As per a study conducted by researchers from Duke University, USA in collaboration with the Central Ground Water Board, and various State Ground Water departments, there is widespread contamination of groundwater across the country.
The level of uranium in groundwater exceeds the limit of 30 micrograms per litre established by the World Health Organization’s (WHO) provisional guidelines for safe drinking water standards. This was observed in various locations of the states like Andhra Pradesh, Chhattisgarh, Gujarat, Haryana, Himachal Pradesh, Jharkhand, Karnataka, Maharashtra, Odisha, Punjab, Rajasthan, Tamil Nadu, Telangana, Uttar Pradesh, West Bengal, and Jammu & Kashmir.
The researchers have sampled water from 324 wells located in the states of Rajasthan and Gujarat, analysed the water chemistry, and measured the uranium isotope ratios. They additionally examined data from 68 similar studies undertaken in the past that evaluated the groundwater geochemistry in Rajasthan, Gujarat, and 14 other Indian states.
The condition of aquifers is the major reason for this contamination. Many aquifers in the concerned regions are composed of clay, silt, and gravel which get carried down from the Himalayan mountain ranges, weathered by streams or uranium-rich granitic rocks. When the groundwater levels decline due to over pumping of water for uses such as drinking, irrigation, etc., it induces oxidation conditions that intensify the extracted uranium’s solubility in the water.
Furthermore, when this extracted uranium interacts with other chemicals that can be found in groundwater, such as bicarbonate, it can supplement the solubility of uranium in water, resulting in further contamination.
Many man made factors such as decline in ground water table due to over exploitation of groundwater to support various human activities, and nitrate pollution contribute to the contamination of water in various parts of the country.
Various studies have shown that exposure to high levels of uranium in drinking water leads to chronic kidney diseases. The grave situation brings forward the need to revise the current water quality monitoring programs in the country, and recognise the health risks people are vulnerable to.
Additionally, it is important to develop appropriate remedial technologies to help combat this situation, and undertake preventive management practices to address the problem. It is important to devise procedures to help identify the at-risk areas for such radioactive contamination, and develop strategies to treat the cases of contamination. Most importantly, a standard needs to be established that specifies the permissible levels of uranium in drinking water that take into consideration the health risks of over exposure.
The Indian Standard (IS) for Drinking Water does specify the maximum permissible level for radioactive residues as alpha and beta emitters, and water containing radioactive residue higher than the specified limits is deemed unsuitable for consumption.
These specified limits are established for all radioactive elements clubbed together, including uranium, and there are no specific requirements for individual elements. According to a written reply by Rattan Lal Kataria, Minister of State for Jal Shakti and Social Justice and Empowerment, given to the Rajya Sabha on March 16, 2020, Bureau of Indian Standard is working to include the maximum permissible limit of Uranium at 30 microgram per litre of water, corresponding to WHO provisional guidelines, in all drinking water standards after following the required procedure.