Hydrogeological conditions and hydrogeochemistry of radon waters in the Zaeltsovsky–Mochishche zone of Novosibirsk, Russia

Abstract

Hydrogeological and hydrogeochemical conditions, the concentrations of major and some minor ions, and 222Rn were determined in the Zaeltsovsky–Mochishche field in the southern part of West Siberia. The water abundance of sediments varies within a broad range, and water discharge yields of the wells are 25–110 m3/day. Waters are fracture-related, cold with the temperature of 6–10 °C, occurring at a depth of 50–200 m. All the wells penetrating granites and near-contact hornstones were tested for 222Rn content in groundwater. The type of groundwater in the zone is Ca HCO3 and Ca–Na HCO3 with total dissolved solids 322–895 mg/l. The concentrations of 238U and 226Ra do not exceed 0.098 mg/l and 1.9∙10–9 mg/l, respectively. The concentration of 222Rn in the groundwater of the Zaeltsovsky–Mochishche field is 11–801 Bq/l. The forms of uranium occurrence in radon waters are represented mainly by the uranyl-carbonate complexes of calcium Ca2UO2(CO3)3(aq) (61–75%) and CaUO2(CO3)32− (25–36%).