According to the USGS the purpose of drilling these deep wells is to get a better definition of the deep aquifer system and to see ifat least in some areasit may provide a viable source of potable water, free of arsenic.
WHO's most recent guideline for the maximum amount of arsenic in drinking water recommends 10 parts per billion (ppb). That was in 1993 when it was lowered to that level from 50 ppb. But most water consumed in arsenic-affected areas in Bangladesh has substantially higher levels, frequently far above 50 ppb.
Arsenic-contaminated water is not restricted to developing countries. In the western states of the United States of America about 13 million people drink arsenic-tainted water, albeit less contaminated than the well water in Bangladesh. Australia, too, has arsenic-contaminated water. So do Argentina, Brazil, Chile, Hungary, Mexico, Taiwan (Province of China), Thailand, Vietnam, and the eastern areas of India in Bengal.
Arsenic poisoning is recognizable from skin color changes, blotches all over the face and body, hyper pigmentation on the chest and upper arms, hard patches on palms and soles of the feet, inability to walk, debilitating pain, and watery eyes.
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