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A recent published
study reveals researchers have pinpointed the source of the mass poisoning in
Bangladesh, according to the Associated Press. For nearly three decades
scientists have struggled to figure out exactly how arsenic was getting into
the drinking water of millions of people in rural Bangladesh. The source of
contamination is tens of thousands of man-made ponds excavated to provide soil
for flood protection. An estimated two million people in Bangladesh suffer from
arsenic poisoning, and health experts suspect the toxic, metal-like element has
caused many deaths as well. A large dose can kill outright, while chronic
ingestion of small doses has been linked to a large range of cancers. It has
long been known that the arsenic comes from water drawn from millions of
low-tech "tube wells" scattered across the country. Ironically the
wells were dug -- often with the help of international aid agencies -- to
protect villages from unclean and disease-ridden surface water. Tragically,
millions of people continue to knowingly poison themselves for lack of an
alternative source of water. Water with the highest concentrations of arsenic
is roughly 50 years old, and the organic carbon in the water does not take long
to filter down from the surface. A team of researchers led by Charles Harvey of
MIT in Boston, Massachusetts cracked the secret. Working in the Munshiganj
district of Bangladesh, the researchers analyzed the flow patterns of surface
and underground water in a six square-mile area. They used natural tracers and
a 3-D computer model to track water from rice fields and ponds, and tested the
capacity of organic carbon in both settings to free up arsenic from soil and
sediments. Chemical analysis showed that the organic compound that unleashes
the poison first settles on the bottom of the ponds and then slowly seeps into
the ground.
