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WHO Guidelines for Drinking-water QualityLaunch Presentation, 21st September 2004,
Marrakech
Jamie BartramCoordinator
Water Sanitation and HealthWorld Health Organization
History of the Guidelines
1958, 1963, 1971: International Standards1984 First edition of “Guidelines”: basis for setting standards but standards responsibility of states1993 Second edition: increase in number of chemicals 2003 Third edition systematic safety approach; application to different settings.
WHO Water Guidelines
AimFeatures
Approach
Protection of human healthAdvisory in natureSupport national standard-setting adapted to social, cultural, economic & environmental contextRisk-benefit philosophyBest available evidence - science and practiceScientific consensusExploit global information and experience
Use of WHO Guidelines
Scientific basis for national and supra national norms and standards e.g. Japan, EU, Australia Active participant-users e.g. USA, CanadaTransposition e.g. some developing countries Used in absence of national standards/GL
Guidelines for Drinking-water Quality
ProcessPlan of work from IG meetings and proposalsIndividuals/teams draft documentsWorking groups initial review (and improvement)Public domain review (and improvement)“Final Task Force” meeting of government-nominated experts
WHO Guidelines for Drinking-water Quality
Microbes (infectious agents)
Chemicals
Radiological aspects
Acceptability aspects
Application ‘settings’
Guidelines and Regulations for Water-borne Infectious Disease
• > 100 years “success” in outbreak control• reliance on end product testing: too little too late• post-exposure• residual disease burden• unrecognised pathogens• diverse health outcomes• in-building hazards (e.g. Legionella)
WHO GDWQ 3rd Edition - Response
Moving away from reliance on output monitoring -measuring parameters in final waterMore input monitoring - measuring parameters that show that the system is workingShort-term quality changesCatchment-to-consumerNeeds transparency openness, inter-sectoralRisk-based
Buildings on multiple barrier, HACCP,….
Framework for Water Safety in3rd Edition WHO GDWQ
Health Based TargetsWater Safety Plans1 System Assessment2 Monitoring of control measures 3 Management PlansIndependent Surveillance
Health-Based Targets
Targets based on public health protection and disease preventionBenchmark for water suppliesPublic health benefitLocal circumstancesQuantitative risk assessmentGuidance developed by WHOFrom simple to complex
WSP part 1: System Assessment
System assessment to determine whether the water supply chain (up to the point of consumption) as a whole can deliver water of a quality that meets
the targets
Reality check before starting WSPSystem capability to meet Water Quality TargetsOutcome identifies system improvementsValidation of processesIdentifying what reduces and prevents contamination
Health based targets
System assessment
Monitoring of control measures
Management Plans
Independent “surveillance”
WSP part 2: Monitoring of control measures
Monitoring of the control measures in the supply chain that are of particular importance in securing water safety
Target barriers identified in system assessmentOperational monitoring - continual effectivenessSimple parameters, from results to action
Health basedtargets
System assessment
Monitoring of control measures
Management Plans
Independant surveillance
WSP part 3: Management Plans
Management plans describing actions to be undertaken from normal conditions to extreme
events; including documentation and communication
Documented:system assessmentcontrol measure identificationmonitoring planmanagement responsessupporting programmes (SOPs, training …)communication plan
Health based targets
System assessment
Monitoring of control measures and actions
Management Plans
Independent “surveillance”
Independent Surveillance
Systematic independent surveillance that verifies that the above are operating properly
Audit of Water Safety Planshows WSP is being adhered to
Verificationend-product final check
Health based targets
System assessment
Monitoring of control measures and actions
Management Plans
Independent surveillance
Guidelines and Regulations for ChemicalsSuccesses and Challenges
very widely used monitoring against GVsscientifical basis clear and soundrefine approach and GVs as new evidence emergesvery many chemicalsrelative disease burden/severityconsistency of approach for ‘materials and chemicals ….’ (“additives”), up to tapshort-term versus long-term exposure
WHO GDWQ 3rd Edition - Response
Mainly “business as usual” - some new or modified GVsmore rigorous assessment of need for GVopportunity for wider commentgroup by source-type (management response)rolling revision and future strategy
Naturally Occurring
Highest priority: arsenic, fluoride, selenium and probably uranium.
Some new data to justify change, e.g. antimony (20 ug/l), uranium (pGV15 ug/l) increase as uncertainty decreased.
Cyanobacteria and their toxins
Natural but management different. More like microbial contaminants.Approach to source control.No new formal guideline values because of limitations in toxicity data.Range of new toxins means that source control and treatment barriers best.
Industrial Chemicals and Human Dwellings
Range of inorganic and organic chemicals - some overlap with other groups.Some may not justify inclusion or guideline value, TBTO (at), mercury (further review, unlikely).Rolling revision
Agriculture
The major chemical contaminants from agriculture: nutrients and pesticides.Nitrate/nitrite considered by JECFA
Future:Practical guidance in groundwater document and ‘chemical monitoring protocol’Pesticides to be assessed through JMPR (list, screening)
Disinfectants and By-products
Most of approach in EHC 216.Chlorite substantially more data so GV will increase.Bromate new data in review; GV driven by treatment achievability.Balancing risks, theoretical versus proven.
Treatment Chemicals
Aluminium and iron no change but for aluminium should achieve 100µg/l in well run plant.Acrylamide and epichlorohydrin no change and regulated through control of materials and dose.
Materials
Lead: no changeCopper: GV no longer provisionalIncreased guidance on regulating materials (rolling revision also).Other substances that might leach from materials unchanged, (vinyl chloride).
Updating the Guidelines
Keeping the Guidelines up-to-date is a major challenge …WHO moving towards a ‘rolling revision’Substantiating the positions and ‘guidance’on good practice makes up most of the workAround 40 lines of work in the rolling revisionPeer and Public domain review have been ‘built-in’
Rolling Revision of WHO Guidelines for Drinking-water Quality
General priorities
‘Additives’Safe plumbing practicesEmerging issues initiativeVulnerable groupsNutrient mineralsIdentifying chemical prioritiesShort-term exceedence of chemical GVs
Rolling Revision of WHO Guidelines for Drinking-water Quality
Application in specific settings
Water and sanitation on ships and in aviation (linked to IHR)DesalinationTemporary water suppliesWater supply in emergenciesSmall community water supplyWater supply in large buildings, health care facilities
Rolling Revision of WHO Guidelines for Drinking-water QualityMicrobial aspects
Progressive finalization and updating of core resource documents dealing with:
- Water Safety Plans- Efficiency of water treatment processes (‘Risk balancing’ in
disinfection)- Groundwater source protection- Surface water source protection- Water quality changes in piped distribution- Sampling and monitoring in ‘Water Safety Plan’ approach
Guidelines Rolling Revision - Chemicals
Phase 1 Target 2003-4 Phase 2 target 2005-6 Phase 3 target 20Trihalomethanes (bromoform, chloroform…
Bromodichloromethane iodine
Formaldehyde Dibromochloromethane temephos
Nickel Cyanogen chloride uranium
Dichloroacetic acid sodium dichloroisocyanurate
Methoprene Boron
1,4 dioxane Molybdenum Selenium Barium and chloral hydrate Petroleum hydrocarbons
Finding the Guidelines
Http://www.who.int/water_sanitation_health/GDWQ/index.htm