|
1
|
- Fluoride Contamination in Ground- and Surface Waters
|
|
2
|
- Introduction
- Problems occurring due to fluoride
- Description of the feature area
- Results
- Fluoride content in the feature area
- Reasons for high fluoride values in the rift valley
- Methods concerning the removal of fluoride
- Conclusion
|
|
3
|
- Average concentration in fluoride of the earth crust is about 300 mg/kg
- About 150 fluoride bearing minerals do exist (most common are Fluorite,
Apatile)
- Fluorine component is easily solvable in water à washed out into ground- and surface waters
|
|
4
|
- Prolonged intake of high amounts of fluoride causes irreversible damages
in health
- Estimated maximum concentration of F in drinking water
- WHO: 1,5 mg/L - EPA: 2,0 mg/L
- problems due to high fluoride concentration in drinking water occur in
23 nations – highest amounts are recognized in the east African rift
|
|
5
|
|
|
6
|
|
|
7
|
|
|
8
|
|
|
9
|
- Fluoride removal based on adsorption properties or the coprecipitation
with calcium
- Use of materials with adsorptive properties:
- clay/clayed soil (Ando soil) enriched in Al- and Fe- hydroxide
- cattle bones, plants
- limestone, charcoal, serpentine
- Researching activities concerning this problem since 1930
- until today there is no method for the removal of fluoride, which is
accepted worldwide
|
|
10
|
- reasons for high F concentrations in water of the rift are known
otherwise reasons for high values in relation to similar regions are not
understood
- no optimal solution for removal of fluoride from drinking water does
exist à development of cheap,
effective and easily treatable
methods is required
- problem of providing drinking water à bad quality in drinking water is accepted due to
limited water quantity
|
|
11
|
- concentration of fluoride in drinking water [mg/L]
|
|
12
|
|
|
13
|
|
|
14
|
- Processes in solving and precipitating minerals are controlled by
temperature
|
|
15
|
|
Note
