Physiological and behavioral effects of prolonged exposure to 915 MHz microwaves.

Long-Evans male adult rats were exposed for 16 weeks to 915-MHz CW microwaves at an average power density of 5 mW/cm2. The resulting dose rate was 2.46 (+/- 0.29 SEM) mW/g. The animals were exposed eight hours a day, five days a week, for a total of 640 h in a monopole-above ground radiation chamber while housed in Plexiglas cages. Daily measures of body mass and of food and water intake indicated no statistically significant effects of microwave irradiation. Measures by activity wheels and stabilimetric platforms of spontaneous locomotion indicate than mean activity levels increased about 25% after microwave exposure, but the findings are doubtful statistical significance (Ps < .10 but > .05). Studies of blood sampled after 2, 6, 10, and 14 weeks of exposure revealed alterations of free sulfhydryls. Measures of levels of urinary 17-ketosteroids at weeks 1, 5, 9, and 12 of exposure, and measures of brain hypothalamic tissue, and of mass of adrenals, heart, and liver at the end of the 16-week period, revealed no significant differences between irradiated and control animals. Cortical EEGs sampled after conclusion of microwave exposures also revealed no significant differences.