By John Iovine, From "Popular Electronics" March 1993
There is a growing concern over possible health hazards from low-frequency electromagnetic fields. When the story first broke, the fields of greatest concern were those given off by overhead power line transformers.
At the time, the reasoning was unless you worked in the electronics field or lived in close proximity to power lines, you could consider yourself unaffected and relatively safe. New evidence suggests that it really isn't the case. It appears that the ELF (extremely low-frequency) magnetic fields given off by many household appliances and computer monitors can be of sufficient strength to be considered potentially hazardous.
For those of us who dabble in electronics, or earn our livelihood in electronics or a related field, the concern becomes more prominent. That being the case you should be aware of what research has taken place and what's been reported thus far.
Why Worry Now? You might be wondering if ELF radiation is such a health hazard, why has it taken so long for anyone to mention its dangers? To answer that question, we must look at how scientists first sized up the potential harm of low-frequency magnetic fields.
To begin with, it was originally believed that weak low-frequency fields could not have a significant impact on living systems. This belief was based on the amount of thermal energy the ELF fields could produce in biological tissue. The energy produced by ELF radiation is much smaller than the normal thermal energy internally generated by a cell's metabolic process. In addition, the quantum energy of the fields is far too low to break any chemical or nuclear bonds in the tissue. Therefore, scientists felt DNA would be safe from mutating. Finally the electric field of the body is much greater than the induced field from ELF radiation. Looking at all these factors, it's easy to understand why the scientific community quickly dismissed epidemological studies that indicated a statistically significant hazard associated with ELF radiation.
As a result, the scientific community has of late been portrayed in the press as a bunch of hacks or bureaucratic puppets genuflecting for grants from government agencies and power companies. However, the reason for the quick dismissal was one of genuine disbelief, not a mass cover up. Although in truth, a few scientists have stepped over the line and maligned good researchers based upon the profit and loss statements of their employers. These scientists are few in number and the entire scientific community should be condemned based upon their isolated unethical endeavors.
The Real Deal. Although the mechanism by which ELF fields affect biological tissue is still not exactly known, it has been unequivocally shown that cells are affected. The best research to date shows that a cell's membrane, or receptor molecules in the membrane, are sensitive to extremely weak low-frequency magnetic fields.
Some of the effects reported so far include changes in the flow of ionic compounds through cellular membranes. Also noted are changes in DNA synthesis, RNA transcription, and the response of cells to signaling molecules such as hormones and neurotransmitters. In addition, changes have been noted in the kinetics of some cellular biochemical reactions.
Not all ELF radiation produces all of those effects, it's more complex than that. Some effects are only noted at discrete frequencies and amplitudes of the magnetic field. Others depend on the strength and orientation of an ambient constant magnetic field. Still others require a threshold of exposure time rather that field strength.
The inherent danger or increased likelihood of various forms of cancer due to ELF radiation has been emphasized in the press. As stated previously, the quantum energy of these fields isn't sufficient to produce any type of chromosomal damage. Simply, that means that ELF radiation doesn't initiate cancer. The increased incidence of cancers is due to the fact that ELF radiation can promote the disease after the cancer has been triggered by another agent. The cancer is promoted because ELF radiation can suppress the body's immune system. In addition, it has been determined that at the cellular level the ELF fields increase the production of the enzyme ornithine decarboxylase, which has been cited to support the promotion of cancer in the body.
The Evidence. As studies progress, more information will be forthcoming. Here is a short list of reported events that indicates the potential hazards of ELF fields:
In 1972, Soviet researchers linked electromagnetic fields with low grade health
problems such as fatigue and headaches.
In 1977, Robert Becker, physician and biophysicist Andrew Marino testified before the New York State Public Service Commission about the results of their experiment that showed negative health effects due to exposure to ELF fields.
In 1979, Nancy Wertheimer an epidemiologist and physicist Ed Leeper published a study that showed a statistical link between childhood cancers and the proximity of certain types of high-current power lines to the home.
In 1982, a Washington State study examined the data for the deaths of 438,000 workers in the State occurring between 1950 and 1979. The results of the study showed that leukemia deaths were elevated in 10 out of 11 occupations where the workers were exposed to ELF fields.
In 1986, Dr. Bernard Tribukait, a professor of radio biology at the Karolinska Institute in Stockholm Sweden, reported that the fetuses of mice exposed to sawtooth electromagnetic fields had a greater incidence of congenital malformation than unexposed mice. The sawtooth waveform is a typical waveform generated by monitors and TV's.
In 1988, the Maryland Department of Health and Hygiene found an unusually high rate of fatal brain cancer among men employed in electrical occupations.
In 1989, John Hopkins University found an elevated risk of all cancers among New York Telephone Company cable splicers.
In 1990, David Savitz, an epidemiologist at the University of North Carolina, determined through a study that pregnant woman who used electric blankets have children who have a 30% increased risk of cancer as compared to children whose mothers didn't use electric blankets.
So far I have concentrated on the negative effects of 60-Hz ELF fields. But
you should know that there are positive medical uses for ELF fields. Robert
Becker had discovered that ELF fields when appropriately applied (at a specific
frequency and amplitude) can promote healing and therapeutic responses in tissue.
The ELF fields appear to be a double-edged sword, being able to heal as well
Computer Monitors. Concern over the radiation from televisions and computer monitors (which are closely related in operation and technology) is nothing new. A number of years ago there was concern as to whether radiation given off by color televisions could have a negative impact on health. This concern was based primarily on ionizing radiation, (low-level X-rays) whose intensity fell off dramatically a few inches away from the TV screen, and turned out to be incidental. But more insidious than this overt threat is one that has passed unnoticed until quite recently: the low frequency magnetic fields generated by the coils on the TV's CRT (Cathode-Ray Tube).
Computer monitors (or VDT's, which stands for video-display terminals) generate these low-frequency magnetic fields, which emanate in all directions, too. They present a greater hazard than TV's because a user must sit closer to them during use. In fact, there have been numerous reports from female computer operators of cluster miscarriages. The word cluster refers to a greater-than-average incident of miscarriages among a group of women.
The latest study on cluster miscarriages was performed in 1988 by doctors Marilyn Goldhaber, Michael Polen, and Robert Hiat of the Kaiser Permanente Health Group in Oakland, California. The study involved 1,583 pregnant women. The results of the study showed that female workers who used computers more than 20 hours a week had double the miscarriage rate as female workers who did similar work without computers.
What the study didn't take into account, but which I'm sure will be studied in the near future, is the incidence of malformations and cancers in the children born to women who use computers as compared to the children of women who don't. If we extrapolate the information from David Savitz's 1990 study, we may see another side to the problem.
Excessive ELF fields emitted by computer monitors is an industry-wide problem, virtually all CRT computer monitors emit excessive ELF radiation unless specifically stated otherwise. Recently, MacWorld Magazine (in the July, 1990 issue) did ELF studies on 10 popular monitors. All of the monitors tested emitted excessive ELF radiation at a close range. The only recommendation that they or I can offer you at this time is to increase the distance between you and the monitor. A working distance of two feet is recommended.
The ELF field propagates from all points around the monitor, not just from the front screen. That fact becomes important in offices where computer terminals are in close proximity to one another, because workers can be exposed not only from their own monitor, but also from a neighbor's monitor.
It's important to realize that the ELF field given off will vary somewhat from monitor to monitor. Table 1 summarizes some measurements I took of the 60-Hz ELF field from my 1084 Amiga monitor. As you can see, the ELF field strength drops off dramatically with distance from the monitor. (I could not check the ELF radiating from the bottom of the monitor because of the way it is situated in my work space).
Table 1-MONITOR RADIATION
Intensity (Milligauss) Distance
(Inches) Front L-Side R-Side Back Top
0 78 97 90 125 270
4 24 14 16 37 65
12 5 1.5 1.5 8 9
24 less than 1 less than 1 less than 1 3 5
Shielding. It would be nice if we could purchase a radiation shield for our monitors, similar to the antiglare shield on the market. Unfortunately none exist. Be very careful, there are some antiglare screens on the market that make a claim of blocking the electric and magnetic fields given off from the monitor. First, electric fields as far as I know have not been reported to have any negative impact upon health. Second, the magnetic field the screens claim to block are in fact the visible-light frequency fields generated by the CRT. Those high-frequency magnetic fields have not been shown to have a negative impact on health. These antiglare screens have no impact on the low-frequency (60-Hz) magnetic fields that I am talking about. There is no easy way to shield that monitor to reduce the propagating ELF fields. I have tried a number of different methods, none had any appreciable impact on the ELF radiation. The best recommendation is to keep the monitor 18-24 inches away from yourself.
Another possibility is to use an alternative type computer monitor. Liquid crystal display (LCD) and plasma display monitors do not emit ELF fields. However, their drawbacks are higher cost and lower resolution.
Precautions Around the Home. There are sources of ELF around the typical home. Before I discuss them, I would first like to explain a little bit about dose-rate. An appliance in the home may generate a very strong ELF field, but if the appliance is only used a short time, its risk factor is probably low. (Note the word "probably" in the last sentence: currently, exact data on short-duration high-strength fields hasn't been gathered).
Electric razors fall into this category. Line-operated (plugged into a wall socket rather than battery-powered) razors do produce extremely strong ELF fields, and are held in very close proximity to the body, but because they are only used for a short time, the total exposure or dose is small and they are probably safe. In contrast to the electric razor is the electric blanket. It emits a much lower ELF field strength, but for a much longer exposure time.
Dr. Nancy Wertheimer, who first published the epidemiological study showing a correlation between 60-Hz power lines and the increased incidence of childhood cancer in this country, has also performed similar research on users of electric blankets. She has found that there is a higher incidence of miscarriages among pregnant women who use electric blankets as compared to pregnant women who do not.
For users of electric blankets, the following recommendations can be made. One, switch to ordinary blankets. If you like electric blankets, use one to heat your bed before going to sleep, but unplug the blanket before you actually get into bed. It is not sufficient to just turn off the blanket because many blankets still produce an ELF field as long as they're plugged into a socket.
Fluorescent light are much more efficient (more light per electrical watt) than ordinary incandescent bulbs. Because of that, they have become the standard lighting system used in most offices, industry, and now around the home. However, fluorescent lights require a ballast transformer that generates an ELF field. If you're using a small fluorescent lamp as a desk light, you may want to consider switching to an incandescent lamp, which generates virtually no ELF.
That also applies to the new energy-saver fluorescent lamps that replace standard incandescent bulbs. They are okay for overhead lighting, but you may want to reconsider using them for close-up work or desk lighting.
Television sets fall into the same category as our computer monitors. Like our monitors, they produce a field that propagates from around the entire set. The ELF field will propagate through standard building materials such as wood and plaster. So if a TV set is placed against a wall, the ELF will propagate through the wall into the adjoining room. So it becomes important not to place a bed against a wall with a TV set on the other side.
The small motors in AC-powered clocks also produce ELF fields. If the clock is an alarm clock that lies close to the sleeper's head, it could be giving that person a significant dose of ELF radiation during the night. The recommendation would be to move the clock a significant distance away. Or purchase either a battery-powered clock or a digital clock that produces a negligible field.
Hair dryers fall in the same category as electric shavers since using them means short-term, high field-strength exposure. They are probably safe for most people. Notable exceptions are people who use them in their occupation, such as hair stylists and hair dressers.
Electric baseboard heaters are another potential problem appliance. A minimum of 4 feet of distance is recommended from such heaters.
It's impossible for me to state what a safe, long-term dose rate is because it hasn't been established. Effects have been reported at dose rates as low as 1.2 to 3 milligauss. So I would venture to say try to limit long-term exposure to 1 milligauss or less.
Bottom Line. A controversy still rages as to the impact and extent of ELF fields on human health. I would try to limit long-term exposure to one milligauss or less.
Warning!! The inforation contained in this article is being provided solely to the readers for educational purposes. Neither the publisher nor the author make any representations as for the completeness or accuracy of the information contained herein and disclaim any liability for damages or injuries, wheather caused by or arising from the lack of completeness, inaccuracies of the information, misinterpretations of the directions, misapplications of the information or otherwise.
A personal note from Guy Cramer, Ion Scientist; These ELF fields trigger serotonin
a brain hormone now associated with cancer (see Project AIR). A
negative ion generator can convert the excess serotonin (the antagonist for most of the problems)
into a harmless chemical called 5HA ( 5-HIAA ).. I have my negative
ion generator blowing at me while I work on my computer.;