The bioeffects of extremely weak power-frequency alternating magnetic fields

We report the results of a study of the influence of extremely-weak alternating magnetic fields (EW AMF) directed co-linearly to the static Earth’s magnetic field on the rate of regeneration in planarians and also on the rate of gravitropic response in the stem segments of flax. In particular we obtained the data on the dependence of the value of bioeffects on the amplitude (at fixed 60 Hz—frequency) and on the frequency (at fixed 1.6 μT—amplitude) of the alternating component. Our data show unambiguously that EW AMF substantially affect the properties of the biosystems. The experimental data may be approximated by the theoretical expression following directly from a general formula, derived in the theory of magnetic parametric resonance. Our data indicate that the nuclear spins of hydrogen atoms serve as the primary targets for the action of the EW AMF on the biosystems. The values of bioeffects of combined magnetic fields with extremely weak alternating component are completely determined by the parameter $$\gamma{B_{AC}/f}$$ , where γ = 42.578 Hz/μT—gyromagnetic ratio of the nuclear spins of hydrogen atoms, and $${B_{AC}}$$ and f correspond to magnetic induction and frequency of the alternating magnetic component. The dependence of bioeffect’s value on $$\gamma{B_{AC}/f}$$ —parameter is polyextremal: well expressed maxima are observed at $$\gamma {B_{AC}/f} = 0.9, 2.75$$ and minor maxima at $$\gamma{B_{AC}/f} = 4.5, 6.1$$ . The bioeffects are absent at $$\gamma{B_{AC}/f}= 1.8$$ , 3.8, 5.3, 6.7. At the values of $${B_{AC}} > 8\hbox{--}10\,\mu\hbox{T}$$ the bioeffect changes its sign—activation of planarian’s regeneration starts to be replaced by its inhibition. The inhibition takes place for the range of the amplitudes from 10 to 140 μT. The observed change in the sign of the effect may result to the prevalence of the effects caused by the induction of the alternating currents in the test-system at relatively high $${B_{AC}}$$ —amplitudes. These results provide the basis for planning of the epidemiological studies and interpretation of the corresponding results.