High levels of uranium in groundwater of eastern Karnataka’s 57 villages: study

What is the news? 

A chemical analysis of groundwater in several villages of Karnataka has found high levels of uranium concentration. 

The study was conducted by the scientists from the Divecha Centre for Climate Change, Indian Institute of Science and Centre for Advanced Research in Environmental Radioactivity, Mangalore University. 

What are the findings of the study? 

– High levels of uranium concentration in groundwater of at least 57 villages out of 73. Concentration ranges from 30 micrograms per litre (μg / l) to even up to 60 μg / l. In some villages it even goes up to 1000 μg / l. 

– None of the bore wells from which water has been sampled is anywhere in the vicinity of nuclear facilities or urban waste disposal channels. 

– Samples collected during January and February had much higher uranium content than those collected during July. Studies are underway to understand this change. 

Why high uranium concentration is harmful? 

Uranium has no known essential biological functions. It is also a toxic chemical. 

Exposure to high levels of uranium can cause cancer, kidney disease. 

For more: Read here

What can be the probable reasons for such high level of uranium in groundwater of these areas?

1) Rock composition of the area– The chemical composition of water is affected by Soil-water and rock-water interactions. 

As per studies, Gneisses (a type of rock) and granitoids (category of rock) of Eastern Dharwar Craton have high uranium concentration as compared to those in Western Dharwar Craton. 

2) High degree of Oxidation: The soils in the eastern part of Karnataka, being red loam with laterite at places, indicate a higher degree of oxidation during weathering. Oxidation of uranous to uranyl ion is promoted by such a weathering process. As uranyl phases are soluble in circulating groundwater, the process leads to a higher concentration of dissolved uranium in groundwater.  

3) Depleting water table: Evidence points towards depleting water table in many parts of eastern Karnataka. Oxidative weathering in the deeper levels is facilitated by this decline in groundwater level. 

It also provides for an extended time of soil / rock-water interactions that lead to the release of more uranium to the circulating water. 

Source– This post is based on the article “High levels of uranium in groundwater of eastern Karnataka’s 57 village-study” published in Down to earth on 16th Dec 2021.