Contamination overdrive

of groundwater in megacities is responsible for the contamination of deep water sources. A study in Dhaka shows that extraction of groundwater is lowering the water table in and around the city by 3 metres a year, driving down shallow water contaminated with arsenic. People in and around the city use deep wells as shallow groundwater is contaminated. Previous studies had said that it takes arsenic 100 years to reach water sources at the depth of 150 m. But the Dhaka study shows that deep water sources in and around the capital could be polluted within a decade. Nature Communications, September 27