ES&T LETTERS Educational opportunities Dear Sir: The Harvard School of Public Health is seeking candidates for enrollment in its graduate programs in occupational and environmental health. People qualified for enrollment range from recent bachelor's degree recipients to mid-career professionals. Areas in which enrollees can specialize include air pollution control, occupa tional health, industrial hygiene, ra diation protection, and environmental health management. Supplementing the teaching program are extensive opportunities for research, both for M S and doctoral candidates, in the development and application of tech niques for monitoring worker and public exposures to airborne particu lates and gases, the development of mathematical models for estimating exposures in indoor and outdoor envi ronments, air and gas cleaning in cluding the control of naturally oc curring airborne radionuclides in buildings, the application of physical and chemical methods for identifying the sources of specific environmental contaminants, and the evaluation of associated risks. A range of traineeship and fellowship support is available. The deadline for applying for fall 1983 admission is March 1, 1983. Potential applicants should contact the De partment of Environmental Health Sciences, Harvard School of Public Health, 665 Huntington Ave., Boston, Mass. 02115; (617) 732-1169. Dade Moeller, chairman Dept. of Environmental Health Sciences Harvard School of Public Health Boston, Mass. 02115 Drinking water disinfectants Dear Sir: I read with interest the fea ture article on drinking water disin fectants in the October issue. (ES& T, Vol. 16, No. 10, p. 5 54A) Last year this time I was a Fulbright-Hays Se nior Lecturer in Liberia, West Africa. Before drinking the water there it had to be filtered, boiled 20 minutes, and refiltered. One of the true pleasures in return ing to the U.S. is being able to drink water from the tap.
I ask your readers to keep the water problem in perspective. The major public health problem the world faces is supplying its developing population with "safe" drinking water. Most of these people face a lifetime of chronic "runny belly." While we in the U.S. are concerned with mutagenic effects of disinfectant by-products in order to prolong our life to an excess of 70 years, the remaining three-fourths of the world is plagued by contaminated water. Let us not neglect these people with the greatest need. Robert J. Hargrove Associate Professor of Chemistry Mercer University Macon, Ga. 31207 Dear Sir: In the October 1982 ES& Τ feature article "Health effects of drinking water disinfectants and dis infectant by-products" by R. J. Bull, several facts pertinent to the evaluation of drinking water disinfectants have been omitted. Bull cites several animal studies (1, 2) in a discussion of chlorite and its role in methemoglobinema and hemolytic anemia. Bull failed to re port, however, that in a recent study human adult males were given drink ing water with various levels of chlo rine dioxide, chlorite, chlorate, chloramine and chlorine ( J , 4). Quoting from that report, "In general, the study affirmed the relative safety and toler ance of normal, healthy adult males and normal, healthy adult male G6-PD deficient individuals to daily twelve week ingestion of 500 m L of chlorine disinfectants at a concentra tion of 5 m g / L . " This report was sponsored by the U.S. E P A Health Effects Research Laboratory, project officer R. J. Bull. In a recent epidemiologic study also conducted by U.S. E P A Health Ef fects Research Laboratory (5), 198 persons were exposed for 3 months to drinking water disinfected with chlo rine dioxide. Bull does cite this report but does not mention the finding that this "study failed to identify any ad verse effects associated with a twelve week exposure to chlorine dioxide disinfected drinking water."
Finally, in Bull's discussion of the carcinogenic and mutagenic activity of a disinfected water supply, he states, "Previous work has shown that treat ing Ohio River water with either chlorine, ozone or chloramine in creased the numbers of tumors in SENCAR mice . . ." What Bull fails to mention is that in the same experi ment Ohio River water treated with chlorine dioxide and dosed to the S E N C A R mice in the same manner as the other disinfectants did not produce tumors in the test animals (6). I agree with Bull's opinion that it is ". . . too early to provide any definitive answer to the question of the relative health risks of the various drinking water disinfectants." But excluding pertinent experimental and epidemi ological data from a review article will not expedite the process of assessing the health effects of drinking water disinfectants. Marco Aieta 143-B Escondido Village Stanford, Calif.
References (1) Heffernan, W. P.; Guion, C ; Bull, R. J. Environ. Pathol. Toxicol. 1979,2, 1487. (2) Abdel-Rahman, M. S.; Couri, D.; Bull, R. J. J. Environ. Pathol. Toxicol. 1980, 3, 431. (3) Bianchine, J. R.; Lubbers, J. R.; Chauhan, S.; Miller, J.; Bull, R. J. "Study of chlorine dioxide and its metabolites in man," ΕΡΑ600/1-81-068, NTIS PB82-109356. (4) Lubbers, J. R.; Chauhan, S.; Bianchine, J. R. "Controlled clinical evaluations of chlorine dioxide, chlorite and chlorate in man," Fund. Appl. Toxicol. 1981, / , 334. (5) Michael, G. E.; Miday, R. K.; Bercz, J. P.; Miller, R. G.; Greathouse, D. G.; Kraemer, D. F.; Lucas, J. B. Arch. Environ. Health 1981,7,36,20. (6) Bull, R. J. J. Am. Water Works Assoc. 1980, 72, 245.
Author's response Dear Sir: In some respects Marco Aieta's comments concerning my ar ticle in the October issue of ES& Τ are justified. However, I would like to point out that this paper was essen tially a reprinting of the paper I pre sented at Asilomar at the 4th Confer ence on Water Chlorination. Dr. Jo seph Bianchine reported on the human studies at the same conference. Environ. Sci. Technol., Vol. 17, No. 1, 1983
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