Abstract
A source of intermediate frequency (IF: 300 Hz to 100 kHz) MFs in a living environment is
induction heating (IH) cookers. Primary MF frequencies of these are from 20 to 90 kHz, and
possible health risks of such MFs are not sufficiently evaluated yet. Among the possible risks,
reproductive and developmental effects are a concern, because the IH cookers' hob is located
close to a cook's reproductive organs. Male and female rats (24/group) were exposed to a 20
kHz, 0.20 mT(rms) or 60 kHz, 0.10 mT(rms) sinusoidal MF from prior to and during mating.
Copulated females were exposed until gestation day-7. The exposure intensity of 0.20 mT is
7.4 times greater than that of the International Commission on Non-Ionizing Radiation
Protection (ICNIRP) exposure guideline, i.e., 0.027 mT. Mated males were examined for the
effects on spermatogenesis. Reproductive examinations were blinded, and experiments were
duplicated per frequency to ensure reproducibility. No statistically significant, exposurerelated
changes were found in the estrous cycle, copulation and fertility indices, numbers of
corpora lutea and implantation sites, or pre- and postimplantation loss. No reproducible
changes were observed in sperm count, motility, or morphological abnormality, or in the
weights of testes and epididymides. Obtained evidence indicates that MF exposure during the
preimplantation period was not toxic to fertility or early embryogenesis. In addition, pregnant
rats (25/group) were exposed to the same 20 kHz or 60 kHz MF from gestation day-7 to day-
17, and their fetuses were examined for malformations. No exposure-related changes were
found in clinical signs, gross pathology, or number of implantation losses. The number of live
fetuses and low-body-weight fetuses as well as the incidence of external, visceral, and skeletal
malformations in the fetuses did not show significant influence attributed to the MF exposure.
Although some fetuses showed changes in skeletal variation and ossification, such changes
were neither reproduced in duplicate experiments. The results indicate that exposure of rats to
IF MFs during organogenesis did not show significant reproducible teratogenicity. All
together, no convincing adverse effects of IF MF exposure on rat reproductive and
developmental systems were found under the experimental conditions. Further studies on
toxicity and carcinogenicity will contribute to secure the safety on application of the IF MFs
among general public.
Links and resources
Tags
community