Arsenic in groundwater in seven districts of West Bengal, India - The biggest arsenic calamity in the world

Arsenic has been found in groundwater in seven districts of West Bengal covering an area 37,493 km(2) having about 34 million population. Our survey indicates that 560 villages are arsenic-affected and more than a million people are drinking arsenic contaminated water and more than 200,000 people are suffering from arsenic-related diseases. About 20,000 tubewell waters were analysed for arsenic Around 45% of these tubewells have arsenic content above 0.05 mg/l. The average concentration of arsenic in contaminated water is about 0.20 mg/l; the maximum concentration of arsenic is found to be 3.7 mg/l. Most of the tubewells water contain arsenic in the form of arsenite and arsenate. People having arsenical skin manifestations and drinking contaminated water have high arsenic in hair, nail, urine and skin scales. Flow injection-hydride generation-atomic absorption spectrometry has been used for arsenic analysis in various samples. Many people have arsenical skin lesions as: melanosis, leucomelanosis, keratosis, hyperkeratosis, dorsum, non-petting oedema, gangrene, skin cancer. More informations are coming where the arsenic patients are suffering from cancers of bladder, lung, etc. The source of arsenic is geological. The reason why arsenic is leached out from the source is not yet clear but owing to heavy groundwater withdrawal the geochemical reaction in underground may be the reason. The vast surface and rain water resource, which West Bengal has should be used properly to combat the situation. Proper watershed management is required urgently.