Q. “Scientists have recently found widespread uranium contamination in groundwater from aquifers across 16 states in India”. Discuss the factors causing such contamination and its ill effects. (250 words)

Model Answer :

Approach:

• Why in news?
• Introduction
• Factors causing uranium contamination
• Its ill effects
• Way Forward
• Conclusion

Why in news?

A new Duke University-led study has found widespread uranium contamination in groundwater from aquifers in 16 Indian states, much above the WHO provisional standard for the country. The findings published in the journal Environmental Science & Technology Letters are the first to demonstrate the predominant prevalence of uranium in India’s groundwater.

Introduction

The WHO has set a provisional safe drinking water standard of 30 micrograms of uranium per litre for India, a level that is consistent with US Environmental Protection Agency standards. Despite this, uranium is not yet included in the list of contaminants monitored under the Bureau of Indian Standards’ Drinking Water Specifications. These findings highlight a major gap in India’s water-quality monitoring. As the Bureau of Indian Standards does not specify a norm for uranium level, water is not tested regularly for it.

Factors causing uranium contamination

• Many of India’s aquifers are composed of clay, silt and gravel carried down from Himalayan weathering by streams or uranium-rich granitic rocks. When over-pumping of these 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 be aggravating the already present natural uranium contamination to dangerous levels.
• 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. In many parts of India, these factors co-occur and result in high uranium concentrations in the groundwater.
• The Environmental Sciencepaper identified two types of terrains with heavy contamination. In Rajasthan and other northwestern regions, uranium occurs mostly in alluvial aquifers; while in southern regions such as Telangana, crystalline rocks such as granite seem to be the source. When groundwater is over-extracted from such soils, the researchers suggest, the uranium is exposed to air, triggering its release. These hypotheses must be explored, because they will help determine where to find safer water. This is what happened in West Bengal, where a decade of research revealed why the contaminant arsenic mainly occurred in shallow aquifers.

Its ill effects

• Much of the high-uranium groundwater tested also had issues like high salinity, fluoride, and nitrate, which make it unsuitable for human consumption. Despite this, a great number of these wells are being used as primary drinking water sources owing to the lack of alternative water sources.
• Several studies have linked exposure to uranium in drinking water to chronic kidney disease. The studies indicate that this is a chemical effect, rather than a radiological one, even though uranium is radioactive. But the chronic effects of uranium consumption are still unknown. There could possibly be a link between the high rates of chronic kidney disease (CKD) in India and uranium exposure.
• Consumption of drinking water contaminated with uranium can also cause deformity of bones and liver.

Way Forward

• The study strongly suggests the 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.

Conclusion

There is an urgent need of a clear and cohesive action plan from the authorities that not only address the sources of uranium and other contaminants that seep into the ground water but also help generate alternate sources of safe water supply to ensure adequate availability for the growing population.

SOURCE :- Dheya IAS