When over-pumping of aquifers’ groundwater occurs and their water levels decline, it induces oxidation conditions that, in turn, enhance uranium enrichment in the shallow groundwater that remains.
While the primary source of uranium is geogenic (naturally occurring), anthropogenic (human-caused) factors such as groundwater table decline and nitrate pollution may further enhance uranium mobilization.
Other factors include the amount of uranium contained in an aquifer’s rocks; water-rock interactions that cause the uranium to be extracted from those rocks; oxidation conditions that enhance the extracted uranium’s solubility in water; and the interaction of the extracted uranium with other chemicals in the groundwater, such as bicarbonate, which can further enhance its solubility.
There is a need for revision of the current water quality monitoring program in India, evaluation of human health risks in areas of high uranium prevalence, development of adequate remediation technologies, and, above all, implementation of preventive management practices to address this problem.
Including a uranium standard in the Bureau of Indian Standards’ Drinking Water Specification based on uranium’s kidney-harming effects, establishing monitoring systems to identify at-risk areas, and exploring new ways to prevent or treat uranium contamination will help ensure access to safe drinking water for tens of millions in India.