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US Geological Society Wednesday October 31st 2007 Richard Wilson

US Geological Society Wednesday October 31st 2007 Richard Wilson Mallinckrodt Research Professor of Physics Harvard University Disinfection of Dugwells in arsenic regions on behalf of scientists at Dhaka Community Hospital Jabed Yousef and Md. Golam Mostofa Project Dugwell, WestBengal

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US Geological Society Wednesday October 31st 2007 Richard Wilson

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  1. US Geological Society Wednesday October 31st 2007 Richard Wilson Mallinckrodt Research Professor of Physics Harvard University Disinfection of Dugwells in arsenic regions on behalf of scientists at Dhaka Community Hospital Jabed Yousef and Md. Golam Mostofa Project Dugwell, WestBengal Meera Smith et al and UNICEF, Bangladesh Rich Johnston http://arsenic.ws http://physics.harvard.edu/~wilson/arsenic/ arsenic_project_introduction.html

  2. DYSPIGMENTATION KERATOSIS GANGRENE BOWEN”S CARCINOMA

  3. 1982: R.C Saha observed keratoses and dyspigmentation in West Bengal -IGNORED1995 DCH physicians saw lesions in Bangladesh.30,000 drinking water with >50 ppb arsenicACTION BEGAN in 1998(1) Use uncontaminated deep aquifer(2) Treat the water at household level (3) return to surface watersALL WILL WORKI will address only the last Rebuilt dug wells

  4. WHO guidelines for constructionNo bucket to get waterAnimals cannot fall inFar from latrinesFlood water cannot enterBut not enough in a tropical climatedeveloping countries slow to chlorinateorganic matter + chlorine -> chlorinated hydrocarbonsANIMAL CARCINOGENS!Many people distrusted chlorinationWHO and other reports chemical danger pale in comparison with bacterial risksFaecal coliform as indicator.Recommendation is 0 /ml; 10/ml not badIn West Bengal Chakriborti chlorinated.Cleaning every 3 months inadequate (DCH)every month inadequate (Project well) Detaied study (Yousef and Mostafa ) Data:July and August 2006 looked goodWorse in 2007

  5. Electrically pumped to tank (R) Sanitary well: no animals fall in no buckets! (L) Lady has running water for first time in history

  6. Piped water system very popular among women who carry the waterEnables more families to be served by one well.Large (INDIRA) wells can serve 50 familiesMaintenance cost spreadLarge size ensures oxidization and inhibits arsenic release

  7. Faecal coliform coun/ 100 ml No. of days after chlorination >10 after 23 days and reached from 35 to 180+ in the water samples of all dugwells at the end of the month. Fig 1: Faecal coliforms count in water samples of 10 dugwells (DW2, DW3, DW6, DW7, DW8, DW10, DW21, DW29, DW34, and DW66) of Pabna district in the month of July.

  8. Remarkable consistencyFaecal coliform below 10 /100ml between 1-20 days after chlorination, then rising(chlorinate every 2 weeks or less)This was monsoon- worst period when ground is sodden and will not filter

  9. Basic data on Sanitation (figures in %, 2003 Progotir Pathey, BBS and UNICEF) Diarrhoea prevalence within last 15 days boys/girls 26/24 25/23 Improved drinking water sources* (2002) 72 75 Access to sanitary latrines* (2002) 39 48 Insanitary hanging latrines 32 31 Open defecation 23 19 Disposal of faeces of children (under 5) in no fixed place 67 61 Washing hands after defecation with water and soap 11 19 Washing hands after defecation with water and soil/ash 67 61

  10. To compare different health outcomes Murray (HSPH) recommended (1991)Disability Adjusted Life Years lost (DALYs)Quality Adjusted Life Years lost (QALYs) Faecal coliform is an indicator of problems. Bacterial disease depend on conditioning Few people in Bangaldesh looked for it,DCH was better, but not frequent enough and after, nor before cleaningAhmed and Howard in 2005took a selection of wells from various technologies dugwells seemed badMEDIAN Faecal coliform was 3500/100mlDCH was at or below 5th percentile(but stll too high till 2006)

  11. DALYs calculated byAhmed and Howard for a sample of Bangladesh technologiesDCH (Pabna) wells are at or below lower (5%) bound of dugwells

  12. Chlorination method of DCH:Using Cloteck (5.25% Chlorine) doses based on water volume. Start summer 2006 with 20 DW in PabnaContinued 2007 in Pabna and LakshamChlorination method by Aqua Welfare Society, “Project Well” of West Bengal has started using theoline of 1/3 of half dose every week based on water volume of water - measured every 21 days. Early tests avaialble on my site alsoUNICEFchlorination started August 2007 not available. Early indications that needed chlorine changes with time

  13. 2007 mean of 20 Pabna wells Before 24h 7d 15 dJuly 34: 3 : 43: 49Aug 92: 0.6 : 17: 59Sept 79+: 3: 27: 33Oct 77: 10: 29: 56LARGE “INDIRA”Pabna well20 before1 to 10 after

  14. Experience of “Project Well” in West Bengal is similar but less consistent measurements.No data for 2007 yet (Smith visits wells Nov 6th-9th)Siridjikan (UNICEF)measurements started August 2007

  15. 2007 Large (Indira) well inLaksham (Comilla) Before 24h 7d 15 dJuly 160: 50 : 1 : 35Aug 180+: 25 :10: 35Sept 160: 40: 35: 40Oct 90: 13: 13: 8Not as good as PABNA wells but still 100 times lower than Ahmed and Howard’s median

  16. MY recommendationfor BangladeshUse deep aquifer when easy(80% of time) BUT ONLY FOR HOUSEHOLD: NEVER FOR IRRIGATIONUse surface waters: for irrigationor for household with chlorinationimmediate application: household arsenic filtersSONO or similarUse piped water system; it leads to the long term

  17. In other tropical countries without a deep separable aquifer (Eastern Argentine)EquadorBurkino Faso;this experience may be vital

  18. ALL DCH tests are on the web at:http://DCHTests.arsenic.wshttp://physics.harvard.edu/~wilson/arsenic/remediation/dugwells/DCHtestsSome project well tests also:

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