BIOLOGICAL EFFECTS OF CHRONIC PRE-AND POST-NATAL EXPOSURE OF SQUIRREL MONKEYS TO SPS FREQUENCY MICROWAVES Joel N. Kaplan SRI International, Menlo Park, California The purpose of this study was to determine whether low-level microwave irradiation, at or below the ANSI-recommended radiation protection guide for human exposure, over an extended time had any effect on the pre- and postnatal development of the squirrel monkey. To date, the only research on ontogenetic effects of microwaves has been with rodents and typically at relatively high power levels [Bereznitskaya and Rysina, 1973; Chernovetz et al., 1977; Michaelson et al., 1976; Rugh and McManaway, 1976]. Since the primary goal of such research is to estimate the danger of chronic low-level exposure to man, a nonhuman primate was selected as our animal model because of its similarities to man in pre- and postnatal development. Microwave irradiation of the entire body of unrestrained squirrel monkeys was achieved by using cavity/cage modules designed and built in our laboratory [Heynick et al., 1977]. The modules consist of a dielectric cage housed within a metal chamber into which microwaves are conveyed and "stirred”. Twelve cavity/cage exposure modules were used to expose pregnant monkeys in pairs during gestation and mothers and infants together as dyads after birth. For simultaneous irradiation of two monkeys (or four when two mother-infant dyads were exposed) in one exposure module, the cage was divided in half by an opaque divider. All switches, controls, timers, and meters for providing and monitoring RF power to each module were mounted on a separate unit attached to the module. This unit also contained all the components necessary to generate, measure, and control the microwave power. Within the cavity, the mode stirrer action and movement of animals modulated the peak field intensity at any point in a complicated manner. Prior to exposure of the animal subjects, cavity measurements were obtained by whole-body calorimetry on two identical rubber dolls [Anne, 1968] approximately the size of an adult squirrel monkey which were filled with saline and enclosed in specially constructed, coffin-like, 2-inch-thick Styrofoam insulating boxes, one in each half of the exposure cage. Plane-wave calorimetry measurements were also obtained on the same dolls in order to determine the wholebody power absorption per milliwatt per square centimeter of incident planewave radiation for extrapolation to the cavity-cage environment. Subjects in our initial experiment were 41 pregnant squirrel monkeys (Saimiri sciureus) from SRI's breeding colony assigned to one of four dosage groups (0, 0.1, 1.0, or 10.0 mW/cm2 equivalent) as pregnancies were diagnosed. As births occurred, animals were randomly assigned to groups that either terminated exposures (i.e., switched to 0. level) or continued exposures. In both cases, infants were treated together with their mothers until they were approximately 6 months old and then alone (after weaning) for an additional 6 months. Exposures occurred 3 hr/day, 5 days/week (Monday through Friday) throughout the study and were interrupted only when certain specific tests on the animals were conducted. A variety of biological and behavioral measures were obtained on pregnant animals throughout gestation and on offspring during the first year of life.
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