The most extensive groundwater contamination by arsenic in human history Danger Zone
Source of groundwater contamination by arsenic in the Indian part of Bengal basin, discovered a few decades ago, is still not installed. This area is home to about 60 million people who are experiencing an acute shortage of water even for washing or bathing. This concentration of arsenic in drinking water causes skin lesions, respiratory failure and cancer.
It has been suggested that the source of pollution are artificial reservoirs, which accumulates large amounts of organic substances, including arsenic. From there, arsenic and into the groundwater. However, Kansas State University researchers claim that the need for thousands of years, the level of contamination of ground water reached a depth of 30 meters. So, even the old artificial reservoirs can not be the source of so much arsenic.
Contamination of ground water by arsenic is natural. But it has become particularly evident with deep tube wells in the Ganges delta. According to estimates for 2007, about 137 million people in more than 70 developing countries exposed to arsenic poisoning. The U.S. also has regions with high levels of arsenic in groundwater. These include the city Fallon, Nevada, Verde River in Arizona, and some springs in the Appalachian Mountains.