The exposed population densities shown above have been calculated from our 1998 regional survey data by overlaying the percentage of sampled wells in each thana that exceed 0.05 mg As/L by the population density of that thana. The 1991 BBS population figures have been inflated by 2.1% per year to account for population growth and it has also been assumed that 95% of the rural population use groundwater. The total number of exposed people in the above sampled area calculated in this way is 25 million people. The error in these estimates is unknown.
Hand-drilling a tube well in western Bangladesh. The ‘slugger’
method being employed can be used down to depths of 100 m or more
in the alluvial sediments of Bangladesh. The ease of drilling tubewells
accounts in part for the large number of tubewells in Bangladesh.
