Bioeffects of Extremely Low-Frequency Electromagnetic Fields: Variation with Intensity, Waveform, and Individual or Combined Electric and Magnetic Fields

Prolonged exposure of the myxomycete Physarum polycephalum to either continuous wave (75 Hz) or frequency modulated wave (76 Hz) electromagnetic fields (EMF) (0.1-2.0 G and 0.035-0.7 V/m) lengthens the mitotic cycle and depresses the respiration rate. Once induced, these effects persist indefinitely in the presence of EMF without increasing or decreasing in magnitude beyond that due to normal variability of the organism. Similar effects are observed when either individual electric fields (0.7 V/m) or magnetic fields (2.0 G) are applied; however, the magnitude of the response is less than that observed with simultaneous fields. The individual field effects appear to be additive for respiration but not for nuclear division rate. For fields applied simultaneously at levels below 0.14 V/m and 0.4 G the response was independent of field intensity. No threshold was observed for simultaneously applied electric and magnetic fields; however, indirect evidence is presented that suggests either the electric or magnetic field is below threshold at levels of 0.14 V/m and 0.4 G, respectively. Frequency modulation of the fields seems to have no major effect on the response induced in P. polycephalum.