The pollution of drinking water by arsenic has become a serious challenge for people living in various parts of Asia as well as Latin America. The problem, by far, is much more severe in South Asia and China. The estimated number of people drinking arsenic-contaminated groundwater are of astonishing proportions; conservative estimates put the total number at greater than 50 million in the Asian region alone.

Tens of thousand cases of arsenicosis patients have been reported in South Asia. Similarly, several thousand patients have been identified in the Shanxi Province of China. Our awareness of this crisis has grown dramatically during the late 1990's - particularly in the context of the presence of arsenic in groundwater extracted from the alluvial aquifer underlying India, Bangladesh and Nepal. Naturally-occurring and human-induced arsenic pollution in drinking water has since been discovered in many parts of the world. We now regard it as a problem of truly global dimensions.