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Drinking Water and Health SAFE DRINKING WATER COMMITTEE Advisory Center on Toxicology Assembly of Life Sciences National Research Council NATIONAL ACADEMY OF SCIENCES Washington, D.C. 1977
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 Engineenng, 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 Engineenng and the Institute of Medicine. . At the request of and funded by the U.S. Enviornmental Protection Agency Contract no. 68-01-3139 Library of Congress Catalog Card Number: 77-089284 International Standard Book Number: ~309-02619-9 Availablefrom Printing and Publishing Office National Academy of Sciences 2101 Constitution Ave. Washington, D.C. 20418 Printed in the United States of America First Printing, November 1977 Second Printing, July 1980 Third Printing, September 1982 Fourth Printing, July 1983 Fifth Printing, October 1984 Sixth Printing, September 1985 Seventh Printing, January 1987 Eighth Printing, May 1988
Contents PREFACE HISTORICAL NOTE I APPROACH TO THE STUDY I I CHEMICAL CONTAMINANTS: SAFETY AND RISK ASSESSMENT III MICROBIOLOGY OF DRONING WATER IV SOLID PARTICLES IN SUSPENSION INORGANIC SOLUTES ORGANIC SOLUTES VI I RADIOACTIVITY IN DRINKING WATER APPENDIXES A LEGISLATION AND TERMS OF REFERENCE OF THE STUDY B LIST OF PARTICIPANTS C EXECUTIVE SUMMARY · -- V 9 19 63 135 205 489 857 905 911 917
Preface This volume presents the findings of a study of the potentially harmful effects that impurities in water may have on the health of those who drink it. The study was conducted by the Committee on Safe Drinking Water of the National Research Council, supported by a contract between the Environmental Protection Agency and the National Academy of Sciences. Several factors combined to place an unusually heavy burden on all those who participated in this effort. At the outset, the purpose, scope, and duration of the study were defined in the Safe Drinking Water Act of 1974 in such a way as to require the Administrator of the Environmental Protection Agency not only to arrange for the study to be performed, but to make prompt use of the findings as the scientific basis for revision or ratification of the Interim Primary Drinking Water Regulations that were promulgated under the Act. These requirements, of necessity, imposed a severe restriction on the time available to the participants. It was also apparent that the application of modern methods of analysis had greatly expanded and diversified our knowledge of the occurrence of trace impurities in water and was continuing to do so much more rapidly than the rate of accumulation of information about their toxicity. This necessitated a careful and laborious scrutiny of a large and diverse segment of the scientific literature. Furthermore, the central effort of the study, namely, assessment of the long-term biological ejects of ingesting the variety of different materials that are present in trace amounts in drinking water, made severe demands on our ability to apply the v
vi Preface contemporary knowledge of toxicology and epidemiology to quantitative estimation of the risks to public health in terms that would be useful in framing regulations. In recognition of these limitations, it was concluded that the intent of Congress and the possibilities inherent in the body of scientific knowledge on which we could draw could best be reconciled in terms of the interpretation of the scope of the study given in Appendix A. To carry out the work of the study, the principal subdivisions of the subject matter were assigned to subcommittees, each of which was chaired by a member of the Safe Drinking Water Committee, which, in turn, was responsible for the general direction of the study (see Appendix By. We are most grateful to all those members of the scientific community who served on these committees, meeting as frequently as the task required, and whose written contributions form the basis for this report. It is a pleasure also to express, on behalf of the entire study group, a special note of thanks to the staff: Dr. Riley D. Housewright, Mr. J. P. T. Pearman, Dr. Robert Golden, Mrs. Susan Chen, and Mr. Ralph C. Wands, whose informed and tireless efforts ably supported the commit- tees, not only in the planning and conduct of the study, but also by procuring the various bibliographic and consulting services that proved to be required. In this connection we are grateful to the International Agency for Research on Cancer for helping to assess the potential carcinogenicity of organic compounds found in drinking water; and to Ms. Libbey Smith, Ms. Judith L. Mullaney, Ms. Florence Carleton, Dr. Penelope Crisp, and Dr. Lana Skirboll, all of whom assisted in an extensive search of the scientific literature. We acknowledge with gratitude the assistance of all those outside consultants who supplied information for our consideration, and the help of many members of the stab of the Environmental Protection Agency, especially Dr. Edgar A. Jeffrey and his successor, Dr. Joseph Cotruvo, and Dr. Robert Tardily and Mr. Lee McCabe, who helped to place at our disposal the information available within that agency. Organization of meetings and the labor of preparing manuscripts was made easier by the dedicated secretarial services of Mrs. Delores Banks, Ms. Helen Harvin, Mrs. Merle Morgan, and Ms. Carol Fisher. Last, but not least, we thank the members of the public who took the trouble to submit suggestions for our consideration and expressed to us their views and concerns at our public meetings. GERARD A. ROHLICH, Chairman Safe Drinking Water Committee
Drinking Water and Health