AbstractThe article starts with a brief introduction to element fluorine, its occurrence in nature and methods of absorption into human body. Ill effects of fluoride on human body are described in detail followed by various research studies in favor and against fluoride concentrations in drinking water.Fluoride in Drinking WaterAccording to the Leonard, Fluorine a halogen is pale, yellow gas with atomic no. 9, atomic weight 18.
9984 and 13th most abundant element found on the earth. Fluorine does not exist in free state but in combination with other elements forming fluoride compounds.Fluoride ingested is absorbed rapidly from gastrointestinal tract rather than the oral cavity, in addition the contribution of fluoride absorbed through the oral mucosa is insignificant relative to plasma fluoride levels.
National Research Council of National Academies, US Environmental Protection Agency has adapted three standards for fluoride concentration in drinking water namely Maximum Contaminant Level Goal (MCLG), Maximum Contaminant Level (MCL) and Secondary Maximum Contaminant Level (SMCL). Public drinking water was found to contain a MCLG of 4 milligrams per liter (mg/L) and an SMCL of 2 mg/L fluoride, and an MCL of 4mg/L was promulgated in 1986.Fluoride may occur as a natural contaminant or may be added to provide public health protection from dental caries.
As per the statistics in 1992 a total of about 10 million people consumed naturally fluoridated water with about 6.7 million consuming water containing fluoride concentrations less than or equal to 1.2 mg/L while exceptionally high concentration of fluoride was found in Colorado (11.2mg/L), Oklahoma (12.0 mg/L), New Mexico (13.
0 mg/L) and Idaho (15.9 mg/l). Fluoride concentrations greater than 1.3 mg/L can be considered as naturally contaminated and when added intentionally a concentration range of 0.7 to 1.2 mg/L is recommended depending on the mean temperature of the locality i.e.
, in localities experiencing higher mean temperatures the fluoride concentration is maintained at 0.7 mg/L and for cooler climes the fluoride concentration is maintained at 1.2 mg/L. The optimal concentrations are recommended to prevent dental caries, limit enamel fluorosis and dose related mottling of teeth ranging from mild discoloration of the surface to severe staining and pitting.According to Life Streams International Manufacturing Company following ill-effects are associated with consumption of fluoridated drinking water, usage of toothpastes and some tablets:1. Research studies showed that moderate level exposure led to fluoride build up in brains of animals damaging the brain and adversely effecting their behavior pattern. Further studies also showed that fluoride exposure effected the central nervous system also leading to a lower IQ in children.
2. Rats suffered from histologic lesions in the brain and damage to blood brain barrier after consuming water containing 1 ppm of Sodium fluoride.3. Possibility of bone cancer was two to seven times in male children belonging to areas where the water was fluoridated.4. Prolonged exposure to fluoride increased hip fractures since the tensile strength of the hip is gradually destroyed.
“Fluoride builds up in the bones causing adverse changes to the bone structure.”5. Studies in UK showed that 30% higher Down’s syndrome and 15% higher perinatal deaths were recorded as compared to non-fluoridated areas.
6. No positive effects have been detected due to fluoridation i.e., no significant dental cavity protecting effects were noticed.7. Chronic immune disorders have developed in people who have consumed fluoridated water in 1960s and 1970s since fluoride impairs functioning of immune system.8. Double blind studies have shown that fluoridated water cause acute adverse reactions and in addition also cause gastrointestinal symptoms, stomatitis, joint pains, polydipsia, headaches, visual disturbances, muscular weakness and extreme tiredness.
9. Prolonged chronic exposure to fluoride can cause severe skeletal fluorosis including pains in bones and joints, burning sensation, pricking and tingling in the limbs, muscle weakness, chronic fatigue, gastrointestinal disorders, reduced appetite, backache, osteoarthritis, etc.,10.
Fluoridation may also lead to contamination of water with lead, arsenic and radio nuclides “since the fluoride compounds are toxic waste byproducts which largely come from pollution scrubbers of fertilizer plants.”11. Fluoride ingestion may contribute to the Repetitive Stress Injury (RSI) since the ingestion may lead to the development of apatite crystal formation.
12. A large number of children experience dental fluorosis leading to a permanent adverse structural change and disfigurement of teeth.13. Gradual fluoride build up in various parts of the body may disrupt actions of many key enzymes.14. In early to mid 20th century fluoride was given in low levels to suppress thyroid function and to treat hyperthyroidism.
Contrary to above discussion Phipps et al stated that long term exposure to fluoridation would reduce the risk of hip fractures and vertebrae in older white women. The studies also supported fluoridation as a control health measure to prevent dental caries.Similarly Donagh et al stated that a systematic review of fluoridation revealed low quality evidence with reduction in number of caries cases. The study also added that prevalence of mottled teeth is highly associated with fluoride concentration in drinking water and association of fluoride in water was not found with other adverse effects.
Isaac et al stated that an increase in the concentration of fluorides in water increases the fluoride content of enamel and it was suggested that fluoride deposition in enamel takes place in 3 stages namely:(i) Fluoride is deposited in the enamel matrix at the time of enamel formation(ii) Fluoride is taken up by external surfaces of enamel from tissue fluids after completion of calcification but before eruption(iii) After eruption and throughout the life span of teeth i.e., from drinking water, food and saliva.Thus it was stated that when the fluoride concentrations were raised from 0.
1 ppm to 5.0 ppm an increase in considerable amount of fluoride is deposited during tooth formation.Yiming Li et al concluded from studies conducted that prolonged exposure to water containing upto 4.32 ppm fluoride concentrations resulted in increased risk of fracture in general and water fluoride levels of 1.00 to 1.06 ppm decreased the risk of fractures as compared to negligible fluoride concentrations.Xiang et al stated that “as the fluoride level in drinking water increased the IQ fell and the rates of mental retardation and borderline intelligence increased” in the villages of Wamiao and Xinhuai in Sihong County, Jiangsu Province, People’s Republic of China.
Evidence and research clearly points that excessive fluoride concentrations certainly impact the normal development of teeth, enamel and bones leading to fluorosis. But research should be further carried out to prove that dental caries can be avoided with least or negligible concentrations of fluoride concentrations since no clear evidence is available in this regards.ReferencesBarry Leonard (1992). Review of Fluoride: Benefits and Risks. Report of the Ad Hoc Subcommittee on Fluoride. Diane Publishing Company.National Research Council of National Academies.
Fluoride in Drinking Water: A Scientific Review of EPA’s Standards (2006). The National Academic Press, Washington D.C.
Life Streams International Mfg. Co. Fluoridation/Fluoride Toxic Chemicals In Your Water.
Page retrieved on December 08, 2006 from:http://www.wholly-water.com/fluoridation.htmlSally Isaac, Finn Brudevold, Frank A.
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org/cgi/reprint/37/2/318Yiming Li, Chaoke Liang, Charles W. Slemenda, Rongdi Ji,Shuzhuang Sun, Jingxiang Cao, Christine L. Emsley, Feng MA, Yunpeng WU, PO Ying, Yang Zhang, Sujuan Gao, Wu Zhang, Barr P. Katz, Shiru Niu, Shouren Cao and Conrad C. Johnston (2001).Effect of Long-Term Exposure to Fluoride in Drinking Water on Risks of Bone Fractures. Journal of Bone and Mineral Research, Volume 16, Number 5, pp 932-935.
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932Q Xiang,Y Liang,L Chen,C Wang,B Chen,X Chen and M Zhou (2003). Effect of Fluorine in Drinking Water on Children’s Intelligence. Fluoride Journal Vol. 36 No.
2, pp. 84-94. Research Report. Page retrieved on December 06, 2006 from: http://fluoride-journal.com/03-36-2/362-084.pdfMarian S McDonagh, Penny F Whiting, Paul M Wilson, Alex J Sutton, Ivor Chestnutt, Jan Cooper, Kate Misso, Matthew Bradley, Elizabeth Treasure and Jos Kleijnen (2000). Systematic review of water fluoridation.
British Medical Journal, Volume 321;pp 855-859. Page retrieved on December 05, 2006 from: http://www.bmj.com/cgi/reprint/321/7265/855Kathy R Phipps, Eric S Orwoll, Jill D Mason and Jane A Cauley (2000).Community water fluoridation, bone mineral density and fractures: prospective study of effects in older women.
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