Fluorine is a common element that does not occur in the
elemental state in nature because of its high reactivity
Accounts 0.3 g/kg of the Earth’s crust
Fluorides minerals are fluorspar, cryolite
and fluorapatite are the most common
oxidation state of the fluoride ion is-1.
univalent poisonous gaseous halogen
Pale yellow-green most chemically reactive and
electronegative of all the elements.
readily forms compounds with most other elements, even with
the noble gases krypton, xenon and radon
In aqueous solution, fluorine commonly occurs as the fluoride
Inorganic fluorine compounds are used in industry for
a wide range of purposes
used in aluminium production
Fluorosilicic acid, sodium hexafluorosilicate and
sodium fluoride are used in municipal water
Annual world production of the mineral fluorite in around 4
Mining areas for fluorite are China, Mexico and Western
occurs naturally in the earth's crust
13th most abundant element in the Earth's crust
Hydrogen fluorides can be released into air through
combustion processes in the industry.
Fluorides that are found in air will eventually drop onto
land or into water.
When fluorine is attached to very small particles it can
remain in the air for a long period of time.
Atomic fluorine and molecular fluorine are used for plasma
etching in semiconductor manufacturing
Fluorine is indirectly used in the production of low friction
plastics such as Teflon
Fluorochlorohydrocarbons are used extensively in air
conditioning and in refrigeration.
Fluorides are often added to
Fluorspar (CaF2) is the principal
fluorine-containing mineral. It has
fluorine content of 48.5%.
The world production of fluorspar in
1979 was estimated to be 4 866 000
tones (US Bureau of Mines, 1980).
In 2010, China produced three million
tons of , sharing 55.6% of the global
Cryolite (Na3AlF6) is a relatively rare
mineral that is an essential raw material in
the aluminum industry; it has a fluorine
content of 545 g/kg.
The formerly important cryolite deposits of
Greenland are now almost exhausted; today
most supplies have to be prepared
synthetically (US NAS, 1971).
Fluorapatite, common phosphate
mineral, a calcium fluoride
It occurs as minute, often green, glassy
crystals in many igneous rocks, and also in
magnetite deposits, high-temperature
hydrothermal vents , and metamorphic
It has Fluorine content of 38g/kg
Rock phosphate is of great environmental significance as it is
the source of fluoride in some areas of endemic fluorosis.
Its vast quantities are mined and consumed in the production of
elemental phosphorus, phosphoric acid, and phosphate
The fluorine in soil originates from rocks which are parent
materials of most of minerals components of soil, from plant and
animal debris that supplies the organic matter of the soil, and
from rain water falling upon it.
The amount of fluoride in soil depends on soil type, pH, salinity
and fluoride concentration.
Soils contain approximately 330 ppm of fluorine, ranging from
150 to 400 ppm.
Some soils can have as much as 1000 ppm and contaminated
soils have been found with 3500 ppm.
The aerial emission of fluoride in the form of volcanic ash
during volcanic eruption, fly ash from the combustion of fossil
fuels result in air enrich with fluorine.
Natural background concentrations are of the order of 0.5
ng/m3. If anthropogenic emissions are included, worldwide
background concentrations are of the order of 3 ng/m3.
In the Netherlands, concentrations in areas without sources are
30–40 ng/m3, rising to 70 ng/m3 in areas with many sources .
In some provinces of China, fluoride concentrations in indoor
air ranged from 16 to 46 µg/m3 owing to the indoor
combustion of high-fluoride coal for cooking and for drying
and curing food.
Weathering of rocks rich in fluoride(granitic rocks ,volcanic
Hydrogen fluorine is one of the most soluble gases in magmas
and comes out partially during eruptive activity
Leeching of industrial discharges , volcanic ash, fertilizers etc.
Fertilizers containing leachable fluoride ranging from 53 to
Coal containing fluoride ranging from 5 to 20 mg/kg
Polluted groundwater with high fluoride in east Punjab,
Pakistan by Farooqi et al. (2007)
Fluoride con. in the groundwater of some villages in China
were greater than 8 mg/liter
Granitic rocks contain fluoride ranging between 500 and
The fluoride content in ash from Hekla eruption in 2010
was 23-35 mg/kg
All foodstuffs and plants contain at least traces of fluorine
Absorbed from soil and water through the roots and
through the leaves
The highest levels are found in curly kale (up to 40 mg/kg
fresh weight) and endive (0.3–2.8 mg/kg fresh weight)
Levels in dry tea can be 3–300 mg/kg so 2–3 cups of tea
contain approximately 0.4–0.8 mg (IPCS, 1984; slooff et
Ti (Cordyline fruticosa) is sort of famous for developing
burnt tips and margins from fluoride
Daily exposure to fluoride depend
In the Netherlands, the total daily intake
is calculated to be 1.4–6.0 mg of fluoride.
From food 80–85%
From drinking-water is 0.03–0.68 mg/day
From toothpaste 0.2–0.3 mg/day
Daily intakes of fluoride vary widely according to the
various sources of exposure.
Ranging from 0.46 to 3.6–5.4 mg/day
Intakes in areas where high-fluoride coal is used
indoors or where there is elevated fluoride in drinking-
water can be significantly higher
in some counties in China where coal has a high
fluoride content the average daily intake of fluoride
ranged from 0.3 to 2.3 mg via air and from 1.8 to 8.9
mg via food (Cao et al., 1992).
In areas with relatively high fluoride concentrations in
groundwater, drinking-water becomes increasingly
important as a source of fluoride.
Daily exposure in volcanic areas with high fluoride
levels in drinking-water may be up to 30 mg for
adults, mainly from drinking-water intake.
When fluorine from the air ends up in water it will settle
into the sediment. When it ends up in soils, fluorine will
become strongly attached to soil particles.
In the environment fluorine cannot be destroyed; it can only
Fluorine that is located in soils may accumulate in plants.
The amount of uptake by plants depends upon the type of
plant , type of soil and the amount and type of fluorine
found in the soil.
With plants that are sensitive for fluorine
exposure even low concentrations of fluorine
can cause leave damage
Too much fluoride retards the growth of plants and reduces
Those more affected are corns and
Animals that eat fluorine-containing plants may
accumulate large amounts of fluorine in their bodies.
Fluorine accumulates in bones. Consequently, animals
that are exposed to high concentrations of fluorine
suffer from dental decay and bone degradation.
Fluorine can also cause low birth-weights.