The purpose of this study was to determine if chronic, low-level exposure of mice prone to mammary tumors to 435 MHz radiofrequency (RF) radiation promotes an earlier onset, a faster growth rate or a greater total incidence of mammary tumors than in sham-exposed controls. Two hundred female C3H/HeJ mice were exposed for 21 months (22 h/day, 7 days/week) to a horizontally polarized 435 MHz pulse-wave (1.0 micros pulse width, 1.0 kHz pulse rate) RF radiation environment with an incident power density of 1.0 mW/cm2 (SAR = 0.32 W/kg). An additional 200 mice were sham-exposed. Animals that died spontaneously, became moribund or were euthanized after 21 months of exposure were completely necropsied; tissues were subjected to histopathological examinations. Concerning mammary carcinomas, there were no significant differences between the two groups with respect to latency to tumor onset, tumor growth rate and overall tumor incidence. Histopathological examination revealed no significant differences in numbers of malignant, metastatic or benign neoplasms between groups. Survival probability was estimated by the Kaplan-Meier method; no significant difference between groups was noted (Cox's test). Under the conditions of this long-term study, low-level exposure of mice prone to mammary tumors to 435 MHz RF radiation did not affect the incidence of mammary tumors, tumor growth rate, latency to tumor onset or animal longevity when compared to sham-exposed controls.

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This study investigated the effects of long-term, low-level exposure to radio-frequency radiation (RFR) on various physiological systems in a large rodent population. Two hundred adult male white rats with chronically implanted aortic cannulas were randomly divided into two groups. Animals in the first group were exposed to the low-level RFR environment for approximately 22 hours daily, seven days a week, for six months. Depending on animal orientation within the home cage (all animals singly caged) the estimated whole-body specific absorption rate (SAR) ranged from 0.04 to 0.4 W/kg. The estimated mean whole-body SAR ranged from 0.3 W/kg (medium-sized rats) to 0.35 W/kg (large-sized rats). A second, sham-exposure group was maintained under identical conditions, but were not radiated. Microsamples of blood were withdrawn on a cyclic schedule from the unanesthetized and unrestrained rats. The blood samples were assayed for plasma adrenocorticotropin (ACTH), plasma corticosterone, plasma prolactin, plasma catecholamines (norepinephrine, epinephrine, and dopamine), hematological end points (hematocrit ratio, complete red blood cell count, complete white blood cell count, and a differential count of neutrophils, eosinophils, and monocytes), and cardiovascular end points (heart rate and mean arterial blood pressure). Analysis of the results showed no significant RFR-induced differences in these end points when the RFR-exposed group was compared to the sham-exposed group. Chronic exposure to the low-level, pulsed field resulted in no adverse effects on animal health, as measured by the spectrum of blood-borne end points.

To study the effects of exposure to long-term, low-level radio-frequency radiation (RFR) on various physiological systems in a large population of rodents, a complete exposure facility was designed and constructed at the Georgia Institute of Technology. The major components of the facility included a set of circular, stacked, parallel-plate waveguides fed by slotted-cylinder antennas. The waveguides provided a TE10 mode, horizontally polarized field in which the maximal power density occurred midway between the parallel plates. The feed antenna and the parallel-plate waveguides generated a field that radiated outward and was uniform in the azimuthal plane. Thus, animals arrayed along the periphery of the plates were exposed to a uniform 1.0 mW/cm2 field (1.0 microsecond pulse width, 1 kHz pulse repetition rate, 435 MHz carrier). The facility transmitter provided four channels of 435 MHz RFR at 200 W average (continuous wave) or 5 kW peak (pulsed-wave) power; in addition, the transmitter outputs could be combined into a single channel capable of energizing one tier of the stacked parallel-plate waveguide system at 800 W continuous wave or at 16 kW of pulsed waves. To individually house the 200 rodents involved in the study, both biological and engineering criteria were examined and used to design and construct special Plexiglas cages.

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