Geochemistry of radon waters in the south of Siberia

Abstract

The geochemical features of 22 deposits and manifestations of radon waters in the south of Siberia (some of them for the first time) are considered. The studied waters are very diverse in terms of gas and chemical composition, total mineralization, geochemical parameters of the environment, and temperature. Three groups of radon waters have been established according to the Eh value: oxidizing conditions, transitional and reducing. Due to the wide variety of waters in terms of chemical composition, some of the studied objects belong to several groups at once, for example, the Choigan natural complex, the Skalinsky, Novobibeevskoye, and Sedova Zaimka manifestations. The concentrations of natural radionuclides are (mg/dm): U (3.68∙10 - 1.40), Th (4.04∙10 - 2.16∙10). The activity of dissolved radon (Rn) varies from 4 to 2257 Bq/dm. The Th/U ratio varies from 2.63∙10 to 26, and its maximal values were detected in ultrafresh, thermal, alkaline waters with reductive geochemical medium in which thorium possesses increased migration capacity. Quite contrary, uranium migrates in the oxidative geochemical setting.