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GLOBAL ISSUES IN WATER, SANITATION, AND HEALTH Workshop Summary Rapporteurs: Eileen R. Choffnes and Alison Mack Forum on Microbial Threats Board on Global Health
THE NATIONAL ACADEMIES PRESS â 500 Fifth Street, N.W. â Washington, DC 20001 NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. This project was supported by contracts between the National Academy of Sciences and the U.S. Department of Health and Human Services: National Institutes of Health, National Institute of Allergy and Infectious Diseases, the Centers for Disease Control and Preven- tion, and the Food and Drug Administration; U.S. Department of Defense, Department of the Army: Global Emerging Infections Surveillance and Response System, Medical Research and Materiel Command, and the Defense Threat Reduction Agency; U.S. Depart- ment of Veterans Affairs; U.S. Department of Homeland Security; U.S. Agency for Inter- national Development; the American Society for Microbiology; sanofi pasteur; Burroughs Wellcome Fund; Pfizer; GlaxoSmithKline, Infectious Diseases Society of America; and the Merck Company Foundation. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project. International Standard Book Number-13:â 978-0-309-13872-7 International Standard Book Number-10:â 0-309-13872-8 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. For more information about the Institute of Medicine, visit the IOM home page at: www. iom.edu. Copyright 2009 by the National Academy of Sciences. All rights reserved. Printed in the United States of America The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The serpent adopted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin. Cover credit: Copyright Ralph A. Clevenger/Corbis. Suggested citation: IOM (Institute of Medicine). 2009. Global issues in water, sanitation, and health. Washington, DC: The National Academies Press.
âKnowing is not enough; we must apply. Willing is not enough; we must do.â âGoethe Advising the Nation. Improving Health.
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FORUM ON MICROBIAL THREATS DAVID A. RELMAN (Chair), Stanford University, Palo Alto, California MARGARET A. HAMBURG* (Vice Chair), Nuclear Threat Initiative/Global Health & Security Initiative, Washington, DC DAVID W. K. ACHESON, Center for Food Safety and Applied Nutrition, Food and Drug Administration, Rockville, Maryland RUTH L. BERKELMAN, Emory University, Center for Public Health Preparedness and Research, Rollins School of Public Health, Atlanta, Georgia ENRIQUETA C. BOND, Consultant, Marshall, Virginia ROGER G. BREEZE, Centaur Science Group, Washington, DC STEVEN J. BRICKNER, SJ Consulting, LLC, Ledyard, Connecticut JOHN E. BURRIS, Burroughs Wellcome Fund, Research Triangle Park, North Carolina GAIL H. CASSELL, Eli Lilly & Company, Indianapolis, Indiana MARK B. FEINBERG, Merck Vaccine Division, Merck & Co., West Point, Pennsylvania DARRELL R. GALLOWAY, Medical S&T Division, Defense Threat Reduction Agency, Fort Belvoir, Virginia S. ELIZABETH GEORGE, Biological and Chemical Countermeasures Program, Department of Homeland Security, Washington, DC JESSE L. GOODMAN, Center for Biologics Evaluation and Research, Food and Drug Administration, Rockville, Maryland EDUARDO GOTUZZO, Instituto de Medicina TropicalâAlexander von Humbolt, Universidad Peruana Cayetano Heredia, Lima, Peru JO HANDELSMAN, College of Agricultural and Life Sciences, University of Wisconsin, Madison CAROLE A. HEILMAN, Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland DAVID L. HEYMANN, Health Protection Agency, London, UK PHIL HOSBACH, New Products and Immunization Policy, Sanofi Pasteur, Swiftwater, Pennsylvania JAMES M. HUGHES,â Global Infectious Diseases Program, Emory University, Atlanta, Georgia STEPHEN A. JOHNSTON, Arizona BioDesign Institute, Arizona State University, Tempe *Until June 9, 2009. Dr. Hamburg is currently the Commissioner of the Food and Drug Administration. â Current Vice Chair. IOM Forums and Roundtables do not issue, review, or approve individual documents. The Âresponsibility for the published workshop summary rests with the workshop rapporteur(s) and the institution.
GERALD T. KEUSCH, Boston University School of Medicine and Boston University School of Public Health, Massachusetts RIMA F. KHABBAZ, National Center for Preparedness, Detection, and Control of Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia LONNIE J. KING, Center for Zoonotic, Vectorborne, and Enteric Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia GEORGE W. KORCH,* U.S. Army Medical Research Institute for Infectious Diseases, Fort Detrick, Maryland STANLEY M. LEMON, School of Medicine, University of Texas Medical Branch, Galveston EDWARD McSWEEGAN, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland STEPHEN S. MORSE, Center for Public Health Preparedness, Columbia University, New York MICHAEL T. OSTERHOLM, Center for Infectious Disease Research and Policy, School of Public Health, University of Minnesota, Minneapolis GEORGE POSTE, Arizona BioDesign Institute, Arizona State University, Tempe JOHN C. POTTAGE, JR., GlaxoSmithKline, Collegeville, Pennsylvania GARY A. ROSELLE, Central Office, Veterans Health Administration, Department of Veterans Affairs, Washington, DC KEVIN RUSSELL, Global Emerging Infections Surveillance and Response System, Department of Defense, Silver Spring, Maryland JANET SHOEMAKER, Office of Public Affairs, American Society for Microbiology, Washington, DC P. FREDERICK SPARLING, University of North Carolina, Chapel Hill TERENCE TAYLOR, International Council for the Life Sciences, Washington, DC MURRAY TROSTLE, U.S. Agency for International Development, Washington, DC Staff EILEEN CHOFFNES, Director KATE SKOCZDOPOLE, Senior Program Associate SARAH BRONKO, Research Associate (until April 2009) KATHLEEN C. OSTAPKOVICH, Research Associate (from May 2009) Kenisha Peters, Senior Program Assistant ALISON MACK, Science Writer FLORENCE ROAN, Christine Mirzayan Fellow (January-June 2007) *Until January 16, 2009. Kent Kester, Commander of Walter Reed Army Institute of Research, is the current U.S. Army Medical Research and Materiel Command representative on the Forum. vi
BOARD ON GLOBAL HEALTH Margaret Hamburg (chair), Consultant, Nuclear Threat Initiative, Washington, DC Jo Ivey Boufford (IOM Foreign Secretary), President, New York Academy of Medicine, New York Claire V. Broome, Adjunct Professor, Division of Global Health, Rollins School of Public Health, Emory University Jacquelyn C. Campbell, Anna D. Wolf Chair, and Professor, Johns Hopkins University School of Nursing, Baltimore, Maryland Thomas J. Coates, Professor, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California Valentin Fuster, Director, Wiener Cardiovascular Institute, Kravis Cardiovascular Health Center, Professor of Cardiology, Mount Sinai School of Medicine, Mount Sinai Medical Center, New York, New York Sue Goldie, Associate Professor of Health Decision Science, Department of Health Policy and Management, Center for Risk Analysis, Harvard University School of Public Health, Boston, Massachusetts Richard Guerrant, Thomas H. Hunter Professor of International Medicine and Director, Center for Global Health, University of Virginia School of Medicine, Charlottesville Peter J. Hotez, Professor and Chair, Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC Gerald T. Keusch, Assistant Provost for Global Health, Boston University School of Medicine, and Associate Dean for Global Health, Boston University School of Public Health, Massachusetts Michael Merson, Director, Duke Global Health Institute, Duke University, Durham, North Carolina Fitzhugh Mullan, Professor, Department of Health Policy, George Washington University, Washington, DC Philip Russell, Professor Emeritus, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland Staff Patrick Kelley, Director Allison Brantley, Senior Program Assistant IOM boards do not review or approve individual reports and are not asked to endorse conclusions and recommendations. The responsibility for the content of the report rests with the authors and the institution. vii
Reviewers This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Councilâs Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evi- dence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report: Rima Khabbaz, Centers for Disease Control and Prevention Bud Rock, Arizona State University Mary Wilson, Department of Population and International Health, Harvard University Although the reviewers listed above have provided many constructive com- ments and suggestions, they were not asked to endorse the final draft of the report before its release. The review of this report was overseen by Dr. Melvin Worth. Appointed by the Institute of Medicine, he was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution. ix
Preface The Forum on Emerging Infections was created by the Institute of Medicine (IOM) in 1996 in response to a request from the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health (NIH). The purpose of the Forum is to provide structured opportunities for leaders from government, academia, and industry to meet and examine issues of shared concern regarding research, prevention, detection, and management of emerging or reemerging infectious diseases. In pursuing this task, the Forum provides a venue to foster the exchange of information and ideas, identify areas in need of greater attention, clarify policy issues by enhancing knowledge and identifying points of agree- ment, and inform decision makers about science and policy issues. The Forum seeks to illuminate issues rather than resolve them; for this reason, it does not provide advice or recommendations on any specific policy initiative pending before any agency or organization. Its value derives instead from the diversity of its membership and from the contributions that individual members make throughout the activities of the Forum. In September 2003, the Forum changed its name to the Forum on Microbial Threats. About the Workshop In the early days of space exploration, the first images taken of our home planet showed the Earth to be a bright blue marble in the vastness of space. The striking blue in these imagesâcovering more than 70 percent of the planetâs surfaceârepresents our planetâs water resources. Yet, despite this seemingly end- less supply of water, only about 2.5 percent is fresh water, two-thirds of which is xi
xii PREFACE trapped as ice in glaciers. Over 90 percent of the fresh water that is not ice may be found in underground aquifers that, once drained, may take hundreds if not thousands of years to recharge. During the past century, the human population has more than tripled, and water consumption has more than quadrupled, placing ever-increasing demands on the worldâs limited freshwater resources. Approximately one-third of the worldâs population now lives in areas with scarce water resources. A U.N. report estimates that water scarcity will affect two-thirds of the population by 2025. In addition, increasing amounts of pollution from domestic, industrial and agricul- tural runoff is contaminating an ever-shrinking water supply. The lack of access to and availability of clean water and sanitation has had devastating effects on many aspects of daily life. Areas without adequate supplies of freshwater and basic sanitation carry the highest burdens of disease which disproportionately impact children under five years of age. Lack of these basic necessities also influences the work burden, safety, education, and equity of women. While poverty has been a major barrier to gaining access to clean drinking water and sanitation in many parts of the developing world, access to and the availability of clean water is a prerequisite to the sustainable growth and development of communities around the world. Worldwide, over one billion people lack access to an adequate water supply; more than twice as many lack basic sanitation. Unsafe water, inadequate sanita- tion, and insufficient hygiene account for an estimated 9.1 percent of the global burden of disease and 6.3 percent of all deaths, according to the World Health Organization. This burden is disproportionately borne by children in developing countries, with water-related factors causing more than 20 percent of deaths of people under age 14. Nearly half of all people in developing countries have infec- tions or diseases associated with inadequate water supply and sanitation. The effects of water shortages and water pollution have been felt in both industrialized and developing countries, and it will be necessary to transcend international and political boundaries to meet the worldâs water needs in a sus- â UNESCO (United Nations Educational, Scientific, and Cultural Organization). 2006. The state of the resource. In Water, a shared responsibility: the United Nations world water development report 2. New York: UNESCO/Berghahn Books. â United Nations. 2006. Factsheet on water and sanitation, http://www.un.org/waterforlifedecade/ factsheet.html (accessed August 11, 2008). â WHO/UNICEF (World Health Organization/United Nations Childrenâs Fund). 2006. Meeting the MDG drinking water and sanitation target: the urban and rural challenge of the decade. Geneva: WHO/UNICEF. â PrÃ¼ss-ÃstÃ¼n, A., R. Bos, F. Gore, and J. Bartram. 2008. Safer water, better health: costs, benefits and sustainability of interventions to protect and promote health. Geneva: World Health Organization. â Bartram, J., K. Lewis, R. Lenton, and A. Wright. 2005. Focusing on improved water and sanitation for health. Lancet 365(9461):810-812.
PREFACE xiii tainable manner that will conserve and preserve this common resource. In the past few decades, national and international organizations from both the public and private sectors have come together to tackle global issues in water and sanitation. Recognizing water availability, water quality, and sanitation as fundamental issues underlying infectious disease emergence, the Forum on Microbial Threats of the Institute of Medicine held a two-day public workshop in Washington, DC, on September 23 and 24, 2008. Through invited presentations and discussions, participants explored global and local connections between water, sanitation, and health; the spectrum of water-related disease transmission processes as they inform intervention design; lessons learned from water-related disease outbreaks; vulnerabilities in water and sanitation infrastructure in both industrialized and developing countries; and opportunities to improve water and sanitation infra- structure so as to reduce the risk of water-related infectious disease. Acknowledgments The Forum on Microbial Threats, and the IOM, wish to express their warm- est appreciation to the individuals and organizations who gave their valuable time to provide information and advice to the Forum through their participation in this workshop. A full list of presenters may be found in Appendix A. The Forum is indebted to the IOM staff who contributed during the course of the workshop and the production of this workshop summary. On behalf of the Forum, we gratefully acknowledge the efforts led by Dr. Eileen Choffnes, direc- tor of the Forum; Kate Skoczdopole, senior program associate; Sarah Bronko, research associate; K. C. Ostapkovich, research associate; and Kenisha Peters, senior program assistant, for dedicating much effort and time to developing this workshopâs agenda and for their thoughtful and insightful approach and skill in planning for the workshop and in translating the workshopâs proceedings and discussion into this workshop summary. We would also like to thank the follow- ing IOM staff and consultants for their valuable contributions to this activity: Alison Mack, Heather Phillips, Bronwyn Schrecker, Jackie Turner, and Jordan Wyndelts. Finally, the Forum wishes to recognize the sponsors that supported this activity. Financial support for this project was provided by the U.S. Depart- ment of Health and Human Services: National Institutes of Health, National Institute of Allergy and Infectious Diseases, the Centers for Disease Control and Prevention, and the Food and Drug Administration; U.S. Department of Defense, Department of the Army: Global Emerging Infections Surveillance and Response System, Medical Research and Materiel Command, and the Defense Threat Reduction Agency; U.S. Department of Veterans Affairs; U.S. Depart-
xiv PREFACE ment of Homeland Security; U.S. Agency for International Development; the American Society for Microbiology; sanofi pasteur; Burroughs Wellcome Fund; Pfizer; GlaxoSmithKline, Infectious Diseases Society of America; and the Merck Company Foundation. The views presented in this workshop summary report are those of the workshop participants and rapporteurs and are not necessarily those of the Forum on Microbial Threats or its sponsors. David A. Relman, Chair Margaret A. Hamburg, Vice Chair* Forum on Microbial Threats *Until June 9, 2009. Dr. Hamburg is currently the Commissioner of the Food and Drug Administration.
Contents Workshop Overview 1 1 Global Problems, Local Solutions 50 Overview, 50 Improving Water, Sanitation, and Health at the Grassroots, 52 Donald R. Hopkins, M.D., M.P.H. The Spectrum of Water-Related Disease Transmission Processes, 60 David J. Bradley Safer Water, Cleaner Hands, and Safer Foods: Disease Prevention Strategies That Start with Clean Water at the Point of Use, 73 Robert V. Tauxe, M.D., M.P.H., Robert E. Quick, M.D., M.P.H., Eric D. Mintz, M.D., M.P.H. References, 90 2 Lessons from Waterborne Disease Outbreaks 96 Overview, 96 The Cholera Epidemic in Peru and Latin America in 1991: The Role of Water in the Origin and Spread of the Epidemic, 97 Carlos Seas, M.D., and Eduardo Gotuzzo, M.D., FACP Lessons from the Massive Waterborne Outbreak of Cryptosporidium Infections, Milwaukee, 1993, 108 Jeffrey P. Davis, M.D., William R. Mac Kenzie, M.D., and David G. Addiss, M.D., M.P.H. xv
xvi CONTENTS Prevention Is Painfully Easy in Hindsight: Fatal E. coli O157:H7 and Campylobacter Outbreak in Walkerton, Canada, 2000, 127 Steve E. Hrudey, Ph.D., and Elizabeth J. Hrudey References, 148 3 Vulnerable Infrastructure and Waterborne Disease Risk 153 Overview, 153 The Changing Epidemiology of Waterborne Disease Outbreaks in the United States: Implications for System Infrastructure and Future Planning, 156 Michael J. Beach, Ph.D., Sharon Roy, M.D., M.P.H., Joan Brunkard, Ph.D., Jonathan Yoder, M.P.H., M.S.W., and Michele C. Hlavsa, R.N., M.P.H. Health, Climate Change, and Water Quality, 169 Joan B. Rose, Ph.D. Quantitative Microbial Risk Assessment of Waterborne Disease, 178 Kelly A. Reynolds, M.S.P.H., Ph.D., and Kristina D. Mena, M.S.P.H., Ph.D. References, 190 4 Addressing Risk for Waterborne Disease 200 Overview, 200 Measures of Water Quality Impacting Disinfection, 205 Philip C. Singer, Ph.D. Civil Infrastructure for Water, Sanitation, and Improved Health: Existing Technology, Barriers, and Need for Innovation, 214 Kevin C. Caravati, Zakiya A. Seymour, and Joseph B. Hughes, Ph.D., P.E., BCEE Improving Urban Water and Sanitation Services: Health, Access, and Boundaries, 235 Kristof Bostoen, Ph.D., M.Sc., Pete Kolsky, Ph.D., and Caroline Hunt, Ph.D. Medical Research and Social Entrepreneurship Communities: Increasing the Dialogue May Lead to New Insights for Public Health, 259 Sharon H. Hrynkow, Ph.D. References, 269 Appendixes A Agenda 277 B Acronyms 281 C Glossary 283 D Forum Member Biographies 285
Tables, Figures, and Boxes Tables WO-1 Estimation of Mortality Due to Diarrhea in India, 5 WO-2 Data Used for Estimation of Burden Due to Diarrhea in India, 6 WO-3 Excreta-Related Transmission, 19 1-1 Revised Classification of Water-Related Disease Transmission, 63 1-2 Excreta-Related Transmission, 66 1-3 A Possible Way to Group Behavior Change for Water and Sanitation Interventions, 69 1-4 List of Some âAgendasâ to Be Considered When Changing Aspects of Water or Sanitation, 71 2-1 Culture Results from Two Farms Resampled on June 13, 144 2-2 Pathogen Strain Typing Comparison Between Human Cases and Cattle Fecal Samples at Farms 1 and 2, 144 3-1 National Research Council Risk Assessment Paradigm, 179 4-1 CT Values (mg-min/L) for Microbial Inactivation by Free Chlorine (pH 7.0, 1.0 mg/L Cl2 residual), 207 4-2 Chlorine Demand of Various Inorganic Reducing Agents, 209 4-3 Conventional Water and Wastewater Treatment Methodologies, 221 4-4 Water Quality Parameters, 222 4-5 Paradigm Shifts Addressing Water and Sanitation Infrastructure, 229 xvii
xviii TABLES, FIGURES, AND BOXES 4-6 Health Impacts of Water- and Sanitation-Related Diseases, 238 4-7 Water Supply and Sanitation Technologies Considered to Be Improved and Unimproved in WHO/UNICEF Global Assessment 2000, 242 4-8 Scales of the Urban Environment and Water, Sewerage and Drainage and Solid Waste-Related Infrastructure Issues, 249 4-9 Key Features of the Two Approaches on Clean Water and Sanitation, 268 Figures WO-1 Population growth, climate change, reckless irrigation, and chronic waste are placing the worldâs water supplies in danger, 3 WO-2 The life cycle of trachoma, 8 WO-3 Carter Center-supported household latrine construction in Ethiopia, 10 WO-4 World population with and without access to an improved drinking water source in 1990, 2004, and 2015, 11 WO-5 World population with and without access to improved sanitation in 1990, 2004, and 2015, 12 WO-6 Guinea worm disease, 13 WO-7 Number of reported cases of dracunculiasis by year, 1989-2007, 13 WO-8 Guinea worm reduction over time, 14 WO-9 Length and dispersion of transmission cycles of excreted infections, 20 WO-10 The seventh cholera pandemic, 24 WO-11 A hierarchical model for cholera transmission, 25 WO-12 Rate of watery diarrhea from March 1 through April 28, 1993, among respondents in a random-digit telephone survey of households in the five-county Greater Milwaukee area, 27 WO-13 Location of Walkerton Well 5 near farms to south and west, 28 WO-14 Water consumption in the United States compared with other countries, 37 WO-15 The âFâ diagram, 38 WO-16 Reduction in diarrheal diseases morbidity resulting from improvements in drinking water and sanitation services, 42 1-1 Patients with early (left) and late (right) trachomatous infections, 53 1-2 Example of a latrine in the Amhara Region of Ethiopia, 54 1-3 Carter Center-supported household latrine construction in Ethiopia, 56 1-4 Guinea worm emerging, 57 1-5 Ghana Guinea Worm Eradication Program, 59
TABLES, FIGURES, AND BOXES xix 1-6 Number of reported cases of dracunculiasis by year, 1989-2007, 60 1-7 Relation of water- and excreta-related transmission categories, 68 1-8 Supervising nurse at a drinking water station at a community clinic in Nyanza Province, Kenya, 80 1-9 Water and hygiene kit currently being distributed to expectant women at antenatal clinics in Malawi, 81 1-10 Two students in the Safe Water Club at Sino SDA Primary School in Nyanza Province collect and treat the water for the school each morning, 83 1-11 Students at a primary school in Fujian Province, China, washing their hands at the start of the lunch hour, 84 2-1 Vibrio cholerae O1 attached to a copepod, 99 2-2 A hierarchical model for cholera transmission, 100 2-3 A shantytown in Peru during 1991, 101 2-4 Cholera in the Americas, 1991-2006, 102 2-5 Typhoid fever cases seen at the Alexander von Humboldt Tropical Medicine Institute in Lima, Peru, 1987-1993, 103 2-6 The seventh cholera pandemic, 104 2-7 Location of patients in Peru with presumed cholera, identified before the epidemic of 1991, 105 2-8 Location of the three rivers that flow through Milwaukee County, Wisconsin, 109 2-9 Maximal turbidity of treated water in the northern and southern water treatment plants of the Milwaukee Water Works from March 1 through April 28, 1993, 110 2-10 Rate of watery diarrhea from March 1 through April 28, 1993, among respondents in a random-digit telephone survey of households in the five-county Greater Milwaukee area, 113 2-11 (A) Dates of arrival and (B) dates of onset of illness for 54 persons with laboratory-confirmed Cryptosporidium infection, 115 2-12 Depiction of the water treatment process used in the northern and southern Milwaukee Water Works water treatment plants in early 1993, 116 2-13 Maximum daily raw and treated water turbidity at the southern Milwaukee Water Works treatment plant, March-April 1993, 117 2-14 Milwaukee skyline demonstrating confluence of rivers merging just west of the Milwaukee harbor, 119 2-15 Milwaukee River emptying into the Lake Michigan harbor following a period of high flow and attendant creation of a plume, 119 2-16 Location of the three rivers that flow through Milwaukee County, Wisconsin, 120 2-17 Location of Walkerton Well 5 near farms to south and west, 136
xx TABLES, FIGURES, AND BOXES 2-18 Outbreak curve for the Walkerton epidemic of gastroenteritis, 138 3-1 Number of reported waterborne-disease outbreaks in public drinking water systemsâUnited States, 1971-2006, 159 3-2 Proportion of deficiencies in public drinking water systems associated with untreated or improperly treated surface waterâ United States, 1971-2006, 159 3-3 Proportion of deficiencies in public drinking water systems associated with untreated or improperly treated ground waterâ United States, 1971-2006, 160 3-4 Percentage of waterborne-disease outbreaks in public and individual drinking water systemsâUnited States, 1971-2006, 161 3-5 Percentage of waterborne-disease outbreaks associated with drinking water use, by illness and etiologyâUnited States, 2005-2006, 162 3-6 Number of recreational water-associated outbreaks of acute gastrointestinal illness (n = 259), by water type and yearâUnited States, 1978-2006, 166 3-7 Cholera cases (1) pre and (2) post Hurricane Mitch in Guatemala in 1998, 172 3-8 Changes in water quality associated with septic tanks and the 1998 El NiÃ±o, 174 3-9 Probability of infection from 10â1 to 10â6 for five pathogens over 60 days, 176 3-10 Percentage of disasters by type, 2000-2004 averages, 178 4-1 Chlorine demand of several raw waters and partially treated waters (MIEXÂ® effluents), 208 4-2 Breakpoint chlorination curve when chlorine is added to an ammonia-containing water, 210 4-3 Schematic of a nephelometer used to measure turbidity, 212 4-4 Schematic of an optical particle counter, 213 4-5 The hydrologic cycle, 216 4-6 Detailed diagram of conventional water and wastewater treatment systems, 220 4-7 The water balance, 236 4-8 F-diagram, 239 4-9 Variation on access in various surveys, 243 4-10 Relation between water consumption and time involved in water collection, 245 4-11 Scales of the urban environment, as seen by a householder, 247 4-12 Scales of water supply infrastructure matched to the urban environment, 248
TABLES, FIGURES, AND BOXES xxi 4-13 Water supply infrastructure and priorities, as seen by technical professionals, 250 4-14 Relationship between urban water access, national water stress, and national GDP per capita, 255 Boxes WO-1 Millennium Development Goals, 11 WO-2 Spectrum of Water-Related Diseases, 17 WO-3 Spectrum of Water-Related Disease in the United States, 32 4-1 Unfiltered Drinking Water for Millions: The New York City Watershed Partnership, 218 4-2 Communities Develop Evidence Base for Water Quality Policies, 262 4-3 Community Leadership to Improve Sanitation, 262 4-4 A Multidisciplinary Approach to Prevent Cholera, 265 4-5 Basic and Behavioral Science to Reduce Arsenic Exposures, 266