The Bangladeshi are being poisoned by drinking well water, usually without knowing it. Only three decades ago health and development experts, and small local contractors, dug between 7-11 million deep tube wells throughout Bangladesh. The experts encouraged the whole nation to drink well water because it was safe. It was free of the bacteria that caused water-borne diseases such as diarrhoea and other intestinal maladies that have long plagued tropical Bangladesh. It has been suggested that there are between 8-12 million shallow tube-wells in Bangladesh. Up to 90% of the Bangladesh population of 130 million prefer to drink well water. Piped water supplies are available only to a little more than 10% of the total population living in the large agglomerations and some district towns.
Until the discovery of arsenic in groundwater in 1993, well water was regarded as safe for drinking.
The people of Bangladesh exchanged water-borne diseases for arsenicosis. In the 1970s public health specialists and government policy-makers did not think of arsenic. It was only in 1993 that the "clean" well water was discovered to contain dangerous quantities of the poison. However, there is a relatively inexpensive solution. The STAR method developed by a New Jersey team of scientists. This method can easily be learned and used by individuals. It requires a bucket and a packet of chemicals. Unfortunately, Bangladesh cannot afford to buy the equipment from the United States. A health worker says "Instead of paying $10 for the buckets and importing the chemical packets from the United States, we could easily manufacture them here in Bangladesh in huge quantities and sell them at a far lower price. To do this we need substantial funding. I’m often told that health funding is available if it’s for a good cause. Coping with the arsenic poisoning of millions of women, children and men –‘the largest mass poisoning of a population in history’ -- is a good cause, is it not?"
further
Arsenic-contaminated water is not restricted to developing countries. In the western states of the United States of America about 13 million people drink arsenic-tainted water, albeit less contaminated than the well water in Bangladesh. Australia, too, has arsenic-contaminated water. So do Argentina, Brazil, Chile, Hungary, Mexico, Taiwan (Province of China), Thailand, Viet Nam, and the eastern areas of India in Bengal
collated from various websites, WHO, Water Aid, Global sustainability. to find out about the water purifier, which could save the lives of many millions of people click this link
http://www.oneworld.org/ips2/august99/03_53_003.html 
