An overview of arsenic mass-poisoning in Bangladesh and West Bengal, India

The largest mass poisoning in the world, perhaps in history, is happening in West Bengal, India, and Bangladesh. Many thousands of people suffer from arsenic skin disorders and are dying from cancer. About 19 million are estimated to be at risk. The discovery of the arsenic poisoning from tubewell drinking water was made in 1983, but it took about 10 years to be formally recognized as a large-scale problem. The source of the arsenic is natural and three hypotheses have been proposed for its mobilization: oxidation of arsenian pyrite, reductive iron dissolution with release of adsorbed arsenic, and competitive adsorption from phosphate. The processes causing arsenic mobilization in the Bengal Delta are still poorly understood and further research is needed to design long-term remediation strategies.