Quantitative Evaluations of Mechanisms of Radiofrequency Interactions With Biological Molecules and Processes

Abstract

The complexity of interactions of electromagnetic fields up to 10(12) Hz with the ions, atoms, and molecules of biological systems has given rise to a large number of established and proposed biophysical mechanisms applicable over a wide range of time and distance scales, field amplitudes, frequencies, and waveforms. This review focuses on the physical principles that guide quantitative assessment of mechanisms applicable for exposures at or below the level of endogenous electric fields associated with development, wound healing, and excitation of muscles and the nervous system (generally, 1 to 10(2) V m(-1)), with emphasis on conditions where temperature increases are insignificant (<<1 K). Experiment and theory demonstrate possible demodulation at membrane barriers for frequencies < or =10 MHz, but not at higher frequencies. Although signal levels somewhat below system noise can be detected, signal-to-noise ratios substantially less than 0.1 cannot be overcome by cooperativity, signal averaging, coherent detection, or by nonlinear dynamical systems. Sensory systems and possible effects on biological magnetite suggest paradigms for extreme sensitivity at lower frequencies, but there are no known radiofrequency (RF) analogues. At the molecular level, vibrational modes are so overdamped by water molecules that excitation of molecular modes below the far infrared cannot occur. Two RF mechanisms plausibly may affect biological matter under common exposure conditions. For frequencies below approximately 150 MHz, shifts in the rate of chemical reactions can be mediated by radical pairs and, at all frequencies, dielectric and resistive heating can raise temperature and increase the entropy of the affected biological system.

Acute Mobile Phones Exposure Affects Frontal Cortex Hemodynamics as Evidenced by Functional Near-Infrared Spectroscopy

“…In this study, the increase in [HHb] could be interpreted as an effect of heat deposition into the brain with a consequent dissipation across cortical areas. This hypothesis has recently been proposed especially for the highest frequencies, in which dielectric and resistive heating could increase the local temperature and increase the entropy of the exposed biologic system (Sheppard et al, 2008). However, a thermal mechanism should be rejected taking into account that: (1) the distance between the antenna and the head drastically reduces the absorbed power (Schö nborn et al, 1999); (2) increase of skin temperature would be easily dissipated through the blood flow (Van Leeuwen et al, 1999); and (3) near-infrared light penetrates through the brain at least 1.5 cm in-depth, in which temperature changes are far below the danger level (Wang and Fujiwara, 1999;Bernardi et al, 2000).…”

Scientific evidence contradicts findings and assumptions of Canadian Safety Panel 6: microwaves act through voltage-gated calcium channel activation to induce biological impacts at non-thermal levels, supporting a paradigm shift for microwave/lower frequency electromagnetic field action

“…Therefore, fields will produce rapid movement of charges in the intracellular and extracellular aqueous phases which will be blocked by the plasma membrane such that voltage sensor will be influenced by greatly amplified electrical forces, in a direction perpendicular to the plain of the plasma membrane. That circa 3000-fold amplification is recognized by Sheppard et al (34) immediately before their Conclusion section. The only example of an integral membrane that may be influenced in this way, that they give (34) is that of bacteriorhodopsin, where light exposure leads to the pumping of a proton across the plasma membrane.…”

“…The above considerations in this section, clearly show that Sheppard et al (34) provide no evidence arguing for biophysical implausibility of the VGCC voltage sensor as a target of low-intensity EMFs, such that when we have compelling empirical evidence that it is the main target, that evidence should be taken at face value. Furthermore, the VGCC voltage sensor is likely to be many orders of magnitude more sensitive to EMF effects than are any nonplasma membrane localized target.…”

“…The only example of an integral membrane that may be influenced in this way, that they give (34) is that of bacteriorhodopsin, where light exposure leads to the pumping of a proton across the plasma membrane. They attempt to estimate the effects of voltages on the proton pumping, by looking a the effects of voltages on the absorption changes that occur in bacteriorhodopsin (34); however, the cycling of bacteriorhodopsin is a complex process (41) where the proton pumping is not rate-limiting and therefore these studies give little insight into the actual effects on proton pumping.…”

Noninvasive Assessment of Metabolic Effects of Exposure to 900 MHz Electromagnetic Fields on Djungarian Hamsters (Phodopus sungorus)

“…However, in practice it is often difficult to assess whether temperature elevation has taken place. No alternative mechanism of interaction has been identified to date (Sheppard, Swicord & Balzano, 2008;Valberg, van Deventer & Repacholi, 2007).…”