This work was undertaken to study the specific relationship between alkalinity and presence of fluoride ion in groundwater. Groundwater samples were collected from 24 different stations in Tiruchengode taluk, Namakkal district, Tamilnadu, India during the month of December 2011 and July 2012. The samples were stored in sterilized 2 L polythene containers and used to carry out the analysis of various physicochemical parameters. The alkalinity values were found to be more than the permissible limit. It plays an important role for the release of fluoride ion from its ore to the groundwater. It was observed that an increase in the alkalinity value made a similar increase in the amount of fluoride. In alkaline environment, the fluoride ion can be easily liberated from their ore because OH- and F- ions have similar radii. Hence they easily exchange with each other.
Groundwater, Fluoride, Anthropogenic, Fluorosis, Namakkal District