Micronuclei formation in somatic cells of mice exposed to 50-Hz electric fields

Male Swiss mice are tested under uniform 50‐Hz electric field intensities of 100, 170, 220, and 290 kV/m. These values on the basis of equal induced current density are equivalent to the case of a human exposed to field intensities of nearly 8, 14, 18, and 24 kV/m, respectively. The latter values may be found beneath or in vicinity of extra‐high‐voltage power lines whose voltages range from 220 to 765 kV. The cytogenetic effect of extremely low‐frequency (ELF) electric fields, as expressed by micronuclei formation, is assessed. Mice are exposed for 24 hr, and samples are taken 48, 72, and 96 hr from the beginning of exposure. Sham‐exposed mice served as controls. The number of micronucleated polychromatic erythrocytes (PCE) in exposed animals are significantly higher than those of the control. The increase in micronucleated PCE was significantly dose dependent at all times. Samples taken 96 hr after exposure show a decrease in percentages of micronucleated PCE, which may be taken as an indication of recovery.