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Drinking Water and Health Disinfectants ant/ Disinfectant By-Prociacts Volume 7 Subcommittee on Disinfectants and Disinfectant By-Products Safe Drinking Water Committee Board on Environmental Studies and Toxicology Commission on Life Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1987
NATIONAL ACADEMY PRESS, 2101 Constitution Ave., NW, Washington, DC 20418 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 report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distin- guished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is auton- omous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel O. Thier is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. This project has been funded by the U.S. Environmental Protection Agency under Contract No. 68-01-3169 with the National Academy of Sciences. The contents of this document do not necessarily reflect the views and policies of the Environmental Protection Agency, and an official endorsement should not be inferred. Library of Congress Catalog Card Number 77-89284 International Standard Book Number 0-309-03741-7 Printed in the United States of America
List of Participants SUBCOMMITTEE ON DISINFECTANTS AND DISINFECTANT BY-PRODUCTS I. DONALD JOHNSON (Chairman), University of North Carolina School of Public Health, Chapel Hill, North Carolina JOSEPH F. BORZELLECA, Virginia Commonwealth University, Richmond, Virginia DAVID I. BRUSICK, Hazleton Laboratories America, Inc., Kensington, Maryland RICHARD I. BULL, Washington State University College of Pharmacy, Pullman, Washington EDWARD I. CAEABRESE, North East Regional Environmental Public Health Center, University of Massachusetts, Amherst, Massachusetts ROBERT M. CARESON, University of Minnesota, Duluth, Minnesota BETSY D. CARETON, Battelle Columbus Laboratories, Columbus, Ohio DEAN E. CARTER, College of Pharmacy, University of Arizona, Tucson, Arizona MARY E. DAVIS, West Virginia University Medical Center, Morgantown, West Virginia WlEElAM H. GLAZE, School of Public Health, University of California, Los Angeles, California PETER ISACSON, University of Iowa, Iowa City, Iowa DAVID I. lOLLOW, Medical University of South Carolina, Charleston, South Carolina . . .
iv List of Participants EARLE R. NESTMANN, Health and Welfare Canada, Ottawa, Ontario, Canada FRANK E. SCUEEY, JR., Old Dominion University, Norfolk, Virginia Technical Consultants MIRAT GUROL, Center for Environmental Studies, Drexel University, Philadelphia, Pennsylvania JOHN HOFF, U.S. Environmental Protection Agency, Cincinnati, Ohio VINCENT OLIVIERI, School of Hygiene and Public Health, The Johns Hopkins University, Baltimore, Maryland SALLY ZIERLER, Brown University, Providence, Mode Island Advisors, Consultants, and Contributors KEITH JACOBSON, Consultant in Toxicology JAMES RElSA, Idea-Tech Associates, Alexandria, Virginia HENRY WILLS, Visiting Professor, Uniformed Services University of the Health Sciences, Bethesda, Maryland SAFE DRINKING WATER COMMITTEE DAVID I. JOLLOW (Chairman), Medical University of South Carolina, Charleston, South Carolina DAVID E. BICE, Lovelace Inhalation Toxicology Research Institute, Albuquerque, New Mexico JOSEPH F. BORZELLECA, Virginia Commonwealth University, Richmond, Virginia DAVID I. BRUSICK, Hazleton Laboratories America, Inc., Kensington, Maryland EDWARD I. CAEABRESE, Nodh East Regional Environmental Public Health Center, University of Massachusetts, Amherst, Massachusetts I. DONALD JOHNSON, University of Nodh Carolina, School of Public Health, Chapel Hill, North Carolina RONALD E. WYZGA, Electric Power Research Institute, Palo Alto, California National Research Council Staff RICHARD D. THOMAS, Project Director EESEYE B. WAKEFIEED, Associate Stay Officer JACQUEEINE BORAKS, Editor
List of Participants v TRACY E. BRANDT, Project Secretary MIRElLLE I. MESIAS, Administrative Secretary BARBARA REAM, Bibliographer Environmental Protection Agency Project Officer KRISHAN KHANNA, EPA Office of Drinking Water, Washington, D.C. BOARD ON ENVIRONMENTAL STUDI ES AND TOXICOLOGY DONALD F. HORNING (Chairman), School of Public Health, Harvard University, Boston, Massachusetts ALVIN L. ALM, Thermal Analytical, Inc., Waltham, Massachusetts RICHARD N. E. ANDREWS, Institute for Environmental Studies, University of North Carolina, Chapel Hill, North Carolina RICHARD A. CONWAY, Union Carbide Corporation, South Charleston West Virginia WILLIAM E. COOPER, Michigan State University, East Lansing, Michigan JOHN DOULL, University of Kansas Medical Center, Kansas City, Kansas BENJAMIN G. FERRIS, School of Public Health, Harvard University, Boston, Massachusetts SHELDON K. FRIEDEANDER, National Center Intermedia Transport Research, University of California, Los Angeles, California BERNARD D. GOEDSTEIN, University of Medicine and Dentistry of New Jersey Robert Wood Johnson Medical School, Piscataway, New Jersey PHILIP I. LANDRIGAN, Mount Sinai Medical Center, New York, New York PHIElP A. PALMER, E. I. du Pont de Nemours & Co., Wilmington, Delaware EMIE A. PFITZER, Hoffmann-La Roche, Inc., Nutley, New Jersey PAUL PORTNEY, Resources for the Future, Washington, D.C. PAUL RISSER, University of New Mexico, Albuquerque, New Mexico WlEElAM H. RODGERS, School of Law, University of Washington, Seattle, Washington F. SHERWOOD ROWLAND, University of California, I - ing, California LIANE B. RUSSELL, Oak Ridge National Laboratory, Oak Ridge, Tennessee EEEEN K. SIEBERGEED, Environmental Defense Fund, Washington, D.C.
vi List of Participants PETER S. SPENCER, Institute of Neurotoxicology, Albert Einstein College of Medicine, Bronx, New York National Research Council Staff DEVRA EKE DAVIS, Executive Director JACQUEEINE PRINCE, Sta~Assistant
Preface The Safe Drinking Water Act of 1974 (PL 93-523) mandated that the U.S. Environmental Protection Agency (EPA) establish federal standards to protect humans from harmful contaminants in drinking water. This law authorized EPA to seek the expertise of a National Research Council committee to identify the health effects associated with specific contam- inants, identify areas of insufficient knowledge, and to make recommen- dations for future research. Since 1977, committees of the National Research Council have issued six volumes of Drinking Water and Health, each of which includes a review of toxicological data and estimates of the risks associated with specific contaminants found in drinking water. The most recently constituted Safe Drinking Water Committee directed the Subcommittee on Disinfectants and Disinfectant By-Products to con- duct the study reported in this seventh volume of the series. At the request of EPA, the subcommittee examined current practices of water disinfection and assessed the human health effects and animal toxicological data for several currently used disinfectants and disinfectant by-products. This volume updates material published in Volume 2 on the chemistry and efficacy of disinfectants and in Volume 3 on their toxicity and the toxicity of the by-products formed. In addition, the volume contains evaluations of several epidemiological studies relating to drinking water disinfection and provides new risk assessments for several by-products. The findings of this study are briefly summarized in the Executive Summary. To help in the preparation of this volume, subcommittee members attended the Second International Symposium on Health Effects of Drink- ing Water Disinfectants and Disinfection By-Products, convened by EPA . . vll
viii Preface in Cincinnati, Ohio, on August 27-29, 1985. In addition to an intensive literature search, the subcommittee used EPA data summaries for each substance as a further indication of the range of available toxicological data. Many of the data resulted from 2-year chronic feeding studies in rodents, reflecting past interest in carcinogenesis testing. However, the subcommittee carefully examined toxicological data on teratogenesis, mu- tagenesis, reproductive effects, metabolism, and neurological effects as well. The data summaries, symposium papers, and published toxicological literature served as the basis for a subcommittee workshop on disinfectants and disinfectant by-products held in October 1985. Whenever possible, the subcommittee evaluated published, peer-reviewed literature pertaining to the substances under study. For several compounds, important new information was made available by researchers of current projects. When unpublished information was provided, the subcommittee conducted its own peer review of the unpublished studies and in some cases subjected the data to additional independent review. The principal goal of disinfecting water supplies is the elimination of pathogens that are responsible for waterborne diseases. Chlorination is a very successful method for achieving this goal in the United States. None- theless, the formation of trihalomethanes (THMs) and other chlorination by-products has prompted the introduction of other disinfection tech- niques. Chlorination and other major methods of disinfection are examined individually. Their chemical characteristics and biocidal efficacy are as- sessed and compared. Economic considerations were not part of this study. Richard Thomas was project director for this volume, and Leslye Wake- field served as research associate. Project editor was Jacqueline Boraks, and Barbara Ream was bibliographer. Tracy Brandt and Mireille Mesias typed the manuscript. The subcommittee extends special thanks to its consultants Keith Jacobson, James Reisa, and Henry Wills, without whose technical support this volume could not have been completed. We are also grateful for the contribution of workshop papers and advice from Mirat Gurol, John Hoff, Vincent Olivieri, and Sally Zierler. Kulbir Bakshi, Ruth Hodges, Alison Kamat, Victor Miller, and Edna Paulson, staff of the Board on Environmental Studies and Toxicology, assisted in research. Devra Davis and Alvin Lazen provided helpful advice and guidance. I. DONALD JOHNSON, Chairman Subcommittee on Disinfectants and Disinfectant By-Products Safe Drinking Water Committee
Contents EXECUTIVE SUMMARY 2 DISINFECTION METHODS AND EFFICACY Current Practices, 4 Chlorination, 6 Alternative Methods, 8 Waterborne Pathogens, 14 CHEMISTRY AND TOXICITY OF DISINFECTION Chlorination, 27 Epidemiological Studies, 50 Alternative Methods, 60 Oxidation Processes, 67 4 CHEMISTRY AND TOXICITY OF SELECTED DISINFECTANTS AND BY-PRODUCTS . Chlorine, 81 Chlorine Dioxide, 83 Chloramines, 90 Chlorite, 99 Chlorate, 99 Trihalomethanes, 111 Haloacids, 133 IX 4 ........... 27 80
x Contents Haloaldehydes, 143 Haloketones, 154 Haloacetonitriles, 156 Chloropicrin, 162 Chlorophenols, 169 CONCLUSIONS AND RECOMMENDATIONS Disinfection Methods and Efficacy, 190 Chemistry and Toxicity of Disinfection, 191 INDEX 190 ................. 201
Drinking Water and Health