The contaminated water comes from underground tube wells introduced widely over the last 20 years as a cheap alternative water supply to prevent outbreaks of deadly diseases such as diarrhea and cholera. Tube wells are steel cylinders sunk into the ground to varying depths to provide underground water for irrigation and drinking. No testing was done, however, for potential dangers such as arsenic, which is both colorless and tasteless. At low concentration levels, it is thought to take between eight and 14 years for the physical symptoms of arsenic poisoning to emerge, but cases are appearing in shorter times. In the Bangladeshi village of Dipordi, tube wells were sunk just seven years ago yet villagers are already showing signs of poisoning.
Many victims are children who have been consuming the poisoned water since birth.
Ingesting small amounts of arsenic over long periods leads to chronic poisoning. Arsenic is normally secreted by the kidneys, but over a prolonged period of ingestion, the body cannot remove the poison fast enough, resulting in increased levels in the system. The first outward manifestation of arsenic poisoning is melanosis or dark spots occurring on the chest, back, limbs and gums. In the more advanced stage wart-like skin eruptions develop on the hands, feet and torso, which can lead to skin cancers. Continual poisoning by arsenic results in the enlargement of the liver, kidneys and spleen which often develop into malignant tumors, lung, skin and bladder cancers and gangrene.