Uranium Contamination in Groundwater
Recently the minister of State for Jal Shakti provided information about the prevalence of uranium contamination in India’s groundwater.
● The occurrence of uranium in groundwater sources depends on several Natural factors like-
o The amount of uranium contained in an aquifer’s rocks
o Water-rock interactions that cause the uranium to be extracted
o Oxidation conditions that enhance the extracted uranium’s solubility in water
o The interaction of the extracted uranium with other chemicals in the groundwater, such as bicarbonate, which can further enhance its solubility.
● Anthropogenic reasons also cause contamination like- The fast declining of groundwater table due to overexploitation for agricultural irrigation purposes and high use of fertilizers does nitrate contamination.
● In Geogenic conditions, the bicarbonate and oxidizing conditions are two of the most important chemical factors controlling uranium concentrations in groundwater.
● Natural phenomena: Many of India’s aquifers are composed of clay, silt and gravel 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.
A report brought by Duke University, Central Ground Water Board and State Ground Water departments concluded that some of States have localized occurrences of Uranium concentration.
Water in more than 300 wells has uranium in much higher quantities than the WHO's provisional standard.
The WHO has set a provisional safe drinking water standard of 30 micrograms of uranium per literwhereas the Bureau of Indian Standard (BIS) is working to incorporate the maximum permissible limit of Uranium as 0.03 mg/l in all drinking water standards.
Elevated uranium levels in drinking water cause chronic kidney disease, deformity of bones and liver.
Contaminated groundwater used for irrigation affects agricultural productivity which can cause food shortage, affect biodiversity at large scale and cause a variety of health risks for humans.
Twin Toxicity: India suffers from chemical as well as radiological toxicity. Groundwater has issues like high salinity, fluoride, and nitrate, which makes water unsuitable for consumption apart from radiological contaminated water, chemical toxicity is a greater threat than the radiological toxicity.
Bicarbonate concentrations in water provides in-situ information about the suitability of the water for drinking purposes and is helpful in studying speciation of uranium radionuclides in aquatic environments.
The threat of twin toxicity has the potential to transform into a chain of toxicity, toxic irrigated water cause toxicity in crops or animals as water is the principal need for survival. Over Reliance on ground water must be checked to address this concern.
Government’s dormancy: Despite such huge prevalence, uranium has yet not been included in the list of contaminants monitored under the Bureau of Indian Standards’ Drinking Water Specifications. The work is being carried out yet to be completed. The evidence of impact of uranium exposure to human health is present but the Centre denied and had cited studies from Canada and Finland where high uranium levels were found without any increase in diseases.
The Indian Standard IS 10500: 2012 for Drinking Water specification has specified the maximum acceptable limits for radioactive residues as alpha and beta emitters, values in excess of which render the water not suitable. These requirements take into account all radioactive elements including uranium. No individual radioactive elements have been specifically identified.
Water Quality: There is a need to revise current water-quality monitoring programs in India and re-evaluate human health risks in areas of high uranium prevalence. Developing effective remediation technologies and preventive management practices should also be a priority to recognize the health costs of uranium traces in drinking water.
Rainwater harvesting as an alternative source for drinking water: There is a dire need to reduce the drinking water dependency on groundwater. Rain water harvesting is a visible alternative to avoid human-uranium contacts.
Nudge farmers to avoid either water intensive crops or use smart irrigation systems in order to avoid excess groundwater extraction.
PEPPER IT WITH
CGWB, NRDWP, Water (Prevention and Control of Pollution) Act, 1974