Guidelines-for-drinking-water-quality.pdf

Guidelines for Drinking-water QualityFOURTH EDITION WHO Library Cataloguing-in-Publication DataGuidelines for drinking-water quality-4th ed.1.Potable water-standards.2.Water-standards.3.Water quality-standards.4.Guidelines.I.World Health Organization.ISBN 978 92 4 154815 1 (NLM classification:WA 675)World Health Organization 2011All rights reserved.Publications of the World Health Organization are available on the WHO web site(http:/www.who.int)or can be purchased from WHO Press,World Health Organization,20 Avenue Appia,1211 Geneva 27,Switzerland(tel.:[phone];fax:[phone];e-mail:bookorderswho.int).Requests for permission to reproduce or translate WHO publications whether for sale or for non-commercial distribution should be addressed to WHO Press through the WHO web site(http:/www.who.int/about/licensing/copyright_form/en/index.html).The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country,territory,city or area or of its authorities,or concerning the delimitation of its frontiers or boundaries.Dotted lines on maps represent approximate border lines for which there may not yet be full agreement.The mention of specific companies or of certain manufacturers products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned.Errors and omissions excepted,the names of proprietary products are distinguished by initial capital letters.All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication.However,the published material is being distributed without warranty of any kind,either expressed or implied.The responsibility for the interpretation and use of the material lies with the reader.In no event shall the World Health Organization be liable for damages arising from its use.Cover designed by WHO Graphics,SwitzerlandTypeset by Value Chain,IndiaPrinted in Malta by GutenbergiiiContentsPreface xvAcknowledgements xviiAcronyms and abbreviations used in text xx1.Introduction 11.1 General considerations and principles 11.1.1 Framework for safe drinking-water 31.1.2 Microbial aspects 41.1.3 Disinfection 51.1.4 Chemical aspects 61.1.5 Radiological aspects 71.1.6 Acceptability aspects:taste,odour and appearance 71.2 Roles and responsibilities in drinking-water safety management 81.2.1 Surveillance and quality control 81.2.2 Public health authorities 101.2.3 Local authorities 111.2.4 Water resource management 121.2.5 Drinking-water supply agencies 131.2.6 Community management 141.2.7 Water vendors 151.2.8 Individual consumers 151.2.9 Certification agencies 151.2.10 Plumbing 161.3 Supporting resources to the Guidelines 181.3.1 Published documents 181.3.2 Capacity-building networks 182.A conceptual framework for implementing the Guidelines 192.1 Health-based targets 202.2 Water safety plans 222.2.1 System assessment and design 222.2.2 Operational monitoring 232.2.3 Management plans,documentation and communication 24ivGUIDELINES FOR DRINKING-WATER QUALITY2.3 Surveillance 252.4 Verification of drinking-water quality 252.4.1 Microbial water quality 262.4.2 Chemical water quality 262.5 Identifying priority concerns 272.5.1 Undertaking a drinking-water quality assessment 282.5.2 Assessing microbial priorities 292.5.3 Assessing chemical priorities 292.6 Developing drinking-water quality standards 302.6.1 Adapting guideline values to locally relevant standards 312.6.2 Periodic review and revision of standards 312.7 Drinking-water regulations and supporting policies and programmes 312.7.1 Regulations 322.7.2 Supporting policies and programmes 333.Health-based targets 353.1 Setting health-based targets 363.2 Disability-adjusted life years,tolerable disease burden and reference level of risk 373.3 Types of health-based targets 383.3.1 Health outcome targets 413.3.2 Water quality targets 423.3.3 Performance targets 433.3.4 Specified technology targets 434.Water safety plans 454.1 System assessment and design 494.1.1 New systems 504.1.2 Collecting and evaluating available data 514.1.3 Resource and source protection 534.1.4 Treatment 554.1.5 Piped distribution systems 564.1.6 Non-piped,community and household systems 584.1.7 Validation 59 4.1.8 Upgrade and improvement 604.2 Operational monitoring and maintaining control 614.2.1 Determining system control measures 614.2.2 Selecting operational monitoring parameters 624.2.3 Establishing operational and critical limits 634.2.4 Non-piped,community and household systems 634.3 Verification 644.3.1 Verification of microbial quality 654.3.2 Verification of chemical quality 664.3.3 Source waters 674.3.4 Piped distribution systems 674.3.5 Verification for community-managed supplies 68vCONTENTS4.3.6 Quality assurance and quality control 684.3.7 Verification of water safety plans 694.4 Management procedures for piped distribution systems 694.4.1 Predictable incidents(“deviations”)714.4.2 Unplanned events 714.4.3 Emergencies 724.4.4 Preparing a monitoring plan 734.4.5 Supporting programmes 734.5 Management of community and household water supplies 744.6 Documentation and communication 754.7 Planned review 764.7.1 Periodic review 764.7.2 Post-incident review 765.Surveillance 775.1 Types of approaches 795.1.1 Audit 795.1.2 Direct assessment 805.2 Adapting approaches to specific circumstances 815.2.1 Urban areas in developing countries 815.2.2 Surveillance of community drinking-water supplies 815.2.3 Surveillance of household treatment and storage systems 825.3 Adequacy of supply 835.3.1 Quantity(service level)835.3.2 Accessibility 855.3.3 Affordability 855.3.4 Continuity 865.4 Planning and implementation 875.5 Reporting and communicating 895.5.1 Interaction with community and consumers 895.5.2 Regional use of data 906.Application of the Guidelines in specific circumstances 936.1 Climate change,water scarcity and heavy rainfall 946.2 Rainwater harvesting 946.3 Vended water 966.4 Bulk water supply 976.5 Desalination systems 986.6 Dual piped water supply systems 996.7 Emergencies and disasters 1006.8 Temporary water supplies 1026.9 Buildings 1046.10 Health-care facilities 1076.11 Safe drinking-water for travellers 1076.12 Aircraft and airports 1096.13 Ships 112viGUIDELINES FOR DRINKING-WATER QUALITY6.14 Packaged drinking-water 1146.15 Food production and processing 1167.Microbial aspects 1177.1 Microbial hazards associated with drinking-water 1177.1.1 Waterborne infections 1187.1.2 Emerging issues 1227.1.3 Persistence and growth in water 1237.1.4 Public health aspects 1247.2 Health-based target setting 1247.2.1 Health-based targets applied to microbial hazards 1247.2.2 Reference pathogens 1257.2.3 Quantitative microbial risk assessment 1287.2.4 Risk-based performance target setting 1317.2.5 Presenting the outcome of performance target development 1337.2.6 Adapting risk-based performance target setting to local circumstances 1347.2.7 Health outcome targets 1357.3 Occurrence and treatment of pathogens 1367.3.1 Occurrence 1367.3.2 Treatment 1387.4 Microbial monitoring 1477.5 Methods of detection of faecal indicator organisms 1507.6 Identifying local actions in response to microbial water quality problems and emergencies 1507.6.1 Boil water advisories 1517.6.2 Actions following an incident 1538.Chemical aspects 1558.1 Chemical hazards in drinking-water 1568.2 Derivation of chemical guideline values 1588.2.1 Approaches taken 1598.2.2 Threshold chemicals 1608.2.3 Non-threshold chemicals 1658.2.4 Data quality 1658.2.5 Provisional guideline values 1668.2.6 Chemicals with effects on acceptability 1678.2.7 Chemicals not included in the Guidelines 1678.2.8 Mixtures 1678.2.9 Adapting guideline values to local circumstances 1688.3 Analytical achievability 1688.4 Treatment 1708.4.1 Treatment performance 1718.4.2 Process control measures for disinfection by-products 1728.4.3 Treatment for corrosion control 1748.4.4 Household treatment 175viiCONTENTS8.5 Guideline values for individual chemicals,by source category 1768.5.1 Naturally occurring chemicals 1768.5.2 Chemicals from industrial sources and human dwellings 1778.5.3 Chemicals from agricultural activities 1798.5.4 Chemicals used in water treatment or from materials in contact with drinking-water 1828.5.5 Chemicals of emerging concern 1898.6 Pesticides used in water for public health purposes 1908.7 Identifying local actions in response to chemical water quality problems and emergencies 1928.7.1 Trigger for action 1948.7.2 Investigating the situation 1948.7.3 Talking to the right people 1948.7.4 Informing the public 1958.7.5 Evaluating the significance to public health and individuals 195 8.7.6 Determining appropriate action 1988.7.7 Consumer acceptability 1998.7.8 Ensuring remedial action,preventing recurrence and updating the water safety plan 1998.7.9 Mixtures 1998.7.10 Water avoidance advisories 2009.Radiological aspects 2039.1 Sources and health effects of radiation exposure 2049.1.1 Radiation exposure through ingestion of drinking-water 2059.1.2 Radiation-induced health effects through drinking-water 2069.2 Rationale for screening levels and guidance levels 2079.3 Monitoring and assessment for dissolved radionuclides 2089.3.1 Screening of drinking-water supplies 2099.3.2 Strategy for assessing drinking-water if screening levels are exceeded 2109.3.3 Strategy for assessing drinking-water if guidance levels are exceeded 2109.3.4 Sampling frequency 2129.4 Guidance levels for radionuclides commonly found in drinking-water 2129.5 Analytical methods 2139.5.1 Measuring gross alpha and gross beta activity concentrations 2139.5.2 Measuring specific radionuclides 2139.6 Remedial measures 2149.7 Radon 2149.7.1 Radon in air and water 2149.7.2 Health risks from radon 2169.7.3 Guidance on radon in drinking-water supplies 2169.7.4 Measuring radon in drinking-water 217viiiGUIDELINES FOR DRINKING-WATER QUALITY9.7.5 Decreasing radon concentrations in drinking-water 2179.8 Risk communication 2179.8.1 Reporting results 2179.8.2 Communicating risks 21710.Acceptability aspects:Taste,odour and appearance 21910.1 Biologically derived contaminants 221 Actinomycetes and fungi 221 Cyanobacteria and algae 221 Invertebrate animal life 221 Iron bacteria 22210.2 Chemically derived contaminants 222 Aluminium 222 Ammonia 223 Chloramines 223 Chloride 223 Chlorine 223 Chlorobenzenes 223 Chlorophenols 224 Colour 224 Copper 224 Dissolved oxygen 225 Ethylbenzene 225 Hardness 225 Hydrogen sulfide 225 Iron 226 Manganese 226 Petroleum oils 226 pH and corrosion 226 Sodium 227 Styrene 227 Sulfate 227 Synthetic detergents 227 Toluene 228 Total dissolved solids 228 Turbidity 228 Xylenes 229 Zinc 22910.3 Treatment of taste,odour and appearance problems 23010.4 Temperature 23011.Microbial fact sheets 23111.1 Bacterial pathogens 232 Acinetobacter 232 Aeromonas 234 Bacillus 235 ixCONTENTS Burkholderia pseudomallei 236 Campylobacter 237 Enterobacter sakazakii 239 Escherichia coli pathogenic strains 240 Helicobacter pylori 241 Klebsiella 242 Legionella 244 Leptospira 245 Mycobacterium 247 Pseudomonas aeruginosa 249 Salmonella 250 Shigella 252 Staphylococcus aureus 253 Tsukamurella 254 Vibrio 255 Yersinia 25711.2 Viral pathogens 258 Adenoviruses 258 Astroviruses 260 Caliciviruses 261 Enteroviruses 263 Hepatitis A virus 264 Hepatitis E virus 265 Rotaviruses and orthoreoviruses 26711.3 Protozoan pathogens 268 Acanthamoeba 269 Balantidium coli 270 Blastocystis 271 Cryptosporidium 273 Cyclospora cayetanensis 274 Entamoeba histolytica 276 Giardia intestinalis 277 Isospora belli 279 Microsporidia 280 Naegleria fowleri 282 Toxoplasma gondii 28311.4 Helminth pathogens 285 Dracunculus medinensis 285 Fasciola spp.287 Free-living nematodes 288 Schistosoma spp.29011.5 Toxic cyanobacteria 29311.6 Indicator organisms 294 Total coliform bacteria 294 Escherichia coli and thermotolerant coliform bacteria 296xGUIDELINES FOR DRINKING-WATER QUALITY Heterotrophic plate counts 297 Intestinal enterococci 298 Clostridium perfringens 300 Coliphages 301 Bacteroides fragilis phages 303 Enteric viruses 30512.Chemical fact sheets 30712.1 Chemical contaminants in drinking-water 307 Acrylamide 307 Alachlor 308 Aldicarb 309 Aldrin and dieldrin 310 Aluminium 311 Ammonia 313 Antimony 314 Arsenic 315 Asbestos 318 Atrazine and its metabolites 319 Barium 320 Bentazone 321 Benzene 322 Beryllium 322 Boron 323 Bromate 324 Bromide 325 Brominated acetic acids 326 Cadmium 327 Carbaryl 328 Carbofuran 328 Carbon tetrachloride 329 Chloral hydrate 330 Chloramines(monochloramine,dichloramine,trichloramine)331 Chlordane 333 Chloride 333 Chlorine 334 Chlorite and chlorate 335 Chloroacetones 337 Chlorophenols(2-chlorophenol,2,4-dichlorophenol,2,4,6-trichlorophenol)337 Chloropicrin 338 Chlorotoluron 338 Chlorpyrifos 339 Chromium 340 Copper 340 xiCONTENTS Cyanazine 342 Cyanide 342 Cyanobacterial toxins:Microcystin-LR 344 Cyanogen chloride 346 2,4-D 347 2,4-DB 348 DDT and metabolites 349 Dialkyltins 350 1,2-Dibromo-3-chloropropane 350 1,2-Dibromoethane 351 Dichloroacetic acid 352 Dichlorobenzenes(1,2-dichlorobenzene,1,3-dichlorobenzene,1,4-dichlorobenzene)353 1,1-Dichloroethane 354 1,2-Dichloroethane 355 1,1-Dichloroethene 355 1,2-Dichloroethene 356 Dichloromethane 357 1,2-Dichloropropane 358 1,3-Dichloropropane 359 1,3-Dichloropropene 359 Dichlorprop 360 Di(2-ethylhexyl)adipate 361 Di(2-ethylhexyl)phthalate 361 Dimethoate 362 1,4-Dioxane 363 Diquat 364 Edetic acid 364 Endosulfan 365 Endrin 366 Epichlorohydrin 367 Ethylbenzene 368 Fenitrothion 368 Fenoprop 369 Fluoride 370 Formaldehyde 373 Glyphosate and AMPA 374 Halogenated acetonitriles(dichloroacetonitrile,dibromoacetonitrile,bromochloroacetonitrile,trichloroacetonitrile)375 Hardness 376 Heptachlor and heptachlor epoxide 377 Hexachlorobenzene 378 Hexachlorobutadiene 379 Hydrogen sulfide 380 xiiGUIDELINES FOR DRINKING-WATER QUALITY Inorganic tin 380 Iodine 381 Iron 381 Isoproturon 382 Lead 383 Lindane 385 Malathion 386 Manganese 386 MCPA 387 Mecoprop 388 Mercury 389 Methoxychlor 390 Methyl parathion 391 Methyl tertiary-butyl ether 392 Metolachlor 393 Molinate 393 Molybdenum 394 Monochloroacetic acid 395 Monochlorobenzene 395 MX 396 Nickel 396 Nitrate and nitrite 398 Nitrilotriacetic acid 403 Nitrobenzene 404 N-Nitrosodimethylamine 405 Parathion 406 Pendimethalin 407 Pentachlorophenol 407 Petroleum products 408 pH 409 2-Phenylphenol and its sodium salt 409 Polynuclear aromatic hydrocarbons 410 Potassium 412 Propanil 413 Selenium 413 Silver 415 Simazine 415 Sodium 416 Sodium dichloroisocyanurate 416 Styrene 418 Sulfate 419 2,4,5-T 419 Terbuthylazine 420 Tetrachloroethene 421 Toluene 422xiiiCONTENTS Total dissolved solids 423 Trichloroacetic acid 423 Trichlorobenzenes(total)424 1,1,1-Trichloroethane 424 Trichloroethene 425 Trifluralin 426 Trihalomethanes(bromoform,bromodichlorom