of the river in different geomorphological conditions and was influenced by sorting of detrital material and technogenic factors. Statistically significant differences between studied segments are confirmed by statistical analysis.

The results of studies of the macro- and microelement composition of the riverbed sediments of the Bureya River are presented. Analysis of the changes in the distribution of microelements (rare-earth...

This paper reports the results of chemical study of bottom sediments of the Zeya and Selemdzha rivers, the largest water streams of the Amur River basin. It was established that the bottom sediments...

The distribution patterns of the chemical elements in the bottom sediments and alluvial soils of the Urkan River valley (one of the largest tributaries of the Zeya River, a tributary of the Amur River) have been examined. It is shown that the concentrations of the chemical elements in the bottom sediments generally correspond to those in the bedrocks composing the river catchment and in the upper part of the continental earth’s crust, though the accumulation of most of the elements in the bottom sediments is somewhat lower. The composition of the microelements in the alluvial soils is mainly determined by the composition of the microelements in the bottom sediments. The alluvial soils are somewhat enriched in Mn, Zn, Co, and Cu, which is related to the biological accumulation of these elements entering the trophic chains.

The chemical composition of the bottom sediments of the Amur River has been analyzed using modern analytical techniques. It was found that their composition and distribution patterns are controlled by several sources. The most probable sources for the bottom sediments of the studied area are siliceous magmatic or metasedimentary rocks.

The soil was sampled in the zone of long-term mining of a gold placer. The total contents of heavy metals, mobile forms of these elements, and the quantitative characteristics of the ecological trophic groups of the soil microbial community have been determined. The soil samples are characterized by stable enrichment with such elements as Co, Ni, Cr, Cu, Pb, Zn, As, and Mo. The amount of mobile forms (relative to total content) varies from 0.5 to 54% for different elements. It has been shown that the abundance of the main ecological-trophic groups of microorganisms depends on degree of pollution. The correlations between increased concentrations of the mobile forms of some heavy metals and microbiological indices are established and illustrated.