A recent analysis has revealed that India’s groundwater contains pollutants in excess of permissible limits. This contamination is driven by both natural geochemical processes and human activities like agricultural and industrial practices, reports contributor Esha Lohia for Mongabay India.
To understand the state of groundwater in India, the Central Ground Water Board (CGWB) assessed more than 15,000 groundwater samples from across the country in 2023. It found that nearly 20% of the samples had high levels of nitrates, while 13.2% exceeded permissible limits for iron, 9.04% for fluoride, 6.6% for uranium and 3.55% for arsenic. Each of these pollutants are linked with serious health effects at unsafe levels, the report notes.
Nitrates, a significant pollutant in India’s groundwater, was found to exceed the safe limit of 45 milligrams per liter in about 56% of India’s districts — an increase from 359 affected districts in 2017 to 440 districts in 2023. The contamination was particularly widespread in states like Rajasthan, Karnataka, Tamil Nadu, Maharashtra, Telangana, Andhra Pradesh and Madhya Pradesh.
Agricultural runoff and overuse of nitrogen-based fertilizers, as well as improper management of nitrogen-rich animal waste, drive nitrate contamination, Lohia writes.
When nitrate levels in groundwater surpass safe limits, they can have major health consequences, including methemoglobinemia, or blue baby syndrome, in infants, which is when the blood’s oxygen-carrying capacity is considerably reduced.
Another concerning pollutant in India’s groundwater is uranium. Lohia writes that most of the uranium-contaminated samples, with levels far beyond the safe limit of 30 parts per billion, came from the states of Rajasthan and Punjab.
While uranium occurs naturally in geological formations, groundwater and surface water in India, unsafe levels of the radioactive element are associated with increased risk for some cancers and kidney damage, according to the CGWB report. However, it’s unclear if the high uranium levels in groundwater in the two states are a consequence of natural geochemical processes or heavy use of fertilizers. Further investigation is needed to determine the source.
The report also found that samples with unsafe uranium concentrations were clustered in areas where groundwater is overextracted, suggesting that overuse of groundwater and the consequent drop in water levels is associated with an increase in uranium contamination in these regions.
Unsafe levels of other groundwater pollutants, such as fluoride and arsenic, are also linked with health impacts, including fluorosis caused by high fluoride, and cancer or skin lesions due to high arsenic levels, Lohia writes.
While both these elements occur naturally in rocks in India, overextraction and improper extraction of groundwater is likely increasing their concentration in some states, the report notes.
This is a summary of “Government report highlights groundwater contamination across India” by Esha Lohia.
Banner image of a woman using a hand pump to draw groundwater in India. Image by India Water Portal via Flickr (CC BY-NC-SA 2.0).
This story first appeared on Mongabay
This article is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
You may republish this article, so long as you credit the authors and Mongabay, and do not change the text. Please include a link back to the original article.
