Feleke Zewge - Fluorosis Mitigation in Ethiopia

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Feleke Zewge - Fluorosis Mitigation in Ethiopia

  1. 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. 2. The Challenge: High Fluoride in GroundwaterThe 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. 3. FLUOROSIS IN ETHIOPIA: DENTAL
  4. 4. FLUORORSIS IN ETHIOPIA: DENTAL
  5. 5. FLUOROSIS IN ETHIOPIA: SKELETAL
  6. 6. FLUOROSIS IN ETHIOPIA: SKELETAL
  7. 7. Issues that Need to be Addressed to Mitigate  FluorosisIdentify 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 levelSetting 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 EthiopiaIntegrating the fluoride problem with other water supply and sanitation issues
  8. 8. Our Projects Our Projects1. Fluoride Distribution Mapping1 Fluoride Distribution Mapping2. Quantitative Chemical Risk Assessment2 Quantitative Chemical Risk Assessment3. Alternative Water Supply3 Alt ti W t S l4. Development, Optimization and Field  l d ld Implementation of Defluoridation Technologies
  9. 9. The Ethiopian RiftTotal area of 1127000 km² Average width of about 100 km  Divides the whole country from the northeast  to the southwestArea of RV about 33000 km²
  10. 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. 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. 12. F Distribution: Main Rift Valley
  13. 13. F Distribution: East Showa Zone
  14. 14. Population at Risk
  15. 15. Quantitative Chemical Risk Assessment Project: To Introduce  Integrated Fluorosis Mitigation ProgramIDE Identification of skeletal  Fluoride in water fluorosisNTIFI Fluoride in food Nutritional status Hazard identificationC QCRAATI Overall  fluoride  Identification of dental O intake fluorosisN Moderate fluorosis risk Low fluorosis risk High fluorosis risk DAILY 10 ‐100/1000 Persons DAILY < 10/1000 Persons DAILY >100/1000 PersonsMI Risk characterization k hT Defluoridation of  Water  Water management OR Nutritional supplementI drinking water managementGATI Defluoridation of of O drinking waterN Rain water  Dilution Nutritional supplement harvesting technique Risk management Risk management Nutritional supplement
  16. 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. 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. 18. FLUORIDE INTAKE THROUGH FOOD AND ( ) BEVERAGES (Exposure) 40 y)  /person/day CF 30 MS 20 GWF (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. 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% 235.00%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. 20. Prevalence of Dental FluorosisAffected Population by Age in Village 1Affected 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. 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. 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. 23. PROJECT ON ALTERNATIVE WATER SUPPLY250 Potential of Rainwater Harvesting20015010050 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Nazreth Ziway Methara
  24. 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 OrganizationSwiss Interchurch Aid
  25. 25. Defluoridation Materials1 Aluminium oxide based methods ⇒ Sorption to surface site ≡ Al — OH + F‐ Al  OH + F ≡ Al F + OH‐ Al F + OH2 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. 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. 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. 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. 29. Bone Char and Contact Precipitation Technology From lab scale tests to household units and to small  community plant
  30. 30. Aluminum Oxyhydroxide Technology
  31. 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. 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, TYPE150The high removal capacity compared to that of AA is an advantage, but needs further investigation
  33. 33. Batch Adsorption Studies/Isotherms
  34. 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 1Ct/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. 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 20mg/L (flow rate 100 BV/day).
  36. 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. 37. Community Defluoridation Plant Based on AO AO Calcite
  38. 38. IMPLEMENTATION OF OTHER DEFLUORIDATION  TECHNIQUE Community Scale Nalgonda Technique l l d h
  39. 39. Improved Community Scale Nalgonda Technique p y g q
  40. 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 lddisseminating knowledge and information, documenting best practices, technology development
  41. 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

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