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Electricity and health
Not long ago, electricity was regarded as a clean, residue-less power source, of remarkable, silent efficiency. If used properly, it produces no smell, no smoke, no sensation of any type. The relationship between electricity and health seemed to be as good as it gets.
Sure, every once in a while, another not widely publicized study would come along with a different, less rosy picture. Among the first of this kind were studies investigating possible link between energy fields produced by power lines and increased incidence of childhood leukemia.
The news wasn't good: children exposed power fields of very moderately elevated intensity, well within the range of common exposures, had
consistently higher rate of leukemia.
What was particularly troubling is that those exposure levels - typically around 4mG (milligaus), or 0.4μT (microtesla) - were hundreds of times below the official safety limit of 1000mG (or 100μT) for the general population. It provoked haunting thoughts: if this is really happening so much below the safety limit, there is something biologically very potent in these weak energy fields that interferes with body processes -
and no one knows what it is!
What else it might be causing? Childhood leukemia was pretty much in focus, ever since Wertheimer and Leeper's keen observation had linked it with power-frequency field exposure in 1979. Possible connection of the common power-frequency field exposures with other ailments and diseases were not investigated to any meaningful extent.
The truth is, it is hard to investigate what you know next to nothing about. How could possibly such a low energy affect body function? Decades of research later, using advances in molecular biology and laboratory techniques, we are beginning to unveil this mystery.
What is, exactly, electricity?
Most simply, by definition that could be applied to the entire electromagnetic spectrum - it is the energy field created by moving charges. With standard electricity, those moving charges are low-energy electrons in the outer portion (orbits) of the atomic shell, moving from one shell to another under the pressure of repulsive magnetic force (voltage) induced by generators. As the electrons move through a wire, they switch from higher to lower energy levels, releasing energy in the form of electromagnetic radiation.
The movement of electrons, called electric current, is very slow, a small fraction of a millimeter per second (in the alternate, or AC current, electrons only move about 2 microns back and forth). On the other hand, the energy radiated by electrons, or electricity, being electromagnetic wave, practically moves at the speed of light. Unlike the current, which remains confined within electrical wire, portion of the radiated energy spreads outside of it, in the form of electromagnetic field.
This energy field consists of two different forces, electrical and magnetic - hence the name. With standard electricity, electric field is created by the voltage differential itself, thus constantly present and steady in intensity. Magnetic field, on the other hand, is created by electrical current (moving electrons), and its strength around the wire depends on current density (for instance, magnetic field strength around power lines varies with the rate of consumption).
Both, electric and magnetic field weaken rapidly with the distance from their source. However, unlike electric waves, magnetic waves are little affected (absorbed) by common building materials, or trees.
In the standard, alternating current (AC), electrons move back and forth at a rate of 60 oscillation per second. This is very low frequency in the realm of electromagnetic waves. Hence, the produced wave energy is also very low (for comparison, electrons in cell phones, which operate in the much higher range of frequencies between 900MHz and 1800MHz, are made to oscillate 15-30 million times faster, creating as much shorter and more intense waves).
Since AC current constantly moves electrons back and forth, both electric and magnetic fields are always present. They form around power lines, interior wiring, cables plugged into wall outlets, and around anything using electricity, from the electric can opener to vacuum cleaner.
Being exceedingly low, power of these fields is far outside the range of senses of average individual. Most people can feel 50/60Hz field stronger than 20kV (kilovolt, 1000V) as a slight vibration moving over the skin; few people can sense fields below 5kV. For comparison, residential exposure for about 95% of people is in the 0.009-0.12kV (9-120V) range.
Thermal effect at this exposure level is entirely negligible; it is also negligible at the level when the induced charge can be sensed on the surface of the skin. But there are
other than skin-deep effects.
They are caused by the penetrating electromagnetic field, which induces electrical currents and affects bioelectric potentials throughout the body. As tiny as these energy fields are, they are strong enough to affect biological processes. This has been demonstrated on thousands and thousands of patients since 1970s, with often spectacular healing effects, by the therapeutic use of pulsed magnetic fields. In the range of intensity and frequencies, they overlap with power-frequency fields.
The simple rule is that anything with the power to produce beneficial effect in the body, has also the power to harm it. Since literally all body processes depend on bioelectricity, from the cellular level up, there are many possible forms through which these fields can negatively interfere with body functions, and as many possible symptoms.
For instance, studies have found that electromagnetic field induced to the body reduces heart's resting rate by 3-5 bits per minute, but only at a particular field intensity: 9kV electrical and 20μT magnetic field. No effect was recorded at 33%/50% stronger (for electrical and magnetic field, respectively), or weaker fields (Cook et al. 1992; Graham et al. 1994).
Studies of occupational exposure to power-frequency fields are mainly consistent in establishing significantly higher incidence of some forms of cancer - leukemia and brain tumor being the frontrunners, but also other diseases like breast cancer (Demers et al. 1991; Matanoski et al. 1991; Tynes et al. 1992; Loomis et al. 1994) or Alzheimer's (Sobel and Davanipour 1996).
A group of electrical utility workers exposed to 0.17-0.34kV electric field combined with 32-70mG magnetic field (yearly average values) had the risk ratio for cancer and leukemia of 1.2 (small group, with confidence interval 0.8 to 15). With identical electric field exposure, and magnetic field over 70mG, risk ratio skyrocketed to 7.8. And with identical magnetic field exposure as the first group combined with stronger electric field (<0.34kV), the risk ratio went even higher, to 11. In all, there was 1484 cancer and 50 leukemia cases among these workers (Miller et al. 1996).
In another occupational study, significantly lower exposure to magnetic field (10.5-12.1mG) resulted in the brain cancer risk ratio increase to 2.38 (Savitz et al. 2000).
Evidently, there is no shortage of suggestive evidence about these weak fields being bioactive, and harmful to some people. Keep in mind that all these exposures, while elevated, still are
much below the official "safety" limit of 1,000mG and 8.3kV
for magnetic and electric field at this frequency, respectively.
Also, even these few examples illustrate quite well how complex and unpredictable is health effect of these energy fields. This, of course, is a direct consequence of the complexity of body's bioelectricity, with unknown number of variations in electro-potentials, electricity-based functions, triggers and interactions.
These findings imply certain conclusions, which reflect both complexity and uniqueness of the way that energy fields affect human body. Some of those conclusions are:
It can be expected that certain field intensities will have adverse effect at some frequencies, but not the others (that pretty much invalidates the dose-response epidemiological criterion in establishing causal relationship).
Or that such effect for given frequency will show at a specific intensity, but not at either higher or lower intensities.
Or that adverse health effect will be caused only when the two fields are specifically combined, or either one or both are combined with some non-EMF factor.
Or that adverse effects are caused by two or more different frequencies, acting synergistically.
On top of it, individual sensitivities to any of possible effects vary rather widely, as they generally do for any agent capable of affecting body processes.
All this is, obviously, a major factor behind the inconsistencies in study results. What is very much certain, though, is that these tiny energy fields are capable of causing serious adverse health effects. Using inconsistencies in study results as a "reason" not to change official safety limits, so much higher than the levels where it is evident that serious adverse effects are possible, simply has nothing to do with the reason.
What is really behind it, can be found easily by answering the right question: "Who is it that benefits from the status quo?". Turns out, rather powerful set of players - huge commercial, and highest-profile political interests, partnering up with the exploitable segment of the scientific community.
For all we can see, the evidence shows that power-frequency fields, created by 50/60Hz electricity, are not harmless. Much is still left to be determined, but the two most important facts should be clearly stated:
? energy fields created by electricity do interfere with body functions
?in sensitive individuals it can cause, or contribute to a variety of adverse health effects, including the most serious diseases, such as cancer
So let's take a closer look at what are our actual exposures to the energy field created by electricity, day in and day out.