Paper presented to the Workshop on possible biological and health effects of RF electromagnetic fields.

Mobile Phones and Health, Symposium, October 25-28, 1998, University of Vienna, Austria.

Reproduced with permission of Henry Lai

INTRODUCTION

Radiofrequency electromagnetic radiation (RFR), a form of energy between 10 KHz-300 GHz in the electromagnetic spectrum, is used in wireless communication and emitted from antennae of mobile telephones (handys) and from cellular masts. RFR can penetrate into organic tissues and be absorbed and converted into heat. One familiar application of this energy is the microwave ovens used in cooking.

The close proximity of a mobile telephone antenna to the user's head leads to the deposition of a relatively large amount of radiofrequency energy in the head. The relatively fixed position of the antenna to the head causes a repeated irradiation of a more or less fixed amount of body tissue. Exposure to RFR from mobile telephones is of a short-term, repeated nature at a relatively high intensity, whereas exposure to RFR emitted from cell masts is of long duration but at a very low intensity. The biological and health consequences of these exposure conditions need further understanding.

Formal research on the biological effects of RFR began more than 30 years ago. In my opinion, the research has been of high quality, innovative, and intelligent. All of us who work in this field should be proud of it. However, knowledge of the possible health effects of RFR is still inadequate and inconclusive. I think the main barrier in understanding the biological effects of RFR is caused by the complex interaction of the different exposure parameters in causing an effect. An independent variable of such complexity is unprecedented in any other field of biological research.

In this paper, I have briefly summarized the results of experiments carried out in our laboratory on the effects of RFR exposure on the nervous system of the rat. But, before that, I will discuss and point out some of the general features and concerns in the study of the biological effects of RFR.

The artificial EMF environment of the U.S. is a superimposition of contributions from many sources having diverse operating characteristics. They include high- and low-power emitters that can be omnidirectional or directional, and that can operate continuously or intermittently. At high frequencies, the general EMF background consists predominantly of the AM radio band (0.535-1.604 MHz) and the FM and TV band (54-806 MHz). About half the U.S. population is exposed to these sources at levels above 0.005 µW/cm2 at any given moment, and about I% is exposed above 1 µW/cm2 (Fig. 10.1)(1). The actual number of people exposed above 1 µW/cm2 in any given day, week, or month is considerably greater because of population mobility.

Environmental studies. Suicide is a stress-related phenomenon that may be viewed as a specific manifestation of depressive mental illness. We studied the relationship between suicide and power-frequency field strength (2, 14). We were concerned with how the field strength at the residences of suicides compared with that at appropriately-chosen control addresses. The study group consisted of the 598 suicides that occurred within the study area (in the Midlands of England) during a 7-year period and an equal number of controls. We first examined the relationship between suicide and the computed electric and magnetic fields of nearby high-voltage power lines. We found a statistically significant correlation between both fields and the occurrence of suicide, but we could not determine whether more or less than the expected number of suicides occurred at locations of high field strengths (14). Since the total power-frequency field at any site is due to contributions from many sources- high-voltage lines, low-voltage lines, household wiring and appliances- we then proceeded with a study of measured field strengths. The mean measured magnetic field strength for the suicide group (867 µgauss), was found to be significantly higher than that of the control group (709 µgauss) (2). The proportion of suicide addresses in the high-field-strength region was 40% greater than the proportion of control addresses (Table 10.6).