Severe uranium contamination in India’s groundwater

• An International study has found widespread uranium contamination in groundwater from aquifers in 16 Indian states
• The main source is natural, but human factors such as groundwater-table decline and nitrate pollution may be exacerbating the problem.

About Uranium Contamination and study:

• Several studies have linked exposure to uranium in drinking water to kidney diseases. The World Health Organisation has set a provisional safety standard of 30 microgrammes of uranium per litre.
• Uranium is not, however, included in the list of contaminants monitored under the Bureau of Indian Standards’ Drinking Water Specifications.
• The researchers sampled water from 324 wells in Rajasthan and Gujarat, and analysed the water chemistry.
• In a subset of samples, they measured uranium isotope ratios. They also analysed similar data from 68 previous studies of groundwater geochemistry in Rajasthan, Gujarat and 14 other states.
• Nearly a third of all water wells we tested in Rajasthan contained uranium levels that exceed the WHO safe drinking water standards
• By analysing previous water quality studies, we also identified aquifers contaminated with similarly high levels in 26 other districts in northwestern India and nine districts in southern or southeastern India.
• Factors contributing to the contamination include the amount of uranium in an aquifer’s rocks and various chemical interactions between rock and water. In many parts of India, these factors co-occur and result in high uranium concentrations in groundwater.
• Human activities, especially over-exploitation of groundwater for irrigation, may have exacerbated the problem. Many of India’s aquifers are composed of clay, silt and gravel carried down from the Himalayas by streams or uranium-rich granitic rocks. When overpumping of these aquifers’ groundwater occurs and their water levels decline, it induces conditions that enhance uranium enrichment in the shallow groundwater that remains.
• One of the takeaways of this study is that human activities can make a bad situation worse, but we could also make it better. The results strongly suggest there is a need to revise current water-quality monitoring programmes in India and re-evaluate human health risks in areas of high uranium prevalence.

By: Vishal