1. ENVE 201 Environmental Engineering Chemistry 1 Fluoride Dr. Aslıhan Kerç

2. Fluoride Removal of fluoride Addition of fluoride to optimum levels SIGNIFICANCE OF HIGH F - Cause mottled enamel (dental fluorisis)>2.0 mg/L If value < 1- 1.5 mg/L  no problem

3. Excessive dosage of fluoride result in bone fluorisis > 5 mg/L Removal of fluoride  passing water through defluoridation media such as tricalcium phosphate, bone char, bone meal, activated alumina

4. LOW FLUORIDE If F decreases, the dental caries increases. 1 mg/L F -  desirable for optimal dental health.

5. Chemistry of Fluorine F 2  Among most active elements known  Forms simple Fluoride compounds and complex ions.

6.  Fluoride added to public water supplies in the form of ; NaF CaF 2 HF Na 2 SiF 6 (sodium silicofluoride) H 2 SiF 6 (hydrofluosilisic acid) (NH 4 ) 2 SiF 6 (ammonium silico fluoride )

7. Methods of Determination Electrode Method Colorimetric Procedures Ion Chromotography ISE ( Ion Selective Electrode)

8.  USEPA MCL for Fluoride  4mg/L To protect against crippling skeletal fluorisis  Secondary MCL (not enforcable)  2 mg/L To protect against dental fluorisis