Occurrence, behavior and distribution of high levels of uranium in shallow groundwater at Datong basin, northern China

Geochemical investigations of uranium (U) occurrence in the environments were conducted at Datong basin of northern China. The results suggest that U contents were generally 100μg/L) are locally found at the west alluvial plains. By contrast, U co-precipitation with secondary carbonate minerals like Ca2UO2(CO3)3 in the dominant Ca–Mg–Na–HCO3 type groundwater may prevail at the east alluvial plains. Besides, bedrocks such as Carboniferous and Permian sedimentary rocks, especially the coal-bearing strata which have higher U contents at the west mountain areas may also account for the abnormally high levels of U in groundwater. •High U groundwater occurs at the alluvial plains of Datong basin.•Redox state, complexation and adsorption are responsible for U enrichment.•Carboniferous and Permian sedimentary rocks have higher U contents at Datong.•Uranyl is preferentially complexed with carbonate in groundwater.•U in the aquifer sediments may be primarily associated with carnotite.