The major sources of fluoride
in groundwater are fluoride-bearing rocks such
as fluorspar, cryolite, fluorapatite and hydroxylapatite.
The fluoride content in the groundwater is a function
of many factors such as availability and solubility
of fluoride minerals, velocity of flowing water,
temperature, pH, concentration of calcium and
bicarbonate ions in water, etc. Though fluoride
enters the body through food, water, industrial
exposure, drugs, cosmetics, etc., drinking water
is the major contributor (75–90% of daily intake).
Due to its strong electronegativity, fluoride
is attracted by positively charged calcium in
teeth and bones. Major health problems caused
by fluoride are dental and skeletal fluorosis
as well as many non-skeletal manifestations