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Chapter 2 - Research on the health effects of electromagnetic radiation
Introduction
2.1
While radio waves and other forms of
electromagnetic energy have been in use for decades, the recent dramatic
increase in the use of mobile phones, the visible proliferation of mobile phone
towers and antennas and accompanying anecdotal and scientific studies showing
biological and possibly health effects associated with these structures, have
led to increased public concern about the safety of mobile phones and other
telecommunications technologies. Many studies have been conducted to examine
the relationship between radiofrequency radiation and biological and health
effects, however to date, the results have been inconclusive.
2.2
Several recent expert reviews provide an analysis
of the relevant scientific literature, with last year’s UK Stewart Report
considered the most comprehensive so far. Other reviews include those
conducted by the CSIRO in 1994, the European Commission in 1996, the
International Commission on Non-Ionizing Radiation Protection (ICNIRP) in 1996
and 1998, the World Health Organization in 1998, and the Royal Society of
Canada and the UK House of Commons Select Committee on Science and Technology
in 1999. The conclusions and recommendations from these reviews will be
referred to throughout this chapter.
2.3
The Committee received submissions and evidence
from a number of scientists and health professionals, as well as community
organisations and individuals. Some claimed that there is ample evidence of
biological and/or adverse health effects associated with non-thermal levels of
exposure to electromagnetic radiation, while others concluded that no clear
relationship has been established.
2.4
This chapter provides a summary of the
scientific research covered by recent major reviews, as part of a discussion of
the evidence presented to this Committee based on the observations and research
of witnesses and submitters to this inquiry. It concludes with an overview of
current Australian and international research in this field.
Exposure to electromagnetic radiation – if
biological effects are shown, what are the health implications?
2.5
Exposure to non-ionising radiation, at exposure
levels sufficient to cause heating above 1ºC, is known to cause adverse health
effects.[1]
Knowledge about and acceptance of the effects of non-thermal exposure to
electromagnetic radiation remains limited and contentious.
2.6
As stated earlier, a number of expert reviews of
the literature have been conducted, which have drawn the following conclusions in
relation to the health effects of non-ionising radiation, including
radiofrequency radiation:
CSIRO, 1994[2]
This report concluded that there was insufficient reliable
scientific evidence on which to base sound conclusions about safety of radio
frequency (RF) exposures in telecommunications. It stated that ‘because of its
equivocal nature, the data base for RF emissions has limited value. It may be
dangerous to make general statements on safety based on lack of evidence of
harmful effects when so little relevant research has been carried out’.
International Commission on Non-ionizing Radiation
Protection (ICNIRP), 1996[3]
Most of the established biological effects of exposure to RF
fields are consistent with responses to induced heating resulting in rises in
tissue or body temperature of greater than 1°C ... In contrast, non-thermal
effects are not well established and currently do not form a scientifically
acceptable basis for restricting human exposure for frequencies used by
hand-held radio telephones and base stations.
European Commission, 1996[4]
Overall, the existing scientific literature encompassing
toxicology, epidemiology and other data relevant to risk assessment, while
providing useful information, provides no convincing evidence that
radiotelephones[5]
pose a long-term public health hazard.
World Health Organization, 1998[6]
... no known health hazards were associated with exposure to RF
sources emitting fields too low to cause a significant temperature rise in
tissue.
ICNIRP, 1998[7]
Epidemiological studies on exposed workers and the general
public have shown no major health effects associated with typical exposure
environments. This is consistent with the results of laboratory research on
cellular and animal models, which have demonstrated neither teratogenic[8]
nor carcinogenic effects of exposure to athermal levels of high-frequency.
Royal Society of Canada, 1999
The Royal Society Expert Panel on Radiofrequency Fields noted
that there were ‘a number of observed biological effects of exposure of cells
or animals to non-thermal levels of exposure to RF fields’, but had found ‘no
evidence of documented health effects in animals or humans’ relating to this
exposure. However, it also expressed the view that ‘many of the studies in
humans and animals addressing the potential for adverse health effects do not
have sufficient power to rule out completely any possibility of such effects
existing’.[9]
UK Independent Group on Mobile Phones Report (Stewart
Report), 2000
The Stewart Report (Mobile Phones and Health) noted that
while there has been little research into the safety of mobile phone and base
station emissions, there was some peer-reviewed literature from human and
animal studies and substantial non-peer-reviewed information, which refer to
the potential health effects caused by exposure to RF radiation from mobile
phone technology. It concluded that the balance of evidence suggests that
exposure to radiofrequency radiation below National Radiological Protection
Board (NRPB)[10]
and International Commission on Non-Ionizing Radiation Protection (ICNIRP)
guidelines ‘do not cause adverse health effects to the general population’, but
noted that ‘[t]here is now scientific evidence ... which suggests that there may
be biological effects occurring at exposure levels below these guidelines’.
The Stewart Report concluded that ‘it is not possible at present to say that
exposure to RF radiation ... is totally without potential adverse health effects,
and that the gaps in knowledge are sufficient to justify a precautionary approach’.[11]
2.7
Animal studies have provided evidence of
significant responses to radiofrequency radiation, including changes in
temperature regulation, endocrine function, cardiovascular function, immune
response, nervous system activity, and behaviour; however, the significance of
biological responses at low exposure levels and their relationship to health
effects are either not agreed with or not well understood.
2.8
The Telstra Repacholi et al study in
Adelaide is one of those which has shown a significant increase in cancer
incidence for mice genetically predisposed to lymphoma, and this study is
currently being ‘confirmed’ and is referred to later.
2.9
The Committee was informed that a growing body
of research provides evidence of biological effects. This was the conclusion
of the Royal Society of Canada Report, which said:
It is clear to the panel that there are a number of observed
biological effects of exposure of cells or animals to non-thermal levels of
exposure to RF fields. These observed biological effects meet the common
standards for scientific observation in that the experiments were
well-designed, had appropriate positive and/or negative controls, contained
valid RF exposure parameters, included appropriate statistical evaluation of
the significance of the data, and have been observed to occur by more than one
investigator ...[12]
2.10
Despite this, the Australian Communications
Authority stated that ‘the evidence for production of harmful biological
effects at relatively low levels of exposure (that is, field intensities lower
than those that would produce measurable heating) is ambiguous and unproven.[13]
2.11
The World Health Organization (WHO) draws a
distinction between effects on health, which it defines as ‘the state of
complete physical, mental and social well-being and not merely the absence of
disease or infirmity’[14]
and biological effects which are ‘a physiological response that may or may not
be perceptible to the exposed organism’.[15]
In his paper on exposure to low level radiofrequency fields, Dr Michael
Repacholi, Coordinator, Occupational and Environmental Health, WHO, stated:
Biological systems respond to many stimuli as part of the normal
process of living. Such responses are examples of biological effects. It is
questionable whether reported ‘effects’, even if substantiated, can be
considered to represent evidence of a hazard simply because the significance of
the effect for the organism is not understood.[16]
2.12
Professor Litovitz, Professor Emeritus of
Physics at the Catholic University of America, said on the question of whether
or not electromagnetic fields caused health effects:
If they cause biologic effects, there is the possibility – not
necessarily, but there is the possibility – that there will be health effects.
A biologic effect does not mean a health effect, but you cannot get a health
effect without a biologic effect.[17]
2.13
Approaches to interpreting experimental results
and determining when a biological response should be considered to constitute a
health hazard include:
- any field-induced response is undesirable and should be avoided;
- exposure should be avoided if a physiological response in an
organism is measurable; and
- where no discomfort or pain is experienced, the stimulus
producing a response should be considered harmless.[18]
2.14
To establish that a biological response has
health implications, Dr Repacholi says a number of conditions need to be
satisfied, including determining whether the biological or psychological
changes are reversible, whether effects are additive, or whether there are
adequate compensation mechanisms to respond to the effects.[19] Dr Repacholi offered the
view that where dose-response relationships have not been established, it is
difficult to extrapolate results between different frequency ranges and
exposure levels, making it important to repeat experiments at different
exposures.[20]
Dose assessment is also important in epidemiological and human studies, because
of differences between ‘near field’ and ‘far field’ exposure.[21]
The role of epidemiology, in vitro and in
vivo studies
2.15
When assessing the literature, it is worth
noting that in vitro studies provide insights into the mechanisms
underlying biological effects, whereas in vivo studies of animals and
humans are considered to provide more convincing evidence of biological effects
that may have implications for adverse health consequences for people.[22] However, the most direct
information on the risks of adverse human health effects come from
epidemiological studies. Dr Repacholi commented:
Most of the known human carcinogens were first identified as
such by epidemiological studies; for this reason such evidence should not be
taken lightly, even if the findings are unexpected or are inconsistent with
other evidence ... Epidemiological studies are important for monitoring public
health impact of exposure, particularly from new technologies.[23]
2.16
This view is supported by medical practitioner
and specialist in occupational medicine, Dr David Black, who noted that
‘[e]pidemiology is frequently misunderstood, and often wrongly criticised as
being limited to showing associations but never proving causation’.[24]
2.17
In his submission, Dr Black describes some of
the criteria of causation for epidemiological studies. It also identifies the
different types of evidence relevant to human health studies. These range from
experimental studies, which he says while providing some of the strongest
evidence of cause and effect, could not be applied to human populations when
the effect is harmful, and have limitations when the results from animal
studies are applied to humans because of species differences; cohort and
case-control studies, which compare groups which do and do not exhibit the
effect, considered to be less precise than experimental studies and requiring a
number of consistent studies before a conclusion can be drawn; ecological
studies which are considered weaker than the two previously described because
they study exposure between population groups rather than individuals, and are
generally used for formulating or refining hypotheses for case-control or cohort
studies; and finally, individual case studies, descriptive studies, anecdotal
evidence etc, which are rarely proof of a definitive relationship but may
suggest the need for further research.[25]
2.18
Dr Black also said the use of statistical
significance to describe scientific results is also defined as indicating ‘the
way the data has fallen but does not take into account reasons for this that
are not related to true cause and effect, such as bias, confounding or
statistical variation’, and therefore ‘statistical significance’ per se
should not be confused with ‘causation’.[26]
2.19
Dr John Moulder, Professor of Radiation Oncology
at the Medical College of Wisconsin, USA, when discussing cancer risk
assessment, observed:
When the epidemiological evidence for an association between a
physical agent and cancer is weak and/or the link is biophysically implausible,
laboratory studies are critical for risk evaluation. If there is strong
cellular (in vitro) and/or animal (in vivo) evidence that an
agent is carcinogenic, it can make even weak epidemiology evidence for an
association credible. Conversely, if appropriate laboratory studies are done
and these studies fail to show any consistent evidence for carcinogenic
activity, then we tend to dismiss weak epidemiological evidence, particularly
if the association is biophysically implausible.[27]
Replication
2.20
One of the most contentious issues with regard
to the way in which evidence from scientific studies is interpreted and
afforded credibility is the question of replication, confirmation or
verification.
2.21
The Mobile Manufacturers Forum argued:
... the results of any individual study cannot be considered
sufficient to establish or refute a possible human health risk. Individual
studies must be validated and replicated before they can be relied on, and the
determination of whether a potential health hazard exists requires a weight of
evidence that evaluates all relevant, credible and valid data.[28]
2.22
Professor Mark Elwood, epidemiologist and public
health expert, stated:
I want to emphasise only one methodological principle relating
to most of these studies, and that is a general principle of epidemiology and,
indeed, of science; that is, when you do a study which finds an unexpected and
new finding which has not been reported before, it is very difficult within
that study to assess whether that finding is meaningful or whether it is due to
chance variation. The only real way to assess it is to set up a second,
independent study to test it.[29]
2.23
Dr Moulder argued that the failure to replicate
results may be indicative of flaws in the original study:
... [the fact] that you cannot confirm and replicate it implies
that there is something at least slightly wrong with the original – not
necessarily totally wrong but something did not happen the way the authors
think it happened. At the first stage of an attempt to confirm, where you have
somebody reporting something and somebody else saying they cannot confirm it,
you really cannot necessarily believe either study ... Sometimes it is not clear
and you basically have to wait for more people to attempt to do it and you end
up making what is basically a weight of evidence argument.[30]
2.24
Dr Neil Cherry from Lincoln University, New
Zealand, reported in his submission that Dr Repacholi had informed an industry
sponsored press conference that there was no evidence that GSM cellphones were
hazardous to health:
At the conference he [Dr Repacholi] presented his paper on the
Telstra funded project that showed that GSM cellphone radiation at quite low
non-thermal levels, doubled the cancer in mice. When challenged by the
conference chairman, Dr Michael Kundi, Dr Repacholi said that a study is not
evidence until it is replicated. The conference rejected this. A study is
evidence. Replication provides confirmation and establishment.[31]
2.25
Dr Cherry also pointed out that in replication
work there can be unforseen variables:
It was shown in the calcium ion efflux work of Dr Blackman that
biological effects in the laboratory can vary with the local magnetic fields,
with temperature and with a number of other factors.[32]
2.26
Professor Litovitz advised the Committee:
There have been a large number of publications, and certainly
over 100 have reported non-thermal biologic effects at exposure levels below
that considered safe by most government standards. If there have been that
many publications, you can ask the question: why is there controversy? If all
of these papers are out there and every scientist is correct, why is there such
a controversy and why is there so much argument? The answer is that the papers
do not all agree. For almost every paper you see on biologic effect, you will
see papers that say ‘I didn’t see anything. I see a big effect, but I didn’t
see anything.’
... So I ask myself: is this field of biomagnetics a junk science
field? Are these scientists out there who see effects at low levels all
incompetent, or worse? The answer is that lack of replication – that is to
say, two scientists disagreeing – is not limited to bioelectric magnetics but
rather it is a general problem in toxicity, it is a general problem in biology.
... Let us take drug X, whose name is not important. We ask this question:
does this drug induce deformed limbs in Norway rats? The results are as
follows. In one set of experiments, those treated with the drug show 60
percent deformed limbs, those untreated eight per cent. You have to conclude
from that experiment that this drug is a teratogen, that is to say it causes
abnormal embryos. ... This is not a story, this is a publication.
The difference between these experiments is that they were both
using Norway rats, but there are all kinds of Norway rats – just like we are
all people but we are genetically enormously different, and we are genetically
enormously different in our susceptibility to various kinds of stress. So even
though you go out and buy these rats that does not mean you have identical
rats. The drug that was used in this experiment was called thalidomide, which,
as you well know, was an enormous disaster. It was a disaster because it was
only studied in one strain and was not studied in the other.
The difference in genetic susceptibility of the test animals was
never taken into account, and this experiment was only done after 10,000
children were born without limbs. So this lack of replication does not mean
that there is no scientific validity. It means that science is complicated; it
means that biology is complicated, and that the human system is complicated –
and even rats are complicated.[33]
2.27
Professor Litovitz also cited an experiment in
the US in which six laboratories with identical equipment tested chick embryos
to see if magnetic fields caused abnormalities:
... When these six laboratories’ results came back, two said yes,
two said absolutely no, and four said, ‘We might see something.’ ... Six months
later we made a measurement again and found no effect. ... As we went through
the three-year period, we found an enormous genetic compound in the response of
chick embryos to electromagnetic fields. ... It is not that you [the laboratory]
did something wrong; it is the genetics. They were working with different
genetic material.[34]
2.28
The Committee queried whether the Vernon-Roberts
study (see Australian research below) could be considered a true
replication of the 1997 Adelaide mouse study, given the modifications that have
been made to the original methodology. Dr Repacholi, from the World Health
Organization and member of the Adelaide mouse study team advised:
... in initial studies they may have done something that is not
particularly helpful or there is a better way of doing it. If the result is a
true result it should still occur in the animal. There is no reason to expect
that you are still exposing the animal to radiofrequency fields using the same
pulsing regimes, maybe different times, different orientations, but if there is
going to be an effect it should still occur. We were very careful in reviewing
the follow-up study in Adelaide, and there is another study being done in
Europe, to make sure that, yes, what was done in the original study is going to
be either confirmed or not confirmed in these studies.[35]
2.29
In referring to the Adelaide mouse confirmation
study, Dr Thomas Magnussen, CEO of the EMX Corporation, said:
... but there are significant differences between the two
experiments. For instance, Repacholi’s first experiment ran for 18 months.
The new one is going to run for 24 months. The way the animals are exposed is
quite different in the two experiments. The genetics can never be the same.
When we are talking about biological experiments, it is virtually impossible to
make a replication.[36]
2.30
The Consumers’ Telecommunications Network
commented that there was insufficient evidence to conclude that there are no
potential health risks associated with radiofrequency radiation.[37]
2.31
Dr Black said that in science it is impossible
to prove a negative, and thus it will not be possible to claim that there are
no health effects, only that the evidence suggests that such a scenario would
be highly unlikely, as illustrated by the following statements:
... it is frequently stated by people who are concerned that the
application of [radiofrequency] technology should not proceed until there is
proof of the absence of any adverse effect. The answer to this can only be
that there will never be such proof about RF, or for that matter anything else
...
It is also equally true that it is theoretically impossible to
provide absolute unarguable proof of an association.
The only conclusion which can be drawn from an understanding of
the principles of epidemiology and of the assessment of scientific data is that
whilst it is possible to prove an association with substantial and convincing
certainty, it is impossible to prove an absence of an association in such a
compelling way.[38]
2.32
Before outlining the research that is currently
under-way both in Australia and overseas into electromagnetic radiation and its
effects as it relates to telecommunications equipment, this section summarises
what is known so far about the biological and health effects of electromagnetic
radiation.
2.33
Expert reviews referred to at the beginning of
this chapter have relied upon existing literature and a number of witnesses
have concluded from scientific abstracts that there are potential health
effects of EMR.
2.34
Mr Stewart Fist, journalist, claims to have the
largest website collection of abstracts of scientific research publications and
says that about 60 per cent of them show effects from non-ionising radiation.[39]
2.35
The World Health Organization website includes a
database of current and published research into the biological and health
effects of radiofrequency radiation.[40]
2.36
Some witnesses expressed the view that while
this information is a valuable resource in understanding the science, it was an
inadequate substitute for a working knowledge of the material. The CSIRO’s
submission to this inquiry commented on its own limitations in relying on
research by others:
CSIRO is maintaining a watching brief, although it appreciates
the limitations of attempting to evaluate research without the benefit of involvement
and participation. Independent, authoritative scientific information is
provided in response to enquiries from Government and the community.
The absence of involvement in scientific research into
biological effects of EMR is a recognised limitation in any assessment of the
state of research. It is only possible to fully understand the complexities of
sophisticated biological procedures through experience gained from working at
the bench. Unfortunately, this level of expertise and understanding is
lacking, or indeed absent, in many of the participants of committees or working
groups that try to make assessments of the veracity of scientific research.[41]
Is the scientific evidence inconclusive?
2.37
The most recent expert reviews of the relevant
electromagnetic radiation literature suggest that the results in this area are
inconclusive.[42]
2.38
Industry submissions generally argued too that
the science was inconclusive. Hutchison Telecommunications, said in its
submission:
... the world’s leading experts and key health advisory bodies
state that there is no substantiated evidence to suggest a link between the use
of mobile phones and long term public health risks, but we acknowledge there is
public concern on this issue.[43]
2.39
Nokia Mobile Phones, Australia, said:
... a substantial amount of scientific research conducted all over
the world over many years, demonstrates that radio signals within established
safety levels emitted from mobile telephone[s] and their base stations present
no adverse effects to human health.[44]
2.40
Motorola Australia, said:
... the scientific evidence does not demonstrate a risk to public
health from wireless phones.[45]
2.41
In his submission, Mr Neil Boucher, said:
Most of the ‘research’ that has been carried out on the health
effects of electromagnetism are top down studies. That is people are
assembled, with largely medical and statistical qualifications (and usually
with little or no knowledge of electromagnetism itself), to look for
epidemiological evidence of some health effect. The fact that nothing
conclusive has been found to date testifies both to the relative insignificance
of any effect (if it exists) and to the futility of the methods employed.[46]
2.42
The Australian Communications Authority (ACA)
submitted that radiofrequency devices that operate in accordance with
recognised human exposure standards do not pose a health risk.[47]
2.43
The Committee notes the observations in the
Stewart Report:
We were struck by certain inconsistencies and inadequacies in
the scientific literature on the biological effects of RF radiation. Many
studies in this field have been exploratory and preliminary in nature, and
claims of effects have sometimes been based on single experiments rather than a
consistent series of hypothesis-driven investigations. In some cases, study design
and statistical analysis have been inadequate, and apparent effects may have
been artefactual or due to random variation. Indeed, the field is troubled by
failures to replicate previous studies and by a lack of theoretical explanation
of some effects that have been claimed. There may also be biases arising from
selective publication and non-publication of results.
Finally, even for effects that appear to be well substantiated,
the biological significance and the implications for health are often unclear.[48]
2.44
Not all witnesses were of the view that the
evidence was inconclusive. Dr Neil Cherry told the Committee that his
work in preparing for a tribunal hearing for the first mobile phone base
station in NZ in 1995 had led him to examine epidemiological and biological
research from around the world:
I was very surprised there is so much published evidence in
reputable, peer review journals that has not been sighted, summarised or
integrated. The more I received the more solid the evidence seemed to be and
the more consistent it seemed to be. And so when I heard people saying that
the evidence was weak and inconsistent, I decided I should debate this with
people and go to conferences and talk to them about it. ... This culminated, I
believe, in a climax last year at the conference at the European Parliament
where I was asked to look particularly at low level effects and epidemiological
studies with those response relationships of low level effects. ... Over 20
studies show that radiofrequency microwave radiation damages the genes, damages
the chromosomes, damages the DNA, and therefore indicates genotoxicity. I am
also aware that many studies only use small samples – they are epidemiological
studies or laboratory samples. They find elevated levels but they are not
specifically significant and they are often described as showing no effects.
But I have supplied with my evidence a summary of brain tumour studies, and I
have characterised them as studies showing elevated effects, studies showing
significantly elevated effects and studies showing dose response effects. And
that is a classical way, I believe, at looking at the evidence trail and
asking: was it elevated, was it significantly elevated and have we found dose
response elevation? ...
... Following those principles, I come to totally different
conclusions than Dr Moulder, Dr Black, Dr Elwood and Dr Repacholi.[49]
2.45
Mrs McLean of Electromagnetic Radiation Alliance
of Australia (EMRAA), said that many studies are showing a range of effects,
including brain tumours, leukaemia, heart problems, neurological problems,
neuro-degenerative diseases, breast cancer and affects on the immune system, as
well as affecting melatonin levels, enzymes, hormones, genes and signal
transduction in cells[50].
These are discussed later in this chapter.
Anecdotal and non-peer-reviewed evidence
2.46
A number of submissions to this inquiry referred
anecdotally to cases of brain tumours,[51]
headaches,[52]
hyperactivity in children and nausea,[53]
skin growths protruding from the ear against which the mobile phone was held,[54] chronic fatigue,[55] nose bleeds,[56] and other health effects,[57] which they linked to mobile
phone use.
2.47
Submissions also noted that expert panels, such
as the Independent Expert Group on Mobile Phones (the Stewart Group), had been
presented with anecdotal evidence of adverse health effects from mobile phones
and their base stations, which were claimed to be related to non-thermal
effects of radiofrequency radiation.[58]
Reference was also made to reports of ‘microwave sickness’ from mobile phones,
including headaches, fatigue, impotence, blood pressure changes, chest pain and
sleep disturbance.[59]
One submission raised the possibility of a link between legionnaires disease
outbreaks with the presence of mobile phone towers and high voltage power lines
in the vicinity of cooling towers.[60]
2.48
The Committee notes the conclusions of the Royal
Society of Canada Report:
Headache and fatigue are nonspecific symptoms. ... Headache is not
an indicator of ‘brain activity’ and in general headaches occur in the absence
of structural abnormalities of either the brain or the blood-brain barrier. ...
Although there is need to consider the possibility of [microwave-induced]
symptoms such as headache and fatigue, existing data do not support the
conclusion that [microwave fields] can induce headaches.[61]
The panel did not find persuasive evidence of the existence of
radiofrequency radiation sickness syndrome, however, some individuals may be
able to sense when they are exposed to radiofrequency fields.[62]
2.49
The Report recommended further research into
this area.
2.50
While the EMR Safety Network International
argued that anecdotal evidence should be heeded,[63] Dr Repacholi argued that this
type of evidence is more valuable in establishing a hypothesis, rather than as
proof of causal effect:
When reviewing the scientific literature, only independently
confirmed effects can be considered when assessing health risk. For
establishing research needs, effects which have not been confirmed, but are
possible and could have implications for health, should be considered because
they may ultimately be established.[64]
2.51
The Committee notes that the Stewart Group
included evidence from sources other than peer-reviewed scientific journals as
part of its assessment of the potential health risks associated with exposure
to radiofrequency fields.[65]
The Committee was advised that material that has not been peer-reviewed can
suffer from several shortcomings, including deficiencies in methodology,
analysis and conclusions.
2.52
Dr Repacholi said that the quality of peer
review can vary and that the results of many studies need to be compared and
evaluated before a conclusion can be drawn.[66]
2.53
Dr John Moulder mentioned difficulties in
selecting suitable independent candidates to undertake peer review,
particularly in small and highly specialised fields such as dosimetry:
What I do is look for people who are involved in the specific
field but who have no direct connections, either positive or negative, with the
authors of the study. Sometimes that is in fact impossible. I will explain
what I would do if I could not find the perfect person by taking the example of
radiofrequency radiation and cancer in animals. If everybody who is in that
field is conflicted, I might look for someone who is an expert in RF dosimetry,
even though they knew nothing about cancer, and then look for someone who was
into carcinogenesis in animal models, even if they knew nothing about
radiofrequency radiation, and then possibly back that up with a statistician
who would not necessarily be familiar with either, but statistics is
statistics.[67]
Publication and research bias
2.54
Dr David Black, in his submission, also drew the
Committee’s attention to what he described as ‘publication bias’, whereby
journals may prefer to publish a paper where the study has produced ‘novel’
results rather than one ‘simply reiterating a well accepted status quo’. A
similar bias was suggested in relation to difficulties in attracting funding
for studies considered ‘likely to be simply reiterating well established fact’,
and that these two biases need to be considered when undertaking a literature
survey.[68]
The Committee also notes the comments of Dr Stan Barnett, CSIRO:
One of the biggest difficulties that we have in this particular
area of research is that there are all sorts of biases in research generally.
That is a given. You have to take adequate controls to make sure that you do
not allow those biases – the experimental biases, the observer biases and the
biases in the statistical analysis program that you use. All of those things
are biases which researchers are familiar with and which we understand ... but
before you even start the research one of the biggest biases that exists
generally is that of selection bias. ... Selection bias is simply that the
person who has the money ... has the resources and therefore has the ability to
select, firstly, the type of research that they want to spend their money on;
secondly, the facility where they would like to have it done ... and, thirdly,
they can select whomever they wish to do that research, whether it is somebody
who has the necessary experience in the area or somebody who has a high
profile. There may be issues other than the essential science that determine
the selection of the research that is undertaken.[69]
2.55
Concerns raised about the difficulties in
obtaining funding for replication studies are referred to in Chapter 3.
Biological effects
2.56
A number of studies have linked exposure to
electromagnetic radiation with a range of biological and health conditions
including: high blood pressure in humans; severe depression of the
immunological and endocrinological responses of young chickens; increases in
the permeability of the blood-brain barrier; calcium efflux from brain tissue;
effects on the dopamine-opiate system considered to be involved in headaches;
influences on epileptic activity; and increases in the mortality of chick
embryos. Studies have also found evidence of chromosome aberrations and
increases in double and single strand DNA breakages, and increases in the promotion
of certain cancers in genetically predisposed mice.[70]
2.57
Biological effects that have been specifically
linked to radiofrequencies include changes to calcium ion mobility in the
brains of cats and rabbits as well as isolated cells and tissues, changes to the
proliferation rate of cells, alterations to enzyme activity, and affects on
genes.[71]
The search for a mechanism
2.58
Various mechanisms have been proposed for the
way in which radiofrequency fields interact with biological systems, generally
involving the induction of movement of molecules.
2.59
Professor Philip Jennings, referred to
ferrimagnetic material in human tissue with possible implications for the
interaction between electromagnetic radiation, particularly extremely low
frequencies, and biological systems.[72]
2.60
Professor Litovitz said:
There are those who believe that only heat can cause an effect
and there are those who believe otherwise, whose experiments suggest that it
takes only a signal to a cell to cause the cell to do something. The cell has
its own energy; you supply the trigger and the cell proceeds to produce enzymes
and proteins, et cetera. ... Let us look at the example of garage door openers ...
You are in your car and you press this and your garage door opens. The
question is: can you believe that this supplied the energy for the garage door
to open? Was it this that supplied the energy for that motor to pick up the
garage door? We are saying no. We are saying that this is a signal that
turned on the energy to the motor. That is the similarity, that is what
athermal effects are all about: cells receive a signal and turn on the engine
inside the cell which produces proteins, which produces enzymes necessary for
survival.
We have studied in detail the target of the EMF and we now know
the number of milliseconds that it takes the cell to be able to say there is a
field there. ... It is well known in biology that this information goes to a
process called signal transduction on the surface of the cell or receptors.
They say something and send a signal to the nucleus, which proceeds to undergo
various biochemical processes. This takes seconds.[73]
... We are now working on a possible mechanism which relates EM
field exposure to health effects. We find that EM fields alter the levels of
protective proteins. It turns out that the major effort in my lab today is to
use these non-thermal effects to protect against damage due to heart attacks,
to treat cancer and to treat inflammation. These non-thermal effects are
remarkably useful, and will be useful in the next few years, in therapy. The
question is: when are they therapeutic and when might they be harmful?
... You have a protein that works, you come in with a
electromagnetic field stressor, the protein is damaged and unfolded, nature
produces protective proteins, goes in and refolds the protein and repairs the
damage. This is one of the most exciting discoveries in the past 30 years in
medicine. These protective proteins, these stress proteins, are being studied
by almost every pharmaceutical company in the country because of their
potential, because they are the basic repair mechanisms ... and we have found
that EM fields can modify the amount of protective proteins that you have. I
say ‘we’ – there is a minimum of four, and I think it is five, labs that have
replicated the concept that EM fields can affect protective proteins. ...[74]
There is a theory now that these protective proteins are related
to Alzheimer’s and that a reduction in protective proteins means a greater
probability of Alzheimer’s. This is a theory which we have not tested, but
there is data out there that appears to relate the incidence of Alzheimer’s to
exposure to electromagnetic fields. ... We cannot necessarily say that there is a
health effect, but we can say that mechanisms exist for potential health
effects.[75]
2.61
Dr Peter French drew a link between evidence of
the role of heat shock proteins in cancer and mobile phones:
In plain English, the point
is that it has been demonstrated by several researchers that increasing the
amount of heat shock proteins in cells results in the increased potential for
developing tumours, increased stimulation of metastasis or spread of cancers,
the direct development of cancer, de novo, and the decreased effectiveness of
anti-cancer drugs. Any one of these outcomes is obviously undesirable, but
there is, within the heat shock protein and medical research literature,
evidence for each of these statements.
... where are we with the
mobile phone cancer link? This is a summary of this part of my presentation.
A mobile phone user will experience energy from the radiation of the phone
going into the brain. That can induce some physiological effects, as has been
published by Krause et al, but, importantly, it can potentially induce the heat
shock response in the brain which can lead to the turning on of heat shock
proteins. For a single event that is fine, because that is the body responding
defensively. Normally it takes four to eight hours for the protein machinery
to work after the protein machinery has been activated. It takes from four to
eight hours for the proteins to be secreted, to be made and then ultimately
they disappear if they are not needed. If you continually use a mobile phone,
you can imagine that the heat shock proteins would be chronically induced,
similar to the over-expression studies which have been described. Continued
regular mobile phone use can result in chronic expression of heat shock
proteins, which can lead to – from
those findings which are referenced there – increased metastasis, initiation and promotion of cancer and resistance
to anti-cancer drugs.
I am not saying mobile
phones cause cancer. I am saying that this is a pathway – which is founded on solid, peer reviewed
international science – which
provides a mechanism whereby mobile phone radiation could lead to cancer.
Given that that is the case, then I would contend that some action is needed.
If this is a possibility, then clearly research is needed to determine whether
in fact heat shock proteins are being induced in the brains of mobile phone
users; furthermore, we do not need to wait 30 years until that bottom line is
confirmed. ...
... The link has been made by
me. Having said that, the mechanism by which microwaves may cause protein
unfolding, leading to the heat shock response, has not yet been determined, and
there are a couple of possibilities. De Pomerai’s group says that there may be
a resonance of the microwave field with the protein or with the water. We have
published, and it is in the written submission, a hypothesis paper in the Journal
of Theoretical Biology which advances those two possibilities as well, for
attributing low power as another stressor to activate the heat shock response.[76]
2.62
Associate Professor Olle Johansson from the
Karolinska Institutet in Sweden, in discussing the health effects of visual
display units, referred to the role of mast cells as a possible mechanism:
Here in Sweden, the problems
around different types of electromagnetic devices arose with the introduction
of radio in the twenties and thirties but it was much more evident in the late
seventies. When the PC explosion came, all the offices were turned into
computer based systems and people were sitting all day long in front of visual
display terminals of different types. At the end of the seventies and at the
beginning of the eighties, a growing number of people complained of different
symptoms, especially from their face, on their neck, arms and hands after they
had been sitting in front of these visual display terminals. From the very beginning,
it was not understood what was going on, but people were searching around in
the working environment for different explanations. Very soon, the ideas
focused upon the radiation from the visual display terminals. With respect to
the symptoms, one could mention, for instance, skin problems, facial burning,
redness, dry skin, facial heat, swelling, tingling sensations and even
blisters. Also, it was connected with feelings of fatigue and headaches, and
memory losses were claimed et cetera. Of course, as scientists we tried to
understand the symptoms.
... In the last years, the
focus has been much more on different high frequency devices, which of course
include modern computer screens but also include light tubes of high frequency,
different kinds of telecommunications systems, such as wireless DEC telephones,
different radio alarm based systems and, of course, mobile telephones.
Parallel to this, a number of investigators – some among them having some very interesting data from Australia –
have documented the results of experiments
at the cellular and tissue level of different animals and humans which show the
effects of, for instance, exposure to high frequency signals from mobile
telephones. ...
... there are now more and
more studies coming out pointing to possible mechanisms, from the cellular and
molecular level, all the way up to more macroscopic events. Our working
hypothesis is very simple actually. For instance, looking at human skin, both
from patients claiming these kind of health problems and from normal healthy
volunteers who have sat in front of visual display terminals, we see
alterations in different cell types. For instance, the histamine contained in
mast cells is identical to what you would see – and it is reported also in the literature – from other irradiation damage sources: for
instance, from sunrays, X-rays and radioactivity. Our very simple and maybe
naive working hypothesis that this irradiation damage is of a more long-term
type compared to other more energetic irradiation damage.
Of course, the molecular
cell biochemistry machinery has to be worked out in detail and this work is, of
course, going on. As I said before, in Australia, you have the research team
around Peter French and his collaborators that has been studying these mast
cells that have been irradiated using high frequency mobile telephone signals.
From their studies, it is evident that these cells are affected. You then have
to imagine what would happen if you have the same situation in a human being.[77]
2.63
Dr Cherry proposed another mechanism:
... The early studies show that oscillating signals interfere with
the brain very significantly and can change the EEG and can change the calcium
ions, and these change reaction times. This is a classical physics approach of
resonant absorption. If a system can oscillate and an oscillating signal comes
in, it can resonantly be absorbed. It is what an aerial does, it is what a
cell phone does, it is what is used in telecommunications, ... It has been
demonstrated in many laboratories that it actually does occur.[78]
2.64
But according to Dr John Moulder, in order to
induce a biological change, ‘radio-frequency radiation must deposit enough
energy to significantly alter some biological structure’.[79]
2.65
In noting some of the current hypotheses about
possible biological interactions, Dr Repacholi stated:
These RF field-induced alterations, if they occur, could be
anticipated to cause a wide variety of physiological changes in living cells
that are only poorly understood at the present time.[80]
2.66
While observing that thermal effects may account
for positive results, the Stewart Report considered that reports of epigenetic
effects should be taken seriously and further research undertaken.[81]
2.67
The Committee notes that a number of studies
cited in submissions as providing evidence of biological or adverse health
effects relate to extremely low frequency (ELF) exposure. Areas of similarity
between the effects of radiofrequency radiation and extremely low frequencies
include effects on calcium efflux, ODC[82]
activity and behaviour associated with the opioid system. The Royal Society of
Canada Expert Panel suggested that ‘many of the efforts now underway to
understand the mechanism associated with ELF effects could be used to
investigate the mechanisms by which ELF-modulated RF fields elicit non-thermal
effects’.[83]
2.68
The importance of determining the biological
mechanism(s) responsible for any observed effects, particularly in relation to
the setting of safety standards, was highlighted by the CSIRO:
... it is generally agreed by various expert panels that research
on mechanisms of interaction is essential. Without an understanding of how low
energy RF fields cause these biological effects, it is difficult to establish
safety limits particularly for non-thermal levels.[84]
How important is it to distinguish between
frequencies?
2.69
Dr Moulder argued for the need to clearly
distinguish between the evidence for adverse health effects from exposure to
radiofrequency radiation as opposed to extremely low frequencies (ELF). The
applicability of ELF research to radiofrequency exposure was referred to by EMF
South World Pty Ltd:
... observed bioeffects induced by mobile phone microwave
radiation[85]
are remarkably similar to bioeffects induced by power-line frequency EMF.[86]
This means that two decades of epidemiological data on power-line frequency EMF
can be used in the debate on potential health effects of mobile phone
radiation, on which there is virtually no epidemiological data.[87]
2.70
Dr Moulder advised that it was not appropriate
to extrapolate the results of exposure to frequencies from different areas of
the electromagnetic spectrum:
... the biophysics of the interaction is completely different. I
do not want to be absolutist ... But, in general, if you want to understand the
biological effects of radiofrequency radiation, you use radiofrequency
radiation.[88]
2.71
Dr Moulder later added:
In general ... most of the effects of radiofrequency radiation
that we know of are not strongly dependent on frequency ... But the bigger the
jump you make, the less certain you can be ... if we finally concluded that
radiofrequency radiation was safe enough for all practical purposes, that does
not tell us whether powerline frequency is safe. ... But, if you demonstrated
that the frequencies used for FM and television were hazardous, then you would
certainly worry about cell phone frequency. It would not prove it, but the
closer together in frequency your information is, the more likely it is to be
relevant.[89]
2.72
The Committee notes, however, the views
expressed by Professor Philip Jennings, who stated:
Our society’s experience with ionising radiation should persuade
us to take great care ... The original standard set for ionising radiation
protection ... has proven to be quite inappropriate and as further research has
been performed and evaluated the public limit has been reduced by nearly a
factor of a thousand. This could also happen with EMR. We are still in the
infancy of EMR research and we should learn from the mistakes we made with
ionising radiation and introduce a principle of prudent avoidance or ALARA’.[90]
2.73
Professor Litovitz argued that:
The cell’s characteristic response to a mobile phone is the same
as that to a power line. This was beautiful for us, because it meant that all
the data out there on powerline problems could be translated to the data on
cell phone or mobile phone problems. That is to say, you could put them
together to try to understand what is going on.[91]
2.74
Many of the studies cited during this inquiry
relate to extremely low frequency (primarily 50/60Hz) exposure, which report
observed effects on the reproductive system, blood changes, ECG[92], heart rate, blood pressure
and body temperature, melatonin and cancer.[93]
Studies have also been conducted into the health implications of exposure to
radars, which operate at radiofrequencies ranging from 300 MHz to 15 GHz.
2.75
Submissions and evidence to this inquiry have
referred to biological and health effects associated with powerlines, radio and
television towers and video display units (see below); however, this inquiry is
concerned with electromagnetic radiation associated with telecommunications
technologies.
2.76
Dr Neil Cherry reported in his submission that:
Ten epidemiological studies have found significant miscarriage
from EMR exposure across the spectrum from ELF, SW, to RF/MW. The Scandinavian
physiotherapist studies, Kallén et al. (1982) and Larsen et al. (1991) also
found significant prematurity, congenital malformation, still birth and cot
death. Ouellet-Hellstrom and Stewart (1993) confirm the causal relationship
with a highly significant dose-response relationship.[94]
2.77
Dr Cherry said it was also important to note
that if an effect is seen with low frequency signals, such as an ELF 50 Hz or
60 Hz signal, or the Schumann Resonance ELF signals, then it is more likely and
likely to be worse for modulated or pulsed RF/MW:
This is because an ELF signal has a very long wavelength and
generally passes easily right through the body. Unless there is a resonant
oscillator, such as for the Schumann Resonances, it induces quite small fields
in the body. On the other hand the RF/MW signals have wavelengths closer to
the dimensions of bodies and body parts, they are more strongly absorbed in
human bodies through the aerial effect.[95]
2.78
The Committee notes that the World Health Organization
draws a distinction between radio and TV broadcasting and telecommunications
facilities. While for the most part the Committee has confined its comments to
telecommunications technologies, in acknowledgment of concerns raised in
relation to electromagnetic radiation generally, the Committee has digressed
into other frequency ranges and technological applications in its review.
Observed biological and health effects of
radiofrequency radiation
Movement of substances across cell membranes
2.79
Studies have examined the effect of
radiofrequency radiation on the movement of substances across cell membranes.
The role of calcium in the functioning of brain and other cells has prompted
research into calcium movement in brain tissue. While some studies have shown
that low levels of RF exposure cause an increase in calcium efflux from brain
tissue, according to the Stewart Report results are contradictory, and evidence
of an amplitude modulated response at extremely low frequencies does not appear
to be relevant to mobile phone technology, ‘where the amplitude modulation
within the critical frequency band is very small’.[96] The Stewart Report further
concluded that ‘[i]f such effects occur as a result of exposure to mobile
phones, their implications for cell function are unclear and no obvious health
risk has been suggested. Nevertheless, as a precautionary measure, amplitude
modulation around 16 Hz should be avoided, if possible, in future developments
in signal coding’.[97]
Exciting
neurons
2.80
The Stewart Report found evidence that exposure
to high intensity radiofrequency fields, sufficient to result in a temperature
rise in tissue, can reduce the excitability of neurons. However, exposure at
non-thermal levels does not appear to have an effect.[98]
2.81
It also reported that various studies have
examined the potential of radiofrequency radiation to affect gene expression
and produced inconsistent results. While the well publicised study showing an
increase in the lifecycle of nematodes may be suggestive of a non-thermal
effect, the report said that there was little evidence to support the
proposition that mobile phone radiation causes a stress response in mammalian
cells.
ODC
activation
2.82
The enzyme ornithine decarboxylase (ODC) plays a
role in the synthesis of polyamines which can trigger DNA synthesis, cell
growth and cell differentiation. Activation of ODC has been related to the
late, ‘promotional’ phase of cancer production, which is usually (but not
always) correlated with an increase in the rate of cell division in the
affected tissue. Again, the results of studies examining the effects of
radiofrequency radiation on ODC activity have been mixed. Positive findings do
not indicate an obvious pattern of dose-response or reveal a mechanism to
explain the changes. The Stewart Report noted that although all carcinogenic
factors stimulate ODC, not all stimuli that increase ODC activity promote
cancer, and said it was unlikely that the small increases observed from
exposure to pulse-modulated radiofrequency fields could, on their own, have a
tumour-promoting effect.[99]
2.83
The Royal Society of Canada Report states that:
... the lack of major [cell] proliferative response in the tissue
of cell line following ELF exposure does not necessarily mean that ELF is
incapable of serving as a tumour promoter, particularly if alterations in ODC
activity are involved .... It is possible that this small change in ODC activity
brought about by ELF is unrelated to human cancer risk.[100]
2.84
The Report suggests that further research is
warranted.
Heat-shock
protein response
2.85
Dr Peter French indicated that the heat-shock
protein response which is activated by external stressors such as chemicals,
heavy metals, drugs and radiofrequency radiation has been shown in a separate
study to be causally linked to cancer formation. Other research submitted by
Dr French suggested a link between RF exposure, cell changes and gene
transduction.
Melatonin
production
2.86
Submissions referred to studies that had shown
that extremely low frequency (ELF) electromagnetic fields reduce melatonin
production by the pineal gland, and the magnetic fields prevent melatonin from
inhibiting the development of breast cancer.[101]
Circulating levels of this hormone have a strong circadian rhythm with
melatonin levels peaking in humans at night. Melatonin affects the mammalian
reproductive system as well as other physiological and biochemical functions.[102] While it may be hypothesised
that similar effects may result from exposure to radiofrequency radiation, the
Royal Society of Canada Report said that additional research is required to
test the effects of RF radiation on pineal function, circulating melatonin
levels, and the utilization of melatonin by target cells and tissues.[103]
2.87
Dr Cherry cited a study from Switzerland on the
Schwarzenberg tower:
... They were sampling melatonin before and after the tower was
permanently turned off and they found a significant rise in melatonin after the
tower was turned off. They found a dose response increase in sleep
disturbance. When the tower was turned off experimentally, the sleep quality
improved and melatonin rose in animals.[104]
2.88
The Stewart Report commented that part of the
brain and the gland involved in melatonin production are further from the
surface of the head in humans than in animals and concluded that:
... even if there were an effect on melatonin production in
animals resulting from a direct interaction of fields within the brain, it
would be much less likely to occur in people.[105]
2.89
In his submission, however, Dr Cherry claims
that EMR reduces melatonin and enhances free radical activity in humans and
that this is genotoxic, damaging the DNA and chromosomes, enhancing oncogene
expression and transforming cells to neoplastic cells and causing cancer in
exposed populations.
We have natural EMR-based communication systems in our brains,
hearts, cell and bodies. External natural and artificial EMR resonantly
interacts with these communication systems altering hormone balances and
damaging organs and cells. The brain and the heart are especially sensitive because
they mediate and regulate primary biological functions that are vital to life,
thinking and heart beat, using EMR signals, the EEG and ECG. When EMR
interferes with the EEG this is communicated to the body by neurotransmitters
and neurohormones, including the serotonin/melatonin system. EMR reduces
melatonin. Melatonin is vital for the health of the Immune System, the Brain,
The Heart and every cell, because it is the most potent naturally produced
antioxidant. It is a potent free radical scavenger that plays a vital
protective role to protect the DNA in every cell. Reduced melatonin causes
cancer, miscarriage, heart disease, neurological diseases, viral and bacterial
diseases, etc....[106]
2.90
In his submission, Dr Cherry says:
Cancer is a chronic disease problem from accumulated genetic
cell damage. Latencies for children and soft tissue cancers are as short as a
few years, for most cancers they take 10 to 40 years to develop. Cancer rates
rise rapidly with age over 65 years because of the life-time of accumulated
cell damage and the drastic reduction in melatonin that occurs after puberty.[107]
Figure 1: Melatonin Production varies with age, Reiter & Robinson
(1995)[108]
This shows how vulnerable very young children are because they
have very low melatonin levels and undeveloped immune systems. It also shows
how reduced melatonin makes older people more vulnerable and much more prone to
disease and cancer.[109]
2.91
Dr Cherry cited a large epidemiological study of
female breast cancer over 24 states in the US which identified several organic
solvents, including organochlorines, that significantly increased the incidence
of breast cancer and which showed that radiofrequency fields were as dangerous
as toxic chemicals and ionising radiation.[110]
Table 1: Breast cancer from occupational exposures,
Cantor et al.
(1995) [111] |
|
Substance
|
Odds Ratio
|
95%Confidence Interval
|
|
Carbon Tetrachloride
|
1.13
|
1.1-1.2
|
|
Methylene chloride
|
1.15
|
1.1-1.2
|
|
Styrene
|
1.18
|
1.1-1.3
|
|
Metals and Oxides
|
1.13
|
1.0-1.3
|
|
Ionizing Radiation
|
1.14
|
0.9-1.4
|
|
Radiofrequency fields
|
1.15
|
1.1-1.2
|
2.92
Dr Cherry says this evidence is backed by more
than 10 other studies showing that EMR across the spectrum increases breast
cancer incidence and 15 studies showing reduced melatonin, including four with
dose-response relationships:
... These are sufficient to classify a causal relationship between
EMR and breast cancer, with melatonin reduction [a]s the biological mechanism.[112]
2.93
Dr Cherry also cited studies which found that
melatonin reduction can be a cause of miscarriage and that microwaves
significantly increased the incidence of miscarriage in a dose-response manner
in the first trimester and that very young babies are sensitive to variations
in the natural EMR at extremely low levels:
One of the most important single studies involved cot death
(Sudden Infant Death Syndrome) in Ontario, Canada. O’Connor and Persinger
(1997) were investigating the GMA melatonin hypothesis by seeing if a
melatonin-related syndrome (SIDS) varied with GMA. They found that SIDS
incidence significantly increased when GMA >30 nT and GMA <20 nT, - a
homeostatic result. This confirms that GMA causes illness and death in
vulnerable people, babies, and involves melatonin homeostasis.[113]
Blood brain
barrier
2.94
A number of studies have examined the potential
of radiofrequency radiation to affect the permeability of the blood-brain
barrier.[114]
While most studies have had negative results, one study did find an increased
blood-brain permeability to albumin in RF irradiated rats. While it has been
suggested that blood-brain barrier breakdown following microwave radiation
exposure may be due to thermal effects, some researchers have suggested that
the disturbance may occur under ‘power window’ conditions where there may be a
range of power intensities at which the barrier remains intact.[115]
2.95
The Stewart Report concluded that ‘[t]he
available evidence for an effect of RF exposure on the blood-brain barrier is
inconsistent and contradictory. Recent, well-conducted studies have not
reported any effects’.[116]
In contrast, the Royal Society of Canada Report stated that effects on the
blood-brain barrier permeability, calcium efflux and ODC activity ‘occur at
exposures not thought to elicit thermal effects, [and] it is likely that these
effects, even if they also occur at higher exposure levels, are non-thermal
biological effects’.[117]
DNA
2.96
A number of studies also have examined the
potential of radiofrequency fields to cause damage to DNA, and some have found
no effects at non-thermal levels of exposure. While radiofrequency fields do
not have sufficient energy to break chemical bonds or directly cause DNA strand
breaks, several studies have shown an increase in breakages at non-thermal
levels of exposure and chromosomal aberrations. Whilst these studies have not
been replicated, they are ‘confirmed’ by the fact that they were similar and
carried out in laboratories independent of each other.
2.97
According to Dr Cherry:
The first identified study that showed that pulsed RF radiation
cause significant chromosome aberrations was Heller and Teixeira-Pinto
(1959). Garlic roots were exposed to 27 MHz pulsed at 80 to 180 Hz. for 5
mins. They were examined 24 hrs later. They concluded that this RF signal
mimicked the chromosomal aberration produced by ionizing radiation and
c-mitotic substances. No increased temperature was observed. ...[118]
Garaj-Vrhovac et al. (1990) noted the differences and
similarities between the mutagenicity of microwaves and VCM (vinyl chloride
monomer). They studied a group of workers who were exposed to 10 to 50 µW/cm2 of radar produced
microwaves. Some were also exposed to about 5 ppm of VCM, a known carcinogen.
Exposure to each of these substances (microwaves and VCM) produced highly
significant (p<0.01 to p<0.001) increases in Chromatid breaks, Chromosome
breaks, acentric and dicentric breaks in human lymphocytes from blood taken
from exposed workers. The results were consistent across two assays, a
micronucleus test and chromosome aberration assay. Chromosome aberrations and
micronuclei are significantly higher than the controls, (p<0.05, p<0.001,
p<0.0001), for each of the exposure intensity.[119]
2.98
Dr Cherry also drew the Committee’s attention to
studies done of staff in the US Embassy in Moscow that was chronically exposed
to radar over a decade and found increased chromosome damage:
... I have found more than 30 studies showing chromosome damage in
people exposed to radiofrequency microwave radiation. This is far more than we
have for benzine, which is a carcinogen.[120]
2.99
The results of genotoxic[121] studies were said by the
Stewart Report to have been generally negative. Dr Cherry says the studies he
cited in his submission show very strong evidence of genotoxic effects from
RF/MW exposures and notes that when chromosomes are damaged, one of the primary
protective measures is for the immune system natural killer cells to eliminate
the damaged cells.
2.100
The Committee notes that the general public
ICNIRP guideline for microwaves above 2 GHz is 1 mW/cm2, and for
workers is 5 mW/cm2. Dr Cherry pointed out that the Garaj-Vrhovac et
al (1991) study of Chinese hamster cells in an isothermal exposure system
showed that even at exposures 100 times below the public exposure guideline a
60 minute exposure kills 28 per cent of the cells and 30 minutes kills 8 per
cent of the cells.
2.101
Garaj-Vrhovac (1999) also found that 12 workers
occupationally exposed to microwaves had significantly increased chromosome
damage as well as disturbances in the distribution of cells over the first,
second and third mitotic divisions.
2.102
Dr Stan Barnett in commenting on the CSIRO’s
unsuccessful proposals for NHMRC funding which was to look at cell response to
radiation at specific periods in the cell division cycle, said:
... One of the biggest failings of all cellular studies is that,
largely, they either use highly transformed cell lines which are very sensitive
to almost anything, or they use cell lines which are general laboratory, fairly
robust cells like lymphocytes. Nobody bothers to try to synchronise the
cells. It is well known in radiation biology that cells respond to radiation
at specific periods in the cell division cycle. Our proposal was to use a
fairly complex system which would allow us to use what we know as a radiation
sensitive cell line and to synchronise it so that we only exposed it in G1, where
we know – because of 30 years of background work – this particular cell is
highly sensitive to radiation. It is deficient in DNA repair enzymes, and we
know that, if you are going to produce any kind of impairment of DNA repair
which would be manifest as single strand breaks as per the Henry Lai study,
this would be an opportunity to use the most sensitive available end point that
we know of to test that scenario.[122]
2.103
It is also the case that studies have shown an
increase in the number of cells with micronuclei, the formation of which are
considered to reflect DNA damage, after exposure to RF radiation. In spite of
this, the Stewart Report concluded that implications for human health are
unclear as normal tissue can also exhibit a high and variable incidence of
micronuclei, making results difficult to interpret.[123]
2.104
Overall, while there have been numerous studies
showing a range of biological effects, and while further research is required
to satisfy the need to replicate positive results and to establish their
implications for human health, the Committee Chair is persuaded that there is
cause for concern.
Health effects discussed
2.105
Sleep disturbance,
chronic fatigue, immune system impairment and learning difficulties have also
been observed in radiofrequency exposed residential populations, and it has been
argued that these effects are consistent with observed biological effects
including calcium ion alteration and melatonin reduction. Various symptoms such as headaches, dizziness, feelings of
discomfort, burning skin, which appear to be highly correlated with ‘warm
sensations’ on and behind the ear against which the mobile phone is held, are
described by Hocking (1998) and later observed in a survey of over 10,000
mobile phone users in Norway and Sweden.[124]
There have also been newspaper reports of more epileptic seizures in a school
since mobile phone use has increased.[125]
Cancer
2.106
Although the development and promotion of cancer
ranks in the general public’s mind as a real health risk associated with mobile
phone and other telecommunications technologies, and indeed with other
artificial sources of electromagnetic emissions, the scientific evidence for
this association is said by many to be less definitive.
2.107
One area of contention is whether radiofrequency
radiation initiates cancer or whether it may be implicated in the promotion of
cancer.[126]
While there is general agreement that the energy in non-ionising radiation
emitted by mobile telephones is unlikely to break chemical bonds, thereby
inducing alterations in the genome,[127]
Dr Cherry informed the Committee that in his view there is now sufficient
evidence to show that EMR interacts and interferes with communication systems
in our brains, hearts, cell and bodies through neurotransmitters and
neurohormones, including the serotonin/melatonin system.
2.108
According to Dr Cherry, both through reducing
melatonin and through enhancing free radical activity, EMR is genotoxic,
damaging the DNA and chromosomes, enhancing oncogene expression and
transforming cells to neoplastic cells and causing cancer in exposed
populations.
2.109
The 1994 CSIRO report says:
For any biological effect to become significant the body’s
homeostatic mechanism has to be overcome. Homeostatis uses cellular
communications via molecules and ions to control the three basic functions of
cells: proliferation, differentiation, and activation. Cancer promotion
involves the disruption of cell-to-cell communication.[128]
2.110
There is more agreement and significant evidence
to support non-ionising radiation as a cancer promoter.
2.111
Dr John Holt stated that cancer cells were three
times as conductive of RF as non-cancer cells, and that non-ionising radiation
rendered tumours more sensitive to ionising radiation.[129]
2.112
In its report of 1994, CSIRO said:
However, because a promoting agent requires high doses, must
continue for long periods of time, and is reversible, it has been argued that
the risks from a promoting agent are less than the risks from an initiating
agent.[130]
2.113
Most epidemiological studies[131] that have been published
focussed on RF exposure not directly related to cellular phones, and provide
primarily indirect evidence from occupational or amateur radio operator
radiofrequency exposure, with exposures being ‘more varied in dose, type of
signal, and anatomical localisation than exposures from cellular telephones’.
These studies had variable findings.[132]
2.114
Professor Mark Elwood, epidemiologist,
concluded:
... overall ... I do not see any consistency in relationships
between cancer and radiofrequencies. There are quite a lot of studies, so there
are some positive results which require further assessment. The studies are
limited by lack of information on exposure, lack of control for other factors
and, in some studies, biases in the data. ... Very often it is the weaker
studies, with much smaller numbers and much weaker study designs, that tend to
show unusual results, which therefore need testing. So, overall, my conclusion
is that there is no consistent evidence relating radiofrequency exposures and
cancer in humans, in terms of current research.[133]
2.115
The information provided by these studies is
considered, by most reviews, to be of limited value because of inherent
selection biases and because they incorporate exposure conditions dissimilar to
those experienced from cellular phone use.
2.116
The Stewart Report notes that studies of brain
cancer have provided ‘inconsistent results’.[134]
The Report also refers to studies of other types of cancer, concluding ‘data on
other types of cancer are more sparse and although some have suggested
increased risks from RF exposure, their limitations are such that these
findings should not be a cause for concern’.[135]
Several studies published since the Stewart Report support this conclusion.[136]
2.117
The recent occupational study of Motorola
employees is considered to have dealt with some of the shortcomings of earlier
studies.[137]
This extensive study of 195,775 Motorola employees between 1976 and 1996 found
that for the nine per cent of employees that had experienced moderate to high
levels of RF exposure, there was no increase in brain or
lymphatic/haematopoietic[138]
cancer mortality than either the general population or employees that had been
exposed to lower levels of RF radiation.[139]
2.118
Professor Elwood, in his submission to the
Committee, commented that the comparisons of employee mortality with general
population mortality in this study were of limited value, but that the analyses
of mortality between employees with different levels of exposure were more
powerful.[140]
His analyses revealed no increased risk for cancers of the brain, all lymphatic
and haemopoetic cancers, leukaemia, non-Hodgkin’s lymphoma and Hodgkin’s
disease (although given the small numbers involved, a slight increase or
decrease could not be discounted), nor for any general increased mortality
risk.
2.119
Professor Elwood noted that an important finding
of this study was the lack of association between degree of exposure and the
incidence of the cancers studied, and that it also indicated no difference in
overall specific risks between the men and women studied.[141] However, he advised:
... even a study of this size cannot confidently exclude a modest
increased risk of specific cancers which occur in relatively small numbers,
although it can confidently exclude increases in total mortality or from major
causes such as all cancers.[142]
2.120
In evidence to
this Committee, Dr Peter French, Principal Scientific Officer, Centre for
Immunology, St Vincent’s Hospital, Sydney, advised that there was no
‘definitive evidence’ for a link between mobile phone radiation and cancer.
However, he added that while there apparently was insufficient evidence on the
surface, buried within the unsubstantiated assertions, fears, anecdotes and
myriad of facts there were clues that point to a link between cancer and mobile
phone emissions.[143]
2.121
Professor Elwood,
on the other hand, concluded that based on an overall assessment of the
research to date, there was ‘no consistent evidence relating radiofrequency
exposures and cancer in humans’.
... the better studies ... are
the ones that show no association. Very often it is the weaker studies, with
much smaller numbers and much weaker study designs, that tend to show unusual
results which therefore need testing. So, overall, my conclusion is that there
is no consistent evidence relating radiofrequency exposures and cancer in humans,
in terms of current research.[144]
2.122
Radiation
oncologist, Dr John Moulder, in his submission to the Committee, concluded
that:
... the epidemiological
evidence for a causal association between cancer and exposure to
radio-frequency radiation is weak to non-existent.[145]
... animal carcinogenesis
studies conducted to date provide no replicated evidence that exposure of
animals to radio-frequency radiation at non-thermal intensities causes or
promotes cancer.[146]
...[o]verall, exposure of
cells to radio-frequency radiation with an intensity that does not
significantly raise cell temperature does not produce any consistent evidence
for genotoxic or epigenetic activity.[147]
2.123
The interpretation of the scientific literature
by some expert bodies, including the ICNIRP in the preparation of its exposure
safety guidelines, has been criticised.[148]
Dr Cherry stated:
They decide that there is no evidence of genotoxicity but they
do not cite any studies that have been published that do show that RF microwave
damages chromosomes – and that is the classic test of genotoxicity... Secondly,
when I looked at two of their studies on cancer, they said that two recent
studies do not show any significant effects. I have those studies and they do
show significant effects.[149]
2.124
Dr Barnett advised that the CSIRO had submitted
two projects to the NHMRC, both of which were shortlisted but unsuccessful,
related to the potential effects of radiofrequency radiation on DNA and cancer
production:
One was an animal system, where we were looking at repeating, I
believe, a very important research finding which has been largely ignored,
which was finally published in 1992 by Chou and others. That work was actually
undertaken at the Brooks Air Force Base in San Antonio. That study looked at
simply exposing rats to 2450 megahertz of radiation throughout their lives.
When the data was analysed for tumour development in the exposed
versus controlled animals, it turned out that, depending on how you chose to
analyse the data, you got either a negative or a positive result. The study
had been largely referred to as providing a negative result. It was only
negative if you separated out each type of cancer and then looked at the
difference in numbers for each type of cancer. Clearly, because they only used
a couple of hundred animals, when it was broken down into all the different
types of cancer, the numbers that were being compared were extremely small, so
the statistical power would be pretty poor. When they compared the incidence
of primary malignancies between the two groups there was a fourfold increase in
the exposed group.[150]
2.125
Some witnesses to this inquiry referred to
anecdotal evidence of people claiming, ‘with hindsight and when prompted’, to
suffer from a range of cancer types resulting from chronic exposure to electromagnetic
radiation.[151]
While it has been claimed that the involvement of electromagnetic emissions in
the proliferation of cancer cells and possibly even as the cause of cancer is
‘beyond doubt’,[152]
this view has not been supported by recent reviews on recently published
papers.
2.126
The results of a case-control study conducted at
five United States academic medical centres between 1994 and 1998 using a
structured questionnaire, were published by Muscat et al in 2000.[153] There were 469 men and women
aged between 18 and 80 years with primary brain cancer, with 422 controls.
Details obtained from interviews included the number of years of use,
minutes/hours of use per month, year of first use, phone manufacturer, reported
average monthly bill, demographics, smoking history, alcohol consumption,
exposure to power frequency fields, occupation and medical history. No
assessment was made of participants’ diet.
2.127
The researchers concluded that the study ‘shows
no effect with short-term exposure to cellular telephones that operate on
(primarily) analog signals’ and recommended that further research is undertaken
to account for longer induction periods, particularly for slow-growing tumours,
and the differences between analog and digital mobile phones.[154]
2.128
There was no association observed between the
duration of cellular phone use and incidence of brain tumours. In the cases
examined, cerebral tumours occurred more frequently on the side of the head to
which the phone had been held, however, for patients with temporal lobe cancer,
the tumours occurred more frequently on the side opposite to that against which
the phone was customarily held. This contrasts with a Swedish study that found
an association between the side of the head a brain tumour occurred and the
side of phone use, although this study also did not find an overall association
between cell phone use and the risk of brain cancer.[155]
2.129
The Committee received a confidential submission
from a person suffering from a growth inside their skull. The growth was
adjacent to the mobile telephone antenna position. This person was a heavy
user of both analogue and digital mobile phones and believes that the excessive
microwave radiation resulting from extremely heavy mobile phone use, most
probably caused the malformation.[156]
2.130
Dr Bruce Hocking undertook a survey of 40 people
to categorize the types of symptoms exhibited by users of mobile phones. The
symptoms mainly affected the head and, for a few, the waist. These symptoms
included dull pain, an unpleasant warmth or heating, as well as ache, throb,
sharp pain and pressure. All respondents could distinguish the sensations from
ordinary headache. Most respondents felt the sensation less than five minutes
after commencing the mobile phone call, but for others the sensation built up
as the day progressed. For some, the sensation lasted less than an hour after
ceasing calls, for others it lasted till bed-time, and five respondents felt it
the next day.[157]
In addition, Dr Hocking co-authored a paper[158]
on a detailed study of a person who had enduring effects on the side of his
head where he used his GSM mobile phone. He experienced persistent unpleasant
feelings lasting for more than a year and underwent extensive investigations by
neurologists to find out if he had brain tumours or some other odd sort of
neurological condition that could have been causing these problems, and nothing
had been found. Dr Hocking informed the Committee:
This is the first time that I am aware of that there has been a
clear demonstration of a health effect in humans attributable to a mobile
phone. I agree it is only one case, and before you get too excited you would
like to see more. Nonetheless, I think it is a significant warning when you
see it in context with the previous 40 cases that I was reporting that were
getting similar sorts of symptoms that there is considerable likelihood that
mobile phones, at the low levels of radiofrequency which they are operate on,
are causing disturbances of neural function.
It is also considerable evidence of an athermal effect. Given
that mobile phones operate at low intensity – we are told by government, WHO
and industry that mobile phones operate well within safety standards – that to
produce this sort of effect we are having effects outside at low levels. [159]
2.131
Since 1994, researchers at the National Cancer
Institute (NCI) in the United States have been conducting an adult brain tumour
study which includes investigating a range of possible risk factors including:
workplace exposures to chemical agents and electromagnetic fields; dietary
factors; family history of tumours; genetic factors; home use of selected
appliances; reproductive history and hormonal exposures; viruses; and medical
and dental exposure to ionising radiation. Cell phones, as another potential
risk factor, were included in the research program in response to public
concern about possible links between cellular phones and brain cancer.
2.132
Results from NCI research into cell phones and
brain cancer were published early in 2001. The case-control study of the
relationship between cellular/mobile phone use and brain tumours was conducted
in three hospitals in the United States between 1994 and 1998. The study
identified 782 patients in these hospitals who had glioma, meningioma or
acoustic neuroma; from the same hospitals, 799 patients with non-malignant
conditions, were used as the control group.
2.133
The study found no evidence that the risks of
glioma, meningioma, acoustic neuroma, or all types of tumours together, was
higher among people who used mobile phones for an hour or more a day or
regularly for five or more years. The researchers concluded that the results
did not support the hypothesis that the use of mobile phones causes brain
tumours, but stated that the results were ‘not sufficient to evaluate the risks
among long term, heavy users and for potentially long induction periods’.[160]
2.134
The Committee acknowledges the difficulty of
testing long term exposure and notes that the results of this study should be
interpreted cautiously for the following reasons:
- widespread use of mobile phones is only a recent phenomenon, with
few people in the United States having used mobile phones prior to the 1990s.
Only a small number of study participants had used a mobile phone for over five
years. Consequently, the study would not have been able to detect the risk of
brain tumours after a long latency period;
- there was a reliance on interviews and the ability of
participants to accurately recall mobile phone use rather than by objective
measurements of exposure;
- the study was designed to assess the risk of all types of glioma,
and the sample was too small to detect increased risk for glioma subtypes; and
- factors other than duration of use influenced the level of
exposure of brain and nervous system tissue in the head to radiofrequency
radiation, including distance from the base station, local topography and
vegetation, whether the phone is used indoors or outdoors, the design of the
phone, and the position of the phone and the antenna in relation to the head.[161]
2.135
In recognition of these limitations, the NCI
advised that ‘it would be premature to conclude that use of hand-held cellular
telephones does not cause tumors of the brain and nervous system’.[162] Noting that analog phones
were predominantly in use during the study period, contrary to recent years
when phones have been increasingly based on digital technology, the NCI
nevertheless offers the view that ‘there is no evidence at this time that
cancer risk would differ for the two types of phones’.[163]
2.136
The results of a unique Danish study into the
relationship between mobile phones and cancer were also published at the
beginning of February 2001 in the Journal of the National Cancer Institute.[164]
2.137
A research team, headed by Dr Christoffer
Johansen, conducted a retrospective cohort study[165] of cancer incidence in
420,095 Danish users of mobile phones between 1982 and 1995, using telephone
subscription lists from two Danish mobile phone operating companies and the
Danish Cancer Registry. The team observed no significant difference between expected
and observed incidence of cancers of the brain, nervous system or salivary
gland, or of leukaemia. Risks for these cancers did not vary by duration of
cellular telephone use, time since first subscription, age at first
subscription, or type of cellular phone used (analog or digital). The study
concluded that the results did not support the hypothesis that there is an
association between the use of mobile phones and tumours of the brain, salivary
gland, leukaemia or other cancers.[166]
2.138
Dr Johansen is reported as stating that ‘[i]f it
is assumed that tumour promotion occurs close to the site of exposure, this
finding provides additional evidence against a link between cellphone use and
brain cancer’. However, Dr Johansen indicated that the study results did
not rule out a relationship between mobile phones and other health risks such
as ringing noises in the head, migraine, headaches, other symptoms of the
conditions associated with the central nervous system, Parkinson’s and
Alzheimer’s diseases, various types of dementia, and skin diseases.[167]
2.139
Responding to the report, Australia’s Dr Bruce
Armstrong, who is undertaking an epidemiological case-control study on the
relationship between exposure to radiofrequency radiation and brain and other
tumours in adults (see Australian research below), stated that while it
was a ‘reassuring study’, it did not ‘give an ultimate assurance of a lack of a
hazard’. A shortcoming of the study was that only a small percentage of the
mobile phone service subscribers had used their phones for more than seven
years and this ‘raised questions on what links there were between cancer and
long term mobile phone users’.[168]
2.140
The Committee Chair considers that there is
sufficient doubt as to the association between radiofrequency and cancer to
warrant further research before the public can be confident that any risks are
adequately safeguarded against through current exposure standards. A discussion
of the efficacy of current standards is discussed in Chapter 4.
Other
effects
2.141
Although a dominant concern, cancer is only one
of the health effects that has been attributed to radiofrequency exposure.
Electromagnetic emissions have also been implicated in many debilitating and/or
serious health conditions, often immune system related, including allergies,
repeated flu-like episodes and auto-immune diseases.[169] There is also some evidence
of genetic predisposition and age-related factors that may influence
sensitivity to potential effects of RF radiation.[170]
2.142
While there have been reports of effects on the
cardiovascular system from exposure to electromagnetic radiation, the Stewart
Report concluded that ‘on the basis of published evidence, [there is] no basis
for concern about effects of mobile phone use on the heart and circulation’.
People subject to chronic electromagnetic energy exposure have also reported
suffering heart attacks and high blood pressure.[171] The Stewart Group said,
however, that while normal use of a mobile phone against the head is unlikely
to have a direct effect on the human heart, influences on cardiovascular
centres in the brainstem and on the carotid body, a body of tissue involved in
the regulation of the heartbeat, were more conceivable, and further
experimental work on human volunteers was warranted. Observed effects were
said to be attributable to thermal effects from acute exposures to
radiofrequency radiation.[172]
2.143
Despite concerns about the possible effects of
mobile phone use on cognitive functions such as memory, attention and
concentration, relatively few laboratory studies have addressed this issue in
people and, of those that have, all have investigated effects from acute rather
than chronic exposure. While exposure to radiofrequency radiation at levels
which cause increases in core temperature of 1ºC lead to changes in performance
of primates in well-learned tasks or other simple behaviour, on which the
current standards are based, the Stewart Report said that results at
non-thermal levels are inconsistent and recommended further research.[173] Most studies which investigated
exposure to low levels of RF radiation focussed on physiological measures of
brain function, such as the electroencephalogram (EEG), rather than indices of
cognitive performance per se. The Stewart Report noted that the
functional significance of different components of the normal, waking EEG is
poorly understood, making it difficult to interpret results showing an
influence of radiofrequency signals on the EEG.
2.144
This was said to be less of a concern with
respect to EEG patterns associated with sleep as these are ‘well characterised
and routinely used as indices of the different sleep stages that a typically
healthy individual will move between during the night’. There have been observations of a
range of sleep-related disorders, including altered sleep patterns, circadian
rhythm and reaction times, from naturally occurring electromagnetic radiation
and short-wave radio exposure.[174]
However, these effects have been observed at lower frequencies than what are
used for mobile phone transmissions. In addition, the Stewart Report said that
results of work on the neurotransmitter system, which is involved in regulation
of emotion, memory and sleep, appear to show temperature-related effects. To
determine the extent to which the results of those studies can be extrapolated
across the electromagnetic spectrum requires that these studies should be
repeated using radiofrequencies. The Stewart Report
concluded that further research should be conducted in both areas.[175]
Alzheimer’s
Disease
2.145
Reference was made to a study that linked
exposure to electromagnetic fields with an increase in incidence in Alzheimer’s
Disease (AD), which, it is hypothesised, is due to a chain reaction of cellular
effects starting with interference to cellular calcium ion homeostasis.[176] In its report, the Royal
Society of Canada acknowledged this and another related hypothesis, but noted
that studies aimed at testing these claims had used exposure to extremely low
frequency fields (powerlines) rather than radiofrequency radiation. In addition,
methodological shortcomings limited the interpretation of the results. The
report concluded that ‘there are no convincing, reproducible data to suggest a
relationship between AD and [microwave] exposure’.[177]
The Immune
System
2.146
While it has been suggested that the evidence
indicates that an increase in diseases connected with the immune system may be
the long term effect of radiofrequency radiation from mobile phone use,[178] other reviews have been more
cautious and point to the ambiguous nature of outcomes in this area of
research. The European Commission Report noted that there is a level of
adaptability and redundancy built in to the immune system via self-regulation.[179] Thermal effects that have
elicited responses in the immune system have been found to be transitory, with
levels returning to normal with the cessation of radiofrequency exposure. The
Stewart Report concluded that, given the inconsistent results from studies
using low level radiofrequency radiation exposure, it was difficult to
attribute any effects to exposure.[180]
The eyes
2.147
The Stewart Report also referred to various
studies that had investigated the effects of high intensity pulsed RF fields on
the eye. Noting that these exposure levels were well above the specific
absorption that could occur from the use of current mobile phones, it warned
that possible adverse health effects in the eye may be associated with high
peak-power pulsed radiofrequency fields.[181]
Reproductive
problems
2.148
Some drugs and environmental hazards are known
to have damaging effects on a developing embryo at exposure levels which are of
little or no risk to the adult animal. According to the Stewart Report,
despite extensive research into the potential effects of radiofrequency fields
on fertility and development, studies have failed to show any convincing
evidence of effects.[182]
The Stewart Report referred to a 1993 study that showed an increased risk of
miscarriage in physiotherapists who reported exposure during the first six
months before or three months after pregnancy and a higher risk in those with
more frequent exposure and concluded that there w |