FLUOROSIS MITIGATION IN ETHIOPIAETHIOPIA

Feleke Zewge

Department of Chemistry,

Addis Ababa University

&

National Fluorosis Mitigation Project Office,g j ,

Ministry of Water Resources

The Challenge: High Fluoride in Groundwater

• Is serious water safety problem mainly in the

The Challenge: High Fluoride in Groundwater

• Is serious water safety problem, mainly in the Ethiopian Rift Valley Regions Ab t 10 14 illi l d t• About 10‐14 million people are exposed to fluoride‐contaminated groundwater

• Several wells failed to supply drinking water due to the presence of fluoridethe presence of fluoride

• This affects the efforts to achieve MDG• This affects the efforts to achieve MDG.

FLUOROSIS IN ETHIOPIA: DENTAL

FLUORORSIS IN ETHIOPIA: DENTAL

FLUOROSIS IN ETHIOPIA: SKELETAL

FLUOROSIS IN ETHIOPIA: SKELETAL

Issues that Need to be Addressed to Mitigate FluorosisFluorosis

Identify and exploit low fluoride drinking water sources in thefluoride endemic areas.fluoride endemic areas.­ Keeping record of the fluoride levels of ground water sources

­ Establishing regional and national fluoride databaseg g•Having clear distribution map  up to village level

Setting fluoride standard for water deprived dry areas of theSetting fluoride standard for water deprived dry areas of thecountry.What should be the safe cut off level?1 5 mg/L 2 mg/L 3 mg/L 4 mg/L 5 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 fluorideintake?

Developing appropriate defluoridation technology for EthiopiaDeveloping appropriate defluoridation technology for EthiopiaIntegrating the fluoride problem with other water supply and

sanitation issues

Our ProjectsOur Projects

1 Fluoride Distribution Mapping1. Fluoride Distribution Mapping

2 Quantitative Chemical Risk Assessment2. Quantitative Chemical Risk Assessment

3 Alt ti W t S l3. Alternative Water Supply

l d ld4. Development, Optimization and Field Implementation of Defluoridation Technologies

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

Fluoride Distribution Mapping Population at risk•14.6 % of the total

/l d kUp to 33 mg/l in drinking water

Source: RiPPLE

•Population exposed is increasing 

•Prevalence of Fluorosis is increasing

Purpose of Fluoride Distribution Mapping 

• To assess the extent of fluoride contamination and

p pp gProject 

To assess the extent of fluoride contamination andproduce GIS maps at smallest administrative level

• To generate fluoride database at national level

• To prioritize actions and to locate the existence of lowfluoride groundwater within reasonable distance

• To know the actual number of exposed population

F Distribution: Main Rift Valley

F Distribution: East Showa Zone

Population at Risk

I

Quantitative Chemical Risk Assessment Project: To Introduce Integrated Fluorosis Mitigation Program

Fluoride in water

Fluoride in food

Identification of skeletal fluorosis

Nutritional statusQCRA

IDENTIFI Hazard identification

Overall  fluoride intake

Identification of dental fluorosis

QCRACATION

High fluorosis riskDAILY >100/1000 Persons

Low fluorosis riskDAILY < 10/1000 Persons

Moderate fluorosis riskDAILY 10 ‐100/1000 Persons

M k hORWater management

Defluoridation of

Nutritional supplementDefluoridation of drinking water

Water management

MITIGATI

Risk characterization

Defluoridation of drinking water

Nutritional supplementDilutiontechnique

Rain water harvesting

ON

Risk management

Nutritional supplement

Risk management

The major activities under QCRAThe 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 t i ti (b d l t d• Fluoride risk characterization (based on prevalence study and DALY (Disability Adjusted Life Years) calculation);

Purpose of QCRA Project

• To assess the health impacts due to excessive fluoride intake

Purpose of QCRA Project

pin relation with nutritional aspects and daily waterconsumption and finally establishing tolerable levels of risk tohuman healthhuman health

• To estimate disease burden due to dental and skeletalfluorosis in the fluorosis affected communities

• To prioritize communities that need immediate intervention

FLUORIDE INTAKE THROUGH FOOD AND( )BEVERAGES (Exposure)

40

y) 

20

30 CF

MS

GW

/per

son/

day

MS

GW

0

10F (m

g/

CFfood

beveragestotal uptake

Fluoride intakeFluoride intake

CF: 1 mg/L, MS: 3 mg/L, GW: 11 mg/L

Prevalence of Dental Fluorosis (Based on Dean`s Index))

35 00%

36.00%

37.00%

Affected population by sex in Village 1

60 00%

Affected population by sex in Village 2

31.00%

32.00%

33.00%

34.00%

35.00% 52.40%

34%

20 00%

30.00%

40.00%

50.00%

60.00%

29.00%

30.00%

Male  Female 

Affected population by sex in Village 

0.00%

10.00%

20.00%

Male  Female 

50%

40%

50%

60%

3

38.80%39.00%40.00%

Affected population by sex in Village 4

20.40%

0%

10%

20%

30%

33.80%

33.00%34.00%35.00%36.00%37.00%38.00%

0%

Male Female 31.00%32.00%

Male Female

Affected Population by Age in Village 1 Affected Population by Age in Village 2

Prevalence of Dental FluorosisAffected Population by Age in Village 1 Affected Population by Age in Village 2

26.50%

40.90% <18 years 

37.30%

33.10% < 18 years

>18 years

>18 years

Affected Population in Village 3 Affected Population in Village 4Affected Population in Village 3 Affected  Population in Village 4

29.60%

58.60%

>18 years 

<18 years 

51.60%

21.50%

< 18 years 

> 18 years 

Prevalence of Skeletal Fluorosis (Based on Physical Exercise) )

8%

8%

5.80%

Village 1 Village 2

2%

4%

6%

8 00%

8.50%

9.00%

9.50%

9 20%0%

Male  Female 

6.50%

7.00%

7.50%

8.00% 9.20%

7.70%

Male Female

6.00%5.60%

Village 3Male  Female

Village 4

0 00%

2.00%

4.00%1.20%

Village 4No skeletal fluorosis was observed

0.00%

Male Female

PROJECT ON ALTERNATIVE WATER SUPPLY

• Low fluoride groundwater from distance villages based on distribution mappingbased on distribution mapping

• Rain water harvesting if there is sufficient rainfallg

• Provision of surface water if available (appropriate level of water treatment will be required)

PROJECT ON ALTERNATIVE WATER SUPPLYPotential of Rainwater Harvesting

250

200

150

50

100

0

50

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Nazreth Ziway Methara

Development, Optimization and Field Implementation of Defluoridation

Eawag &  CDN

pTechnologies

Eawag & AAU

CDN

Catholic Diocese of NakuruD fl id ti i 1998

HEKSOSHO

Defluoridation programme since 1998

Oromo Self‐Help OrganizationSwiss Interchurch Aid

Defluoridation Materials

Aluminium oxide based methods1⇒ Sorption to surface site

1

≡ Al — OH + F‐ ≡ Al F + OH‐

Bone char and Calcium phosphate‐based methods⇒ Incorporation into mineral phase

2≡ Al  OH + F ≡ Al F + OH

Ca5(PO4)3OH + F- Ca5(PO4)3F + OH-

⇒ Incorporation into mineral phase

5 3 5 3hydroxyapatite fluorapatite

Bone Char and Contact Precipitation Technology

Contact Precipitation Ca and PO4 is added to the filterContact Precipitation  Ca and PO4 is added to the filter

11

Bone Char and Contact Precipitation Technology

Fluoride Removal Capacity

Bone Char

C t t P i it tiContact Precipitation

Capacity increase from ≈ 0.7 to 3 – 4 mg F/g

12

Bone Char and Contact Precipitation Technology

Uptake Mechanism?By adding pellets that release calcium and phosphate the uptake of fluoride can be increased.

HAP coatingF

PO4 BC 

FCaF2?Influence:

BC: pellet ratioCa

ptemperature

Bone Char and Contact Precipitation TechnologyFrom lab scale tests to household units and to small 

community plant

Aluminum Oxyhydroxide Technology

Characterization of AOCharacterization 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.

Decrease in Surface Area as Preparation Temperature IncreasesTemperature 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

5 Sample 5 (AO 500 oC) 12.9

Capacity of F removal = 23.7 mg F/g AO

6 Sample 6 (AO 600 oC) 12.7

7 Reference material Aluminiumoxide, TYPE150

79.9Aluminiumoxide, TYPE150

The high removal capacity compared to that of AA is an advantage, but needs further investigation

Batch Adsorption Studies/Isotherms

Continuous Adsorption Studies

1

1.2525 cm 20 cm15 cm 10 cm

0 .2 2 5

0 .3

o

2 5 cm 2 0 cm1 5 cm 1 0 cm

0.25

0.5

0.75

Ct/C

o

0

0 .0 7 5

0 .1 5Ct/C

o

00 10 20 30 40 50 60

Time (h)

00 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5

T im e (h )

0.375

0.45

0.525

0.6

12 ml/min 23 mL/min40 mL/min

0.450

0.525

0.600

10 mg L-1

20 mg L-1

0.075

0.15

0.225

0.3

Ct/C

o

0.075

0.150

0.225

0.300

0.375

C t

/ C o

recommended level for 10mg L-1

Recommended level for 20 mg L-1

00 10 20 30 40 50 60 70

Time (h)

0 10 20 30 40 50 600.000

Time (h)

Release of Aluminum Ion from AO Column

141516

1011121314 pH (F-

0 mg/L)

Al (F-0 mg/L)

F- pH (F-

20 mg/L)

56789

Con

c. (m

g/L)

20 mg/L

Al (F-20 mg/L)

12345C

Recomended level for F

0 100 200 300 400 500 600 700 800 900 1000 11001200 1300

01

BV (cm3)

Fig. Fluoride removal curves for deionized raw water with influent fluoride concentration of 0 and 20mg/L (flow rate 100 BV/day).

Release of Aluminum Ion from AO Column

12131415

pH without clacite Al without calcitepH with calcite

789

1011

(mg/

L)pH with calcite Al with calcite F- with calcite

34567

Con

c.

0 50 100 150 200 250 300 350

012

( 3)

Recomended level for F-

BV (cm3)

Fluoride removal curve for synthetic raw waterwith and without calcite at post treatment (Co = 20with and without calcite at post treatment (Co 20mg/L, flow rate 10 BV/day).

Community Defluoridation Plant Based on AO

AOCalcite

l l d h

IMPLEMENTATION OF OTHER DEFLUORIDATION TECHNIQUE

Community Scale Nalgonda Technique

Improved Community Scale Nalgonda Techniquep y g q

INTERNATIONAL COLLABORATIONS

• Swiss Federal Institute of Aquatic Science and Technology (AEWAG), Switzerland

• Oklahoma University, WaTER Center, USA

• National Environmental Engineering Institute ( )(NEERI), India

C it b ildi i t ti f diff t t k h ldCapacity building, reorientation of different stakeholders, disseminating knowledge and information, documenting best practices, technology development

A k l dAcknowledgements

• 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)

• Swiss Federal Institute of Aquatic Science and Technology (EAWAG)q gy ( )

• CRS Ethiopia, HEKS, OSHO

• Catholic Diocese of Nakuru (CDN)

• Water Center, School of  Civil Engineering and Environmental Sciences, 

University of Oklahoma