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