Chemical and Microbiological Characteristics of Soils Formed during Overgrowing the Wastes from Rare Metal Ores Enrichment in the Subarctic

The development of rare metal ore deposits in Murmansk oblast over the past 70 years has been accompanied by the storage of fine-grained concentration wastes, which caused the formation of two tailing fields. The field, which was decommissioned 35 years ago, undergoes natural overgrowth processes. Studies of the mineral and chemical composition, quantitative and qualitative characteristics of microbial communities of technogenic surface formations (TSF) and soils formed on wastes being accumulated from the enrichment of loparite ores have been performed. With increasing age of TSF and the destruction of weakly stable alkaline minerals, there was a simultaneous increase in carbon content from 0 to 4.5% in the upper soil horizon. Differential thermal analysis has shown that the organic matter composition in the raw humus horizon of the conventionally background soil was more complicated in comparison with the organic matter formed on the material of the tailings of rare metal ores. There was an increase in the number and biomass of bacteria and microscopic fungi and in the species diversity of microfungi, as well as leveling of the physiological profile of microbial communities during the transition from the initial tailing material to areas with vegetation. The results obtained can form the basis for the development of a nature-based technology for initializing the soil-forming process, using indigenous strains of microorganisms resistant to unfavorable conditions of rare metal tailings.