Behavioral and physiological effects of chronic 2,450‐MHz microwave irradiation of the rat at 0.5 mW/cm²

Abstract

Adult male Long-Evans rats were intermittently exposed to 2450 MHz CW microwaves at an average power density of 0.5 mW/cm2 for 90 days. The resulting SAR was 0.14 W/kg (range 0.11 to 0.18 W/kg). The animals were exposed 7 h/day, 7 days/wk, for a total of 630 h in a monopole-above-ground radiation chamber while housed in Plexiglas holding cages. Daily measures of body mass and food and water intake indicated no statistically significant effects of microwave exposure. Monthly assessment of reactivity to electric footshock, levels of cholinesterase and sulfhydryl groups in blood, and 17-ketosteroids in urine revealed no reliable differences between 14 sham-exposed and 14 microwave-exposed rats. After the 90 days of exposure, seven rats, randomly chosen from each group, were assessed for open-field behavior, shuttlebox performance, and schedule-controlled (IRT schedule) lever pressing for food pellets. Statistically significant differences between microwave-exposed and sham-exposed rats were observed in shuttlebox performances and lever pressing. Post mortem measures of mass of several organs and microscopic examination of adrenal tissue revealed no differences between the two groups of animals.

Intermittent exposure of rats to 2450 MHz microwaves at 2.5 mW cm2: Behavioral and physiological effects

“…At this point in the training sequence the microwave-exposed group performed poorly with a greater number of lever-presses emitted, fewer food pellets received, and an overall drop in efficiency of performance as compared to the sham-exposed group. A similar effect was also observed in our previous experiments for rats exposed to 2450-MHz microwaves at 500 pW/cm2 where exposure-by -trial interactions were significant [D'Andrea et al, 1986;DeWitt et al, 19841. For this behavioral measure two comments can be made.…”

“…Physiological changes have also been reported for intermittent exposures of rats to power densities as low as 10 pW/cm2 [Dumanski and Shandala, 19741. At a recent conference similar results have been reported for rats exposed chronically to 2450-MHz microwaves at 500 pW/cm2 [Lovely et al, 19781. In contrast, two separate experiments completed in our laboratory have failed to reveal reliable patterns of behavioral or physiological effects during or after intermittent exposure of rats to 2450-MHz microwaves at 500 pW/cm2 [D'Andrea et al, 1986;DeWitt et al, 19841. In our experiments some endpoints did differentiate microwave-from sham-exposed rats, but these were not consistent for the two experiments. For example, in the performance of a time-related schedule of leverpressing microwave-exposed rats were less efficient in earning food pellets compared to sham-exposed rats in some sessions [D'Andrea et al, 19861.…”

Behavioral and cognitive effects of microwave exposure

“…A following study at 2.5 mW/cm 2 reported additional effects that were statistically reliable, but this study was never replicated [D'Andrea et al, 1986b]. The few biological effects reported subsequent to chronic microwave exposures [Lovely et al, 1983] such as reduced food intake in exposed rats, cannot be viewed as adverse to the health of the exposed laboratory animal.…”

Estimation of Core Temperature Elevation in Humans and Animals for Whole-Body Averaged Sar

“…This threshold is based on the fact that RF exposure of laboratory animals in excess of approximately 4 W/kg has revealed a characteristic pattern of thermoregulatory response [4]. In addition, decreased task performance by rats and monkeys has been observed at WBA-SAR in the range of 1-3 W/kg [5] According to Adair and Black [6], the physiological heat loss mechanisms are different for different species. In particular, small animals would be poor models for human beings.…”