‘OVER HALF OF SOUTH ASIAN GROUNDWATER UNFIT FOR USE’

PARIS: Sixty per cent of the groundwater in a river basin supporting more than 750 million people in Pakistan, India, Nepal and Bangladesh is not drinkable or usable for irrigation, researchers said on Tuesday.

The biggest threat to groundwater in the Indo-Gangetic Basin, named after the Indus and Ganges rivers, is not depletion but contamination, they reported in the journal Nature Geoscience.

“The two main concerns are salinity and arsenic,” the authors of the study wrote. Up to a depth of 650 feet, some 23 per cent of the groundwater stored in the basin is too salty, and about 37 per cent “is affected by arsenic at toxic concentrations,” they said.

The Indo-Gangetic basin accounts for about a quarter of the global extraction of groundwater — freshwater which is stored underground in crevices and spaces in soil or rock, fed by rivers and rainfall.

Fifteen-to-twenty million wells extract water from the basin every year amid growing concerns about depletion. The new study — based on local records of groundwater levels and quality from 2000 to 2012 — found the water table was in fact stable or rising across about 70 percent of the aquifer.

It was found to be falling in the other 30 per cent, mainly near highly populated areas. Groundwater can become salty through natural and manmade causes, including inefficient farmland irrigation and poor drainage.

THIS WATER SUPPORTS 75-CRORE PEOPLE IN PAK, INDIA, NEPAL AND BANGLADESH. SALINITY, ARSENIC MAIN CONCERNS; INDO-GANGETIC BASIN FIGHTS CONTAMINATION