Uranium Contamination in Groundwater

Uranium Contamination in Groundwater

• The Central Ground Water Board (CGWB) has produced a study titled "Groundwater yearbook 2021-2022" on the health of groundwater.

Important Findings:

• In twelve Indian states, uranium levels in groundwater exceed permitted limits.
• In terms of the percentage of wells with uranium concentrations greater than 30 ppb, Punjab is the worst-affected state.
• Haryana is the second most contaminated state in terms of uranium in groundwater.
• Uranium was found in high concentrations in 9.2 per cent of the samples from Uttar Pradesh.
• Uranium concentrations have been judged to be safe in 13 states.
• The Bureau of Indian Standards (BIS) and the World Health Organization (WHO) recommend a safe limit of 30 ppb.

What is an appropriate upper limit?

• The Indian Standard IS 10500: 2012 for Drinking Water specification specifies the maximum allowable limits for radioactive residues as alpha and beta emitters, values over which deem the water unfit for consumption.
• These standards apply to all radioactive elements, including uranium. Individual radioactive elements have not been identified.
• According to the Bureau of Indian Standards (BIS), the maximum permitted limit of Uranium in all drinking water standards is 0.03 mg/l (as per WHO provisional guidelines).

The following are the primary causes of uranium contamination:

• The amount of uranium found in the rocks of an aquifer.
• Water-rock interactions result in the extraction of uranium from certain rocks.
• Conditions of oxidation that increase the solubility of extracted uranium in water.
• The interaction of extracted uranium with other compounds in groundwater, such as bicarbonate, can increase its solubility even further.
• Human-caused issues such as groundwater table decline and nitrogen contamination may be exacerbating the situation. This is also due to man-made causes:
• Irrigation-related over-exploitation of groundwater exacerbates uranium mobilisation.
• It is most likely one of the causes of uranium and other geogenic pollutants such as arsenic and fluoride.
• Pollution from nitrates.
• Falling groundwater table

What should be done?

• Revision of India's present water quality monitoring programme.
• Human health concerns in uranium-rich locations are being assessed.
• Creation of appropriate remediation technology.
• To overcome this issue, preventive management methods must be implemented.
• Based on uranium's kidney-harming effects, the Bureau of Indian Standards' Drinking Water Specification now includes a uranium standard.
• Developing monitoring systems to identify high-risk locations and researching novel methods to prevent or treat uranium contamination.

What is Uranium?

• Uranium is a mildly radioactive element that remains such due to its lengthy physical half-life (4.468 billion years for uranium-238).
• Uranium has a biological half-life of roughly 15 days (the average time it takes the human body to clear half of the quantity in the body).
• It is a naturally occurring element that can be found in trace amounts in every rock, soil, and water.
• This is the highest-numbered element found in considerable quantities naturally on Earth.
• It is more abundant than antimony, beryllium, cadmium, gold, mercury, silver, or tungsten.
• It is roughly as plentiful as tin, arsenic, or molybdenum.

Groundwater Threat:

• Human-caused degradation, which is frequently coupled with inadequate land, agricultural, and waste management, threatens:
• Current groundwater utilisation and human and ecosystem health
• Future generations' benefits are limited.
• Because much of the groundwater in South Asia is heterogeneous, the situation is exacerbated. Only 30% of South Asia's land cover hosts 70% of groundwater, with the remainder hosted in areas covered by Himalayan rivers.
• Another issue is water contamination, as much groundwater is contaminated by toxins such as arsenic and fluoride. These pollutants affect more than 400 million individuals. So, in India, there is not only a quantity problem, but also a water quality one.

The Importance of Groundwater:

• Groundwater has become an increasingly important natural resource in India, meeting the freshwater needs of numerous industries.
• Groundwater has increasingly emerged as the foundation of India's agricultural and drinking water security.
• The majority of this was used for irrigation, with the remainder going to towns and villages.
• Groundwater is the primary source of water for one-fourth of the world's population. India is the world's greatest groundwater user, with approximately 250 cubic kilometres extracted in 2017.

Way Forward

• There is an urgent need for all parties to respond. Groundwater protection must be ensured in all industries, including agriculture.
• More research and experiments on the removal of uranium from drinking water using a hybrid membrane approach are required.