"Results of experiments with monkeys exposed to 60-Hz electric and magnetic fields at intensities
typical of those in the vicinity of high-voltage transmission lines indicated that a decrease in neurotransmitter concentrations occurs during chronic
A few studies have investigated the carcinogenic potential of microwave radiation in whole animals. Male Swiss albino mice were exposed to a radar
transmitter with 9.27-GHz frequency modulated with 2-µsec pulses at a pulse repetition frequency of 500/sec for 59 wk, 5 d/wk and 4.5 min/d.70 The
power used (1 kW/m2) caused a temperature rise of 3.3ºC. There was no difference between exposed and control animals in a number of characteristics
examined, including body weight, red-cell and white-cell counts, and body temperature. Testicular degeneration occurred in 23 of 57 (40%) of treated
animals and in 3 of 37 (8.1%) of the controls. Monocytic or lymphatic organ tumors or myeloid leukemia was seen in 21 of 60 (35%) treated and 4 of 40
(10%) control animals. However, that increase was seen in the animals killed at 16 mo—I mo after cessation of treatment—but not at 19 mo. In
addition, there has been considerable criticism of the experimental methods (e.g., definition of leukosis as an increase in circulating leukocytes,
which could have been due to infection) and statistical analysis.71, 72 Thus, the study is of questionable use for supporting an increase in cancer
risk. The incident power density was approximately 100 times greater than the highest relevant GWEN levels.
Female RFM mice were exposed to 0.8-GHz microwave radiation for 2 h/d, 5 d/wk for 35 wk at 430 W/m.73 Red and white cell counts, hemoglobin,
hematocrit, activity, body weight, and survival were measured, but no histopathologic examinations, were carried out. The only statistically
significant finding was an increase in body weight of animals older than 86 wk in exposed mice over control animals.
A University of Washington study on male Sprague-Dawley rats was designed to simulate the maximum absorbed power (0.4 W/kg) of 0.45-GHz radiation.74
The frequency was chosen as typical of a midrange radar system. Rats were exposed at 2.45 GHz, because it yielded a ratio of wavelength to maximum
body dimension similar to that of children exposed at 0.45 GHz. Benign pheochromocytoma of the adrenal medulla was the only lesion with a
statistically significant increase in incidence. However, that incidence was not higher than that seen in control rats of other colonies. The time for
appearance of first tumor was also shorter in treated animals (457 d) than in control animals (540 d). When all malignant tumors observed at all sites
are combined, there is a statistically significant increase in incidence in the exposed animals. That holds true for carcinomas, but not for
An effect on the process of carcinogenesis has been reported in several studies that used injected tumor cells or animals treated with low doses of a
known carcinogen. The effects of 2.45-GHz microwave radiation at 50 and 150 W/m2 in an anechoic chamber was determined.75 Lung sarcoma cells were
injected intravenously into Balb/C mice, and the lung-cancer colonies were counted after 1, 2, and 3 mo of treatment. After 3 mo, the numbers of lung
nodules were 3.6 ±2.2. 7.7 ± 2.0, 6.1± 8, and 10.8 ± 2.1 in control animals, chronically stressed animals, animals exposed at 50 W/m2, and animals
exposed at 150 W/m2, respectively. The time to appearance of spontaneous breast tumors in 50% of C3H/HeA mice decreased in animals treated with
chronic stress, 50 W/m2, and 150 W/m2 (255, 261, and 219 d, respectively, compared with 322 d in controls). The time of appearance of skin tumors
induced by benzo[a]pyrene was also shortened when irradiation for 1 or 3 mo preceded carcinogen application or when radiation and carcinogen were
given at the same time.75 Again, stress closely duplicated the effect of 50-W/m2 radiation, and, although the results of 150 W/m2 were significantly
greater than those of stress or 50 W/m2, thermal effects might be responsible for the results at 150 W/m2. The power density of 50 W/m2 is
approximately 7 times the low-frequency power density at the GWEN site boundary.
Negative and beneficial results of exposure have also been reported. The effect of continuous or pulsed waves of 2.45 GHz (10 W/m2; SAR, 1.2 W/kg) was
studied in black C57/6J mice with B16 melanoma.76 No significant effects on tumor development or survival times were observed. Beneficial effects of
induced hyperthermia have been observed after treatment with microwave radiation.77,78 Lung sarcoma cells injected into Balb/C mice demonstrated
temporary regression after exposure to 2.45-GHz radiation. After radiation exposure was stopped, tumor volumes increased and lung metastases exceeded
those in untreated animals.77 Sarcoma cells were implanted on postpartum day 16 into CFW mice that had been irradiated in utero with 2.45-GHz
microwaves (35 W/kg) during days 11-14 of gestation; the mice were then subjected to additional exposure to microwave radiation. Fetal exposure to
radiation that increased the dam's colonic temperatures by an average of 2.2ºC decreased tumor incidence (13%, with 46% in controls). Both
tumor-bearing and tumor-free animals that were irradiated as fetuses lived longer, on the average, than controls. Enhanced immunocompetence related to
increases in temperature was suggested as an explanation.
In summary, several studies have provided some evidence of possible carcinogenic potential, and others have shown no effect. Consistent reproducible
studies demonstrating a dose-response relation in animals are lacking, and the interpretation of several studies is complicated by thermally induced
stress. All studies were conducted with electromagnetic fields larger than the relevant GWEN fields.
Considerable interest has arisen concerning a possible role of electromagnetic fields as cocarcinogens or cancer promoters. Results of cellular
studies that support such speculation are discussed in Chapter 7. Studies by McLean et al.79 have begun to explore directly the possible role of 60-Hz
magnetic fields as cancer promoters. In their studies, cancers in SENCAR mice—known for their sensitivity to the promoting effects of
12-O-tetradecanoylphorbol-13-acetate (TPA)—were initiated with dimethylbenzanthracene and then promoted with TPA, a 2-mT magnetic field, or a
combination of TPA and a magnetic field. Tumor development was then observed for 20 wk. There was no significant difference in tumor development
between those promoted with TPA alone and those promoted with TPA and a magnetic field. However, recent results of another experiment by the same
group of investigators suggest that a 60-Hz magnetic field acts as a co-promoter. Additional studies are required to substantiate those findings.
Beniashvili et al.80 treated rats with nitrosomethyl urea and then exposed them to either a 0.2 G static or 50-Hz magnetic field for either 0.5 or 3
h/d for up to two years. They found an increased incidence and number of mammary tumors in the groups exposed to the magnetic fields, with the ac
field being more active than the static one. They also reported an increased tumor response in rats exposed to the 50-Hz field alone."
10-4-2020 by JimERustler because: (no reason given)