Intermittent extremely low frequency electromagnetic fields cause DNA damage in a dose-dependent way

Objectives. Epidemiological studies have reported an association between exposure to extremely low frequency electromagnetic fields (ELF-EMFs) and increased risk of cancerous diseases, albeit without dose-effect relationships. The validity of such findings can be corroborated only by demonstration of dose-dependent DNA-damaging effects of ELF-EMFs in cells of human origin in vitro. Methods. Cultured human diploid fibroblasts were exposed to intermittent ELF electromagnetic fields. DNA damage was determined by alkaline and neutral comet assay. esults. ELF-EMF exposure (50 Hz, sinusoidal, 1-24 h, 20-1,000 muT, 5 min on/10 min off) induced dose-dependent and time-dependent DNA single-strand and double-strand breaks. Effects occurred at a magnetic flux density as low as 35 muT, being well below proposed International Commission of Non-Ionising Radiation Protection (ICNIRP) guidelines. After termination of exposure the induced comet tail factors returned to normal within 9 h. Conclusion. The induced DNA damage is not based on thermal effects and arouses concern about environmental threshold limit values for ELF exposure.