Groundwater in Karnataka contaminated with uranium: Study
Scientists found that uranium concentrations ranged from 1.9 to 2744 micrograms per litre, which far exceed national and international safety limits
Alarmingly high levels of uranium have been found in a large proportion of potable groundwater in eastern Karnataka, according to a new study done by scientists.
As per the study, published in the journal Environmental Science & Technology, 78 per cent of tested groundwater exceeded safe drinking limits for uranium, and some groundwater uranium contamination reached levels 75 times the United States Environmental Protection Agency (USEPA) and Atomic Energy Regulatory Board (AERB), India thresholds, respectively.
Samples from 13 districts
Water samples from 46 borewells across 13 districts in the eastern part of Karnataka were analysed, as per the study. The scientists found that uranium concentrations ranged from 1.9 to 2744 micrograms per litre, which far exceed national and international safety limits.
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“Uranium contamination in groundwater becomes a critical concern when its concentration exceeds permissible limits. Groundwater samples (46) from Eastern Karnataka exhibit U concentrations ranging from 1.9 to 2744 μg/L (micrograms per litre), with 78% and 66% of sites exceeding the United States Environmental Protection Agency (USEPA) and Atomic Energy Regulatory Board (AERB), India thresholds, respectively. These high U levels are primarily geogenic,” the scientists said.
Uranium exposure can affect kidneys, bones, and the liver.
The study is titled "Isotopic Insights into Redox Processes Driving Uranium Distribution in Eastern Karnataka Groundwater.”
What scientists said
“We’re moving beyond simply detecting uranium to understanding its origin, movement, and long-term behaviour. These insights can guide interventions to protect millions of people,” said lead author Arijeet Mitra, PhD, a postdoctoral scientist in the Department of Environmental Health Sciences at Columbia Mailman School.
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The study’s framework is applicable to other regions dealing with naturally occurring uranium contamination, including several states in the western and midwestern US. The research underscores the urgent need for a more robust and long-term monitoring network to track uranium levels and environmental changes, said Columbia Mailman School of Public Health.
How uranium moves in groundwater
“How uranium moves in groundwater depends on how oxidising the water is,” said the study’s senior author, Anirban Basu, PhD, research scientist in the Department of Environmental Health Sciences, Columbia Mailman School of Public Health.
“When there is plenty of oxygen, uranium stays dissolved and flows with the water. But when there is no oxygen — like in deeper layers where certain bacteria break down iron oxides — uranium changes into a form that does not dissolve and settles out as a solid. The proportion of uranium isotopes in the water works like a fingerprint. It helps us track where uranium enters and leaves the water and whether it comes from a nearby or faraway source,” Basu added.