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.
Support for this project was provided by the Environmental Protection Agency under contract no. X-826345-01-0.
Library of Congress Catalog Card Number 98-88191
International Standard Book Number 0-309-06293-4
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National Academy Press
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Copyright 1999 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
COMMITTEE ON DRINKING WATER CONTAMINANTS
WARREN R. MUIR, Chair,
Hampshire Research Institute, Alexandria, Virginia
R. RHODES TRUSSELL, Vice-Chair,
Montgomery Watson, Inc., Pasadena, California
FRANK J. BOVE,
Agency for Toxic Substances and Disease Registry, Atlanta, Georgia
LAWRENCE J. FISCHER,
Michigan State University, East Lansing
WALTER GIGER,
Swiss Federal Institute of Environmental Science and Technology, Zurich
BRANDEN B. JOHNSON,
New Jersey Department of Environmental Protection, Trenton
NANCY K. KIM,
Center for Environmental Health, Albany, New York
MICHAEL J. MCGUIRE,
McGuire Environmental Consultants, Santa Monica, California
DAVID M. OZONOFF,
Boston University, Massachusetts
CATHERINE A. PETERS,
Princeton University, New Jersey
JOAN B. ROSE,
University of South Florida, St. Petersburg
PHILIP C. SINGER,
University of North Carolina, Chapel Hill
DEBORAH L. SWACKHAMER,
University of Minnesota, Minneapolis
PAUL G. TRATNYEK,
Oregon Graduate Institute of Science and Technology, Portland
Staff
JACQUELINE A. MACDONALD, Study Director
CAROL A. MACZKA, Director,
BEST Toxicology and Risk Assessment Program
MARK C. GIBSON, Research Associate
KIMBERLY A. SWARTZ, Project Assistant
WATER SCIENCE AND TECHNOLOGY BOARD
HENRY J. VAUX, JR., Chair,
University of California, Riverside
CAROL A. JOHNSTON, Vice-Chair,
University of Minnesota, Duluth
RICHELLE ALLEN-KING,
Washington State University, Pullman
JOHN S. BOYER,
University of Delaware, Lewes
JOHN BRISCOE,
The World Bank, Washington, D.C.
DENISE FORT,
University of New Mexico, Albuquerque
EVILLE GORHAM,
University of Minnesota, St. Paul
CHARLES D. D. HOWARD,
Charles Howard & Associates, Victoria, British Columbia, Canada
WILLIAM A. JURY,
University of California, Riverside
WILLIAM M. LEWIS, JR.,
University of Colorado, Boulder
GARY S. LOGSDON,
Black & Veatch, Cincinnati, Ohio
RICHARD G. LUTHY,
Carnegie Mellon University, Pittsburgh, Pennsylvania
JOHN W. MORRIS,
J. W. Morris, Ltd., Arlington, Virginia
CHARLES R. O'MELIA,
Johns Hopkins University, Baltimore, Maryland
PHILIP A. PALMER,
DuPont Engineering, Wilmington, Delaware
REBECCA T. PARKIN,
The George Washington University, Washington, D.C.
JOAN B. ROSE,
University of South Florida, St. Petersburg
ERIC F. WOOD,
Princeton University, New Jersey
Staff
STEPHEN D. PARKER, Director
JACQUELINE A. MACDONALD, Associate Director
CHRIS ELFRING, Senior Staff Officer
LAURA J. EHLERS, Staff Officer
JEFFREY W. JACOBS, Staff Officer
JEANNE M. AQUILINO, Administrative Associate
MARK C. GIBSON, Research Associate
ANITA A. HALL, Administrative Assistant
ELLEN A. DE GUZMAN, Senior Project Assistant
KIMBERLY A. SWARTZ, Project Assistant
BOARD ON ENVIRONMENTAL STUDIES AND TOXICOLOGY
GORDON ORIANS, Chair,
University of Washington, Seattle
DONALD MATTISON, Vice-Chair,
University of Pittsburgh, Pennsylvania
DAVID ALLEN,
University of Texas, Austin
MAY R. BERENBAUM,
University of Illinois, Urbana
EULA BINGHAM,
University of Cincinnati, Ohio
PAUL BUSCH,
Malcolm Pirnie, Inc., White Plains, New York
PETER L. DEFUR,
Virginia Commonwealth University, Richmond
DAVID L. EATON,
University of Washington, Seattle
ROBERT A. FROSCH,
Harvard University, Cambridge, Massachusetts
JOHN GERHART,
University of California, Berkeley
MARK HARWELL,
University of Miami, Florida
ROGENE HENDERSON,
Lovelace Respiratory Research Institute, Albuquerque, New Mexico
CAROL HENRY,
American Petroleum Institute, Washington, D.C.
BARBARA HULKA,
University of North Carolina, Chapel Hill
DANIEL KREWSKI,
Health Canada and University of Ottawa, Ontario
JAMES A. MACMAHON,
Utah State University, Logan
MARIO J. MOLINA,
Massachusetts Institute of Technology, Cambridge
WARREN MUIR,
Hampshire Research Institute, Alexandria, Virginia
CHARLES O'MELIA,
Johns Hopkins University, Baltimore, Maryland
KIRK SMITH,
University of California, Berkeley
MARGARET STRAND,
Bayh, Connaughton and Malone, Washington, D.C.
GERALD N. WOGAN,
Massachusetts Institute of Technology, Cambridge
TERRY F. YOSIE,
Ruder Finn, Inc., Washington, D.C.
Staff
JAMES J. REISA, Director
DAVID J. POLICANSKY, Associate Director and Program Director for Applied Ecology
CAROL A. MACZKA, Program Director for Toxicology and Risk Assessment
LEE R. PAULSON, Program Director for Resource Management
RAYMOND A. WASSEL, Program Director for Environmental Sciences and Engineering
KULBIR BAKSHI, Program Director for the Committee on Toxicology
COMMISSION ON GEOSCIENCES, ENVIRONMENT, AND RESOURCES
GEORGE M. HORNBERGER, Chair,
University of Virginia, Charlottesville
PATRICK R. ATKINS,
Aluminum Company of America, Pittsburgh, Pennsylvania
JERRY F. FRANKLIN,
University of Washington, Seattle
B. JOHN GARRICK,
PLG, Inc., Newport Beach, California
THOMAS E. GRAEDEL,
Yale University, New Haven, Connecticut
DEBRA KNOPMAN,
Progressive Foundation, Washington, D.C.
KAI N. LEE,
Williams College, Williamstown, Massachusetts
JUDITH E. MCDOWELL,
Woods Hole Oceanographic Institution, Massachusetts
RICHARD A. MESERVE,
Covington & Burling, Washington, D.C.
HUGH C. MORRIS,
Canadian Global Change Program, Delta, British Columbia
RAYMOND A. PRICE,
Queen's University at Kingston, Ontario
H. RONALD PULLIAM,
University of Georgia, Athens
THOMAS C. SCHELLING,
University of Maryland, College Park
VICTORIA J. TSCHINKEL,
Landers and Parsons, Tallahassee, Florida
E-AN ZEN,
University of Maryland, College Park
MARY LOU ZOBACK,
United States Geological Survey, Menlo Park, California
Staff
ROBERT M. HAMILTON, Executive Director
GREGORY H. SYMMES, Assistant Executive Director
JEANETTE SPOON, Administrative & Financial Officer
SANDI FITZPATRICK, Administrative Associate
MARQUITA SMITH, Administrative Assistant/Technology Analyst
Preface
Americans expect to be able to drink the water that comes from their taps without fear for their safety. While this expectation has been largely fulfilled in this century, on occasions and in certain systems, chemicals and microbes still contaminate drinking water supplies in the United States. Thus, continuing vigilance is necessary to assure that important drinking water contaminants are identified and appropriately addressed.
In 1996, Congress enacted the Safe Drinking Water Act Amendments of 1996, substantially revising the way in which public water supplies are regulated. Among the amendments is a requirement that the Environmental Protection Agency (EPA) develop a list of currently unregulated contaminants that may pose risks in drinking water. Every five years, EPA must decide whether to regulate at least five of those contaminants and whether to conduct additional monitoring and research for the others. The first of these lists, known as the Drinking Water Contaminant Candidate List (CCL), was published by EPA in March of 1998.
EPA has asked the National Research Council (NRC) for assistance in addressing three aspects of this effort:
- developing a scientifically sound approach for deciding whether or not to regulate contaminants on the current and future CCLs,
- convening a workshop that will focus on emerging drinking water contaminants and the database that should be created to support future decision making on such contaminants, and
- creating a scientifically sound approach for developing future CCLs.
This report, written by the NRC's Committee on Drinking Water Contaminants, addresses the first of these topics. It includes a review of ten different governmental and private schemes used to rank environmental contaminants in other contexts to identify whether, and in what manner, such schemes might apply to the three tasks being addressed by the committee. The committee consists of 14 volunteer experts in water treatment engineering, water chemistry, analytical chemistry, microbiology, toxicology, public health, epidemiology, risk assessment, and risk communication. This report's findings are based on a review of relevant technical literature, information gathered at two committee meetings, and the expertise of committee members. The committee will address the remaining two topics in subsequent reports.
On behalf of the committee, I wish to thank Jim Taft, Evelyn Washington, and Chuck Job of EPA for supporting this important three-phased review. In addition, thanks go to William Carpenter, attorney and member of the National Drinking Water Advisory Council's Working Group on Occurrence and Contaminant Selection; Stephen Clark, EPA Office of Ground Water and Drinking Water; and Thomas Yohe, Philadelphia Suburban Water Company. All of these individuals made presentations and supplied valuable background information at the first committee meeting.
This report has been reviewed, in accordance with NRC procedures, by individuals chosen for their expertise and broad perspectives on the issues addressed herein. The purpose of this review is to provide independent, candid, and critical comments that will help the NRC to be assured that the report is sound and meets the NRC's standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft report remain confidential to protect the deliberative process by which the report was developed. The committee wishes to thank the following people for their participation in this review and for their many constructive comments: Richard Bull, Washington State University and Battelle Pacific Northwest Laboratory; Gunther Craun, Gunther F. Craun & Associates, Staunton, Virginia; Joseph Delfino, University of Florida; George Hornberger, University of Virginia; Eric Olson, National Resources Defense Council; David Reckhow, University of Massachusetts, Amherst; Robert Spear, University of California, Berkeley; and Thomas Yohe, Philadelphia Suburban Water Company. Notwithstanding this review, however, the final content of this report is the responsibility of the Committee on Drinking Water Contaminants.
I speak for the whole committee in thanking the very capable and professional NRC staff for the assistance we have received throughout our deliberations and during report preparation. In particular, I want to acknowledge the outstanding efforts we have received from
Jacqueline MacDonald, study director and associate director, Water Science and Technology Board (WSTB),
Carol Maczka, director of toxicology and risk assessment programs, Board on Environmental Studies and Toxicology,
Mark Gibson, research associate, WSTB, and Kimberly Swartz, project assistant, WSTB.
These staff members worked extraordinarily hard and effectively to help us produce this report in a very short time, in order to be of maximum utility to EPA as it moves forward to implement the recently enacted drinking water protection mandates.
Finally, I want to thank the diverse and talented members of the committee, who were able to bring together their diverse perspectives and broad expertise to produce this report. I look forward to continuing to work with this wonderful group in making a contribution to addressing the second and third phases of our effort.
WARREN R. MUIR, Ph.D.
CHAIR, COMMITTEE ON DRINKING WATER CONTAMINANTS
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished 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. Bruce M. Alberts 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 autonomous 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. William A. Wulf 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. Kenneth I. Shine 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. Bruce M. Alberts and Dr. William A. Wulf are chairman and vice-chairman, respectively, of the National Research Council.
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