The bane of Bangladesh
Amongst the 21 countries which are affected by a high amount of arsenic in drinking water, Bangladesh and India (mainly West Bengal) are the worst affected. In Bangladesh, the arsenic level is more than 50 microgrammes per litre in 50 out of its 64 districts with a population of 104.9 million people. According to a study conducted by the British Geological Survey, 35 million people consume contaminated water in the country.
The problem assumed breathtaking proportions in Bangladesh after the United Nations Children's Fund (UNICEF) and other international agencies sank millions of tubewells in the country during the 1970s and 1980s. Ironically, these deep tubewells were dug to ensure the availability of pathogen-free water. The process of digging wells has somehow changed the geology of the area. A new theory suggests that the lowering of the water table allows the inflow of organic carbon into the aquifer and leads to mobilisation of arsenic from the rocks into the water.
Long-term exposure to arsenic can cause cancer of the skin, lungs, urinary bladder and kidney. It is estimated that arsenic in drinking water will cause 200,000-270,000 cancer deaths in Bangladesh. It can also result in skin pigmentation and thickening.
The main source of arsenic is drinking water. Food, too, contains the element. Even contaminated water used for irrigating fields can prove dangerous.