The document discusses efforts to mitigate fluorosis in Ethiopia caused by high fluoride levels in groundwater. It presents several challenges including that about 10-14 million people are exposed to fluoride contaminated water. Projects discussed include fluoride distribution mapping to identify low fluoride sources, quantitative risk assessment to estimate disease burden and establish safe fluoride limits, developing alternative water sources, and defluoridation technology optimization. The goal is to address fluorosis through identifying low fluoride water, setting standards, developing defluoridation methods, and integrating with other water and health initiatives.

1. FLUOROSIS MITIGATION IN
ETHIOPIA
Feleke Zewge
Department of Chemistry,
Addis Ababa University
&
g j ,
National Fluorosis Mitigation Project Office,
Ministry of Water Resources

2. The Challenge: High Fluoride in Groundwater
The Challenge: High Fluoride in Groundwater
• Is serious water safety problem mainly in the
Is serious water safety problem, mainly in the
Ethiopian Rift Valley Regions
• Ab t 10 14 illi
About 10‐14 million people are exposed to
l dt
fluoride‐contaminated groundwater
• Several wells failed to supply drinking water due to
the presence of fluoride
the presence of fluoride
• This affects the efforts to achieve MDG
This affects the efforts to achieve MDG.

3. FLUOROSIS IN ETHIOPIA: DENTAL

4. FLUORORSIS IN ETHIOPIA: DENTAL

5. FLUOROSIS IN ETHIOPIA: SKELETAL

6. FLUOROSIS IN ETHIOPIA: SKELETAL

7. Issues that Need to be Addressed to Mitigate
Fluorosis
Identify and exploit low fluoride drinking water sources in the
fluoride endemic areas.
­ Keeping record of the fluoride levels of ground water
sources
­ Establishing regional and national fluoride database
g g
•Having clear distribution map up to village level
Setting fluoride standard for water deprived dry areas of the
country.
What should be the safe cut off level?
1.5 mg/L, mg/L, mg/L, mg/L,
1 5 mg/L 2 mg/L 3 mg/L 4 mg/L 5 mg/L ?
What is the risk level in relation to the total daily fluoride
intake?
Developing appropriate defluoridation technology for Ethiopia
Integrating the fluoride problem with other water supply and
sanitation issues

8. Our Projects
Our Projects
1. Fluoride Distribution Mapping
1 Fluoride Distribution Mapping
2. Quantitative Chemical Risk Assessment
2 Quantitative Chemical Risk Assessment
3. Alternative Water Supply
3 Alt ti W t S l
4. Development, Optimization and Field
l d ld
Implementation of Defluoridation Technologies

9. The Ethiopian Rift
Total area of 1127000 km²
Average width of about 100 km
Divides the whole country from the northeast
to the southwest
Area of RV about 33000 km²

10. Fluoride Distribution Mapping
Population at risk
•14.6 % of the total
Up to 33 mg/l in drinking
/l d k
water
Source: RiPPLE
•Population exposed is increasing
•Prevalence of Fluorosis is increasing

11. Purpose of Fluoride Distribution Mapping
p pp g
Project
• To assess the extent of fluoride contamination and
produce GIS maps at smallest administrative level
• To generate fluoride database at national level
• To prioritize actions and to locate the existence of low
fluoride groundwater within reasonable distance
• To know the actual number of exposed population

12. F Distribution: Main Rift Valley

13. F Distribution: East Showa Zone

14. Population at Risk

15. Quantitative Chemical Risk Assessment Project: To Introduce
Integrated Fluorosis Mitigation Program
I
D
E Identification of skeletal
Fluoride in water fluorosis
N
T
I
F
I Fluoride in food
Nutritional status Hazard identification
C QCRA
A
T
I
Overall fluoride Identification of dental
O
intake fluorosis
N
Moderate fluorosis risk Low fluorosis risk
High fluorosis risk
DAILY 10 ‐100/1000 Persons DAILY < 10/1000 Persons
DAILY >100/1000 Persons
M
I Risk characterization
k h
T Defluoridation of Water
Water management OR Nutritional supplement
I drinking water management
G
A
T
I
Defluoridation of
of
O
drinking water
N
Rain water Dilution Nutritional supplement
harvesting technique
Risk management
Risk management
Nutritional supplement

16. The major activities under QCRA
The major activities under QCRA
• Identification of fluorosis hazard (fluorosis indicated
malnutrition and analysis of food and water sample) and
fluorosis hazard assessment;
• Fluoride exposure assessment (to estimate the total
quantity of fluoride consumed by the community);
• Fluoride dose‐response assessment (clinical assessment);
• Fl id i k h
Fluoride risk characterization (based on prevalence study
t i ti (b d l t d
and DALY (Disability Adjusted Life Years) calculation);

17. Purpose of QCRA Project
Purpose of QCRA Project
• To assess the health impacts due to excessive fluoride intake
p
in relation with nutritional aspects and daily water
consumption and finally establishing tolerable levels of risk to
human health
• To estimate disease burden due to dental and skeletal
fluorosis in the fluorosis affected communities
• To prioritize communities that need immediate intervention

18. FLUORIDE INTAKE THROUGH FOOD AND
( )
BEVERAGES (Exposure)
40
y)
/person/day
CF
30
MS
20 GW
F (mg/
10 GW
MS
0
CF
food
beverages
total uptake
Fluoride intake
CF: 1 mg/L, MS: 3 mg/L, GW: 11 mg/L

19. Prevalence of Dental Fluorosis (Based on Dean`s
Affected population by sex in Village
)
Index)
1 Affected population by sex in Village
37.00%
36.00% 2
35.00%
35 00% 60.00%
60 00% 52.40%
34.00% 50.00%
33.00%
40.00% 34%
32.00%
30.00%
31.00%
20.00%
20 00%
30.00%
29.00% 10.00%
Male Female 0.00%
Male Female
Affected population by sex in Village
3 Affected population by sex in
60%
50%
Village 4
50% 40.00%
38.80%
40% 39.00%
38.00%
30% 37.00%
20.40% 36.00%
20%
35.00%
33.80%
10% 34.00%
33.00%
0% 32.00%
Male Female 31.00%
Male Female

20. Prevalence of Dental Fluorosis
Affected Population by Age in Village 1
Affected Population by Age in Village 1 Affected Population by Age in Village 2
Affected Population by Age in Village 2
26.50% < 18 years
33.10%
>18 years
37.30%
40.90% <18 years
>18 years
Affected Population in Village 3
Affected Population in Village 3 Affected Population in Village 4
Affected Population in Village 4
29.60% 21.50%
>18 years < 18 years
<18 years > 18 years
58.60%
51.60%

21. Prevalence of Skeletal Fluorosis (Based on Physical
Exercise)
)
Village 1 Village 2
8%
8% 5.80%
6% 9.50%
4% 9.00%
2% 8.50%
8.00%
8 00% 9.20%
9 20%
0%
7.50%
Male Female 7.70%
7.00%
6.50% Male
Male Female
Village 3
5.60%
6.00% Village 4
Village 4
4.00% No skeletal fluorosis was observed
1.20%
2.00%
0 00%
0.00%
Male Female

22. PROJECT ON ALTERNATIVE WATER SUPPLY
• Low fluoride groundwater from distance villages
based on distribution mapping
based on distribution mapping
• Rain water harvesting if there is sufficient rainfall
g
• Provision of surface water if available
(appropriate level of water treatment will be
required)

23. PROJECT ON ALTERNATIVE WATER SUPPLY
250
Potential of Rainwater Harvesting
200
150
100
50
0
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Nazreth Ziway Methara

24. Development, Optimization and Field
p
Implementation of Defluoridation
Technologies
Eawag & CDN
AAU
Catholic Diocese of Nakuru
Defluoridation programme since 1998
D fl id ti i 1998
OSHO
HEKS
Oromo Self‐Help Organization
Swiss
Interchurch
Aid

25. Defluoridation Materials
1 Aluminium oxide based methods
⇒ Sorption to surface site
≡ Al — OH + F‐
Al OH + F ≡ Al F + OH‐
Al F + OH
2 Bone char and Calcium phosphate‐based methods
⇒ Incorporation into mineral phase
Incorporation into mineral phase
Ca5(PO4)3OH + F- Ca5(PO4)3F + OH-
hydroxyapatite fluorapatite

26. Bone Char and Contact Precipitation Technology
Contact Precipitation
Contact Precipitation Ca and PO is added to the filter
Ca and PO4 is added to the filter
11

27. Bone Char and Contact Precipitation Technology
Fluoride Removal Capacity
Bone Char
Contact Precipitation
C t t P i it ti
Capacity increase from ≈ 0.7 to 3 – 4 mg F/g
12

28. Bone Char and Contact Precipitation Technology
Uptake Mechanism?
By adding pellets that release calcium
and phosphate the uptake of fluoride
can be increased.
HAP coating
F
PO4
BC
F
Influence: CaF2?
BC: pellet ratio
p
temperature Ca

29. Bone Char and Contact Precipitation Technology
From lab scale tests to household units and to small
community plant

30. Aluminum Oxyhydroxide Technology

31. Characterization of AO
Characterization of AO
• Density: 2.41 (g/cm3)
y (g/c 3)
• XRD: Mixture of amorphous/crystalline
• BET Surface Area: 37.7 m2/g
BET Surface Area 37 7 m2/g
• SEM Analysis:
• It shows that the material contains Na2SO4 having
particle size ranging from 5‐10 µm and also aluminium
oxide ranging from 200 300 nm.
oxide ranging from 200‐300 nm.

32. Decrease in Surface Area as Preparation
Temperature Increases
Temperature Increases
S/N Sample name Specific surface area
(m2/g)
1 Sample 1 (AO 100 oC) 38.9
2 Sample 2 (AO 200 oC) 38.2
3 Sample 3 (AO 300 oC) 37.7
4 Sample 4 (AO 400 oC) 27.1 Capacity of F removal
5 Sample 5 (AO 500 oC) 12.9 = 23.7 mg F/g AO
6 Sample 6 (AO 600 oC) 12.7
7 Reference material 79.9
Aluminiumoxide, TYPE150
Aluminiumoxide, TYPE150
The high removal capacity compared to that of AA is an advantage, but needs
further investigation

33. Batch Adsorption Studies/Isotherms

34. Continuous Adsorption Studies
0 .3 2 5 cm 2 0 cm 1.25
1 5 cm 1 0 cm
25 cm 20 cm
15 cm 10 cm
0 .2 2 5 1
Ct/Co
o
0 .1 5 0.75
Ct/Co
0 .0 7 5 0.5
0 0.25
0 5 10 15 20 25 30 35 40 45 50 55
T im e (h ) 0
0 10 20 30 40 50 60
Time (h)
0.6
-1
10 mg L
12 ml/min 23 mL/min
0.525 -1
40 mL/min 20 mg L
0.600
0.45 0.525
0.375 0.450
Ct/Co
0.375
0.3
Ct/Co
0.300
0.225
0.225 recommended
-1
0.15 level for 10mg L
0.150
Recommended
0.075 0.075
level for 20 mg L
-1
0.000
0 0 10 20 30 40 50 60
0 10 20 30 40 50 60 70 Time (h)
Time (h)

35. Release of Aluminum Ion from AO Column
16
15
14 -
pH (F0 mg/L)
13
-
12 Al (F0 mg/L)
-
11 F
-
10 pH (F20 mg/L)
Conc. (mg/L)
9 -
Al (F20 mg/L)
8
7
6
C
5
4
3
2 Recomended level for F
1
0
0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300
3
BV (cm )
Fig. Fluoride removal curves for deionized raw water with influent fluoride concentration of 0 and 20
mg/L (flow rate 100 BV/day).

36. Release of Aluminum Ion from AO Column
15
14
13
pH without clacite
Al without calcite
12
pH with calcite
11
Al with calcite
10 -
F with calcite
9
Conc. (mg/L)
8
7
6
5
4
3
2
1 -
Recomended level for F
0
0 50 100 150 200 250 300 350
3
BV (
(cm )
Fluoride removal curve for synthetic raw water
with and without calcite at post treatment (Co = 20
mg/L, flow rate 10 BV/day).

37. Community Defluoridation Plant Based on AO
AO
Calcite

38. IMPLEMENTATION OF OTHER DEFLUORIDATION
TECHNIQUE
Community Scale Nalgonda Technique
l l d h

39. Improved Community Scale Nalgonda Technique
p y g q

40. INTERNATIONAL COLLABORATIONS
• Swiss Federal Institute of Aquatic Science and
Technology (AEWAG), Switzerland
• Oklahoma University, WaTER Center, USA
• National Environmental Engineering Institute
(NEERI), India
( )
Capacity building, reorientation of different stakeholders,
C it b ildi i t ti f diff t t k h ld
disseminating knowledge and information, documenting best
practices, technology development

41. Acknowledgements
A k l d
• Ministry of Water Resources of Ethiopia
• UNICEF Ethiopia
• Addis Ababa University
• DFID through the National Wash Coordination Program
• Swiss National Science Foundation (SNSF)
Swiss National Science Foundation (SNSF)
• International Foundation For Science (IFS)
• q gy ( )
Swiss Federal Institute of Aquatic Science and Technology (EAWAG)
• CRS Ethiopia, HEKS, OSHO
• Catholic Diocese of Nakuru (CDN)
• Water Center, School of Civil Engineering and Environmental Sciences,
University of Oklahoma