Evaluating Household Water Treatment Options: A health-based approach

Transcription

1 Evaluating Household Water Treatment Options: A health-based approach Maggie Montgomery Water, Sanitation, Hygiene and Health Unit, WHO Southern Africa Household Water Treatment and Safe Storage Workshop Maputo, Mozambique 21 June 2012

2 Overview Basis for health-based criteria for evaluating HWT Elaboration of water quality targets Example of national efforts Challenges and conclusion

3 WHO Guidelines for Drinking-water Quality History '84/'85 first edition published Aim Protection of human health Support setting of national standards and regulations Approach Risk/benefit, advisory in nature, multiple barriers, incremental improvements Target audience Regulators, water suppliers, implementers Risk Framework Based on quantitative microbial risk assessment (QMRA)

4 Technical Basis for HWT Unlike other public health interventions (i.e. bednets), no single proven HWT technology Criteria provide important basis by which to evaluate and regulate technology(ies) WHO, global normative agency on health, ideal organizations to provide recommendations on HWT Recommendations based on WHO Guidelines on Drinking-water quality WHO/ R Granich

5 Application of WHO Guidelines- Evaluating HWT Options Goal:Protect health of users, increase access to safe water Audience: government/regulators, evaluators, manufacturers & implementers Target pathogens: viruses, bacteria and protozoa Derivation of targets: Based on Guidelines for drinking-water risk-based approach (QMRA models) Tiered approach: Highly protective, protective, interim Laboratory protocols: Methods to verify performance

6 Performance Criteria Rating Highly protective (10-6 DALYs/ P/yr) Protective (10-4 DALYs/ P/yr) Interim (must be supported by health evidence) Log 10 reduction: bacteria Log 10 reduction: viruses Log 10 reduction protozoa Examples: Boiling, ultrafilters, combined approaches Examples: Membrane (micro) filters, flocculant-disinfectant Achieves protective target for two classes of pathogens and results in health gains Examples: Chlorine, ceramic filters, biosand filters

7 Principals of protocols Technology specific and flexible May be based on local capabilities and resources Based on actual field use conditions Microbes and low-cost methods are now accessible to a reasonably equipped lab anywhere in the world Assay influent and effluent water, approximating use conditions and cycle of use for technology Log 10 reductions are calculated: LRV = log 10 (C untreated /C treated )

8 Labelling, Certification and Regulation (WHO does not endorse or certify technologies) Procter and Gamble, Coagu-Floc Cascade Design, Microfilter PUR packets have been proven to eliminate disease causing microorganisms. PUR packets result in removal of more than % of intestinal bacteria (including those that cause cholera), 99.99% of intestinal viruses (including those that cause hepatitis A) and 99.9% of protozoa. PUR packets remove dirt and other pollutants. PUR packets are considered an effective technology by the World Health Organization. Hindustan Unilever, Microfilter Effective against bacteria and protozoa % removal of bacteria and 99.99% removal of viruses, 99.9% protozoa Recommendations: Meets EPA standards for virus and bacteria removal. Locally developed and understood, supply sufficient information to make an "informed choice".

9 WHO Implementation Activities Distribute and promote document Ministries of Health, Environment, WHO Country Offices Information sheet for policy-makers and regulators Workshops and international meetings Support individual national efforts Technical support, including in-country guidance and advice (ex. Cambodia, Ethiopia, Kenya) Include criteria in programming; integration efforts International scheme + national support Centralized vetting and evaluation of technologies at recognized laboratories and international organizations Strengthen national technical and regulatory capacity

10 Implementation of Criteria - International Evaluation Scheme Why an international scheme? Ensures criteria are appropriately adopted Ensures standards met for health-based evaluation Streamlines evaluation of technologies used in many countries Effective mechanism to build national capacity Precedent for International Regulation/Certification NSF Certification of drinking water treatment WHO Pesticide Evaluation Scheme (WHOPES)

11 Example of efforts in Ethiopia Semi-autonomous entity, within Ministry of Health oversees testing Components: Use river water, analyze fecal indicators, turbidity, and nitrates Results used as basis to regulate sales and distribution of HWT As of 2012, Ministry of Health has strategy on drinking-water quality Multi-barrier approach to reduce health risks posed by contaminated water, including HWTS Working to strengthen HWT testing based on WHO guidance IPA/ L Lehmann

12 Complimentary efforts: Monitoring and evaluating HWTS use WHO/UNICEF finalizing HWTS monitoring and evaluation toolkit with input from Network Toolkit important for: Focus on Outcomes Increasing rigour and objectivity of M&E efforts Understanding user behaviour ; translate understanding into improved implementation and follow-up Compare and share data and justify further investments

13 Challenges and Conclusion Consideration of local data and priority pathogens of health concern Harmonized laboratory protocols Technical capacities to test and evaluate Linking testing to government regulation Certification and labelling Optimizing performance AND consistent and correct use HWT only has health impact if used consistently (approximately 90% of the time), correctly, and exclusively when drinking-water is contaminated!

14 Acknowledgements and links Waltaji Terfa (WHO, Ethiopia) Joe Brown (LSHTM) HWTS Survey on National Policies tml Evaluating household water treatment technologies: healthbased targets and microbial performance specifications. r/en/index.html

15 Thank you-questions? Dancing for safe drinking-water solutions.