Safe Drinking Water: Lessons from Recent Outbreaks in Affluent Nations

510 Pages·2010·10.49 MB·English

by  Steve E. Hrudey

Safe Drinking Water

Safe Drinking Water
Lessons from Recent Outbreaks in
Affluent Nations
Steve E. Hrudey and Elizabeth J. Hrudey
Department of Public Health Sciences
Faculty of Medicine and Dentistry
University of Alberta
Edmonton, AB
Canada
Published by IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK
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First published 2004
© 2004 IWA Publishing

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ISBN: 1 84339 042 6
CONTENTS
Dedication xi
Foreword xiii
Preface xvi
Acknowledgements xix
List of abbreviations xxi

1 INTRODUCTION 1

2 CAUSES OF WATERBORNE DISEASE OUTBREAKS 6
2.1 Historical background 6
2.2 Major classes of waterborne pathogens 20
2.2.1 Viruses 21
2.2.2 Bacteria 22
2.3.3 Protozoa 24
2.3 Specific pathogens relevant to outbreak case studies 25
2.3.1 Hepatitis A virus 25
2.3.2 Norovirus (Norwalk virus) 27
2.3.3 Rotavirus 29
2.3.4 Campylobacter 30
2.3.5 Escherichia coli (enterohemorrhagic E. coli, enterotoxigenic 32
E. coli)
2.3.6 Salmonella 34
(v)
vi Safe Drinking Water
2.3.7 Shigella 36
2.3.8 Giardia lamblia (syn. G. intestinalis, G. duodenalis) 37
2.3.9 Cryptosporidium parvum 38
2.3.10 Toxoplasma gondii 41
2.4 Indicator and surrogate organisms 42
2.5 Summary of pathogens 45

3 CAPABILITIES OF WATER SAFETY BARRIERS 50
3.1 Introduction to water quality 51
3.2 Source water protection 55
3.3 Conventional water treatment processes 56
3.3.1 Coagulation, flocculation and sedimentation (clarification) 57
3.3.2 Filtration 62
3.3.3 Disinfection: chlorination 67
3.4 Advanced water treatment processes 73
3.4.1 Membrane filtration 74
3.4.2 Ozonation 75
3.4.3 Ultraviolet radiation disinfection 75
3.4.4 Other processes 76
3.5 Water distribution and storage 76
3.6 Risk management for safe drinking water 78

4 WATERBORNE OUTBREAK CASE STUDIES 81
4.1 Introduction 81
4.2 Walkerton, Ontario, Canada 95
4.2.1 Scope of the outbreak 95
4.2.2 The Walkerton drinking water system 96
4.2.3 The outbreak experience in May 2000 97
Box 4.1 Key players in the course of the Walkerton outbreak 98
Box 4.2 Timeline of major events in Walkerton for May 2000 108
4.2.4 Direct causes of the outbreak 110
4.2.5 Commentary 118
4.3 Outbreaks in the 1970s 123
4.3.1 Overview 123
4.3.2 Richmond Heights, Florida, U.S.A., January–March 1974 125
4.3.3 Rome, New York, U.S.A., November 1974–June 1975 128
4.3.4 Crater Lake, Oregon, U.S.A., June–July 1975 130
4.3.5 Camas, Washington, U.S.A., April–May 1976 132
4.3.6 Berlin, New Hampshire, U.S.A., March–May 1977 134
4.3.7 Bennington, Vermont, U.S.A., May–June 1978 137
4.3.8 Bradford, Pennsylvania, U.S.A., July–December 1979 139
Contents vii
4.4 Outbreaks in the 1980s 142
4.4.1 Overview 142
4.4.2 Georgetown, Texas, U.S.A., June 1980 142
4.4.3 Red Lodge, Montana, U.S.A., June–August 1980 144
4.4.4 Bramham, Yorkshire, England, July 1980 147
4.4.5 Rome, Georgia, U.S.A., August 1980 150
4.4.6 Grums and Vålberg, Vårmland, Sweden, October 1980 152
4.4.7 Eagle-Vail, Colorado, U.S.A., March 1981 155
4.4.8 Mjövik (Karlskrona), Blekinge, Sweden, October 1982 158
4.4.9 Drumheller, Alberta, Canada, February 1983 161
4.4.10 Greenville, Florida, U.S.A., May 1983 165
4.4.11 Braun Station, Texas, U.S.A., May–July 1984 168
4.4.12 Alsvåg, Norway, June–July 1984 170
4.4.13 Orangeville, Ontario, Canada, April 1985 172
4.4.14 Pittsfield, Massachusetts, U.S.A., November 1985– January 1986 174
4.4.15 Penticton, B.C., Canada, June and November 1986 177
4.4.16 Sälen, Dalarna, Sweden, December 20 1986–January 17 1987 181
4.4.17 Carrollton, Georgia, U.S.A., January 1987 183
4.4.18 Sunbury, Diggers Rest and Bulla, Victoria, Australia, October 1987 186
4.4.19 Boden, Sweden, March–April 1988 189
4.4.20 Saltcoats/Stevenston, Ayrshire, Scotland, March–April 1988 191
4.4.21 Skjervøy, Norway July–August 1988 194
4.4.22 Swindon, Oxfordshire and Wiltshire, England, December 1988– 195
April 1989
4.4.23 Oakcreek Canyon, Sedona, Arizona, U.S.A., April 1989 199
4.5 Outbreaks in the 1990s 202
4.5.1 Overview 202
4.5.2 Cabool, Missouri, U.S.A., December 1989–January 1990 202
4.5.3 Moama, New South Wales, Australia, December 1989–January 1990 207
4.5.4 Creston / Erickson, B.C., Canada, January–April 1990 210
4.5.5 Nursery School / Kindergarten, Saitama, Japan, October 1990 213
4.5.6 The Isle of Thanet, Kent, England, December 1990–January 1991 215
4.5.7 Naas, County Kildare, Ireland, October 1991 217
4.5.8 Ugglelose, Denmark, December 1991–January 1992 220
4.5.9 Jackson County, Oregon, U.S.A., January–June 1992 222
4.5.10 Bradford, West Yorkshire, England, October–December 1992 226
4.5.11 Warrington, Cheshire, England, November 1992–February 1993 228
4.5.12 Kitchener–Waterloo, Ontario, Canada, February–May 1993 231
4.5.13 Milwaukee, Wisconsin, U.S.A., March–April 1993 234
4.5.14 Gideon, Missouri, U.S.A., November–December 1993 248
4.5.15 Noormarkku, Finland, April 1994 253
4.5.16 Temagami, Ontario, Canada, February–May 1994 255
viii Safe Drinking Water
4.5.17 Victoria, B.C., Canada, October 1994–May 1995 258
4.5.18 Village in Fife, Scotland, March 1995 263
4.5.19 Yukon Territory, Canada, June–July 1995 265
4.5.20 South Devon (Torbay and District), England, August– 268
September 1995
4.5.21 Klarup, North Jutland, Denmark, December 1995–March 1996 273
4.5.22 Cranbrook, B.C., Canada, May–June 1996 276
4.5.23 Ogose Town, Saitama Prefecture, Japan, June 1996 279
4.5.24 Strömsund, Jämtland, Sweden, August–September 1996 282
4.5.25 NW London & W Hertfordshire (North Thames), England, 285
February 1997
4.5.26 Resort Hotel, Bermuda, February 1998 287
4.5.27 Heinävesi, Finland, March 1998 290
4.5.28 Alpine, Wyoming, U.S.A., June–July 1998 292
4.5.29 Brushy Creek, Williamson County, Texas, U.S.A., July 1998 294
4.5.30 La Neuveville, Bern Canton, Switzerland, August 1998 297
4.5.31 Washington County Fair, New York, U.S.A., August– 300
September 1999
4.6 Outbreaks in the 21st Century 305
4.6.1 Overview 305
4.6.2 Clitheroe, Lancashire, England, March 2000 305
4.6.3 Belfast, Northern Ireland, April–May 2000, August 2000 and 307
February–April 2001
4.6.4 Resort, Gulf of Taranto, Italy, July 2000 312
4.6.5 Asikkala, Finland, August 2000, August 2001 and October– 314
November 2001
4.6.6 North Battleford, Saskatchewan, Canada, March–April 2001 316
Box 4.3 Key players in the course of the North Battleford outbreak 319
Box 4.4 Timeline of major events in the North Battleford case study 337
4.6.7 Boarding School, Hawke’s Bay, New Zealand, May 2001 341
4.6.8 Camp/Conference Center, Stockholm County, Sweden, 345
May–June 2001
4.6.9 Transtrand, Dalarna, Sweden, February–March 2002 347
4.7 A waterborne outbreak of bad news – Sydney, Australia 351
4.7.1 Scope of the Sydney water crisis, July–September 1998 351
4.7.2 The Sydney drinking water system 352
4.7.3 Bad news experience 354
Box 4.5 Sydney water crisis timeline 354
Box 4.6 Media reporting of the Sydney water crisis 356
4.7.4 Direct causes of the incident 362
4.7.5 Commentary 367
Contents ix
4.8 A waterborne outbreak by any other name – Edmonton, Alberta, Canada 369
4.8.1 Scope of the outbreak, October 1982 – June 1983 369
4.8.2 The Edmonton drinking water system 370
4.8.3 The outbreak experience, October 1982 – April 1983 371
Box 4.7 Newspaper coverage of the Edmonton giardiasis outbreak 374
1982–1984
4.8.4 Direct causes of the outbreak 376
4.8.5 Commentary 379

5 OVERVIEW AND RECURRENT THEMES 381
5.1 Summaries of outbreaks available in the literature 381
5.1.1 Introduction 381
5.1.2 Recent summaries of waterborne outbreaks in the U.S.A. 382
5.1.3 Summaries of drinking waterborne outbreaks in the U.K. 386
5.1.4 Summaries of drinking waterborne outbreaks in Sweden 387
5.1.5 Summaries of drinking waterborne outbreaks in Finland 388
5.1.6 Summaries of drinking waterborne outbreaks in Canada 389
5.1.7 Summaries of drinking waterborne outbreaks in Japan 391
5.1.8 Summaries of drinking waterborne outbreaks in Switzerland 392
5.1.9 Summaries of drinking waterborne outbreaks – 392
multiple countries
5.2 Recurring themes 394
5.2.1 Converting hindsight into foresight 394
5.2.2 Pathogens pose the greatest risk to drinking water safety 395
5.2.3 Robust multiple barriers are essential 398
Box 5.1 Strategies for reducing pathogen risk 399
5.2.4 Trouble is preceded by change 406
5.2.5 Operators must be capable and responsive 407
5.2.6 Drinking water professionals (providers, regulators and health 410
officials) must be accountable
5.2.7 Risk management – making sensible decisions under uncertainty 413
5.2.8 Other recurring themes 418
5.3 Routine microbial safety of drinking water 421

6 OUTBREAK PREVENTION – SAFE WATER 424
6.1 Introduction 424
6.2 Challenges 426
6.3 Limitations 427
6.4 Elements of prevention 428
6.5 Preventive approaches 429
6.5.1 Insights from expert reviews and inquiries 429
6.5.2 Drinking water safety programs 435