Fluoride In Natural Waters And Health Hazards

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Fluoride In Natural Waters And Health Hazards

  1. 1. FLUORIDE IN NATURAL WATERS AND HEALTH HAZARDS by SK SABUR ALI UG-III, ROLL-000620401019 JADAVPUR UNIVERSITY Email ID: sabur.ju@live.com
  2. 2. Fluorine <ul><li>Element of halogen group. </li></ul><ul><li>Atomic number 9 , Atomic wt. 19. </li></ul><ul><li>Most electronegative element. </li></ul><ul><li>Ionic radius similar to (OH) -. </li></ul><ul><li>Low dissociation energy (38kcal/mole) </li></ul>
  3. 3. Sources of F in natural water <ul><li>Natural : </li></ul><ul><li>Igneous rocks/mineralized veins </li></ul><ul><li>Sedimentary formation </li></ul><ul><li>Water from Geothermal areas/hot spring. </li></ul><ul><li>Volcanic emission, evaporation, marine aerosols. </li></ul><ul><li>Anthropogenic : </li></ul><ul><li>Industrial aerosol, coal burning, brick making, aluminum smelting, introduction of CFC. </li></ul><ul><li>Fertilization with super phosphates (ATSDR, p146).” </li></ul><ul><li>Fluoridation of low fluoride concentration water. </li></ul>
  4. 4. Release of fluorine in water during weathering of rocks <ul><li>Abundance of fluorine in the rocks. </li></ul><ul><li>Controlled by solubility product. </li></ul><ul><li>For fluorite, CaF 2 =Ca ++ +2F − </li></ul><ul><li>K fluorite =(Ca ++ ).(F − ) 2 =10 -10.57 at 25 ◦ c. </li></ul><ul><li>inversely proportional to Ca ++ concentration. </li></ul><ul><li>2Na + ->Ca ++ increases fluoride concentration. </li></ul><ul><li>Longtime water-rock interaction. </li></ul><ul><li>Positive correlation with temp & depth </li></ul><ul><li>& negative correlation with hardness of water. </li></ul><ul><li>High in neutral to alkaline water (pH 7-9). </li></ul>
  5. 5. Health hazards <ul><li>Fluoride enters the human body by ingestion (food and water), and in extreme cases through the skin. </li></ul><ul><li>The maximum permissible limit of Fluoride content in groundwater is 1.5 mg/l (WHO, 1994). For the Indian sub-continent, the desirable limit of ‘F’ is 0.6 mg/l and maximum permissible limit is 1.2 mg/l (ISI, 1983). </li></ul><ul><li>Low concentration causes dental caries </li></ul><ul><li>High concentration promotes dental fluorosis, skeletal fluorosis, crippling fluorosis. Ca 10 (PO 4 ) 6 (OH) 2 ->Ca 10 (PO 4 ) 6 (F) 2 </li></ul>
  6. 6. Non skeletal health hazards <ul><li>Destruction of stomach & intestinal lining (mucosa). F − +HCl =HF+Cl − </li></ul><ul><li>High concentration causes Nervousness & Depression, Muscle Weakness & stiffness. </li></ul><ul><li>Early destruction of RBCs causes anemia. </li></ul><ul><li>soft tissues like ligaments, blood vessels tend to harden and calcify and the blood vessels may be blocked. </li></ul><ul><li>Excessive fluoride intake since early childhood would reduce mental work capacity (MWC) (case study). </li></ul><ul><li>May causes cancer (less clearly defined). </li></ul>
  7. 7. Remediation of high fluoride water <ul><li>Identifying the source and mapping of affected area </li></ul><ul><li>Defluoridation of water containing excessive fluoride concentration. </li></ul><ul><li>Promote & support research & development on removal of excessive fluoride. </li></ul><ul><li>Develop suitable local guideline and standards of fluoride in drinking water. </li></ul><ul><li>Develop & survey alternative source of drinking water, such as rain water. </li></ul><ul><li>Detailed study on the vertical variation of the fluoride concentration and identify aquifers with less fluoride concentration–sealing aquifers with high fluoride concentrations </li></ul>
  8. 8. References <ul><li>Edmunds M.,Smedley p.(2004);Fluoride in natural waters, in Selinus O., Alloway B.J. , Centeno J.A. , Finkelman R.B. , Fuge R. , Lindh U. , Smedley P. (eds) Medical geology; Elsevier; pp:812. </li></ul><ul><li>http://en.wikipedia.org/wiki/Fluoride </li></ul><ul><li>http://jdr.sagepub.com/ </li></ul><ul><li>http://www.atsdr.cdc.gov/ </li></ul><ul><li>http://www.webelements.com/ </li></ul>
  9. 9. THANK YOU

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