One of the more contentious issues in the
scientific community today are the biological effects
of electromagnetic fields (EMFs) and whether or not
they are adversely affecting our health. This issue
has caused more concern and controversy than any
other human health issue, including smoking . Many
scientific studies do indeed indicate statistically
significant adverse health effects, while other
studies do not report such a correlation.
With this controversy going on, it is perhaps
understandable why many national and international
regulatory organisations have found it difficult to
set accurate guidelines for maximum human exposure
levels to powerline electromagnetic fields. The
epidemiological research has in general indicated
that there is a low-level risk which may be less than
some other recognised risk factors, such as air
pollution in cities. However recent research
indicates that most of the previous epidemiological
studies which only considered powerline frequency
magnetic fields, may have been looking at the wrong
parameter of the electromagnetic field. Studies such
as the Ontario Hydro Worker Study and the Henshaw
Study on electric fields and Radon (Electro-magnetics
Forum, Vol.1, No.2, Autumn 1997) indicate that the
magnetic AND electric field can have a greater
biological effect than the magnetic field in
isolation.
The real stumbling block for the regulatory
agencies setting maximum exposure standards for both
residential and occupational exposures to 50 or 60
Hertz powerline frequency electric and magnetic
fields has been a lack of a recognised biological
mechanism showing how such low-level fields could
possibly effect biological processes. In fact, the
original 1990 guidelines states: " The major
reason for the interim nature of these guidelines was
the inability to arrive at a scientifically based
judgment concerning any causal relationship between
50/60 Hz magnetic field exposures and the excess
occurrence of cancer."This was reconfirmed in
the current guidelines.
The same was true with tobacco smoking, but in
that case the epidemiological evidence overwhelmingly
indicated a significant risk. With tobacco smoking,
lack of a proven biological mechanism did not stop
regulatory action on behalf of the authorities to
warn the public of the potential dangers from
smoking.
The International Commission on Non-Ionizing
Radiation Protection (ICNIRP), who have set the
current maximum exposure guidelines, in 1993
concluded that "The data related to cancer do
not provide a basis for health risk assessment of
human exposure to power frequency fields."
Australian regulatory authorities such as the
Australian Radiation Laboratory (ARL) and the
National Health & Medical Research Council
(NH&MRC) have taken the ICNIRP Guidelines as the
standard for Australia. They are as follows:
I. Occupational - Magnetic Field
Intensity (whole working day) is 5,000
milliGauss
II. General Public (Residential)
Magnetic Field Intensity:-
·24hour day is 1,000 milliGauss,
·2 hours a day limit is 10,000 milliGauss
When you consider that the epidemiological studies
generally found a low-level cancer risk in the order
of 2 to 3 milliGauss it is understandable why these
guidelines have received so much criticism.
The ICNIRP's rational for setting these levels can
be defined as; 1) The epidemiological evidence to
date (1993) does not clearly show that an association
between powerline EMFs and cancer is real. there may
be another factor as yet to be identified. 2) There
are no clear physical or biological models to explain
such an effect, if it does exist. 3) They had no idea
of the risk factor (effect per unit exposure), nor
even a clear understanding of what exposure measure
we should be considering.
In fact the current guidelines specifically do not
provide any protection from chronic exposure to
powerline frequency EMFs. This, in effect, was
admitted in 1991 by Dr Keith Lokan, from the
Australian Radiation Laboratory, in a conference
paper published in Radiation Protection in Australia
(1991). Vol 9, No.4 . Discussing the current power
line frequency exposure guidelines. To quote:
"One thing which we have done, though it
has little direct bearing on the issue of chronic low
level exposure, is to adopt the WHO/IRPA
(predecessor to ICNIRP Guidelines with identical
limits) recommendations on field limits. These limits
represent plausible field values, below which immediate
adverse health effects are unlikely, and as such
serve a useful purpose. They are not intended to
provide protection against possible cancer induction
by continued exposure at the lower field levels
implicated in the studies..."
In 1993 the ICNIRP reconfirmed the interim
guidelines which were published in 1990. As stated
above, a major reason of maintaining the high
exposure levels "was the inability to arrive at
a scientifically based judgment concerning any causal
relationship between 50/60 Hz magnetic field
exposures and the excess occurrence of cancer."
This can no longer be justified, as there
is now one extensively researched and several times
replicated biological interaction (The melatonin
hypothesis) with powerline magnetic fields, which as
stated at the June 1997 World Congress for
Electricity and Magnetism in Biology and Medicine,
represents "one of the more well
documented/tested interactions in the field of
bioelectromag-netics." (see page 10). This
effect occurs at a level around 12 mG, which is far
below the Guideline limits. So we now have, 1) A
credible biological causal relationship between 50/60
Hz magnetic field exposures and promotion of cancer,
and 2) A clear understanding of what level of
exposure causes the effect.
In the previous two issues of Electromagnetics
Forum we have been following the continuing research
on the connection between breast cancer, melatonin
which is produced by the pineal gland, and exposure
to low level powerline frequency magnetic fields.
Since the last issue (Vol.1, no.2, Autumn 1997) still
more research confirms that the "melatonin
hypothesis" as stated above, is "one of the
more well documented/tested interactions in the field
of bioelectro-magnetics."
The melatonin hypothesis is supported by nine
research papers from four laboratories with results
showing that low level powerline frequency magnetic
fields, at levels easily encountered in the
environment (12 milligauss) can block melatonin
and/or Tamoxifen's (a cancer therapy drug) ability to
suppress breast cancer cells in vitro. In addition,
we have three recent human exposure studies showing a
reduction in melatonin among workers exposed to low
level EMF's.
If we were dealing this much evidence against a
chemical carcinogen, the scientific and medical
community would be calling for immediate government
action. However with human exposure to
electromagnetic fields there is a major bureaucratic
problem, when existing guidelines are being
questioned. In the lead article in this issue,
Putting a Spin on Science: The NCI Linet Study, it is
clearly demonstrated the extent vested interest
groups will go to to disprove a connection between
EMFs and cancer. In the article Poweline Litigation
Concerns, page 9, it is shown that the power industry
is preparing to actively fight litigation claims
against the industry. In light of this, the reality
is that in all likelihood we will not soon see any
official change to the existing Guidelines, despite
the evidence.
