Arsenic contamination in ground water: Indian scenario.

The ground water in a huge alluvial tract along the river Hooghly covering a stretch of about 470 km., encompassing eight districts in the state of West Bengal (India) is affected by arsenic pollution of ground water. The probable source of arsenic has been reported to be through geological formations. Occurrence of iron-pyrite and the change of geo-chemical environment due to over-exploitation of ground water or excessive fluctuation of ground water table are the possible reasons of decomposition of pyrite to ferrous sulphate, ferric sulphate and sulfuric acid. However, no definite explanation regarding the source of arsenic could be established so far. Keeping in view the severity of the problem, an attempt has been made to bring out the nature and extent of arsenic problem in ground water of West Bengal, India, as well as need for watershed management to combat the situation.