Heavy Metals in the Soils of Steppe Ecosystems in Western Transbaikalia

The results of an experimental study of the transformational flow of heavy metals (copper, zinc, nickel, and lead) from soil-forming rocks into chestnut soils and then into virgin herbage and humic substances are presented. The soil-forming rocks include deluvial and deluvial–proluvial sediments, as well as sand and pebble sediments; their weathering, displacement, and redeposition lead to unequal granulometric, mineralogical, and chemical rock compositions, thereby influencing the composition of the soil cover. Chestnut soils are characterized by an arid climate, a long-term frozen state, low bioproductivity, low thickness, a light granulometric composition, and low humus content. Humic substances were extracted with the Grimme method. The concentrations of microelements were determined via atomic absorption with direct electrothermal atomization of samples. Heavy metals were determined on an atomic absorption spectrophotometer (AAS-15 Perkin Elmer). It has been revealed that the amount of copper and nickel is low in the soils due to the depletion of rocks in these metals, while the content of zinc and lead is higher, which is reflected in the state of vegetation and humus.