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"It is a violation of the most fundamental human rights to impose risk of death upon individuals without their consent. Human rights should not be sacrificed to the pursuit of a healthy economy, affluence, progress, science, or any other goal"Dr. John Goffman, Professor Emeritus, University of California School of Medicine, in 'Radiation and Human Health', 1981. |
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Today, the computer screen has become a familiar part of modern life. Its ubiquitous presence permeates homes, replacing the manual, electric and electronic typewriter, or doubling as computer games machine for the bored child. Pioneering companies like Sinclair, Amstrad, Commodore, and others have opened up large consumer markets almost non-existent in the mid- 1970s, a mere two decades previous. A myriad computer software programs, from the archetypal Space Invaders to complicated spread sheets and accounting packages, have helped enchant even the most resistant souls - particularly the youngsters of five upwards - to familiarise theselves with the language of the computer programmer. Rarely do children or adult users actually learn to program the machines themselves. Nevertheless its vocabulary is infiltrating into our ordinary speech: software, downloading, and hard copy are but a few examples of computerese retrovirally inserted into the English language. In 1985 there were around 13 million VDTs in the United States and Canada, but by 1990, these had grown to over 30 million in the U.S. alone. In Britain (where VDTs are called VDUs, or visual display units) the number is now between 5 and 8 million. Unlike the TV set, whose somnolent spectators sit perhaps ten feet from the screen, a VDT operator's head is less than 30 inches from its cathode rays. The first indication that these devices were irradiating at a distance can perhaps be linked to complaints that home computers were affecting TV reception, not only in the user's own home, but even next door: (I have observed one extreme case where the neighbour's sensitivity enabled her to say exactly when the computer games machine next door was switched on). In the office, the cost efficiency of the VDT is undisputed. Ursula Huws records that at the Grattan mail-order warehouse in Bradford, Northern England, full time staff were reduced from 1000 to 550 and part-timers from 100 to 50 over a period of a few months when a new computerised system for dealing with orders was introduced in 1979, despite an increase in the volume of business (Huws, 1988). If computing was cost effective then, it is now remarkably more so, with prices for hardware decimated: the machine which types out this book cost only ten percent of the same performance machine of a decade ago, and not only publishers but even some readers receive a diskette which does not need to be manually re-keyed and composed into book typestyles. Moreover the PC’s mean time between failures has diminished considerably, and no longer does the occasional infuriating voltage variation lose program or data the way it used to. Software packages, thanks to the efforts of millions of man-hours over the years, (and Bill Gates of Microsoft) have improved and are available off the shelf for hundreds instead of thousands of pounds. The development of OCR (optical character recognition) means that documents no longer need to be laboriously imput by a keyboard operator. And before long terminals will be actuated by voice alone, and respond in the same vein. Finally, advances in technology will substitute liquid crystal displays for the cathode ray tube itself, eliminating any outflowing electric fields. Smaller versions of the VDT have helped expand its domain into the retail point of sale: the supermarket, pub, bar, and online banking system cash dispensers in Main Street U.S.A. and every British high street incorporate their own video display. The benefits of this technological advance are evident. Supermarket print-outs are fully itemised, cash is available any time of the day or night, machine operatives can control the production process from afar, the brewery chains can monitor sales down to the last gin and tonic or whisky sour, and the supermarket check-out clerk's effort is reduced from a wearisome mental effort to a few deft hand flicks over the laser reader. It is only a short step from there to the fully automated supermarket, with potentially several hundred thousand further staff redundancies, who can then go home and play on their PCs.. In fifteen short years, then, there has taken place a fundamental and probably irreversible change in the way advanced nations buy and sell their daily bread, not to mention the sophisticated dealing consoles which are their counterparts in the financial world. Ursula Huws believes these changes were initiated by a slow down in postwar growth which forced management to turn attention to the cost efficiency of their business. Doubtless the vagaries of staff attendance and the possibility of strike action had also their part to play. The VDT operates by firing electrons at a phosphor-coated screen, in some ways similar to the fluorescent lighting in offices, but much closer, and by means of magnets deflecting them en route to form the required image. These emissions are at many frequencies including ELF, visible light, UV, and even soft x-rays. The screens are designed to filter out soft x-rays, a task they do not always accomplish over their entire life. Soft x-rays can also emerge from the back and side of a machine, and since such VDTs are often used in reception areas, waiting clients can find themselves gently irradiated while waiting for their appointment. A National Institute for Occupational Safety and Health (NIOSH) report in 1985 states: "X-radiation tests conducted by NIOSH since 1977 found maximum levels of between 0.25 and 0.3 millirems (mR) per hour emitted from VDTs. While this is below the 0.5 mR/hr standard, a continuous dose of 0.3 mR/hr over a working year would be equivalent to 450 mR which is nearly the same as the x-ray exposure standard maximum for therapeutic applications for the general public (currently 500 mR per year). This does not allow for any other irradiation from screens at home or outside the working environment". To understand the meaning of these measurements a few words of explanation. A "rem" stands for Roentgen Equivalent Man. When an x-ray's energy is emitted it is measured in Roentgen, but since different substances absorb more or lesser amounts, it was seen necessary to express the amount of absorption rather than simply the energy emitted, so the term rad (radiation absorbed dose) was determined. At x-ray strengths one rad is equivalent to one rem, but at other frequencies they will not equivalate. One rem is equivalent to ten milliSieverts, which is the international unit of dose equivalent. One Sievert is calculated by multiplying the absorbed dose in Grays by a quality factor for the particular effectiveness of the radiation. Before you ask, the Gray is equivalent to one joule of energy absorbed per kilogram of matter such as body tissue. One hundred rad is equivalent to one Gray (abbreviated to Gy), but the Gray is now replacing the rad in common parlance, and the milliSievert is replacing the rem.. Understand? No? I'm not surprised; the history of radiation measurement is full of changed nomenclature and confusing terms. It is also a history of falling exposure limits, which, by contrast, needs little explanation:
The awful truth is that we still don't know what limits to impose. Long-term studies are showing that the effects may not become apparent for decades, and may even not show up until the next generation. Since we have only mapped a percentage of the human genome, damage from ionising radiation and non-ionising radiation alike may have caused mutations yet unrealised in our species. Furthermore it may not simply be a question of rems or milliSieverts: repeated doses of low intensity over a period of time are currently thought to be more damaging than its equivalent dose in a few short bursts of radiation. The guidelines of Hiroshima and Nagasaki are unreliable, in that the explosions wiped out all the high voltage electricity systems, which might otherwise have had a synergistic effect. Today we have much higher background levels of radiation than in the early parts of this century, even though only a fraction is caused by nuclear installations themselves. Though it might seem strange to find a report on low level radiative emissions from the Sellafield nuclear reprocessing plant discussing the AIDS virus, the connection between radiation and AIDS is never far from the surface. Sir Douglas Black's 1984 report on cancer in West Cumbria (the site of Sellafield) says : "(A3.22) Human adult T-cell Leukemia virus (HTLV-1 or ATLV) is the only human virus that has been implicated in human leukemia to date. This is a retrovirus which induces an aggressive variant of mature T-cell leukemia. HTLV-1 has so far been identified as occurring mainly in South West Japan, in the Carribean basin, in Central America, and in Africa (Gallo 1984)". Black does not comment that all these areas of the earth are where solar radiation is at its highest, but continues: "The natural mode of transmission of these agents has not yet been established. More recently a new virus, LAV or HTLV-3, has been identified as the probable cause of Acquired Immune Deficiency Syndrome (AIDS) (Weiss, 1984). HTLV-1 and HTLV-2 have not been detected in any cases of childhood leukemia". His last sentence supports helps the view that the immune deficit was in place before the virus arrived. Hundreds of thousands of people each year visit Sellafield's multimillion pound exhibition just outside the site, and are proudly given glossy booklets which include the table below (BNFL, 1988, M71):
These in total amount to some 135 to 185 mR per year, which is already the same as the annual dose which a VDT operator might receive to the thyroid gland (190mR/yr) from the machine which provides her livelihood (Aitken & Hirning, 1982) These authors concluded that "whilst it is true that neither of these hypothetical doses exceeds the current recommended dose limits for individual members of the public (0.5rem/yr) the large and growing number of VDU users could result in substantial collective doses if their units were emitting x-rays at levels close to the limit". The table above excludes non-ionising radiation, and it is not easy for the layman to understand how this compares with ionising radiation, because although they are part of the same EM spectrum, the measurement terms are entirely different. As well as x-rays, VDTs emit radiation in the UV and non-ionising microwave frequencies. Skin cancers have been known for decades to result from UV radiation, but the effects of microwave irradiation of the head are only just being realised, as a result of research not on VDTs at all, but on mobile phones. (The long term follow-up of early Israeli x-radiation for headlice by Baruch Modan has already been mentioned). My task in relating the background of hazards to health from chronic VDT exposure has been made infinitely easier by the publication of a book by Peggy Bentham, VDU Terminal Sickness. This quickly sold out and was reissued in 1996 with a new section, though sadly not with any updating revision to speak of to the original text, so here and there the main text is clearly out of date. Nevertheless her effort in bringing together between two covers most of the published research, as well as detailed references to scientific studies makes the work the most definitive todate. In this chapter I am really only dotting her is and crossing the ts in areas most appropriate to bioelectromagnetics, and mentioning some relevant new studies not to be found in her book.. An early study by Weisburd (reported in Science News, vol 12) found that the DNA helix will resonate when irradiated by microwaves. When more recent studies by Henry Lai at Washington University reported that exposure to microwaves at the frequencies used by mobiler phones can cause single strand breaks in DNA (Lai & Singh, 1996), it caused a furore in bioelectromagnetics circles which permeated to the media. Not quite so much in the limelight was a study published in the same journal around the same time by Chiang, Wu and colleagues at the Microwave Institute, Zheijiang, China (Chiang Wu, et al., 1995). They took 89 Swiss Webster impregnated mice and divided them into four groups, one as a control, one for exposure to pulsed magnetic fields, one for injection with a teratogen ara-C, and one poor group destined for irradiation and ara-C combined. The radiation at 40 microTesla with the saw-tooth waveform characteristics of an average VDT took place for 4 hours a day from day 6 to day 17. After 18 days the mother mice were euthanised and their fetuses were examined. The results left no doubt that exposure to the pulsed fields had a teratogenic effect on the unborn animals: Group No. of live fetus No. per litter No. dead Resorption A. Control 196 8.2 7 4 B Pulsed MF 181 8.6 2 14 C. ara-C 161 7.3 20 19 D. ara-C and PMF 159 7.2 22 17 The results were statistically significant as tested by c 2 and p<0.005 when comparing the individual fetus with the control group. This means that exposure of a fetus to VDT radiation could be hazardous, a suspicion left from an earlier study of 1583 pregnant VDT operators working more than 20 hours a week at the terminals (Goldhaber, Polen et al., 1988). The Lai study further suggests that exposure of the kind used in mobile phones is in danger of fracturing DNA and possible mutation of the developing fetus. I have already pointed out that the mutational forms of leukaemia, the myeloid group, are found most often near radio and TV transmitters near Sellafield, and Helen Dolk has now found a similar result near Sutton Coldfield. Other early researchers like Webb and Booth (1969), Don Justesen (1980), and Dumansky & Shandala (1974) had already found sinister biological effects. One doctor, William Ham, was moved to advise that "both the retina and the lens should be protected throughout life from both blue light and near -UV radiation". His admonition followed the discovery that the retina is more sensitive to injury when exposed to light in the blue portion of the spectrum, - the blue light that we see in fluorescent lighting and VDT screens (Ham, 1983). Dr. Mays Swicord of the U.S. FDA bravely reported at an annual meeting of the American Physical Society in 1984 that DNA absorbed 400 times more energy than the surrounding salts, thus supporting first done by S.J. Webb in the 1950s and 1960s (Webb, 1975, Webb & Booth, 1969) which found that DNA was affected by very specific frequencies, as if tuned to receive them. Don Justesen, who now works for Kansas City's Medical Center, in 1980 reviewed eastern bloc studies uncovering an even worse concern. We have a barrier, known as the blood brain barrier (BBB), which keeps out contaminating agents from our cerebrospinal fluid. Microwaves, reported Justesen in his literature review, appear to damage this barrier, making it permeable, though the evidence needed serious replication. Later the evidence was forthcoming to show by means of a dye that there is albumin leakage of the BBB with microwave exposure (Salford and Brun, 1993). In Poland Yuri Dumansky and his research team was investigating the effect of microwave and related radiation in built-up areas in the early 1970s. They found that blood sugar levels rose and there were changes in carbohydrate metabolism as a result of exposure to densities as low as 100 to 1000 microWatts (Shandala & Dumansky, 1979). In the US Deitrich Beischer also found blood changes, notably in what are known as triglycerides (a form of blood sugar) as a result of exposure to extra low frequency radiation for just one day from a simulation of Project Sanguine (Beischer & Brehl, 1975), but his work was said to be hastily refuted, and his research funds terminated. Meanwhile Dumansky had extended his work and found that changes in liver function were another corollary of MW exposure (Dumansky & Rudichenko). Another early researcher into the effects of microwaves on our eyes, was Dr. Milton Zaret. He noticed that unusually large numbers of radar technicians were coming to him with post-lens cataracts, and eventually pinned it down to the microwave radiation to which they were occupationally exposed (Zaret, 1965). The same sort of cataracts showed up in pilots, air traffic controllers (Zaret & Snyder, 1977), radar technicians, radio operators, and VDT operators (Zaret, 1984). "Except for the VDT operators", says Bob DeMatteo in his brilliant and exhaustive review of VDT hazards, "most of these other groups have been awarded compensation. In most of the cases the exposure levels were below the official Canadian limits of 1mW per square centimetre." (Dematteo, 1986) In 1987 Arthur "Bill" Guy was awarded the BEMS accolade of the D'Arsonval award, after a lifetime in bioelectromagnetic research. During his role as adviser to IBM he discovered that even exposure as low as less than half a milliWatt/cm2 could cause malignant tumours in rats (Guy, Chou et al., 1985). He was not alone in this finding: Stanislaw Szmigielsky from Warsaw (Szmigielsky, 1988), Susan Praunitz and Charles Susskind of Berkeley, California (1962), and Bill Morton from Oregon all found correlations between extremely low (nanoWatt) levels of broadcast radiation and leukaemia, as did doctors John Lester and Dennis Moore from Kansas (Lester & Moore, 1982). Changes in brain wave patterns are also induced by the kind of radiation coming from a VDT, even as low as power densities of 20 microWatts/cm2 , and this was reported 20 years before this book was published (Dodge & Glaser, 1977). The result is to induce behavioural symptoms such as sluggishness, depression, and inability to concentrate. These may subsequently turn into myalgic encephalomyelitis and chronic disability. How does the VDT produce this deadly cocktail? Microwaves are emitted by the two sweep oscillator circuits at the back of the CRT, and are therefore measured at their strongest at the flyback transformer at the rear, rather than the front of the screen, thus irradiating nearby workers. "A simple test for radio frequency radiation". states Ursula Huws, "is to hold a transistor radio tuned to a VHF station near your VDU. As you move it around, you can tell where the emissions are strongest by listening to the interference to the sound" These sweep oscillators are of two types, one vertical deflection coil, and one horizontal. The vertical coil moves the beam of electrons from top to bottom and up again sixty times a second, and thus produces a pulsed ELF field of the kind which Ross Adey found could damage cerebral tissue (7-20). The horizontal deflection coils move the electron beam left to right and back again 15 to 20 thousand times a second and thus pulses out a VLF field at 15 to 20 kHz. There is a possibility that the higher frequencies from VDTs also have biological effects. One of these is RF hearing, where low intensity radiation affects the cochlear myosin filaments connecting the inner hair cells of the ear with the neural pathways to the brain (Frey, 1988), and induces a sensation of noise. This may well persist in the head of the person exposed long after the "sound" has been switched off (Frey, 1961). De Matteo cites several studies of the effects of the two kinds of sweep oscillator: 1. Ontario Hydro Research Divn. 1982. The peak field strength at 30 cm. from the screen was upto 170 V/m from older types of VDTs and the average was 55 V/m. This strength I have found (at power frequencies) causes hyperactivity in young children, and so it may cause the same effect in computer-games crazy youngsters at VLF frequencies, which are more energetic. 2. Dr. Hari Sharma of Ontario's Waterloo University found averages of 1200 V/m at the screens' surface and 25 V/m at a 30 cm. distance. He conducted a study among the VDT operators in the accounts department of the Surrey Memorial hospital at British Columbia, where from a total of seven pregnancies there had been three miscarriages and three babies born with birth defects. Dr Sharma found that the VDTs in the accounting office had significantly higher pulsed VLF emissions than those in the medical records office, where pregnancy outcomes were normal . These results actually led to a change in the Ontario laws, excusing pregnant operators from VDT duties. No such regulations protect British women at this time, but fortunately U.K. employers seem to be aware of the risks and accordingly tolerant. But not all: most national newspapers have updated their technology in the last decade, and reporters now phone in their stories to VDU operators waiting at the screens all day. Most of these screens as I write are unprotected and no real allowance is made for pregnancy, even when the operator has become aware of her conception. Their proprietors can take refuge behind the statement by Britain's Health and Safety Executive (published in March 1987, well after this and other studies had been reviewed), that "In the population as a whole one in five to one in ten known pregnancies ends in miscarriage. Occasionally, however, a group will show a much higher or lower level than these average figures. Higher levels have been reported among groups of VDU operators, but investigations show that they are not peculiar to VDU work and are to be expected on the basis of statistical chance rather than the result of VDU work. The very latest research studies have not been able to show a link between miscarriage or birth defect and VDUs". (HSE, 1983). 3. Arthur Guy, at Washington, who was an adviser to IBM, found a 10 V/m electric field at 25-30 cm from the screen, though older models were as high as 50 V/m. Guy also showed that fields at these intensities still induced electrical currents in human tissue which were biologically significant, and in 1984 expressed concern about their long term effects on operators at the BEMS annual meeting in Atlanta Georgia. His concern is one which I share: these levels of field strength are not uncommon in domestic houses when the return current is unbalanced, and if infants are chronically exposed to them it is my observation that cot death may occur within weeks. Guy also showed that the waveforms from the VDTs were not of the gentle sinusoidal type, but sawtooth, a shape known to be more biologically damaging. This shape has a fast rise time, which means the magnetic field is changing quickly, and thereby it has an important electric component. Notwithstanding the advice and concern of IBM's chief adviser regarding older machines, the HSE say in the same pamphlet quoted above: "As a VDU ages it is more likely to develop faults such as drift and jitter of the images on the screen. It is possible that the brilliance control will need to be turned up but this does not mean that there will be any increase in the other non-visible radiations. Machines should be serviced if there is deterioration in the visual image but there is no need for periodic radiation checks". About the same time as the HSE were preparing their pamphlet, Dr Marilyn Goldhaber of the Kaiser Permanente Medical Care program was conducting a case-control study of 1,583 pregnant women from Northern California. The group is called in medical terms a cohort, and their progress is monitored to see what happens to them over time (Goldhaber, Polen, 1988). Dr. Goldhaber was a little concerned that other studies in Finland, Sweden and Canada, as well as the U.S., were missing early miscarriages because of the way they were set up, and that the conclusions which they had come to, namely that it was probably safe to use VDTs while pregnant, were therefore wrong. Originally however the cohort had been established in 1983 to test for the effects of the pesticide malathion. The research team sent a questionnaire to over 1800 of the original cohort, and eventually got answers from over eighty percent of them. The questionnaire included routine questions about their work and whether they used VDTs and if so, for how long each week. Other questions were about their use of tap water, bottled water, caffeine, alcohol, and cigarettes. When they analysed the results they found that the estimated relative risk with any form of VDT work was only 1.2 to 1.0 and not enough to get excited about. But when they looked at the risk for women working more than 20 hours a week on the machines, they found the risk rose to 1.8. In other words the chance of miscarriage was nearly twice the normal expectation for that group. Even then the risk of birth defect was not quite so high at 1.4. It could of course be that the women who had suffered miscarriage overeported (i.e. blamed) their time spent at the console. This is one of the dangers of using questionnaire techniques in epidemiology. But there were so many other questions on the sheet that this is unlikely. Another possibility is that the long exposed women were less mobile than the others and the lack of exercise was a contributing factor. Since the Goldhaber results were published substantial further studies have emerged to support their conclusions: "Our case-control study provides the first epidemiological evidence based on substantial numbers of pregnant VDT operators to suggest that high usage of VDTs may increase the risk of miscarriage. The implication of this finding is yet unknown. No biological mechanism has been postulated , nor has a clear pattern of risk been observed across all occupational categories. Our data do however suggest the need for further investigations". What can be done to avoid these hazards? Obvious, costless and immediate steps begin with siting the VDT itself so that it does not irradiate nearby personnel. Are you sitting with your back towards someone else's machine? Electric field strengths attenuate with the square of the distance, and magnetic fields with the cube. Thus if an electric field is 100 V/m one metre away from a source it will only be 25 V/m at two metres. Magnetic fields are more complicated than this because they have several components and vary in strength during any period of time.. Given the educated guess that an E-field of less than 10 V/m is relatively safe, and taking a lead from Guy's work, at two metres the average electric field from a VDT should be only about 8 V/m. Of course averages are always composed of higher and lower figures, and the only real way to know is by means of a field-measuring device. (The manufacturer of the VDT may be prepared to take these measurements in situ and advise you, especially if more equipment sale prospects are possible.) The other uncertainty is the age of the VDT itself. Bearing in mind that your own body is the other component of the potential difference between the VDT and you, it is a simple precaution to make sure you are yourself properly earthed. Nikola Tesla, who always wore thick rubber boots when working on his high voltage experiments, was also the world's first electrically sensitive person, and was constantly suffering from immune deficit, so that he would even polish his plate and use a dozen napkins at table for fear of germs. For the VDT operator the reverse is necessary: wearing natural leather soles, slipping your shoes off, or even a surreptitious wire clipped to the ankle and earthed while working are ways of ensuring that your electric charges do not build up. Do not forget the hook-up when about to leave! Further, the VDT should also be properly earthed for the same reason. Electric fields are relatively easy to shield. There are a number of anti-radiation devices or screens on the market, and the mail order computer companies offer an inexpsnsive selection. NoRad were fine screens and claimed superiority of protection over others in the market, and the screen protection is achieved by means of a black-coated very fine copper mesh which catches the electrons, which are then led to earth by a wire. Some screens have plastic cases, so it is never a bad idea to earth the screen separately. Which ever screen you buy, make sure it includes radiation protection and is not simply for glare. (the latter are obviously much cheaper, but this may be a false economy if you are incapacitated for a year or so, as some VDT operators are) Authors, who have to work in isolation, are particularly vulnerable to financial calamity from VDT irradiation. It is no accident that the President of the ME Action Campaign is Clare Francis, a former yachtswoman who took to writing best-sellers. After a couple of years in front of her VDU she developed ME. Another patron of the same Campaign is Melvyn Bragg, also prolific novelist, though it was his daugher not himself who becvame an ME patient. The back and sides of the VDT can also be shielded. In our catalogue I list a number of suppliers in the U.S., Canada , and Britain who can supply metallic fabrics, some adhesive backed, to cover the machine. Fortunately the Federal Communication Commission (FCC) members found that VDT radiations at radio frequency were interfering with their TV viewing, and instituted maximum permitted RF radiation levels. We pay more attention to our entertainment than to our health, it seems. A common health hazard for VDU workers is reepetitive strain injury or tenosynovitis. Bearing in mind the possibility that the myosin filaments in the muscles of the hands might be more affected by radiation and cause greater discomforting myalgia than the operation itself, it is worth putting a metal screen between the cathode ray tube and the keyboard, low enough to see the CRT over the top, but high enough to keep off any electric fields. Earthing this screen will improve its performance as a Faradic barrier. I discovered an old TV set with a bakelite case, and in disembowelling it in order to put in modern guts, I was surprised to see that its interior had been shielded with aluminium foil. I would not however recommend that you tamper with the inside of the modern VDT! Better to make sure that all new VDT purchases are of radiation reduced apparatus, and though this parameter is not often specified on the sales literature, the manufacturer will tell you quickly enough if a sale is in the offing. Ericsson's VDTs were designed in this way, and their present owners, the Nokia Group of Finland, who are one of Europe's leading VDT suppliers, have continued and extended this policy. By using a higher than normal refresh rate (70 Hz in character mode) the ELF frequency is kept away from the kind of frequencies near those emanating from the brain's own carrier frequency of around 4 to 20 Hz. I hope they will extend the same consideration to mobile phones, where they are also a leading supplier. Conventional monitors give out static electricity of 6kV against only half a kV by the screens above, magnetic induction of 88mT/s (against the > 25 shown above), and flux density of 270 nT, compared to about 50nT with the Nokia and Taxan screens. Nokia are now also producing liquid crystal displays with almost non-existent electric fields, which is the way the technology is going, especially since the footprint is so small (and takes up minimum desktop space). IBM too has lately started patenting low radiation screens and offering lower emissive products. Another means of E-field shielding is to use nickel-base acrylic paint (see list). The risk is that the paint cracks after drying, and it is more difficult to ground. Possibly also it is not cosmetic enough for smart modern offices! Magnetic field shielding by contrast is notoriously difficult if not impossible to achieve, though some VDTs have been balanced enough not to emit magnetic fields (or H-fields as they are sometimes known). We might learn from nature here: as everyone knows our blood contains iron, which is of course magnetisable. I have observed that the complicated structure of haemoglobin seems designed to prevent magnetisation of the haem's ferric material by curling the globin round it like four horseshoes, and then lining up the ends so that the opposite polarities are facing each other. I do not think that anyone have ever considered the complex structure of haemoglobin as designed for that purpose, but if so it would be in accordance with CMR theory: electified or magnetised blood would fog the brain's signals. Maybe something like that happens with the new kind of immune deficits we are now experiencing. Certainly for some reason the haem's iron, amounting to 22 mg in weight in the average body, is retained and little relinquished even though iron passes through the body in much greater quantities than that every day. A magnetic field is measured by a coil of a known number of turns of wire connected to a device which measures the current in milli- or nano-Tesla. Again there are variant measures such as Oersted, Gauss, and gamma but they need not concern us here.The magnetic field and the electric field when multiplied together usually give the total power density of an EM source. Which of these two components of EM energy is more biologically damaging is still the subject of debate and research, complicated because the magnetic field can pass through most substances, and re-induce an electric field as it changes in intensity. There are other less orthodox techniques claimed to reduce CRT radiation, which I will mention because there appears to be an element of truth in them. Even science should be entertaining. The first device is a large quartz crystal placed on the top of the VDT! I have observed that this does actually seem to absorb the E-field even though it is not directly in the way, and presumably it absorbs electrons or ions which must (again presumably) be washed out in running water every day. How such crystals can pull the ions from the front of the screen beats me, but the instruments show that they do. Early radio sets contained crystals which were capable of accepting the frequencies imposed on them, which were subsequently amplified. Another bizarre method is to place a certain cactus, Cereus peruvianus near the screen! Claims for its effectiveness come not only from Cirrus Associates, a former distributor, but also from Institut de Recherches en Geobiologie at Chardonne, Switzerland, whose spokesperson Blanche Merz, in October 1986 said: "We have distanced ourselves from a large number of protective devices, especially those which have had a lot of publicity. And yet the concern about coming to grips with the seemingly aggressive emissions from TV and computer screens besides the background radiation has always remained with us. "Even if coincidence is said not to exist, the ancient wisdom of nature has enabled us to make an important discovery three years ago on the high plateaux of Mexico: a plant is an effective antidote for the intelligent inventions of the human brain in those cases where technology does not concern itself with damaging side effects. "We have carried out a lot of tests in the meantime, so as not to come to any rash conclusions. For the greatest reliability the practical tests can be carried out using the Bovis biometer. For two years certain people in the U.S.A. have conducted blind tests on Wall Street: an approx. 40cm. high cactus was placed next to every computer screen. The employees who used to suffer from headaches and tiredness felt both physically and mentally, in top form afterwards." The Bovis Biometer mentioned is even more bizarre than the cactus, since it was invented by the man who discovered pyramid energy and managed to patent his device for sharpening razor blades under them. I would personally be interested more in the blind tests than the somewhat subjective measuring methods of Bovis! However one should keep an open mind on these things. After all, the humble aspirin is nothing more than a concentrate from the willow tree, and many pharmaceuticals are of plant origin, so why not EM protection devices? One can at least admit that cacti, which spend most of their life under the gruelling sun, - our most important source of electroamagnetic energy - might have developed techniques for absorbing its excesses. I look at the morphology of cacti in a new light these days: what are those little aerial-like spines for, anyway?! Are they emitting negative ions in compensation for the pos-ion emissions from the VDT or the sun? No one seems to be trying to make capital out of this little plant, and even if it doesn't work, it can do no harm to have a cactus by your screen. I have one here as I write, and it is quite comforting! However a quick check with the meters tells me that the E-field a foot away is about 10V/m and is modifed down to 8 V/m by the cactus (as it would be by any opaque object), whilst the H-field's vertical component is fluctuating around 50 nT minimum whether the plant is there or not. Another curious device or devices, for this is only representative of a whole class of neutralisers, is called the Cosmoton. Originally made in Germany, by Ordo-Stiftung a non-profitmaking concern, it is marketed in Britain by Hildegard Pickles of Leeds. The Cosmoton, like the Harmotron and others, is worn as a pendant. Since it takes between three months and a year to show its full effect, measurement of effectivness is not easy, but it was apparently developed by the same Dr H. Palm mentioned elsewhere, and originates with the multiwave oscillator developed by Lakhovsky against cancer. It seems to consist of seven horseshoe-like rings of diferent gold and silver metals like the planets. It requires no battery, being "charged from the cosmos". I do not intend my tone to sound mocking: the ancient Greeks wore crystals round their necks in similar fashion, and our word "cosmetic" comes from that practise, which was said to keep one in tune with the universe or cosmos. "When the cosmoton is worn on the chest or placed on the TV or VDU screen", says the sales pamphlet, "it helps by protecting children and adults in tolerating the radiation of the screen far better without ill-effects.. .The diameter of the effect is about two metres". Again I doubt whether such a device can do any harm, and might be a fairly attractive adornment. It looks like a miniature multiwave oscillator, invented by Lakhovsky after an idea by the great Tesla, who also strayed for a while into medical electronics, and did rather nicely out of it, unlike many of his schemes. Regarding Lakhovsky, he comes nearest of the earty twentieth century scientists to understanding radiobiology, and was in fact a pupil of D'Arsonval, one of the best 19th century biophysicists, who praised his research. Lakhovsky's multiwave oscillator is still being manufactured today, and is, like Konig's horseshoe, a series of open oscillating circuits which, he claimed, will cure cancerous conditions. In a previous work (The Dark Side of the Brain) I showed photographs of cancers cured in this way. Some millionaire ought to put up funds for proper scientific research of these concepts, for until they are replicated no one can say if they are effective. Given the seriousness of cancer incidence today, the venture would at least settle the issue, and might even lead to a great scientific breakthrough. It may appear like stating the obvious, but another form of protection is simply to avoid working at the VDT for more than two hours a day or less. No research has ever found that such levels of exposure are hazardous. A quiet and informed discussion with a reasonable and caring boss could well lead to altered work schedules designed to accommodate such exposures. That way no one gets saddled with overexposure at the possibly dangerous levels of 20 hours and more. Another device on the market is a protective jacket called the Microshield (not to be confused by the pouch of the same name used to reduce mobile phone radiations).. This jacket attracted some flack from the NRPB on British television, but the attack itself was unfair in denouncing the manufacturers' claims. They had not claimed that the jacket could stop magnetic fields, which is what the NRPB demonstrated. On the other hand the wording in the firm's literature was imprecise, because they referred to electromagnetic fields, when they should have said electric fields. Accordingly they deserved a certain amount of critical treatment. The jackets do not protect the face and more important the brain of the operator, which is where I personally think the trouble starts. The jackets will certainly reduce the radiation levels from E-fields. the question is, however, whether it is the E-fields or the H-fields which do the damage, or both, and the NRPB ought really to be finding out the answers, rather than just quoting a few selected negative reports, and following blindly the American guidelines. From Switzerland comes A-Nox, another curious device which consists of two translucent spheres containing "rare earths", which are placed diagonally on either side of the screen frame. They need no power supply. The constituent elements are claimed to enter into resonance with the electromagnetic field of the cathode tube of the screen and "generate an energy field acting as a magnetic shield for the operator's protection". Jacques Surbeck, who markets the device world wide, produces test results claimed to support his product's efficacy. Unfortunately he omits to say who carried them out, a vital piece of information I would have thought. If the pedigree of the testing laboratory were found to be acceptable, the results would certainly justify the use of A-Nox devices, despite their price. However I could not find any diminution of the E- or H- fields with my own equipment. Perhaps the most bizarre protection device of all those offered the concerned VDU operator is a plastic card, called the Charge card. This looks like a bank credit card with some small circuits on it. The user is supposed to charge the card up with his or her own vibrations, though I cannot see how it works from inside a handbag or wallet! There are also various kinds of pulsing devices available, such as Biomag and Mecos, which are unfortunately quite expensive. These claim to offer protection from noxious rays by pulsing out a steady protective EM pulse, presumably thereby acting as a carrier wave for the body's own signals,. I have no opinion on them since no-one has ever established blind trials of their effectiveness. To protect the brain of a VDT operator from E-fields some kind of veiled head gear is necessary. However, fashion and human self esteem being what it is, it is unlikely that any operator will wear such a covering until it becomes acceptable behaviour, like hard hats on a building site, welding visors, or motor bike crash helmets. The hazard is so invisible and long term that few will be prepared to pioneer the idea. More sensible in the short term is a pair of plain glass spectacles, which at least will shield the eyes from the UV component of the radiation, and lessen the risk of cataracts. Ferrous metal frames are not a good idea, since they concentrate magnetic fields. Noble metals are better, but so many spectacles have plastic-coated ends that a static charge could build up in the unearthed metal and might cause a headache. Finally one should be aware of negative ionisers as a way of limiting the positive ions discharged from VDT screens: some operators complain of blotchy faces after working on the VDT, and this may be due to the impact of pos-ions on their mildly negatively charged facial skin. A negative ioniser will lessen this risk. Really the biggest protection of all is simply being aware of the hazard. Believe me, there are plenty of cautionary tales to tell of VDT operators who have been seriously debilitated. For example, a president of the M.E. Action Campaign was an author Clare Francis who was smitten with this dreadfully debilitating "Yuppie Flu" after having sat down at a VDT every day for several years to write her novels. I gather that after changing the computer to a low radiation version she is now much better. Fortunately myalgic encephalomyelitis seems to be reversible, unlike the more serious immune deficits, which may also be the result of radiation. The Radiation Safety Corporation of Palo Alto, California, a private firm, can supply prepaid x-ray monitoring tabs, called On-Guard, which you wear for the allotted time and return for processing and analysis. Each test cost (in 1990) about $35, though there were discounts for bulk. As a way of influencing your employer to do something about possible VDT hazards it might be a good idea to try one, especially since according to the firm, "a recent Food and Drug Administration Study (report No. 81-8153) found that one out of twelve normal appearing computer monitors emitted x-rays in excess of the federal safety limit". Unfortunately the limit applies only to monitors which can display a picture. Thus VDTs without graphics are outside the juridiction of the legislation. Eventually the problem of VDTs may simply go away: quite rapidly a new kind of screen, using liquid crystals is arriving on the market place which gives off very little radiation. Currently more or less confined to lap-top computers, as the technology and volume gets underway, the liquid crystal screen will supplant that bulky old CRT on your office desk, and give off very little radiation in use. |