Better sanitation made groundwater safer, says IIT study

NEW DELHI: Rising income and improved access to sanitation facilities has led to a decrease in disease-causing bacteria that cause acute diarrhoea in groundwater, according to a study by researchers from Indian Institute of Technology, Kharagpur.

Open defecation is a major contaminant of groundwater, which is the most common source of drinking water in India. Acute diarrhoea is the cause of 9% of all deaths among children under the age of five.

On October 2, Prime Minister Narendra Modi declared India to be open defecation free with toilet coverage increasing from 38.7% in 2014 to 100% in 2019.

The study, published in a Nature group of journals, Scientific Reports on Wednesday, shows that the concentration of faecal coliform in groundwater reduced by 38.5% between 2002 and 2017. Coliform are organisms that are found in the environment and the faeces of warmblooded animals.

“This is probably the first time we are systematically studying the actual impact of improvement in sanitation conditions in India and its impact on the drinking water quality and health. For the study, we have mainly used government data sources for drinking water and health parameters and used NASA images of nightlight in the areas as a measure of urbanisation and economic development,” said Abhijit Mukherjee, the lead author of the paper and the associate professor of hydrogeology in the department of geology and geophysics at IIT Kharagpur.

The progress, however, is not uniform across regions. Of the 7,010 blocks that were covered in the study, nearly 43% or 3,000 blocks showed over 90% reduction in faecal coliform during the study period. It decreased by 70-90% in nearly 23% of the regions, and 50- 70% in 7.1% of the study regions.

“We largely saw that these reductions in faecal coliform in drinking water and the cases of acute diarrhoea correlated highly with economic development and urbanisation,” said Mukherjee. The study clearly shows a relation between the Prime Minister’s Swacch Bharat Mission and improvement in water quality and health.

“Improving sanitation and access to safe drinking water will not only reduce bacterial diarrhoea and the resulting deaths in children, but also improve various nutritional parameters,” said Dr KC Tamaria, paediatric consultant at Safdarjung hospital.

The researchers, however, saw that in the group of blocks that showed minimal improvement during the study period, the improvement in the economic condition and access to sanitation did not have strong correlation with better health outcomes.