EDITORIAL
Editor: Russeii F. Christman Associate Editor: Charles R . O'Melia WASHINGTON EDITORIAL STAFF Managing Editor: Stanton S . Miller Associate Editor: Juiian Josephson Assistant Editor: Lois R. Ember MANUSCRIPT REVIEWING Manager: Katherine I. Biggs Assistant Editor: David Hanson
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Advisory Board: P. L. Brezonik, Joseph J. Bufalini, Arthur A. Levin, James J. Morgan, Sidney R . Orem, Frank P. Sebastian, John H. Seinfeld, C. Joseph Touhill, Charles S. Tuesday Published by the AMERiCAN CHEMICAL SOCIETY 1155 16th Street N.W. Washington, D.C. 20036 (202) 872-4600 Executive Director: Robert W. Cairns BOOKS AND JOURNALS DiVlSlON D. H. Michael Bowen, Director
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Chloroform controversy Indications are that the Environmental Defense Fund will bring suit against EPA over the latter's failure to regulate the concentration of chloroform in drinking water. At issue here is whether or not the Administrator of EPA has complied with the requirement of the Safe Drinking Water Act to set standards or require treatment for contaminants, which in his judgment, . . may have adverse effect on the health of persons." What scientific basis does the Administrator have for determining that chloroform has an adverse human health effect? EPA's NORs survey has established that chloroform, , and often other trihalomethanes, are present in virtually every chlorinated public drinking water. Data on the effect of chloroform on living systems are not extensive but are available for three species (rat, mouse, and dog) by two routes of exposure. In five studies a tumorigenic response has been noted, although in four studies no tumors were found. The National Cancer Institute found kidney epithelial tumors in male rats and a high frequency of hepatocellular carcinoma in mice of both sexes exposed to chloroform for a year and a half. Most importantly, both the incidence of tumor development and the latency period showed a dose-related response. Differences in exposure levels and in metabolic pathways make extrapolation of these findings to man difficult but not impossible. Preliminary extrapolation by EPA scientists indicates that the risk to humans may be somewhere between zero and a maximum of 1.6 cancer deaths per million per year from the consumption of chloroform in drinking water. Available data and present experimental tools do not permit a more accurate description of the human risk at this time. EPA has handled this matter in an open, scientific, and responsible manner. They have performed surveys of chloroform occurrence, sponsored and performed research on the mechanism of chloroform formation and removal, established health effects as a principal focus in their research budget, and have actively sought public discussion and comments on options for Agency action. As a result of the suit, however, lawyers may now decide whether the present scientific evidence defines a human health hazard. It will be unfortunate if their decision forecloses the available option of waiting for more adequate scientific data. I'.
Volume IO, Number 9 , September 1976
839
