ABSTRACT
India has an increasing incidence in fluorosis, dental and skeletal, with some 67 M people at risk. High fluoride groundwaters are present especially in the peninsula and in the arid northwestern part of the country. The phenomenon is connected to groundwaters with residual alkalinity (Ca2+<HCO3 −). Fluoride concentrations are governed by fluorite solubility. Evapotranspiration causes precipitation of calcite, lowering calcium activity and leaving room for increase in fluoride levels. In southern India dolomite seems to be a sink for magnesium while sepiolite is a sink in Rajasthan. The increase in sodic soils caused by irrigation is likely to be behind part of the increase in the incidence of fluorosis.
