Naturally occurring arsenic pollutes wells across the world, especially in south and southeast Asia, where an estimated 100 million people are exposed to dangerous levels. Now, scientists working in Vietnam have shown that massive pumping of groundwater from a clean aquifer is slowly but surely drawing the poison into the water fro a nearby polluted one. The study, done near Hanoi, confirms suspicions that booming water usage could eventually threaten millions more people across Asia.

Source: Pumping draws arsenic toward a big-city aquifer