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FLUORIDE LEACHING IN SURFACE AND SUBSURFACE WATER CRIPPLES LIFE IN PARTS OF INDIA

Congress: 2008
Author(s):
AbstractFluoride problems are wide spread in India especially in nine States covering almost the entire country. In order to assess the water quality and the related health problems due to high fluoride content, water samples from surface, subsurface and thermal water from these nine States have been collected, brought to the laboratory and analyzed as per standard procedures of APHA, 1985. Analyses show a fluoride concentration ranging from < 0.2 to 20 ppm. The probable source of high fluoride relates to the water-rock interaction within the sedimentary basins. During rock weathering and subsequent circulation of pore water through the soil and rock matrix, fluorine is leached out, mainly from the mineral fluorite (CaF2) and calcium difluoride, and dissolved in the ground water. Among the various minerals responsible for high concentration of fluoride, the flour - apatite [3Ca 3 (PO 4) 2], calcium difluoride [CaF2] and fluorite, CaF2 are important. However, the most important being the Fluorite, CaF2 and the leaching of fluoride from the metamorphic rocks hornblende gneiss of Proterozoic age. Even with a sizeable atmospheric source, the mobility of the F - should, once it is deposited, be governed by the soil and rock conditions. The fluoride content of ground water varies greatly depending on the type of rocks from which they originate. Human health affects of high fluoride content in water are manifested in the form of ‘endemic fluorosis’ causing tooth mottling and inducing the prevalence of osteoporosis and collapsed vertebrae. Fluorosis has no known treatment other than early detection and limiting the amount of fluoride ingested. It is considered to be a deadly disease. Concentration of fluoride below 1.5 ppm according to World Health Organization (WHO) is helpful in prevention of tooth decay, and such level of fluoride also assists in the development of perfect bone structure in human and animals. However, doses of fluoride above 1.5 ppm increases the severity change in shape and color of the fruits and vegetation. Long term ingestion of drinking water having fluoride above a concentration of 1.5 ppm leads to dental and skeletal fluorosis as well as non skeletal manifestations. High fluoride consumption leads to the fluorosis of the bones which is generally found in Asian region but it is particularly acute in India. Reducing the high fluorine content of groundwater may be done by dilution or by defluorination process. Dilution with the surface water is one very simple technique but not very practical in water scarce India where high fluoride concentration are found. But the addition of Ca++ ions to the fluoride rich groundwater causes an appreciable decrease in fluoride concentration which appears to be the potential cost effective solution to high fluoride problem in an otherwise water scarce India. Key words : Groundwater, Fluoride, Endemic fluorosis, Tooth decay, Defluorination
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