Powerline Frequency Electromagnetic Fields and Human Health - Is it the time to end further research?
J. Aust. Coll. Nutr. & Env. Med. Vol. 17 No. 1 (June 1998) pages 5-16
An Overview of Three Recent Studies
Don Maisch (1) and Bruce Rapley (2)
Abstract
On March 2nd of this year the results of a study by the Royal Adelaide Hospital
were released which found “no evidence for cancer link with powerlines”,
and has been quoted as confirmation that it “should be of great peace of
mind to the many thousands of people who live near or under powerlines”.
On July 3rd 1997 the USA National Cancer Institute’s Linet study was released
which “found no evidence that magnetic fields (EMFs) in the home increase
the risk for the most common form of childhood cancer”.
On October 31st 1996 the USA National Academy of Sciences National Research
Council issued a review of the EMF literature and concluded that “there is
no conclusive and consistent evidence showing that exposure to residential
electric and magnetic fields produces cancer, adverse neurobehavioral effects,
or reproductive and developmental defects”.
Largely on the basis of these three studies, there are calls in Australia
and the USA to put an end to further research into the possible adverse biological
effects from human exposure to powerline frequency EMFs.
However, a careful examination of the limitations of these three studies
does not support this conclusion.
Introduction
One of the more contentious issues in the scientific community today is that
of the biological effects of electromagnetic fields (EMFs) and whether
or not they are adversely affecting our health. This issue has caused much
concern and controversy, which largely dates from 1979 when epidemiologist
Nancy Wertheimer et al. reported a link between powerline magnetic fields
and childhood leukemia in Denver, Colorado. Many epidemiological studies
since that time have reported a statistically significant connection with
magnetic field exposure and cancer, while other studies do not report such
a correlation.
Many people who have been following this issue for the last few years would
have some justification in thinking that recent studies have ‘concluded’
that there are no health hazards associated with human exposure to electromagnetic
fields generated from our use of electric power.
A brief examination of media reporting and press releases from several recent
scientific studies would certainly indicate that the possible dangers from
powerline EMF exposure have been overstated and perhaps it is time to direct
research funding into other areas.
The Studies
The Royal Adelaide Hospital ELF Mice Study, Australia, 1998)
In March of 1998 the American scientific journal Radiation Research published
the results of the Royal Adelaide Hospital ELF (Extremely Low Frequency)
mice study, titled: “A Test of Lymphoma Induction by Long-Term Exposure of
Eu-Pim 1 Transgenic Mice to 50 Hz Magnetic Fields”. In this study, which
looked at 50 Hertz powerline frequency magnetic fields, five groups of approximately
120 mice per group were exposed to different levels of magnetic field strengths:
Zero milliGauss (mG) (Sham exposure group), 1, 100, 1,000, 10,000 and pulsed
10,000 milliGauss.1
On March 2, 1998 the Centenary Institute of Cancer Medicine and Cell Biology
issued a press release on the findings from the Royal Adelaide Hospital ELF
mice study:
“No evidence for Cancer Link with Powerlines - No increase in incidence of
a cancer of the immune system called lymphoma was detected in mice after
prolonged exposure to magnetic fields of the type emitted by electric power
lines and equipment.”
Professor Tony Basten, Chairman of the research team, was quoted in an interview
with the Sydney Morning Herald:
“In view of the earlier reports of a possible association between proximity
to powerlines and incidence of childhood leukemia, a close relative of lymphoma,
our clear cut negative results should be very reassuring,” said Professor
Basten, [it] “supports other carefully conducted studies showing no measurable
increase in cancer risk and really should be of great peace of mind to the
many thousands of people who live near or under powerlines.”2
The NCI, Linet Study, USA, 1997
On Friday July 4th 1997, both The Australian and The Sydney Morning Herald
featured articles about the National Cancer Institute’s Linet study, which
found that there was no evidence that powerline electromagnetic fields
increase childhood leukemia risks. This study was published on July 3rd
in the New England Journal of Medicine.3
The researchers compared magnetic field exposures of 638 children with leukemia
and 620 children without leukemia who were similar in age and race.
To quote from the National Cancer Institute’s press release, dated July 2nd,
1997:
“A comprehensive study by researchers from the National Cancer Institute
(NCI) and the Children’s Cancer Group (CCG) found no evidence that magnetic
fields (EMFs) in the home increase the risk for the most common form of childhood
cancer.”
In this case-control study the researchers found that, in general, children
who lived in homes with high measured magnetic fields were not significantly
more likely to be diagnosed with acute lymphoblastic leukemia (ALL) than
children living in homes with lower magnetic field levels. Nor was ALL found
to be more likely among those whose homes were classified in high categories
of ‘wire-code,’ a surrogate measure of magnetic fields that is based on the
thickness, configuration, and distance from the home of nearby power lines.”
As reported in the February 1998 issue of EMF Update, published by the Electricity
Supply Association of Australia:
“A major scientific study published in the 3 July edition (1997) of the New
England Journal of Medicine reported no statistically significant correlation
between magnetic field exposure in the home and the incidence of childhood
leukemia.”
Don MacPhee from LaTrobe University’s School of Microbiology was quoted in The Australian that the results of the NCI Study backed his claims that power lines did not emit enough energy to cause childhood cancer or any other form of cancer. MacPhee said that it was mostly the media, and scientists of “dubious quality”, that had perpetuated the myth that there was any link between power lines and cancer. “Its just absolute non-sense”, Dr. McPhee said.4
The NAS/NRC Report, USA, 1996
On October 31st, 1996, the USA National Academy of Sciences, National Research
Council (NAS/NRC) issued a review of the EMF literature: “Possible Health
Effects of Exposure to Residential Electric and Magnetic Fields”. The conclusions
of this report are that “there is no conclusive and consistent evidence
showing that exposure to residential electric and magnetic fields produces
cancer, adverse neurobehavioral effects, or reproductive and developmental
defects”.
Of significant importance are the words, “conclusive and consistent”. Like
the more familiar phrase in law, ‘beyond reasonable doubt’, ‘conclusive and
consistent’ implies a certain standard of evidence that warrants more serious
action. Using that type of reasoning, the NRC Committee concluded that research
results do not show that EMF exposure at a residential environmental level
causes adverse health effects.5
According to the newsletter EMF Health Report, (Nov/Dec 1996) published by
the USA-based Information Ventures: “The findings to date do not support
claims that EMFs are harmful to a person’s health,” said Dr. Charles Stevens
of the Salk Institute, who was the chair of the NRC Committee which wrote
the report.
The official NRC/NAS news release headline states: “No Adverse Health Effects
Seen From Residential Exposure to Electromagnetic Fields.”
In the Electrical Supply Association of Australia’s (ESAA) newsletter EMF
Update of January 1997, it is reported:
“In an extensive review of the scientific literature relating to the possible
health effects of exposure to residential electric and magnetic fields… the
(NAS) concluded that ‘the current body of evidence does not show that exposure
to these fields presents a human-health hazard…’ NAS appointed an expert
committee of 16 scientists to review 17 years of research . . . in hundreds
of studies on three continents. The present report is the result of that
effort . . . It [the NAS report] is an important benchmark document in the
history of the EMF scientific debate against which future research findings
will need to be viewed.”
As a result of the ‘not guilty’ verdict from the National Academy of Sciences
and the National Cancer Institute, the USA Department of Energy (DOE) is
ending practically all bio-electromagnetic research in September 1998, and
there is the likelihood that the USA House of Representatives and the Senate
will drastically cut the budget for future research.
Acting on the press releases from both the NCI and NAS studies, the Victorian
Radiation Advisory Committee, in its annual report to the Victorian Parliament
for 1997 stated:
“. . . However, the weight of opinion as expressed in the USA National Academy
of Sciences report and the negative results from the National Cancer Institute
study (Linetet al. 1997) would seem to shift the balance of probability more
towards there being no identifiable health risks.”6
Commentary on the Studies
Considering that the USA National Academy of Science, the USA National Cancer
Institute and other organisations have made the above statements on the
EMF health debate, it would seem quite reasonable to conclude that at long
last we have settled this issue.
However, before any firm conclusions can be drawn, let us go back and carefully
re-examine the three studies mentioned above to see if the press releases
and media statements on safety are really reflected in the study findings
themselves.
The Royal Adelaide Hospital ELF Mice Study (1998) - Limitations
One important admission of the authors of this study, and one which should
have been mentioned in the press release, is the following:
“Perhaps the increased incidence of cancer, that in some epidemiological
studies has been associated with residential proximity to high-current power-distribution
wiring, results from exposure to high-frequency transients rather that the
primary 50/ 60 Hz magnetic fields. Transients originate from the operation
of devices such as light switches, electronic controllers and electric motors
during start up. They are of short duration (<1 s) and have frequencies
peaking in the megahertz range and intensities up to several microtesla [mcT].
. .
In our study, the magnetic fields to which the mice were exposed were switched
on and off in a manner that minimised the production of transients. Thus
the possible carcinogenic consequences of exposure to transients have yet
to be tested.”7
This statement is in conflict with the statement in the official press release
where it is claimed: “No increase in incidence of a cancer of the immune
system called lymphoma was detected in mice after prolonged exposure to magnetic
fields of the type emitted by electric power lines and equipment”.
The researchers had understandable reasons for filtering out the possible
effect of transients, as this could have been a possible confounder if a
positive result was found. That is, if transients were not filtered out and
an effect was found, they would not know if it was the 50 Hz magnetic field
or the transients which were responsible. Therefore they decided to eliminate
one of those for the purposes of the study. However, by doing so the relevance
for real world exposures is severely limited, as the following indicates.
Transients
Quoted from the paper “How You Can Avoid or Eliminate Pulsing Electric or
Magnetic Fields within Your Home and Bedroom” by James B. Beal, EMF Interface
Consulting, 5500 Prytania, #406, New Orleans, LA 70115, USA:
“Repetitious transients and surges (pulse spikes) occur on power lines too,
but the more influencing transients are created by factors in home and business
wiring, water piping (poor grounding/ balancing), appliances and equipment.
This repetitious long-term exposure may provide a kind of irritation or suppression
factor, posing potential hazards to our health. . . . Persons at risk would
be those exposed for years in constant proximity to power line components
(transformers, sub-stations), appliances (electric blankets, hair dryers),
power tools, TVs and computer monitors, switching systems, and other sources
of potential rapid transient (switching) EMFs.”8
The relevance of studies that only consider field magnitude, while excluding
other factors such as transients, are now being questioned by some researchers.
This issue was highlighted in a recent article by
2 - Journal of the Australasian College of Nutritional and Environmental
Medicine - June 1998
Janet Raloff in Science News, Jan. 10th, 1998, “EMFs’ Biological Influences
- Electromagnetic fields exert effects on and through hormones”, in an interview
with Charles Graham, an experimental physiologist at the Midwest Research
Institute (MRI) in Kansas City, Missouri:
“What concerns me,” Graham says, is that the public “tends to get so worried
about the magnitude of a field. The bigger it is, the worse it’s supposed
to be.” In fact, Loscher has found that very high fields, as well as those
below a certain strength, have little impact on tumor growth. Only those
across a relatively narrow range consistently foster tumors and other negative
health effects.
“We’ve seen the same thing in our studies,” Graham told Science News.
Moreover, he says, it’s beginning to appear that a field’s magnitude matters
less than its intermittency or other features, such as power surges called
electrical transients.
These surges can pack a big burst of energy into a short period of time.
They occur whenever lights or other electric devices turn on [or off], when
motors or compressors (such as those in refrigerators and air conditioners)
cycle on, or when dimmer switches operate. “Being transient doesn’t mean
they’re rare, just quick,” Graham notes. “Transients are hard to avoid because
they may stem from surges elsewhere - in a neighbor’s house or even power
lines up the street.”9
The argument that powerline EMFs are too weak to possibly affect cellular
processes does not necessarily apply to transients. Research by Dr. Antonio
Sastre and colleagues indicates that when it comes to powerline EMF transients,
the induced signal can rise above the background cellular noise.10
Considering that the Adelaide Hospital ELF mice study specifically filtered
out the possible effect of transients, the results of this study cannot be
used to justify any assurance of safety with real world exposures. It would
be far more accurate to rewrite the press release from the Centenary Institute
to state the following:
No Evidence for Cancer Link with Laboratory 50 Hz Magnetic Fields - no increase
in incidence of a cancer of the immune system called lymphoma was detected
in mice after prolonged exposure to magnetic fields of the type emitted by
laboratory Helmholtz coils.
The NCI, Linet Study, 1997 - Limitations
It is unfortunate that the authors of the official NCI press release, which
gives the impression that this study is convincing evidence that a risk
does not exist from long term exposure to powerline electromagnetic fields,
did not take the time to critically examine what the study actually found,
and to examine the criteria which led to the NCI researchers’ conclusions:
“The researchers actually acknowledge, in no less than four places, a statistically
significant increase in acute lymphoblastic leukemia (ALL) in children exposed
to powerline magnetic fields in excess of 3 milliGauss. This is a confirmation
of many previous studies which have shown a similar level of association
between childhood leukemia and magnetic fields from electricity.”
The article in The Australian mentions that the researchers dismissed as
a “statistical fluke” a 24% increase in leukemia risk for children exposed
to what is termed “especially high magnetic fields”.
The NCI researchers were able to dismiss this fact by arbitrarily setting
a 2 mG level as a cut-off limit. Only by setting that artificial limitation
could they conclude that there was no association. The fact is, that if they
had used the 3 mG level as a cut-off point in their calculations, the conclusions
would have been exactly the opposite •that there is a statistically significant
connection between powerline magnetic fields and childhood leukemia at levels
over 3 mG.
On July 4th 1998 this writer [D. Maisch] contacted Professor Ross Adey, one
of the best known bio-electromagnetic researchers in the world. Dr. Adey
is the author of numerous books and research papers on the bio-effects of
EMFs. He recently conducted a $3 million research program for Motorola and
was a committee chairman on the USA National Council on Radiation Protection
and Measurements (NCRP). His comments on the NCI study are as follows:
“A number of us worked on the NCI paper through last weekend. Sam Milham,
the Washington State epidemiologist and a pioneer in this field, points out
that if they had included the 3 mg level in their cutoff, the conclusions
would have been exactly the opposite
-that there is a significant risk. And selection of 2 mG is quite arbitrary.
David Savitz used 3 mG in some of his work. Obviously there is no steep threshold
beyond which risks rise exponentially. At the recent Bologna International
Symposium, Schuz from the Uinversity Mainz had a paper combining kids from
Berlin and Southern Saxony in high exposure homes to give leukemia odds ratio
of 6.8 for young kids (under 4 years). So the dismissive attitude of NCI
is totally unrealistic.”11
Also contacted at the same time for comment on the NCI study was Alasdair
Philips from Powerwatch Network in the UK. Mr. Philips was a principal researcher
for the UK study “Measured Electric Fields in the Bed Places of Leukemic
Children”, published in the June 1997 issue of the European Journal of Cancer
Prevention.
“Surprisingly, for a modern study, the NCI researchers only measured magnetic
fields and did not include electric fields which are being increasingly implicated
in cancer development and many other adverse health conditions. Both magnetic
and electric fields are being measured in the landmark UK Childhood Cancer
Study due out early next year, as UK researchers understand the potential
importance of electric fields. In the 1996 Ontario Hydro adult worker study
conducted by Dr. Anthony Miller of Toronto University in Canada, when they
took both fields into account, the risk rose from 1.6 (magnetic fields only,
and similar to the 1.79 in this study) to 11.2 (of the magnetic and electric
fields considered) - it is likely to be a similar increase for children.”12
It should also be noted that the magnetic field is not the equivalent of
EMF. It is only one of the now ‘five or six’ known EMF metrics. Of these,
the electric field may well be the most important, though the role of transients,
harmonics, ground currents, radon daughters and the radio frequencies that
‘ride’ on power lines are also suspect. Any study which only considers one
of these metrics cannot give any assurance of ‘safety’.
Comments on the NCI Linet study by Allen H. Frey, author of On the nature
of electromagnetic field interactions with biological systems, (RG Landes
Co., Austen TX, USA, 1994):
“Are the conclusions of the Linet epidemiological study and associated editorial
by Campion justified? I think not.”
As is often the case in science, the fault is in assumptions made before
the study began, assumptions upon which the study is based. If the assumptions
can not be shown to be true, then the conclusions are not valid.
In their statistical study, it was assumed that the active agent in power
line biological effects is the 60 Hz sinusoidal wave. But there is substantial
data and biological theory to indicate that the primary active agent would
be the transients that are found on power lines in varying forms to varying
degrees in various places (Frey, 1994). A broad statistical study such as
Linet et al. would tend to obscure such effects, since data from areas where
there are effective transients would be submerged in the mass of data from
areas where there are no such transients.
Epidemiological studies, and statistical studies in general, are quite useful
for hypothesis generation. But they are not appropriate for drawing conclusions.
Causality can not be shown. There are just too many unknown and uncontrolled
factors operating in a large statistical study, as compared to wet biological
experiments. This is particularly the case with magnetic fields as an agent,
for it is not yet clear what parameters of the agent are of importance biologically.
Is it appropriate to draw what may be life and death conclusions on the basis
of one statistical study that is based on an assumption about what is the
active agent, an assumption that can not be shown to be true? I doubt that
many people would be willing to stake their life on one such study.”13
Comments on the NCI Linet study by A.R. Liboff, Professor of Physics, Oakland
University, Rochester, MI, July 14, 1997
“Like Allan Frey, I too have doubts concerning the implications of the Linet
study.
Frey points to the possibility of transients as the metric underlying the
earlier correlations.
Another possibility is that the geomagnetic field may be a complementary
factor, either because of cyclotron resonance or some other type of resonance
interaction. In connection with this it appears that Denver was not one of
the areas examined, which is puzzling considering the fact that data from
the Denver vicinity was the impetus for such epidemiological studies.
The media has characterized this study as the largest yet. For some time,
I have had the feeling that funding for such studies would continue until
the funders got the answer they wanted. Never mind the original objections
to the Wertheimer and Savitz results - that epidemiological studies were
‘innately non-scientific’ and did not prove anything. Now that the results
are more in line with what is desired, we are subjected to newspaper and
TV reports saying that this report is the final word.
Nowhere does the media awaken the public to the fact that, since Wertheimer’s
original 1979 results, there has arisen a wealth of (laboratory) evidence
showing that ELF magnetic fields can have profound effects on living things.
What in 1979 seemed inconceivable no longer appears improbable.
Perhaps now that we have had, in the words of the media, the ‘final word’,
the rest of us can get on with the science underlying these ELF interactions
and, through the science, determine the consequences for human health.”14
With this in mind, the only thing the NCI study indicates is that children
with magnetic field exposures at, or under, 2 mG are not at apparent increased
risk of developing leukemia from their EMF exposure. Rather than exonerating
EMFs, the NCI study gives further support for the 1995 draft guidelines from
the USA National Council of Radiation Protection and Measurements. (NCRP).
These guidelines generally endorse a 2 mG exposure limit.
The NCRP Draft Guideline conclusions:
“In arriving at the proposed guidelines, the committee has considered available
laboratory studies on bioeffects and epidemiological reports of health hazards
from electric and magnetic field exposure. . . In key areas of bioelectromagnetic
research, findings are sufficiently consistent and form a sufficiently coherent
picture to suggest plausible connections between Extremely Low Frequency
(ELF) EMF exposures and disruption of normal biological processes, in ways
meriting detailed examination of potential implications in human health.”15
The NAS/NRC Report, 1996 - Limitations
As mentioned earlier, this report found that there is no “conclusive and
consistent evidence showing that exposure to residential electric and magnetic
fields produces cancer, adverse neurobehavioral effects, or reproductive
and developmental defects”. Using their criteria for admissible evidence,
the NRC Committee concluded that research results do not show that EMF
exposure at a residential environmental level causes adverse health effects.
Is the NAS/NRC report a conclusive vindication for EMFs in the health issue?
The answer to that question depends upon your viewpoint. If you take a narrow
legalistic interpretation, the ‘not guilty’ verdict may seen appropriate,
especially if you take into account only the evidence considered by the NRC
Committee.
However if you take a scientific interpretation and consider all the available
evidence, the conclusion is inescapable. So many scientific studies were
excluded from the ‘extensive’ NAS/NRC report, that its conclusions cannot
be considered a proper review of current scientific findings.
• In its review of the literature, the NRC Committee restricted itself to
considering only studies published in peer-reviewed journals up to mid-1995,
when the report was drafted. The NRC press release states: “To date, they
have found no evidence to show that EMFs can alter the functions of cells
at levels of exposure common in residential settings. Only at levels between
1,000 and 100,000 times stronger than residential fields have cells shown
any reaction at all to EMF exposure… In fact, exposure may actually help
the body in some subtle ways, for example by speeding up the healing process
after a bone is broken.”
“To date” means the cut off date of early 1995 for peer reviewed and published
research, a process which can take years, thereby omitting many studies which
had results opposed to the NAS/NRC report’s own findings.
In fact the NAS/NRC Committee only considered approximately half the evidence
which was available to it. Dr. Kjell Hansson Mild of the National Institute
for Working Life in Sweden, asked Dr Stevens, chair of the NRC Committee,
how “the report turned out to be so biased in its selection of papers”. Mild,
past president of the Bioelectro•magnetics Society, noted that the report
mainly included papers that showed no effect and omitted those that found
a biological response.16
•
Excluded from the NAS/NRC findings was the extensive body of occupational
studies, such as the Ontario Hydro worker study, which found that workers
exposed to high levels of magnetic and electric fields had leukemia rates
that were up to 11 times greater than expected.17 In fact the committee acknowledged
that workplace studies “have increased rather than diminished the likelihood
of an association between occupational exposure to [EMFs] and cancer”. The
NAS committee only did what has been called a “superficial overview” of this
literature because (the official reason) it was not directly relevant to
the committee’s assignment.18
•
Excluded from the findings was the entire body of research into the effect
of environmental low level EMF exposure on melatonin, known as the melatonin
hypothesis (low level magnetic field exposures may reduce the pineal gland’s
production of cancer-inhibiting melatonin and the ability of melatonin
to suppress breast cancer cells). This hypothesis is supported by five
in vitro studies, from three major laboratories, as well some human exposure
studies finding a reduction in melatonin levels in workers exposed to EMFs.
The body of this research implicates prolonged powerline frequency magnetic
field exposure in the order of 12 mG with possible hormone disruption.
Besides melatonin being affected, levels of the stress hormone ACTH may
be increased as a consequence.19
This body of research featured greatly at the Second World Congress for
Electricity and Magnetism in Biology and Medicine, held in Bologna,
4 - Journal of the Australasian College of Nutritional and Environmental
Medicine - June 1998
Italy in June of 1997, where over 600 scientific papers on many topics were
presented, it was mentioned in the official program bulletin:
“A number of experimental studies have been conducted to test the [melatonin]
hypothesis. Although the literature is still evolving and consensus is being
built, it is fair to say, a) there exists credible scientific support for
the hypothesis and, importantly, b) this support encompasses in vitro, in
vivo, and epidemiological research. The melatonin hypothesis thus currently
represents one of the more well documented/tested interactions in the field
of bioelectromagnetics.”
The NAS press release states: “The committee also called for more research
into the relationship between high exposures to EMFs and breast cancer in
animals already exposed to other carcinogens, and on reasons why electromagnetic
fields seem to affect the levels of the hormone melatonin in animals, an
effect not reproduced in humans.” This statement gives the impression that
there is no evidence that low level EMFs affect melatonin in humans.
The NAS can only state this by ignoring the melatonin hypothesis research
because it did not meet the committee’s strict criteria for admissible evidence.
To be fair to the NAS/NRC report, the meta-analysis of 11 residential epidemiological
studies was one of the most thorough to date. What it did find is that there
is a reliable statistical association between childhood leukemia and power
line proximity, as classified by wire codes.
However, because the committee was looking for conclusive evidence of a connection
with EMFs, it was able to dismiss all data which failed to meet this criterion
and therefore could not conclude EMFs were to blame. Epidemiology looks for
increases in risk factors, it does not deal with conclusive proof. By setting
such an impossible standard, the National Academy of Science was able to
dismiss the EMF link with childhood cancer and announce to the world that
there was nothing to worry about.
So rather than being an “important benchmark document in the history of the
EMF scientific debate against which future research findings will need to
be viewed” the NAS/NRC study appears to be designed, by its limitations,
to give an assurance of safety, when the evidence does not warrant that conclusion.
Published Guidelines
NCRP draft report guidelines (1995)
The USA National Council on Radiation Protection and Measurements (NCRP),
a congressionally chartered organisation, was contracted by the Environmental
Protection Agency (EPA) in 1983 to conduct a review of the biological effects
of Extremely Low Frequency (ELF) EMFs. Work was discontinued in 1986 due
to funding cuts at the EPA, but resumed in 1991. In early 1995 the draft
of the 800 page NCRP report was leaked to the New York based publication
Microwave News, which published the report’s findings in August 1995. The
final report was supposed to be publicly available in early 1996, but has
received such intense industry opposition to its findings that its final
outcome remains uncertain.
The Committee’s membership was described by chairman Dr. Ross Adey as “carefully
selected to cover the great majority of societal interests on this scientific
problem, including power industry engineers, epidemiologists, public health
specialists as well as molecular and cellular biologists”. The draft report
generally endorses a 2 mG exposure limit. It would immediately affect new
day-care centres, schools and playgrounds, as well as having implications
for new transmission lines near existing housing.
A somewhat more flexible policy would be applied to new housing and offices.
For existing facilities, the committee recommended a more gradual approach,
with stronger restrictions phased in over time if the evidence of a health
risk continues to grow.
From the Committee’s conclusions: “In arriving at the proposed guidelines,
the committee has considered available laboratory studies on bioeffects and
epidemiological reports of health hazards from electric and magnetic field
exposure… In key areas of bioelectro-magnetic research, findings are sufficiently
consistent and form a sufficiently coherent picture to suggest plausible
connections between ELF EMF exposures and disruption of normal biological
processes, in ways meriting detailed examination of potential implications
in human health.”
From studies on humans the committee cites evidence for a link between EMFs
and:
1.
childhood and adult cancer, including leukemia and brain cancer;
2.
teratological effects and other reproductive anomalies;
3.
neuroendocrine and autonomic responses which, separately or collectively,
may have pathophysiological implications;
4.
neurochemical, physiological, behavioural and chronobiological responses
with implications for development of the nervous system.
From laboratory studies the committee notes that EMFs:
1.
affect cell growth regulation in animal and tissue models in a manner consistent
with tumour formation;
2.
increase tumour incidence and decrease tumour latencies in animals;
3.
alter gene transcriptional processes, the natural defence response of T-lymphocytes
and other cellular processes related to the development and control of
cancers;
4.
affect neuroendocrine and psychosexual responses.
In relation to the effect of low level EMFs on melatonin (evidence which
the NAS/NRC report excluded), the committee concluded:
“There has been a strong focus on ELF field actions in the pineal gland,
relating to… the pineal hormone melatonin, and on a broad series of regulatory
functions mediated by this hormone. Melatonin plays a key role in controlling
the 24-hour daily biological rhythm. Disturbance of the normal diurnal melatonin
rhythm is associated with altered estrogen receptor formation in the breast,
a line of experimental evidence now under study, on possible links between
ELF field exposure and human breast cancer.
“Further, melatonin has general properties as a free radical scavenger, with
the possibility of a preventative role in oxidative stress, recognized as
a basic factor in a broad spectrum of human degenerative disorders, including
coronary artery disease, Parkinson’s and Alzheimer’s diseases, and aging.”
According to the committee, problematic sources of ELF EMF include local
electrical distribution systems, as well as high voltage power transmission
systems. Particular appliances, including electric blankets and VDTs also
rate highly as problem sources, along with “various occupational environments”.
The committee states that the evidence points to human health hazards in
common exposures to EMFs, particularly magnetic fields exceeding
0.2 mcT (2 milli-Gauss) and electric fields at intensities in the range 10-100
V/m (volts per metre). (An electric blanket on setting II can expose the
sleeper to a field of 12 mG.)
“..there is an implication that a significant proportion of the world’s population
may be subjected to a low level of risk, but a risk factor with significant
societal consequences, by reason of its pervasive nature and the serious
consequences for affected individuals.”
NCRP interim exposure guideline recommendations:
The committee concludes that “neither laboratory studies nor epidemiological
findings… can yet establish well-defined thresholds for safety guidelines.”
Still, it contends: “From available epidemiological and laboratory data,
it appears both prudent and responsible to set limits on permissible future
exposures”. Therefore it calls for “interim exposure guides”, measures
that “fall short of establishing either a standard or guideline, but offer
guidance to limit exposure”.
ALARA policy endorsed:
While the report notes that committee members were not unanimous, it recommends
a policy in which exposures would be “As Low As Reasonably Achievable”,
known as ALARA. Over a three year period, ambient exposures in existing
homes, schools and offices would be reduced to 10 mG. After six years,
there would be an option to establish a guideline of 5 mG.
Each of these decisions would be based on whatever epidemiological and laboratory
studies were then available. After ten years, a goal of 2 mG would be considered.
The report stipulates that mitigation of the existing EMF environment to
this level should be adopted only after “a careful evaluation of its socio-economic
impact, as well as its cost-effectiveness”.
With respect to future construction, the report recommends observing a 2
mG exposure limit for schools and for new transmission lines near existing
housing, with somewhat less strict guidelines for new housing and offices.20
Committee member Dr. David Carpenter, of the School of Public Health at the
State University of New York, Albany, said:
“In almost any other type of environmental exposures, if the evidence were
as strong as the association between EMFs and cancer, there would be extensive
government regulation. The major reason that many members of the committee
were unwilling to set more rigorous standards was that it would be horrendously
expensive and unrealistic to enforce them.”21
It must be pointed out that the NCRP report is still in a draft form and
as such it has no official standing at this time. Because of this, there
are many who would prefer that this report be ignored, while the NAS/NRC
and NCI studies be taken as the definitive evaluation on the health effects
from exposure to EMFs. It will be a sad day for science if studies which
can only arrive at their conclusions by ignoring a significant body of evidence,
are accepted as the definitive statement on the issue.
Considering further studies, published since the 1995 NCRP draft guidelines,
epidemiologist Nancy Wertheimer has proposed a 3 mG cut off-level as a benchmark.
She wrote in the September/October 1997 issue of the Bioelectromagnetics
Society Newsletter that:
“...taken as a whole, the accumulated evidence from all the studies appears
to show quite consistent and significant evidence that increased cancer risk
accompanies measured or carefully calculated fields at the very high end
of the field range (over about 3 mG). The same studies show little evidence
that fields in the 2 mG to 2.9 mG range are indicators of risk.”22
Australian maximum exposure guidelines
(Relevance to cancer and other adverse health states) When you take the 2
mG NCRP guideline or Nancy Wertheimer’s 3 mG benchmark, as a measure of
protection from cancer, there is an apparent discrepancy between these
levels and the current maximum exposure limits, as set by the National
Health & Medical Research Council (NH&MRC). These limits are based
on the guidelines set by the International Commission on Non-Ionizing Radiation
Protection
(ICNIRP) in 1993: for residential exposures - 1,000 mG; for occupational
exposures -5,000 mG.
The reason for this large difference in levels is because the ICNIRP (and
Australian) guidelines specifically do not address the issue of chronic exposure
to powerline frequency EMFs. This was admitted in 1991 by Dr. Keith Lokan,
from the Australian Radiation Laboratory, in a conference paper published
in Radiation Protection in Australia:
“One thing which we have done, though it has little direct bearing on the
issue of chronic low level exposure, is to adopt the (above) recommendations
on field limits. These limits represent plausible field values, below which
immediate adverse health effects are unlikely, and as such serve a useful
purpose. They are not intended to provide protection against possible cancer
induction by continued exposure at the lower field levels implicated in the
studies . . .”23
The attention solely on proximity to powerlines and cancer in many of the
studies may be an over-simplification. Fields generated inside homes due
to house wiring, faulty earthing and electrical appliance use, can give greater
cumulative exposures than fields emitted by nearby powerlines. School and
occupational exposures are usually not taken into consideration. The overall
affect of these additional exposures could act as a ‘confounder’ to reduce
the significance of any study which only looks at one condition (cancer)
and distance from powerlines.
Also the preoccupation solely with cancer and EMFs does not consider other
adverse health states which may be implicated as well. The draft NCRP report
mentions these in detail, but the majority of epidemiological studies to
date mainly focus on cancer.
Evidence indicates that electromagnetic fields may play a role in a number
of disease conditions apart from cancer, possibly acting as an immune system
stressor. One recent New Zealand study which looked at homes near powerlines
examined combined chronic health problems, not just cancer. They found significant
increased risks for asthma, arthritis, type-II diabetes and other chronic
health problems.
“Although numerous studies of animals and cell cultures indicate effects
of power frequency magnetic fields on immune-system function, few studies
have looked for evidence of an association between environmental power-frequency
magnetic field exposure and immune-related illnesses in humans.
The results are consistent with a possible adverse effect of environmental
magnetic field exposure on immune-related and other illnesses.”24
Protective action or more research?
At what point does the weight of evidence warrant some form of protective
action for both home and occupational exposures? This question was addressed
by Les Dalton, author of Radiation Exposures, in a paper on ethics of radiation
exposures:
“At some point a growing body of evidence of an association between a disease
and a biologically active agent raises ethical as well as scientific questions.
The ethical questioning becomes more pertinent if exposure is involuntary
rather than voluntary. A genuine scientific urge to resolve uncertainties
over association between an imposed exposure and an incidence of disease,
in a study population, cannot be allowed to obscure the fact that continued
exposure takes on some aspect of human experi•mentation. At some point we
have to decide who should have the benefit of the doubt, those who are exposed
to, or those who emit, the agent in question.”25
6 - Journal of the Australasian College of Nutritional and Environmental
Medicine - June 1998
Conclusions
As a direct result of the USA National Academy of Science/National Research
Council’s report in 1995, the USA National Cancer Institute’s Linet study
in 1996, and now in Australia the Royal Adelaide Hospital ELF mice study,
we see calls for the ending of further research into possible adverse human
health effects from exposure to powerline frequency electromagnetic fields.
Upon careful examination of these three studies, this call is not justified
.
When one considers the totality of evidence now available, there are indications
that a risk may indeed exist. That risk may be small when compared to other
risks in our modern society, but important due to its pervasive nature and
possibility of serious consequences for affected individuals.
For medical practitioners who are dealing with patients on a daily basis,
there is the possibility that some of their patients may be adversely affected
by prolonged exposure to powerline magnetic fields in excess of 2 to 3 milliGauss
(NCRP-Wertheimer). The extent of that possibility is uncertain. It may be
that only a small subset of the population is affected by these fields. It
may be that the 50-60 Hertz sinusoidal wave is not the active agent, but
that transients riding on that wave may be the active agent. Most research
has centred on the magnetic component of the electromagnetic field. It may
be that in situations of exposure to the electric field, adverse effects
may also occur.
For now, any conclusive answers to the question of the possible adverse effects
of exposure to these fields must remain an uncertainty. However, it is the
opinion of the authors that when the totality of existing scientific evidence
is considered, a recommendation to patients (when there are indications of
possible excessive EMF exposure), to avoid or lessen this exposure, is clearly
warranted.
This could be considered a Precautionary Principle, which in this case could
be stated as:
The precautionary principle should guide medical practitioners when confronted
by potential threats to human health. The lack of full scientific certainty
should not be used as a reason for postponing measures to prevent exposure
to these potential threats. If measures generally reducing exposure can be
taken at reasonable expense and with reasonable consequences in all other
respects, an effort should be made to reduce exposures to a level below that
which evidence indicates may be harmful to health.
References
1.
Harris AW, Basten A, Gebski V, Noonan D, Finnie J, Bath ML, Bangay MI , Repacholi
MH, "A Test of Lymphoma Induction by Long-Term Exposure of Eu-Pim1 Transgenic
Mice to 50 Hz Magnetic Fields." Radiation Research, 149 (3): 300-307,
(1998)
2.
Interview with Professor Tony Basten, Chairman of the Adelaide Hospital’s
research team, by the Sydney Morning Herald, March 2, 1998.
3.
Linet MS, Hatch EE, Kleinerman RA, Robinson LL, Kaune WT, Freidman DR, Severson
RK, Haines CM, Hartsock CT, Niwa S, Wacholder S, Tarone RE, "Residential
Exposure to Magnetic Fields and Acute Lymphoblastic Leukemia in Children." The
New England Journal of Medicine, 337 (1):1-7, (1997)
4.
The Australian, July 4, 1997.
5.
National Research Council, Possible Health Effects of Exposure to Residential
Electric and Magnetic Fields, National Academy Press, Washington DC, USA,
1996.
6.
The Annual Report of the Radiation Advisory Committee for the Year Ending
September 1997 Radiation Advisory Committee, Melbourne Australia.
7.
Harris AW, Basten A, et al. (as above), page 306.
8.
Beal JB, How You Can Avoid or Eliminate Pulsing Electric or Magnetic Fields
Within Your Home and Bedroom, EMF Interface Consulting, 5500 Prytania,
#406, New Orleans, LA 70115, USA. E-mail: EMFEFFECTS@aol.com
9.
Raloff J, “EMFs’ Biological Influences - Electromagnetic fields exert effects
on and through hormones”, Science News, Vol.153, Jan 10,1998.
10.
Sastre A, et al., “Residential Magnetic Field Transients: How Do Their Induced
Transmembrane Voltages Compare to Thermal Noise?" Paper No. A-33,
DOE, 1994; and Johnston GB, Kavet R, and Sastre A, “Residential Magnetic
Field Transients. Effect of Residential Services on Fields Arising from
Distribution Line Capacitor Bank Switching.” Paper No. P-130A, BEMS, 1995.
11.
E-mail correspondence with Dr. Ross Adey, July 7, 1997.
12.
E-mail correspondence with Alasdair Philips, editor of UK based Powerwatch
News , July 1997, website: http//www.powerwatch.org.uk
13. Published Statement on the NCI Linet study by Allen H. Frey, author
of On the nature of electromagnetic field interactions with biological systems.(1994),
Address: Randomline, Countyline and Mann Roads, Huntington Valley, Penn.
19006,USA.
14.
Published Statement on the NCI Linet study by A.R. Liboff, Professor of Physics,
Oakland University, Rochester, MI USA, July 14, 1997.
15.
Draft report of NCRP Scientific Committee 89-3 on Extremely Low Frequency
Electric and Magnetic Fields. Section 8.5.1 Conclusion.
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Letter by Dr. Kjell Hansson Mild to Dr. Charles Stevens, chairman of the
NAS Committee. Microwave News, Jan/Feb 1997, p. 2.
17.
Microwave News, July/August 1996.
18.
Microwave News, Nov/Dec. 1996, p.8.
19.
Maisch DR. Melatonin, Tamoxifen, 50-60 Hertz Electromagnetic Fields and Breast
Cancer: A Discussion Paper. Tabled in the Australian Senate, 29 October
1997.
20.
Draft report of NCRP Scientific Committee 89-3 on Extremely Low Frequency
Electric and Magnetic Fields. As reported in Microwave News, July/August
1995, p. 12-15.
21.
Microwave News, July/August 1995, p. 11.
22.
BEMS Newsletter, Sept/Oct, 1997.
23.
Radiation Protection in Australia (1991). Vol 9, No.4
24 Beale IL, Booth RJ, Pearce NE. Chronic Health Problems in Adults Living
Near High-Voltage Transmission Lines: Evidence for a Dose-Response Relation
with Magnetic Field Exposure. Second World Congress for Electricity and Magnetism
in Biology and Medicine, Bologna, Italy, June 1997.
25. Dalton L, Social Policy and the Regulation of Electromagnetic Field Exposures,
Radiation Protection in Australia (1993), Vol. 11, No.1.
Authors
1.
Don Maisch, EMFacts Information Service, PO Box 96, North Hobart, Tasmania
7002, Australia. Fax: +613 6243 0340, e-mail: emfacts@tassie.net.au Web:
http://www.tassie.net.au/ emfacts/
2.
Bruce Rapley, Bioelectromagnetic Research And Information Network of New
Zealand. Suite 2, 37 Ferguson Street, Palmerston North, New Zealand. Fax:
+64 6 3571075
AUSTRALIAN VACCINATION NETWORK
Informing the public on all issues relating to vaccination. Know both sides
of the story before you choose to vaccinate or not.
PO Box 177, Bangalow, NSW 2479
ph: (02) 6687 1699 fax: (02) 6687 2032
web: http://www.avn.org.au
.