Authigenic Mineral Formation in Aquifers near the Uranium Sludge Storage Facility of Chepetsky Mechanical Plant during the Formation of a Biogeochemical Barrier in a Laboratory and Field Experiment

Abstract

In this work, authigenic microbial mineral formation in groundwater near the uranium sludge storage at SC Chepetsky Mechanical Plant (ChMP) (Glazov, Russia) was analysed in field and laboratory experiments using thermodynamic modelling when the microbial community was activated by a mixture of acetate, glucose and whey. It was found that the mineral basis of the barrier consisted of aggregated soil particles with freshly deposited phases of carbonate and sulphide minerals of different degrees of crystallinity. An important factor in the formation of calcium phases is microbial denitrification, which is accompanied by an increase in pH values of the medium. The main factors of uranium immobilisation in the biogeochemical barrier were revealed, including its reduction to insoluble forms of uranium dioxide, adsorption on ferrous and sulphide-ferrous minerals, as well as the formation of phosphate phases through the addition of phosphorus-containing whey and co-precipitation or co-crystallisation in calcite phases.

Microbial and Monosaccharide Composition of Biofilms Developing on Sandy Loams from an Aquifer Contaminated with Liquid Radioactive Waste

“…The samples, in a pre-dried state, were pulverized to a powder in a corundum mortar prior to XRD analysis. The subsequent preparation of the samples, clay minerals’ identification and elemental composition, and results interpretation were performed as described previously [ 12 ].…”

“…As a result, the presence of denitrifying and nitrate-reducing microorganisms leads to a decrease in nitrate levels in groundwater. This not only lowers the redox potential of the environment but also causes immobilization of the redox-active radionuclides in less soluble compounds [ 12 , 13 ]. Remarkably, microorganisms possess the ability to utilize various metals and metalloids such as technetium [ 14 ], uranium, and chromium [ 15 ], among others [ 16 , 17 , 18 , 19 ], in dissimilatory processes.…”