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EMFs and Health - the history up to 2000

Science index » Overview | Article library | List of studies | Basic guide to EMFs | International guidance levels | Unit conversion | Frequently asked questions | Other resources

In recent years electromagnetic radiation has been implicated as a contributory factor in a variety of adverse health effects. These range from skin cancers due to exposure to increased levels of ultra-violet radiation from the Sun because of the thinning of the ozone layer, through various childhood and adult cancers (especially childhood leukaemia) due to power line magnetic fields, to such things as cases of clinical depression and 'Cot deaths'.

Investigating 'man-made' EMFs

Initially most research was done investigating the effects of time-varying electric fields, though in the last ten years the effort has concentrated on power frequency magnetic fields. They are probably both involved in some, or all, of the reported effects, and later in this chapter we look at some of the suggested ways in which they can interact with our bodies.

Some extensive reports on the subject and detailed reviews of the literature have been produced by such organisations as the U.S.A. Environmental Protection Agency (EPA), the National Institute of Environmental Health Sciences (NIEHS), the World Health Organisation (WHO), the U.K. National Radiological Protection Board (NRPB) and the International Radiation Protection Association (IRPA).

There have been thousands of laboratory studies, both on isolated cells, animals, and occasionally, people. These are primarily to try and identify possible interactions and effects of electric and magnetic fields on living systems, and to try to test hypotheses about how the effects could occur.

Both 'in vivo' (i.e. in the living organism) and 'in vitro' (e.g. in a test-tube) studies have been done. Many of them have actually injected electric currents using implanted electrodes, or used simplistic magnetic fields. Given the latest ideas as to possible mechanisms of interaction, it is unlikely that those studies will be able to tell us much about real life EMF-life interactions. Many of the magnetic field experiments, assuming that the larger the field the greater the effect, used fields considerably above the 300 nT levels that are now being implicated by the field epidemiological studies. Virtually none of them allowed for the background static geomagnetic field or ac electric fields in the laboratory these could be the main reasons why it has been so difficult to replicate and confirm the work in other laboratories.

The results are often confused and apparently contradictory, though this can often be traced to the way the work has been planned and carried out. There are so many different parameters which can affect the outcome of the experiments and it seems that work is rarely repeated under exactly the same conditions.

Epidemiology is where the health of individuals in populations are studied in order to try and identify possible causes of ill health. There are two main types of study. The first, and the more common in EMF research, is the case-control study, where the EMF exposure of people with a particular health problem (cases) is compared with the exposure of similar people in similar places without the same health problems. These have been used to study headaches, depression & suicide, birth outcome, but mainly childhood cancer. This is because it is (relatively) easy to study childhood cancer as the medical records are quite good and children are not usually exposed to many carcinogenic hazards.

The other main type of epidemiological study is the cohort study. This is where the general health outcome of an exposed population is compared with either a matched group (e.g. a similar village), or with the general population's health record. Cohort studies tend to be more difficult to carry out and analyse, although they offer the chance to pick up a variety of possible adverse health effects. Very few residential EMF exposure cohort studies have been done, although a number of occupational ones have.

There are hundreds of published studies, the results of many of which give us cause for concern.

Extremely Low Frequency Studies

This includes power-line fields and ELF pulsed radio-frequency and microwave signals.

Professor Ross Adey of the Loma Linda University Medical School in California has been researching electrical bio-effects for over 35 years. He was previously Director of the NASA Space Biology Institute, Professor of Anatomy & Physiology UCLA, Founder UCLA Brain Research Institute, and a member of the National Academy of Science Committee studying the bio- physical effects of the Seafarer ELF Communication System.
Regarding the possible adverse health effects of ELF fields he stated in 1992:
"As far as the science itself goes, I think that there are four major areas about which there can be very little doubt as to the significance of the findings:

  1. The effects on the immune system. A reduction in the ability of the circulating white blood cells to kill tumour cells. This has been shown in cell culture work and partially corroborated in animal studies.
  2. Effects on fetal development. There is evidence not only of fetal abnormalities but also in psycho-sexual development. Epidemio-logical work has shown evidence that miscarriages may be linked to electrical blanket use and some electrical home heating systems.
  3. The area of the control and regulation of cell growth, including tumour formation.
  4. The effects on the central nervous system and the brain in the ways which affect very powerful hormonal mechanisms, which in turn have connections to cancer and cancer related problems.

The work is being conducted in many laboratories world-wide so that the old fiction that this research describes uncorroborated experiments is no longer true. The most significant finding is, I believe, although many of the effects can be seen from the fields alone, they appear to be strongly synergic with chemical factors. Some known chemical promoters are significantly enhanced in their action by the presence of power-line frequency magnetic fields. This may be a pointer to the clustering of cases, where there may be a common chemical factor as well as the magnetic fields.

The chemicals which seem to be the problem are those which work on cell membranes, and not on cell nuclei. The concept of cancer arising from damage to DNA is now being supplanted by a different view of what the tumour problem really is; that it is a problem at cell membranes where the electromagnetic fields and these chemicals act together. I think that 'conclusive' is too strong word to describe the evidence, but I think that the evidence is very strong that there is this relationship. In consequence, as a matter of public policy, I think what Granger Morgan at Carnegie Mellon University has suggested, namely that Prudent Avoidance be part of Public Policy is a very necessary way to tackle the problem. This implies not putting power lines over peoples' heads, restricting the access of builders to vacant land next to high-voltage power lines, and specific avoidance of school sites as a matter of public responsibility.

I think that the British authorities' reaction is a living dinosaur attitude, that it absolutely avoids confronting the evidence as it now exists. The NRPB, however, is doing work of the highest merit in its scientific content, and it indicates that there is reason to be concerned."[8]

The start of awareness about these issues

In the West the story really starts in the 1960s. Work in these areas has often been funded directly or indirectly by the military or large firms with vested interests. Controversial work is often classified, stopped, or planned in ways which minimise the chances of detecting statistically significant risks. In fact much of the initial informative work was done personally by the researchers in their own time and with their own money. It is hardly surprising, then, that official bodies can voice the criticism that the work hasn't been done on a sufficient scale with sufficient controls. Let us consider some specific examples.

Microwaves and eyes

In 1964 Dr. Milton Zaret was one of the first scientists to speak out about the dangers of microwave radiation and ocular effects. According to Zaret, exposure to EMF radiation at either thermal or non-thermal levels can cause cataracts which sometimes remain latent for months or years. Zaret then had his laboratory research funds cut off. "Now that's a very strong signal to everybody else in the field" says Zaret in the 1984 Central TV documentary "The Good, the Bad, and the Indefensible" [9].

Project Sanguine

One of the early bio-electromagnetics researchers is an author of two of the books in our recommended reading list, Dr. Robert Becker [4][10]. He started medical research work in 1947 and went on to become an eminent orthopaedic surgeon and research scientist. He was twice nominated for a Nobel Prize for his pioneering work on healing bone fractures and oedemas with externally applied ELF electromagnetic fields.

In 1963 he also showed that there was a relationship between psychiatric illness and magnetic storms. In 1973 he was appointed to a secret Navy civilian advisory committee to assess the environmental impact of Project Sanguine, a planned large scale ELF (45 & 70Hz) submarine communications system.

This committee was presented with a corpus of data generated by some twenty or so programs run or funded by the U.S.Navy which contained enough data to indicate that there were biological effects which were potentially hazardous to human health. The frequencies were 45Hz and 75Hz and, after considering the evidence, the committee unanimously felt that major segments of the American population were "currently at risk" from 60Hz power-line fields, and went on record to recommend that the White House be advised of the possible significance of their findings.

Shortly afterwards Becker became aware of a plan to erect ten new high-power lines in New York State, so he wrote to the N.Y. Public Service Commission to suggest that they contact the Navy and get some details of the Sanguine studies. He even provided a senior contact name and telephone number, but the Navy denied that any such reports, or even the committee itself, existed! One of the chief researchers for the Navy to whom Dr. Becker had been talking was Dr. Deitrich Beischer at the U.S.Navy's Pensacola Research Labs. Becker tried again to contact him and was told that the Labs. did not know of such a person. It was subsequently shown that he had been prematurely retired and all his work in this area classified. Dr. Beischer had been one of the U.S.Navy's principle investigators since the late 1940's.

New York State Power Lines Project

The result of this was a lengthy series of public hearings, called the New York State Power Lines Project (NYSPLP) at which Dr. Becker decided to testify, which concluded with a five-year moratorium and a $5million series of studies. The power companies, supported by the federal government, had an interest in seeing that the hearings, if at all possible, did not take place, or if they did, that the result cleared electromagnetic fields as providing no health hazard. The line was given the go-ahead.

To quote Dr. Robert Becker subsequently: "Now it's impossible for me to prove this, but the coincidences in time and place are too evident not to believe that there was a relationship with this public hearing. Prior to my involvement with this public hearing I was supported by several granting agencies to do my research work. I had access to the scientific literature so that my papers could get published in the appropriate journals. Following the opening of the hearings we lost every research grant that we had. In addition we were subject to administrative harassment by the agency for which I was basically working, the United States Veterans Administration. The entire circumstances were apparently designed to diminish my enthusiasm for proceeding with these public hearings" [9]. Becker's crime was to establish a clear link between power lines and health hazards. His punishment was scientific exile. After some digging for information he discovered that pressure to remove him had come from high up in the Department of Defence".

He writes: "I want to tell the public about it because it makes me furious. I want the general public to know that science isn't run the way they read about it in the newspapers and magazines. I want lay people to understand that they cannot automatically accept scientists' pronouncements at face value, for too often they're self-serving and misleading. The way science is currently funded and evaluated, we are learning more and more about less and less, and science is becoming our enemy instead of our friend."[10]

Wertheimer and Leeper

Around the same time (1974) Dr Nancy Wertheimer started working on her own, using her own funds, to investigate childhood cancer clusters in Denver, Colorado. She soon noticed that many seemed to be close to electrical pole-mounted transformers. During the next few years she, and an physicist friend Ed. Leeper, collected data and measurements. They eventually had their paper published in the prestigious American Journal of Epidemiology in March 1979 [11]. Their work was ridiculed by the scientific and medical community who said that there was no known mechanism by which such low levels of magnetic fields could possibly affect human health. This attitude was supported by the electricity utilities.

Some supportive evidence came from a Swedish study by Dr Lennart Tomenius [12]. He started his work in 1979 and presented some preliminary findings at a conference in June 1982, although his final Report was not published until 1986. He had measured the fields at the entrance door to the residence of the children, and found that for fields over 300 nT (3 mG) the chance of getting cancer was more than doubled. For brain tumours the increase was almost four-fold (Odds Ratio = 3.86).

The N.Y. State Power Line Project studies mentioned above include one by Dr David Savitz. He announced his preliminary results in November 1986 which showed "prolonged exposure to low-level power-frequency magnetic fields may increase the risk of developing cancer in children". Indeed Savitz not only found a statistically significant association between all types of childhood cancer and external magnetic fields, but also determined that children living close to high-current wiring had a five-fold increased risk of developing cancer. His final Report was not published until 1988 [13]. This showed almost a doubling (1.93) in childhood leukaemias at fields above 200 nT. Indeed the 1987 NYSPLP report points out the possibility that 10 to 15% of all childhood cancer cases in the U.S.A. might be attributable to power frequency magnetic fields of around 250 nT (2.5 mG) and above.

Some U.K. epidemiological studies

Before privatisation the U.K.'s Central Electricity Generating Board (CEGB) sponsored two main studies.

The first, called "Overhead Power Lines and Childhood Cancer", done in conjunction with the University of Leeds and Cockridge Hospital, Leeds, was first published at an IEE meeting in December 1985 [14]. This is the only study they have published following up the work of Nancy Wertheimer et al, and it has very significant shortcomings. The Wertheimer and Tomenius studies are quoted as the background to the Leeds study and so it would seem sensible to include some areas where the background 50 Hz magnetic fields were likely to exceed 250 nT.

Looking at the data presented in the report we find that the magnetic fields were only calculated by computer modelling of the overhead power lines, and were not actually measured. This seems specifically to exclude locally generated fields. Secondly, that out of the 376 case and 590 control children included in the analysis, 361 cases and 567 controls were below 10 nT, a further 9 cases and 15 controls were in the range 10 nT to 100 nT, and only 6 cases and 8 controls were in calculated fields above 100 nT.

If we take the one figure suggested that 15% of all childhood cancer cases may be due to fields of 200 nT or above, and allow that the six cases were, in fact, in fields over 200 nT, and that we had an ideal sample, then the researchers were ONLY likely to have included 0.9 case in their survey! The conclusion that "within the bounds of the present analysis, there is no apparent relationship between overhead power lines and childhood cancer" was therefore to be expected.

The CEGB Chief Medical Officer at the time, Dr John Bonnell, is on record as saying: "At the present time I do not believe any action is justified. If we accepted the dangers it would mean an enormous turn about for industry and for the country as a whole. There are no contingency plans to cope with such a turn about. If there are any effects at all due to exposure to electric fields then they are slight, and it is certainly extremely difficult to disentangle them from other causes of ill health."[9].

The above study has been repeatedly used to claim 'a clean bill of health' for overhead power lines. The study was based around calculated fields from high voltage power lines so as to exclude the effects of street and house wiring. In other words, it was only designed to try and detect a link between childhood cancer and high voltage power lines, rather than actual 50 Hz EM fields.

The C.E.G.B. sponsored U.K. studies assumed a very low background 50 Hz magnetic field level of 10 nT, and only used calculated levels due to overhead electrical lines at the birth addresses. National Grid now recognise that 60 nT is a more typical background level, and measurements suggest that a significant proportion of the U.K. population live in 50 Hz fields approaching or exceeding 100 nT, with people living near high power feeds being subject to fields up to 25 mT (25,000 nT).

In fact the study does comment on a sample of 44 properties, not otherwise included in the study, where the house internal magnetic fields were measured. The highest field of 130 nT was reported as being due to a neighbouring overhead local power line and not a high voltage transmission line and so it would have been assessed as having only a background field of 10 nT. This agrees with typical levels measured by the author, Alasdair Philips, some details of which are given in the next chapter. A 1990 CEGB paper [15] also supports the view that local distribution cables are a major source of domestic magnetic fields. This means that many houses which the study has assumed to have only background levels may well have had quite high magnetic fields.

A second study [16] of adult leukaemia and allied diseases, covering Yorkshire and part of Lancashire, suffered the same methodology, only using magnetic fields calculated from high voltage transmission lines [17].

The childhood study was extended and re-analysed [18] and it was admitted that: "This study stood no realistic chance of detecting any raised relative risk associated with a field of more than 100 nT".

In January 1992, Dr. David Jeffers, speaking for National Grid, publicly stated: "We have a number of strong players in this program. We have had what you call epidemiological studies, carried out in Yorkshire, of how childhood cancer correlates with the fields in the houses and how close the houses are to power lines, and the answer was 'no', we did not find a correlation in Yorkshire. A similar study of adult leukaemias, carried out in Yorkshire and Lancashire, also did not find an association." [2]

It is difficult to see how these studies can be described as 'strong players', other than as part of a planned "effort to put their fears to rest".

Some other epidemiological studies

One Swedish study by Feychting and Ahlbom [19] drew their subjects from corridors of land beneath Sweden's network of high voltage pylon lines and they found that between 1960 and 1985 around 500,000 people had lived within 300 metres of the lines.

They calculated that children younger than 15 were 2.7 times more likely to contact leukaemia when exposed to magnetic fluxes greater that 200 nanotesla and 3.8 times when exposed to 300 nT. These figures agree very well with the earlier Wertheimer and Savitz ones. The field levels are about 6,000 times less than the current UK limit.

Further Nordic studies were published in 1993 and a combined analysis supported the link between ELF magnetic fields and childhood leukaemia at field levels above 200 to 300 nT [20].

There are a number of other studies which indicate other illnesses e.g. headaches, depression, suicide, myalgias, asthenias, leucocyte count disturbance leading to impaired immune response, etc.

An American study showed a statistically significant doubled elevation of headache and depressive symptoms among populations living within sight of power lines. Another study has shown up to a five-fold increase in risk of miscarriage among women who use electric blankets [21], which is the fifth report to show that EMFs can adversely affect pregnancy.

Initially when Dr. Stephen Perry started investigating the possible relationship between power lines and suicides and clinical depression in the West Midlands, the C.E.G.B and local Electricity Boards were extremely helpful and provided copies of their maps showing the power lines. When he told them that there were three times as many suicides as there should have been in the urban roads that carried their heavy underground cables they stopped giving him any more information. When the study was published it showed that people living in high magnetic fields next to power lines were 40% more likely to commit suicide [22].

Dr. Perry went on to do a second study of the distribution of illnes in multi-story blocks of flats in Wolverhampton [23]. Here he found that in blocks where there was underfloor or electric storage heating systems, the proportion of cases of depressive illness living in the flats nearest to the main cable duct rose to a highly (P = 0.013) significant 82% of cases of depressive illness admitted to hospital from such blocks.

In a third paper [24] he investigated, in 1985, all the admissions to hospital from Wolverhampton for myocardial infarct (600) and depressive illness (359), with regard to the measured magnetic field levels at the patients residential address. He found a significant (P=0.033) correlation between higher magnetic field levels and cases of depressive illness, but not for myocardial infarction.

Public money has not been forthcoming to replicate Dr. Perry's work on depressive illness which, if the asscociations it found are real, point to a much more significant public health problem than childhood leukaemia, which although devastating for the people concerned, is actually quite rare. Dr. John Dennis, while Assistant Director of the NRPB issued a statement in 1989 which includes: "if the link is real then EM fields may be responsible for upto 15% of all childhood cancers, but as childhood cancer is a comparatively rare disease the increased risks, if real, are within the levels generally regarded as acceptable."

ELF epidemiology conclusions

There have now been many ELF epidemiological studies published. Overall, the results are varied and inconclusive, though the vast majority have shown increased risks of ill health with increasing ELF EM field levels. In particular, the childhood cancer studies have pointed fairly consistently towards a two to three fold increase at levels of 200 to 300 nT. All the studies can be criticised on the basis of low detection power and questionable surrogate measures of exposure, which would give rise to a considerable under-estimate of the level of risk.

In fact most of the studies have only calculated the magnetic fields from high voltage transmission lines and assumed a relatively low ambient background field in all other houses. Some have only directly used distance from these lines and/or from substations. As we attempt to show in the next chapter, firstly it is almost impossible to calculate the field with any degree of accuracy with the available data and, secondly, the ambient field level in many houses is dominated by the fields from local distribution cables and can be up to 1000 nT, or more. It is surprising that, with these two sources of error alone, that the studies have almost all shown small raised levels of risk, and suggests that the real increase in risk with ELF EMFs is likely to be much higher.

Recently Dr. Nancy Wertheimer, the epidemiologist working in this field since 1974, made a number of comments about survey work [25]. She suggests that because most studies have not checked that their control groups actually do live in a low exposure situation, they are like those that compare people who smoke 2.5 packs of cigarettes a day to those who only smoke two packs. She goes on to say that evidence suggests that the critical period is between one and two years before diagnosis. Just using the birth address, as done in the U.K. study, will therefore lead to invalid data.

Part of the reason for these limitations is that much of the work has only been designed to see if there is an increased risk of childhood cancer with proximity to high voltage power lines. In fact the real question, of whether there is a relationship between ELF EM fields and adverse health effects, is not really addressed in a meaningful way by these studies.

Confounding factors

Another, very puzzling, omission is that virtually no studies have measured the relationship between the man-made fields and the Earth's geomagnetic field, even though a number of the more likely resonance theories are based around these inter-relationships. This seems most odd, because it is usual to start out by designing a study methodology in order to investigate the validity, or otherwise, of any of the suggested mechanisms of interaction. This is to try to reduce the number of 'confounders', which are variables that are likely to affect the phenomena that are being studied. Socio-economic class, housing density, traffic density, cigarette smoking in the house, local climate, race, etc., are typical examples of these. As the Earth's magnetic field strength and direction in relation to the ELF fields are fundamental to the suggested resonance mechanisms, it seems essential to collect this data.

It has been suggested that given the nature of the data (relatively few cases in populations of varying size), that the "rate per thousand" is not the most revealing method of ranking. In these cases it is often better to use the Poisson probability. This tests the important question as to whether the observed incidence in each community group can be explained by chance or by the likelihood that the observed cases have a common cause. It is not evident that this has been used in any of the published epidemiological studies.

Other health effects

The major studies have concentrated on cancers. In view of the fact that the effects may well be due to a general lowering of the body's overall immune competence, it would seem appropriate to carry out various cohort studies looking at all health aspects of exposed population groups living under or near large power lines, and comparing the data with that for similar populations which are not near major EMF sources. It would be necessary to actually record the fields in each study person's home with a data logger in order to get a good exposure assessment. This would need to include the geomagnetic data discussed above.

Such a study would also be able to follow up Dr Stephen Perry's work linking power-line magnetic fields with clinical depression and suicide. The NRPB have described this as interesting but having flawed methodology. For some reason they have chosen not to encourage or sponsor a better study, although clinical depression is actually much more of a major public health problem than childhood leukaemia is. There is also a suggested way EMFs could affect this condition via pineal melatonin & serotonin, which we discuss later. In March 1991 at the 'Doll Report' Press Conference, in reply to a question regarding Dr Perry's work, theNRPB Director, Professor Roger Clarke, replied with: "Depression and suicide are not in our scheme of things".[26]

Pulsed Radio-frequency and Microwave Studies

Until relatively recently, the general public has not generally been exposed to significant levels of higher frequency EMFs, unless they live near a major civilian or military transmitting site.

Research in this area began to emerge in the 1960s, mainly as a result of Russian work. This led the Russians to develop a standard for public exposure to microwave and RF EM fields of 10 mW/cm2, which was 1000 times lower that the limit of 10 mW/cm2 in the West. Current U.K. 'restrictions' (Investigation Levels) rise from 0.66 mW/cm2 at 12MHz up to still the 10 mW/cm2 level at microwave frequencies [27].

Dr Stanislaw Szmigielski reported [28] on a five year retrospective study of Polish military personnel exposed to RF and microwave fields at work-day levels below 200 µW/cm2, the Polish 'safety level'. The highest risk appeared for malignancies originating from the haemato-lymphatic systems, with a death rate raised about seven-fold. Other common neoplasms were located in the alimentary tract and the skin. An ongoing study of the same group showed a continuing, highly statistically significant, increase in the incidence of all forms of cancer.

A study of cancer in the Swedish electronics industry also found significantly elevated incidence of cancers [29]. Sam Milham, in the U.S.A., studying a group of amateur radio operators, found a significant excess of deaths due to acute myeloid leukaemia, multiple myeloma, and non-Hodgkin's lymphomas [30].

A number of people have found increased eye cataract problems associated with low levels of RF exposure and with extensive VDU (computer screen) use.

In Britain the Royal Signals Research Establishment, at Malvern, has had a brain tumour incidence over six times the national average.

In June 1993, in an unprecedented move, a military research laboratory in the U.S.A. unilaterally declared a 100 µW/cm2 limit for 30 MHz to 100 GHz. Dr Cletus Kanavy wrote [31]:
"The biological effects of microwave radiation on living organisms have been the subject of extensive research for the past four decades. The most comprehensive programs were conducted by the Soviet and Eastern Bloc nations. The U.S. research community was aware of the Soviet findings of deleterious biological effects at exposures well below the (U.S.) ANSI standards. The Soviet findings were rejected for various reasons." "The literature published in the late 1980s is abundant with information on non-thermal effects which are produced at levels below the ANSI standards." "The principle electromagnetic biological effects of greatest concern are behavioural aberrations, neural network perturbations, fetal (embryonic) tissue damage (inducing birth defect), cataractogenesis, altered blood chemistry, metabolic changes and suppression of the endocrine and immune systems".

One of the concerning issues is an apparent breakdown of the blood-brain barrier, allowing blood-borne toxins into the brain.

A large amount of data exists, both experimental animal data and human clinical evidence, to support the existence of chronic, low-level field exposure, non-thermal effects at levels below 100 mW/cm2.

The heads of users of cellular telephones will experience levels above this, as will the bodies of operators of hand held radar speed meters. Cellular telephone masts are now appearing on and near residential housing in the U.K. Many schools in the U.S.A are now banning them on their property.

Possible mechanisms

Scientific acceptance of the ELF interaction has been hampered by a lack of a believable mechanism. The way that the biological and physical sciences are separately taught has also hindered understanding.

However this, in itself, should not be a barrier to introducing restrictions to exposure. We still do not know the actual mechanisms by which cigarette smoking, asbestos fibres or DDT cause cancers, but we have accepted the epidemiological evidence and have introduced laws to limit or reduce human exposure. Electric and magnetic ELF fields induce currents in living tissue. The basis of most interaction models has involved cell membrane field changes which then affect the cell.

Free-radical interactions have also been implicated, particularly in regard to the actual initiation of a cancer. It has been repeatedly shown that once a cell has become deranged then the potential tumour is more likely to develop, and to develop more quickly, in the presence of low levels of ELF magnetic fields.

Indeed, in the author's view, it is much more likely that low levels of ELF fields are a hazard because of their effect of reducing the immune system's competence at dealing with problems, rather than actual direct cell damage.

A number of possible resonance mechanisms have now been proposed to explain how low levels of low frequency electric and magnetic fields could affect biological processes. The most promising of these seem to involve interactions which appear to occur at ion cyclotron resonance frequencies. Complex nuclear electro-magnetic resonances require a steady background magnetic field combined with either an oscillating electric field applied at right-angles to the background field, or an oscillating magnetic field applied parallel to the background magnetic field. The magnitudes and relative directions of the two fields are a critical factor in the resonance conditions.

The magnitude of the background 'steady' field sets the resonance frequencies which need to be applied - the actual strength of the alternating field does not have a linear relationship with its effect. There is likely to be a threshold level below which the energy which the alternating field adds to the resonant particles is inadequate to produce a measured effect. There will then be a band where the effect will increase, and there will come a point where the alternating field dominates the particle's environment and the resonance conditions will then practically cease to be effective.

Just as a radio receiver can be used to detect and decode a specific signal at an intensity below background noise, there is considerable evidence that coherent time-varying fields which coincide with natural cellular resonances can have biological effects at very low levels. Resonances are likely to be activated at their fundamental and harmonic frequencies.

In 1982 Dr Jafary-Asl, at Salford University, reported that yeast cells displayed various complex resonances which depended on both the steady background magnetic field acting together with smaller alternating magnetic (or electric) fields. The advantage of NMR (nuclear magnetic resonance) or other complex electromagnetic resonances being the activating cause basis of cellular interactions is that the energy in the field is concentrated on specific charged particles or ions and this would give a feasible and scientifically acceptable mechanism of interaction.

In 1985, both Dr Carl Blackman of the US EPA, and Dr Abe Libhoff, working independently, integrated Jafary-Asl's ideas with attempts to explain Bawin and Adey's experiments which showed such cellular responses as calcium ion efflux when living nerve cells were exposed to ELF fields. When other labs had tried to replicate the work they found the similar calcium ion efflux but at different ELF frequencies. Blackman & Libhoff found that they could mathematically relate the frequency required to cause calcium efflux from cells with the local geomagnetic field in the laboratory. Dr Libhoff, and others, have shown that cell mitosis (division) can be speeded up by applying ELF fields, and the likelihood of genetic errors increased.

One theoretical mechanism, originally described as ion cyclotron resonance, has gained support [32]. This relates the motion of electrically charged particles to the magnetic fields surrounding them. A number of the ions in blood are in the critical mass range for resonance in the Earth's geomagnetic field and an alternating field between 25 and 500Hz. Power-line fields together with the Earth's geomagnetic field can provide resonance conditions for Calcium, Sodium, Lithium, Potassium, hydroxyl and hydronium ions in an aqueous mix [33], all of which play key roles in living systems [34]. Calcium ions have a powerful effect on human cell membrane function and affect physiological processes such as muscle contraction, egg fertilisation and cell division.

Unfortunately the use of the word 'cyclotron' has caused some confusion, as it is not classical cyclotron resonance. Calculating the likely resonance frequencies is difficult because ions in an aqueous environment have attached numbers of water molecules which will reduce the resonant frequencies. A number of fairly similar models have been proposed, one by Lednev [35], and another by Drs. Male (Nat.Grid) and Edmonds [36]. Drs Jafary-Asl and Smith of Salford University have also proposed a relevant quantum magnetic resonance model [37]. Although all these models show how ELF fields could explain some cellular observations, they do not necessarily mean that these effects will have human health implications.

Dr John Male (Nat. Grid, ex CEGB) has published a paper describing one of these complex resonances which he calls 'ion vibrational precession occurring at the Larmor frequency' which is affected by fields which satisfy the above 'cyclotron' resonance conditions [38]. He points out that although this is a possible interaction mechanism there is no reason to assume it would produce adverse health effects.

A clear example of how modern medical physics uses NMR is in the NMI scanners which can now be found in most major hospitals. Here they apply very high steady magnetic fields and correspondingly high radio frequencies in order to obtain the fine detail that they need, but the principle is exactly the same. Hydrogen nuclei in cancer tissue return a different signal to ones in normal healthy tissue. This is just the same sort of resonance as is discussed above.

While the effects of these complex resonances at the level of ions and molecules may be significant, the resulting changes in the structure and functioning of the cells is likely to be far more important as regards the possibility of causing adverse health effects.

To our knowledge, only one study has actually looked with some detail at these issues. This is in a retrospective analysis of a previously published study carried out in Los Angeles County, U.S.A. The original study [39] was published in 1991 and had looked at 232 leukaemia cases in children under the age of 10 between 1980 and 1987, 128 of which had also had their home's static magnetic field measured although not used in the analysis. As originally reported the study had found a statistically significant 115% increased risk of childhood leukaemia associated with proximity to high current cables, but not to measured magnetic fields.

Dr Bowman, wanting to investigate the resonance theories, calculated that there would be two resonance bands which fell into the Los Angeles conditions. Only 46 of the original 128 cases, for which the value of the static magnetic field was known, satisfied his theoretical resonance conditions. He found that the data showed an odds ratio (OR) of 2.4 for cases who lived in average fields from 70 to 140nT, rising to an OR of 6.0 for children exposed to background ambient fields above 300nT. This compares with the original analysis of the data which ignored the static field level and did not find a leukaemia/ELF magnetic field asscociation. His study was limited by many factors, but shows evidence of the need to include this important extra information in epidemiological studies. "This is the way to the future", he said.

Since before seeing Dr Bowman's results, the author (Alasdair Philips) has repeatedly called for the strength and direction of the background static field to be measured in relation to the power-frequency electric and magnetic field strengths. It would be normal scientific practice to include the measurement of all parameters which are implicated in any of the proposed mechanisms of interaction of the phenomena being studied. It is difficult to understand why this has not been done in the epidemiological work done to date, nor has it been included at the time of writing this (February 1994), in the Protocol of the latest UKCCS childhood cancer study.

Another hypothesis shows how electro-magnetically altered spin states in haemoglobin molecules can produce a significant net magnetic moment. This would attract and trap lymphocyte cells, significantly impairing the immune system response [40].

The Pineal connection

Deep in the centre of our head we have a tiny, pea-sized, pine-cone shaped pineal gland. Some early philosophers considered it the "seat of the soul". Until fairly recently the gland was considered a fairly insignificant curiosity. Indeed, this was just what Sir Richard Doll said about it at the Doll Report Press Conference. However, in recent years, it has become recognised as a highly important endocrine organ of the human body.

The Pineal is the remnant of the philosophers' and mystics' "third eye". It was sensitive to light levels and was located on the top of the head of many early vertebrates. For most animals, including humans, this gland has moved down to be in one of the innermost, and protected, areas of the head. It is a very active organ, having the second highest blood flow after the kidneys, and is equal in volume to the pituitary. While being right in the centre of the brain, it is actually outside the blood-brain barrier. This is a membrane which goes right around the brain and protects it from unwanted chemicals in the blood stream.

During the past fifteen years scientists have discovered just what an important function this gland seems to play. It produces a number of very active chemical substances, including important neuro-hormones. Some affect the actions of most of the other glands in the body, including the pituitary. In 1980 it was found that EMFs affected the activity of pineal cells, and this was confirmed in 1983 [41].

A main function of the pineal gland is the synthesis of the neurohormone melatonin from the neurochemical serotonin.

Melatonin plays a major part in controlling human circadian rhythms, its production peaks at night and is suppressed by bright lights and low level ELF magnetic fields. Serotonin plays important roles in many bodily processes including the effectiveness of the immune system. Both of these chemicals are known to affect mood changes and are linked with depressive illness. An interesting study of clinically depressed people published in the Lancet in 1987 [42] showed lowered levels of serotonin in every case.

Lowered melatonin has been associated with sleep problems, lethargy, mood alterations, psychiatric disorders immunodeficiency, and Alzheimer's disease.


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