Ground water shortages have long been predicted but what is surprising is the rapid contamination of ground water with elements such as uranium and nitrate
At a time when municipal water supplies are slowly drying up, people in urban and rural areas are increasingly banking on groundwater even though the availability of the same is 130 feet and deeper in most of the places. Successive failure of monsoons has also taken a toll on the ground water table in India, as water bodies have dried as the quest for this precious resource has resulted in excessive exploitation of ground water.
Take Maharashtra for instance wherein out of the total area of 3,07,713 sq km, the groundwater level has fallen to around 1,50,000 sq km area. Situations such as these have pretty much become the norm across the country as there is a marked decline of 61 per cent in groundwater level in wells in India between 2007 and 2017.
The National Capital is the third highest groundwater exploited state in India. According to a study published in the International Journal of Advance and Innovative Research in March 2018, 67 per cent of the residents (four million) in 1,797 unauthorised colonies in Delhi are drawing underground water. The majority of the unauthorised colonies are largely dependent on illegal borewells to meet their water requirement in absence of piped supply. Off late Delhi’s condition has started to worsen.
According to the recent report by the Central Ground Water Board (CGWB), there is a critical drop in water tables across Delhi. Groundwater levels have been falling for a long time now but the increasing drop in groundwater reserves is alarming.
The report revealed that groundwater level is declining by 0.5 to 2 metres annually in most parts of Delhi. Rajasthan precedes Delhi with nearly 66 per cent overexploitation rate. Punjab is the highest groundwater exploited state, where 76 percent of the assessment units being overexploited.
Ground water shortages have long been predicted but what has taken both the authorities and the population off guard is the rapid contamination of the remaining ground water with harmful elements such as uranium and nitrate. These findings were revealed in a study conducted by the scientists of the Duke University, the US in association with the CGWB.
The study eventually published in the Environmental Science & Technology letters journal, showed that water in more than one-third of the 324 wells sampled had uranium in much higher quantities than the WHO’s provisional standard of 30 µg/l for the country.
Moreover, of the 324 wells analysed, 226 were in Rajasthan, of which 75 had high uranium levels, and five of the 98 were in Gujarat, which crossed the WHO permissible limits. The study also pointed out that 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.
Much of the high-uranium groundwater tested also had issues like high salinity, fluoride, and nitrate, which make it unsuitable for human consumption. Despite this, a great number of these wells are being used as primary drinking water sources owing to the lack of alternative water sources, noted the study.
Direct evidence of the impact of uranium exposure to human health is present as it has been proved that consumption of drinking water contaminated with uranium can cause chronic kidney disease, deformity of bones and liver. Though the main source of the uranium contamination is natural, human factors such as groundwater table decline and prevalence of nitrate pollution may exacerbate the problem, the study noted.
Adding to the problem is the further contamination of groundwater with heavy metals due to inefficient processing of e-waste recycling. Various studies have tested and analysed ground water samples and found that there is a clear presence of heavy metals in all the underground water samples exceeding the limits for drinking water.
The contamination of soil and water in the sampled areas was due to heavy metals released during processing of e-waste rendering the ground water unsuitable for drinking. Given these circumstances, it is surprising that there is a lack of a clear and cohesive action plan from the authorities that not only address the sources of these pollutants and contaminants that seep into the ground water but also help generate alternate sources of supply to ensure adequate availability for the growing population.
(The writer is an environmental journalist)
