Hydrogeochemical Processes Governing Uranium Mobility: Inferences from the Anthropogenically Disturbed, Semi-arid Region of India
Abstract Khetri Copper Belt, Rajasthan is anthropogenically active and geologically belongs to the Delhi supergroup. To study the active geochemical processes controlling the elemental mobility, representative groundwater samples were analysed for heavy metals and radionuclide (U). A maximum U concentration (average 87 µgL− 1) is observed in the quartzite mine zone whereas minimum (average 13 µgL− 1) is found to be in the copper mine zone samples. Despite the presence of Jaspura and Gothra granitoid in the copper mine zone, the abundance of U is low suggesting the scavenging of U by sulphides or iron oxides. Additionally, at the confluence of two geological groups, Fe concentration is found high with a low concentration of U which further confirms scavenging of U. In the region, aquifers are shallow which supports the weathering of minerals. Thus, a high concentration of U in groundwater is attributed to mineral dissolution, faults or fractures. It is evident from the results that in the absence of iron-bearing sulphides, U concentration in groundwater would be very high compared to the current concentration. It also indicates low concentration of U in the copper mine zone, area is covered with abundant quantity of Fe sulphide rich waste. The present study recommends further research to understand the feasibility of mining waste for the removal of U contamination from groundwater.