Chandrasekharam, D., Jalihal A.A., Hema, C.T.
Department of Earth Sciences, Indian Institute of Technology, Bombay, 400076, India.
World Bank estimated that around 260 million people worldwide in 30 countries have been drinking water with > 1 ppm of fluoride. India is one among such countries where 1 million people are affected by endemic fluorosis. This is particularly so in the state of Karnataka where 6 districts, comprising 4.6% of the geographical area is affected with this problem. We report here the problem of fluorosis in Hungud district of Karnataka, a drought prone area, where previous investigation has not been carried out. Fluoride concentration in the groundwater varies from 0.1 to 7.6 ppm, which is well above the limit of 1.5ppm prescribed by the WHO. Groundwater occurring in gneisses has the maximum concentration of fluoride (7.6ppm) and is saturated with fluorite. Granites, Gneiss and schist are the main hard rock aquifers, which contain fluorine-bearing minerals such as fluorite (5% modal) and biotite with 2% of F. Besides natural sources, granite industry is enhancing F in groundwater. The best solution to mitigate this problem is inter-basin transfer of water from the Western Ghats catchment area into the Krishna River basin. Inter-basin transfer of water will reduce the incidence of F in groundwater in other affected regions of the country also. This is possible if only water becomes a “Centre” rather than a “State subject”.