The report reviews compilation of information about arsenic pollution in groundwater experienced by many countries in the world and in particular the eight districts of West Bengal. The science of arsenic pollution and the state of art of arsenic removal have been discussed and some immediate remedial measures suggested.
Arsenic pollution in groundwater in West Bengal has been described as the world’s biggest calamity. Eight districts in the Bhagirathi-Hoogly river basin covering an area of 37,493 sqkm with more than 4.5 million people affected by arsenic pollution. The source of occurrence of arsenic has been reported to be geological.
Occurrence of iron-pyrite and the change of geo-chemical environment due to over-exploitation of groundwater or excessive fluctuation of groundwater table is considered to be the reason of decomposition of pyrites to ferrous sulphate and sulphuric acid.
The concentration of arsenic is mostly dominant in the intermediate layer and is spreading over time and space in the linear track starting from Malda to 24 Parganas district. The interesting feature of arsenic pollution is that it has a positive correlation with the iron concentration.
A number of research organizations and departments are involved in the monitoring of arsenic pollution in groundwater in West Bengal. Different agencies are addressing this challenge through development of appropriate technologies for removal of arsenic from water.
However, unless reasons and sources of arsenic pollution are found out and appropriate scientific management done with a view to prevent its spread, it will be difficult to combat the problem and the risk as well. Watershed management and conjunctive use of surface and groundwater can be used as an approach to mitigate arsenic pollution.
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