Chemical and microbiological characteristics of soils formed during self-growing of waste from the enrichment of rare metal ores in the subarctic

The development of rare metal ore deposits in the Murmansk region over the past 70 years has been accompanied by the storage of fine-grained enrichment waste, which led to the formation of two tailings fields. The field, which was decommissioned 35 years ago, is undergoing natural overgrowth processes. Studies of the mineral and chemical composition, quantitative and qualitative characteristics of the microbiota of technogenic surface formations (TSF) and soils, formed on waste from the enrichment of loparite ores, have been carried out. With increasing age of TSF, the destruction of weakly stable alkaline minerals was observed simultaneously with an increase in carbon content from 0 to 4.5% in the upper soil horizon. Differential thermal analysis has shown that organic matter of the coarse humus horizon of the conditionally background soil had a more complex composition in comparison with the organic matter formed on the material of the tailings of rare metal ores. An increase in the number and biomass of bacteria and microscopic fungi, the species diversity of micromycetes, and a leveling of the functional profile of microorganisms during the transition from the initial tailings material to areas with vegetation were noted. 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 that are resistant to the unfavorable conditions of rare metal tailings.