ИСТИНА

This work presents data on the aerobic and anaerobic microbiological processes impact on uranium migration in upper aquifers polluted with sulfate and nitrate ions near to sludge depository of Novosibirsk chemical concentrate plant. Sludge depository was built in 1960x and it is still operating. Uranium concentration in subsurface water in several zones reached 1-2 mg/l and its migration process depends on geochemical aspects of water horizon: mineral sorption capacity, TOC, Eh, oxidizers concentration (O2, NO3, Fe+3 etc.) and biogeochemical processes. We analyzed chemical and microbiological characteristic of water samples of polluted and not polluted areas and get main data for biogeochemical modeling of Uranium migration capacity. Aerobic organotrophic, denitrifying, sulfate- and iron-reducing bacteria where found in natural microbial community by 16 S rRNA sequencing and cultural techniques. There where strains capable forming biofilms on sandy minerals in aquifer. Due to biogeochemical modeling using PHREEQC software data Uranium immobilization is possible in local areas with high content of organic substances. The most important microbiological process is the redox potential reduction due to aerobic respiration. After that in anaerobic conditions redox-dependent uranium reduction can be expected. Moreover, in the presence of sulfate ions, further anaerobic processes of microbial sulfate reduction and iron reduction lead to the formation of iron sulphide, which plays the significant role of an antioxidant buffer in the case of oxygen migration.