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The problem of high fluoride concentration in groundwater resources has now become one of the most important toxicological and geo-environmental issues in India and in most part of the world. Due to the scarcity of surface water in arid and semi-arid areas the groundwater becomes important water resource for drinking and agriculture purposes.
Fluoride is an essential ion from the health point of view and it helps in the normal mineralization of bones and formation of dental enamel. However, Fluoride when consumed in inadequate quantities (less than 0.5 mg/l) causes health problems like dental caries, lack of formation of dental enamel and deficiency of mineralization of bones, especially among the children and if fluoride is consumed or used in excess (more than 1.2 or 1.5 mg/l), it can cause different kinds of health problems, which equally affect both young and old.
Fluoride content in groundwater depends on rock type and the interaction period of groundwater with host rock as well as the dissolution kinetics of fluoride minerals on one side and also the contaminated recharge from rainfall on the other side. Water samples were collected and analyzed for 12 seasons viz., pre and post monsoons of the years 1999 to 2005 from 32 representatives bore wells in a granitic aquifer in india. The study area is underlain by granites of Achaean age. The Achaeans are very rich in fluorine bearing minerals. The results indicate that the Fluoride content of the groundwater significantly increases after post monsoon recharge. Higher F distribution in post monsoon groundwater is on account of increased CaF2 solubility due to lower Ca and high HCO3. In study area Fluoride and pH values show increasing trend. The Fluoride content of groundwater in study area is mainly due to dissolution process during rock water interaction.
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