INDICATORS FOR WATERBORNE PATHOGENS
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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. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by Grant X-82928901 between the National Academies and the United States Environmental Protection Agency. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
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The Committee on Indicators for Waterborne Pathogens thanks the following organizations and individuals for use of their images on the cover of this report:
City of Wilsonville, Oregon
Isle Royale National Park (Michigan), National Park Service, U.S. Department of the Interior
Randal Kath, The State University of West Georgia, Carrollton
National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services
National Institute of Allergy and Infectious Diseases, National Institutes of Health, U.S. Department of Health and Human Services
Southern California Coastal Water Research Project Authority, Westminster
James Terry, Jr., Concord, Massachusetts
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COMMITTEE ON INDICATORS FOR WATERBORNE PATHOGENS1
MARY JANE OSBORN, Chair,
University of Connecticut Health Center, Farmington
R. RHODES TRUSSELL, Vice Chair,
Trussell Technologies, Inc., Pasadena, California
Metropolitan Water District of Southern California, La Verne
DANIEL Y.C. FUNG,
Kansas State University, Manhattan
CHARLES N. HAAS,
Drexel University, Philadelphia, Pennsylvania
DEBORAH A. LEVY,
Centers for Disease Control and Prevention, Atlanta, Georgia
J. VAUN MCARTHUR,
University of Georgia, Savannah River Ecology Laboratory, Aiken, South Carolina
JOAN B. ROSE,
Michigan State University, East Lansing
MARK D. SOBSEY,
University of North Carolina, Chapel Hill
DAVID R. WALT,
Tufts University, Boston, Massachusetts
STEPHEN B. WEISBERG,
Southern California Coastal Water Research Project Authority, Westminster
MARYLYNN V. YATES,
University of California, Riverside
MARK C. GIBSON, Study Director
JENNIFER KUZMA, Co-Study Director (until January 2003)
SETH H. STRONGIN, Project Assistant
The activities of the Committee on Indicators for Waterborne Pathogens were organized and supported by the National Research Council’s Board on Life Sciences (lead) and Water Science and Technology Board. Biographical sketches of committee members are contained in Appendix E and current rosters of the two parent boards are contained in Appendix D.
WORKSHOP ON INDICATORS FOR WATERBORNE PATHOGENS PARTICIPANTS
September 4, 2002
JOHN M. COLFORD, JR., University of California, Berkeley
CHRISTOPHER S. CROCKETT, Philadelphia Water Department
RAYMOND P. MARIELLA, Lawrence Livermore National Laboratory
PETER MARSDEN, Drinking Water Inspectorate of the United Kingdom
J. MICHAEL RAMSEY, Oak Ridge National Laboratory
GEOFFREY I. SCOTT, National Oceanic and Atmospheric Administration
MARK D. SOBSEY, University of North Carolina, Chapel Hill
TIMOTHY J. WADE, University of California, Berkeley
The use of bacterial indicator organisms to signal the possible presence of human pathogens in drinking water began more than a century ago in the United States, at a time when contamination of drinking and source waters by enteric bacterial pathogens, such as the typhoid bacillus, was a major public health threat. In subsequent decades, the use of bacterial indicators, predominantly coliforms, has been expanded to U.S. ambient, recreational, and shellfish waters and continues to focus on identification of fecal contamination, principally of human origin. Although these approaches have been extremely effective in reducing outbreaks of waterborne human disease, significant numbers of such outbreaks are still reported annually, many of unknown etiologic origin, and it is generally agreed that a substantial number of occurrences of waterborne human disease go unrecognized or unreported.
Recent advances in understanding the diversity and ecology of waterborne human pathogens as well as the ongoing rapid development of new techniques for detection and identification of waterborne microbes make it timely to reevaluate the standard indicators and indicator approaches employed to determine the microbiological quality of waters used for recreation or as sources of drinking water. Accordingly, the National Research Council (NRC) formed the Committee on Indicators for Waterborne Pathogens in 2002 at the request of the U.S. Environmental Protection Agency (EPA) to report on candidate indicators and/or indicator approaches (including technologies for detection) for assessing contamination of U.S. recreational waters and source water (including groundwater) for drinking water. The original charge to the committee excluded coastal marine and marine-estuarine waters, but these were added after subsequent discussion
with EPA, and it was agreed that the study would then give less emphasis to some other aspects of the charge as described in Chapter 1. For example, the committee did not explicitly address indicators of water treatment performance. Furthermore, the report does not specifically address the threat of bioterrorism or the protection of vulnerable subpopulations such as infants and immunocompromised persons regarding microbial water quality.
To address its charge, the Committee on Indicators for Waterborne Pathogens met four times, starting in April 2002. The committee quickly concluded that it is not possible to identify a single, unique indicator or even a small set of indicators that is capable of identifying all classes of waterborne pathogens of public health concern for all applications and water media. Rather, priority should be given to the development of a phased monitoring approach for assessing microbial water quality that relies on a flexible “tool box” containing a spectrum of indicators and indicator approaches (to include direct monitoring of pathogens) that can be matched according to specific circumstances and needs. Thus, the committee did not conduct a comprehensive evaluation of candidate indicators or specific pathogens per se.
The committee would like to thank the many experts who contributed to this report by participating and/or speaking at committee meetings, including Rita Schoeny, Betsy Southerland, Ephraim King, Alfred Dufour, and Rebecca Calderon, EPA; and Roger Fujioka, University of Hawaii.
The committee also sponsored a one-day public workshop on candidate indicators and indicator approaches for waterborne pathogens on September 4, 2002, in Washington, D.C. This workshop provided insight on a wide variety of subjects related to the committee’s charge, ranging from epidemiology to emerging detection technologies. The names and affiliations of the workshop presenters are listed in the front of this report.
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 NRC’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the NRC in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We thank the following individuals for their review of this report: Jennifer Clancy, Clancy Environmental Consultants, Inc.; James Crook, Consultant; Mark Gold, Heal the Bay; Robert Haselkorn, University of Chicago; Mark LeChevallier, American Water; Laura Leff, Kent State University; Daniel Lim, University of South Florida; Christine Moe, Emory University; Erik Olson, Natural Resources Defense Council; David Relman, Stanford University; and Gary Toranzos, University of Puerto Rico.
Although the reviewers above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommenda-
tions nor did they see the final draft of the report before its release. The review of this report was overseen by Edward Bouwer, Johns Hopkins University. Appointed by the NRC, 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 NRC.
This report would not have been possible without the hard work and dedication of Mark Gibson, study director and staff officer for the NRC’s Water Science and Technology Board. The committee would like to thank project assistant Seth Strongin from the Board on Life Sciences (BLS) for logistical support throughout the study. We would also like to thank former co-study director Jennifer Kuzma and research associate Laura Holliday of the BLS for their early contributions to this report.
Finally, I would like to thank the 12 members of this committee for bringing this report together. Their diverse backgrounds and perspectives provided for lively and insightful discussions throughout the course of the entire study.
Mary Jane Osborn, Chair