Uranium, Lithium, And Arsenic In Salt Lakes Of Eastern Transbaikalia

Distribution analysis of lithium, uranium, and arsenic in water of mineral lakes of Eastern Transbaikalia that are different by mineralization degree, macrocomponent composition, and water pH was performed. Lithium is mainly concentrated in more mineralized lakes, and arsenic and uranium - in less saline, i.e. soda, as established. According to thermodynamic calculations, lithium is mainly present as Li+ ion; LiCO3- acts as second biggest in soda water bodies, and LiCl - in chloride. Uranium is mainly found as uranyl tricarbonate ([UO2(CO3)(3)](4)(-)) and dicarbonate ([UO2(CO3)(2)](2)(-)). Arsenic in oxidative environment of lakes is presented by hydroarsenate (HAsO42-), and in reductive hydrosulphuric - by dihydrogenarsenite (H2AsO3-). Lithium does not form its own minerals in lakes. Reducing environment, in which uranium is precipitated as uranium hydroxide (U(OH)(4)), may be a geochemical barrier for uranium. The formation of sodium uranospinite (NaUO2AsO4) that may limit arsenic content in water too is probable under oxidative conditions. Asimilar trendin the distribution of their contents in chloride lakes is observed for lithium and chlorine. Direct dependence of the concentrations of uranium and arsenic on the contents of hydrocarbonate and carbonate ions is typical of soda lakes. The lack of appropriate specialization in the catchment areas of most lakes with a wide variation of contents of lithium, uranium and arsenic in their water, and also the presence of direct dependencies on the contents of the main macrocomponents indicate the prevailing influence of geochemical environment in their accumulation, the formation of which is mainly determined by evaporative concentration of water and hydrolysis of alumino-silicate rocks. The prevalence of this or that process ensures the formation of a certain chemical type of lakes and the appropriate set of elements.