Physicochemical and biological monitoring of deep repositories for liquid radioactive wastes

The objective of this work was to study the physicochemical conditions and the microbiological composition of underground water in the second level of the Severnyi site at the Mining and Chemical Works and to clarify the possibility of biogenic gas production by formation microflora from macrocomponents of the wastes (nitrates and sulfate ions). Chemical analysis of samples of formation liquid from wells located in the dispersion zone of the wastes showed an increase in the content of dissolved carbonic acid, sodium nitrate, and nitrates of radionuclides and an increase of their concentrations in the sampling part. In all other samples, the contents of the main cations and anions were close to the background values. Microbiological investigations showed an increase in the number of microorganisms capable of forming gases from possible macrocomponents of the wastes and in the rate of sulfate reduction and methane generation processes within the propagation boundary of the wastes.