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1990s
Bangladesh
Bangladeshi

People around the world rely on groundwater as a safe drinking source. But, as University of Wisconsin hydrogeologist Jean Bahr notes, groundwater can sometimes contain toxic substances - like arsenic.

Jean Bahr: [---1---] But it wasn't on our list of things we analyzed for regularly outside of those areas.

[---2---]

[---3---] Bahr added that, today, scientists look for broader features to suggest the presence of arsenic.

Jean Bahr: Is there arsenic in the rocks of sediments? And then, are the conditions of the waters, water chemistry conducive to actually dissolving those minerals and releasing the arsenic?

[---4---]

Today we are celebrating The International Year of Planet Earth. Thanks to the National Science Foundation and US Geological Survey. More at ES, a clear voice for science.

【视听版科学小组荣誉出品】
We know that in areas of volcanic activity, in areas where metallic mines occur that arsenic is a common constituent in the groundwater. Bahr said that changed in the 1990s, when health care workers in Bangladesh discovered that arsenic in the groundwater had been causing widespread illness. She said the incident surprised scientists, because the Bangladeshi groundwater source wasn't near a volcano or a mine. Bahr suggested that water drawn from private wells be tested for potential toxic substances.