Book Review

Radio-Frequency and ELF Electromagnetic Energies: A handbook for health professionals

N Engl J Med 1995; 333:1293-1294November 9, 1995

Article

Radio-Frequency and ELF Electromagnetic Energies: A handbook for health professionals
By R. Timothy Hitchcock and Robert M. Patterson. 542 pp. New York, Van Nostrand Reinhold, 1995. $79.95. ISBN: 0-442-00945-3

We live in a sea of electromagnetic fields. But the sea is shallow, and the fields are so minute that they are detectable only with sophisticated technology and are arguably undetectable by biologic systems and, hence, harmless. But a host of biologic studies have been interpreted to suggest that weak fields can affect biology, and a substantial number of epidemiologic studies are thought by some to suggest that these effects can be harmful. Although no such conclusion, biologic or epidemiologic, is at all firm, science is hard put to prove a negative. But if the reality of the effects of weak fields is very much in doubt, there is no doubt that public concern about the possible effects, perhaps driven more by journalism than by science, is real, and this book responds to that concern.

Both Hitchcock, an independent consultant, and Patterson, professor of environmental health engineering at Temple University, are industrial hygienists and thus “health professionals,” in the sense of the subtitle. The strength of this book would therefore seem to lie in the authors' sensitivity to the needs of readers who, like them, must use the information from studies of this complex, controversial, multidisciplinary subject in discharging their professional responsibilities in industrial health and safety. But the weakness of the book derives from the limitations of the authors, whose competence is not centered in the studies themselves.

The topics addressed by the book range from the basic physics of electromagnetic fields and the interaction of such fields with matter, through the biologic effects of the fields, to instrumentation and measurement procedures and exposure standards. Elsewhere (as in the exemplary CRC Handbook of Biological Effects of Electromagnetic Fields, edited by Charles Polk and Elliot Postow. Boca Raton, Fla.: CRC Press, 1986), so broad an agenda has been addressed by a group of experts in the various areas. The attempt by Hitchcock and Patterson to cover everything themselves may have an advantage in terms of coherence, but any such advantage appears to be offset by weaknesses in exposition and accuracy. These weaknesses compromise the book.

The problems with the book are most definite in the areas that are most objective. The important introductory chapter on general concepts is naive and confused. Simple, fundamental matters, such as the part of the Lorentz force law that pertains to magnetic fields, are mishandled, and the section called “Free-Space Impedance” is bizarre. Weaknesses in discussions of elementary physics and engineering may not be important to many readers, but there are also serious deficiencies in the chapter called “Exposure Standards and Guidelines.” For example, the “averaging time,” a measurement protocol, set under most circumstances at six minutes, is properly described in the glossary of the report presenting the IEEE C95.1-1991 standard: “The appropriate time period over which the exposure is averaged . . .” (Adair ER, Gaudhi O. IEEE standard for safety levels with respect to human exposure to radiofrequency electromagnetic fields, 3 KHz to 300 GHz [IEEE C95.1-1991]. New York: Institute of Electrical and Electronics Engineers, 1993). Hitchcock and Patterson, however, define the averaging time as an exposure protocol: “The acceptable duration of exposure at the applicable exposure limit. . . .” In fact, there is no limit on the duration of exposure, if the average field intensity, measured for any six-minute averaging time, is below the standard limit. So gross an error has serious operational consequences.

Though I find the book an unreliable guide to procedure, it will be useful to many readers as a compendium of information. The index of authors lists nearly 1200 references — though many of the articles that those who work in the field consider important are not listed. The authors have addressed the almost impossible task of reporting fairly the conflicting literature on the biologic effects of weak fields — a task in which the reporter is caught between equally fervent believers and nonbelievers — about as evenhandedly as possible.

Robert K. Adair, Ph.D.
Yale University, New Haven, CT 06511