Testimony by: Magda
Havas, Ph.D.
Concerning: Health
Effects Associated with Power Lines
Date: March
22, 2001
Location: Minnesota,
USA.
Q: Please
introduce yourself.
A: My
name is Magda Havas. I'm an Associate
Professor of Environmental & Resource Studies at Trent University
(Peterborough, Ontario, Canada). I
received my Ph.D. at the University of Toronto in 1980 where I trained as a
biologist, ecologist and environmental toxicologist. I completed two years Post Doctoral Research at Cornell
University with Professor Gene Likens and then returned to Canada and worked as
an Assistant Professor at the University of Toronto and later as an Associate
Professor at Trent University. I have
served as a member of the Mayor’s Committee on Sustainable Development; as a
science advisor to CBC; as a member of the Emerging Issues Subcommittee of the
International Joint Commission (Canada/US); as a member of the Environmental Appeal Board of Ontario
(Ministry of the Environment); and as an advisor to Tribhuvan University in
Nepal on their Environmental Sciences Program.
At Trent University I have served on the Board of Governors and on Senate
(the two key bodies responsible for university governance). I am a member of the Health Research Group and am founder and past Chair of
the Energy Working Group which consists of physicians, alternative health care
practitioners, environmental scientists, biologists, physicists, and electricians
who are interested in the biological effects of energy fields from natural and
man-made sources.
My expertise is on the biological and
environmental effects of environmental contaminants. I have worked on acid rain, metal pollution, drinking water
quality and more recently electromagnetic fields. For the past 15 years I have taught a course on Pollution Ecology
which deals with the environmental and health effects of chemical pollutants
(asbestos, metals, chlorinated organics, hydrocarbons, air pollution, water
pollution, among others) and for the past 4 years I have taught a course on the
Biological Effects of Electromagnetic Fields.
Q: Why
are you here today?
A: I'm here because I'm concerned about the
adverse health effects of electromagnetic fields generated during the
production, distribution, and consumption of electricity. For the past 8 years I've been studying this
with growing intensity and growing concern.
Based on the literature and my own research I am convince
that power frequency electromagnetic fields can and do cause biological
effects; that these effects can be both beneficial and harmful; that we know
some of the mechanisms involved and are close to understanding others but that
more research in this area of mechanisms and in the area of exposure remains to
be done.
Regarding
Public Policy and Scientific Evidence: I do
not think that it is necessary for public policy makers to wait until ALL the
scientific facts about electromagnetic fields are in before they act to protect
the public by minimizing exposure. We
already have considerable information.
What remains to be known in terms of mechanisms is unlikely to
significantly change what we already know, and we know enough to act.
1.
We know that high electric
fields and high magnetic field have adverse health effects based on studies
of residential exposure and childhood leukemia, on studies of occupational
exposure, and on laboratory experiments.
2. We know that magnetic fields above 2.5 milli Gauss (mG) (the range being debated
is between 2 and 4 mG) are critical for children under the age of 14 and that
magnetic fields at 12 mG (value is between 2 and 12 mG) are critical for adults
with estrogen-sensitive breast cancer.
3. We have yet to determine what levels of the electric fields are harmful. Values
of several thousand volts per meter (V/m) have been suggested for adults but
children are likely to be more sensitive as they are to most environmental
pollutants. Electric fields below 100
V/m are common in residential settings and we do not know if these cause
biological or health effects.
4. We know that the home environment,
particularly the bedroom is critical
for children and that night-time exposure may be more important than
day-time exposure.
5. We know that disruption of the natural
production of melatonin is one of
the mechanisms involved in the adverse health effects. There is evidence that electromagnetic
fields have been implicated in depression,
disturbed sleep, and higher rates of suicide.
6. We know that electromagnetic fields have been
linked with leukemia, lymphomas, nervous
system tumors and breast cancer as well as with various reproductive abnormalities.
7. We know that electromagnetic fields do not initiate cancer (at the levels found in
residential and most occupational settings) but seem to promote cancer by changes in the rate at which cells divide and
differentiate.
8. There is emerging evidence that the electric field may be interacting with air
pollutants. More research is needed
in this area, but if the results from future studies support this relationship
then limits may need to be set on high voltage power lines in residential
communities.
Knowledge of the specific mechanisms
involved is not going to significantly change the harmful exposures (2.5 and 12
mG) mentioned above, unless history repeats itself as it has with lead,
asbestos, and DDT. Blood lead levels,
deemed safe in the early 1970s, were lowered as more scientific evidence became
available.
A prudent
avoidance public policy regarding the location of both above and below
ground power lines would be to limit
the magnetic field to 2 mG or less during peak energy consumption in the
residents nearest the power line. This
would not be precedent setting since several multinational companies (including
the World Bank) have been specifying low levels of power frequency magnetic
fields of less than 2 mG for their new building designs. Sweden has guidelines of 3 mG for areas where
children play.
Full Cost
Accounting and Decision Making:
Decisions are often made (or not made) based on short-term accounting to minimize economic costs. If full cost and long-term accounting is
considered then hospital stays
and sick leave have to be factored into the equation and in the long-term
this is likely to be costly.
Legitimate
Debate and the Scientific Process: I'm
also concerned that as scientists we do a poor job explaining how science is
done and how it should be interpreted.
Consequently the public is confused by scientific disagreement presented
by the press. They are unable to judge
whether the disagreement is motivated by a legitimate desire to understand some
aspect of the world or if it is motivated by other concerns.
The
current scientific debate about electromagnetic fields is tainted. It is motivated by concerns other than a
desire to better understand the biological effects of electromagnetic
fields. While there is some legitimate
debate and disagreement about the harmful effects, the mechanisms involved, and
the specific exposure characteristics there is also an element of deception and
bias.
Sadly this type of activity is not
unusual and is certainly not restricted to EMF issues. Manipulation of
scientists; attempts to discredit individuals and to cut off their funding;
publication of red herrings and other attempts to mislead the public have
occurred time and again with asbestos, DDT, tobacco, lead, acid rain, endocrine
disrupters. When industry feels
threatened it reacts and not always in the most honorable way. Few scientists are comfortable and willing
to speak out when this is the case.
The statements below were published in the
National Research Council (1997) document entitled “Possible Health Effects of
Exposure to Residential Electric and Magnetic Fields” in a section devoted to
occupational exposure.
Across a wide range of
geographic settings . . . and diverse study designs . . . workers engaged in
electrical occupations have often been found to have slightly increased risks
of leukemia and brain cancer (Savitz and Ahlbom 1994, NRC p. 179).
Matanoski et al. (1993)
. . . found little support for increased risk due to increased average fields,
but increasing field levels at peak exposure were associated with increased
leukemia risk
(NRC, p. 180).
Floderus
et al. (1993) . . . the most highly exposed workers were estimated to have a
3-fold increased risk of chronic lymphocytic leukemia and a 1.6-fold increased
risk of total leukemia. Brain-tumor was
increased by a factor of 1.5 in the highest category (NRC, p. 180).
. . . a large
well-designed study of utility workers in Canada and France provided evidence
of a 2- to 3-fold increased risk of acute myeloid leukemia among men with
increased magnetic field exposure (Theriault et al. 1994). Brain cancer showed much more modest
increases (relative risk of 1.5-2.8) with increased magnetic field exposure (NRC, p. 180).
Savitz and Loomis (1995)
. . . Leukemia mortality was not found to be associated with indices of
magnetic-field exposure, whereas brain-cancer mortality was associated. Brain cancer mortality generally was found
to increase in relation to accumulative exposure, reaching a relative risk of
2.3-2.5 in the most highly exposed workers (NRC, p. 180).
All three studies found
no evidence of confounding by the presence of workplace chemicals (NRC p. 180).
A series of three
studies reported an association between electrical occupations and male breast
cancer (Tynes and Andersen 1990; Matanoski et al. 1991; Demers et al. 1991) . .
. (NRC,
p. 181).
Female breast cancer in
relation to electrical occupations was evaluated by Loomis et al. 1994 . . .a
modest increase in risk was found for women in electrical occupations,
particularly telephone workers . . . (NRC p. 181).
The relative risks in
the upper categories of 2-3 reported in the high quality studies of Floderus et
al. 1993 and Theriault et al. 1994 cannot be ignored (NRC, p. 181).
Yet this is exactly what NRC did. It ignored some vital information in its
executive summary on the health effects of electromagnetic fields where it
states that:
. . . the current body
of evidence does not show that exposure to these fields presents a human health
hazard.”
(NRC, p. 2).
How they can make that statement based on the
previous references they also cite is not something I can comprehend.
Q: How can scientists examine the same
data and come up with different interpretations?
A: First
we must differential between a deliberately biased attempt to defend a
particularly view and between a legitimate disagreement with a genuine desire
to understand what is happening. I’m
going to assume the later for my answer.
Scientists who study electromagnetic
fields fall into one of three categories.
They can be theoreticians, lab scientists, or field scientists.
Theoreticians approach a problem from the
perspective of the basic underlying theory.
Einstein is a prime example. He
predicted results based on his theories and others tested them once the tools
became available. If the theory is
wrong so are the predictions. When data
contradict theory we have to revisit the theory rather than discard the
data. Physicists have disregarded the
data because it doesn’t fit their theory of ionization and thermal effects that
occur and are readily explained at high electromagnetic frequencies. They don’t have a theoretical mechanism that
explains the effect at power frequencies (60 Hertz) so they disregard the
data.
Laboratory scientists are accustomed to
controlling all of the essential factors that might affect the results of a
particular experiment and often work on systems that have minimal
variability. They work on systems that
have a high signal to noise ratio. This
is true for cellular biologists and experimental physicists. Provided they expose their test “organisms” to
realistic conditions, they have some of the most powerful tools to determine
the underlying mechanisms involved in a particular response.
Field scientists are unable to control
many of the external variables although they have techniques to determine their
relative contribution to an end result.
They work on systems that have a low signal to noise ratio.
Epidemiologists and ecologists fit into this category. They are often the first to determine
associations between environmental stresses and biological response but are not
able to ascertain the underlying mechanisms.
Q: How do we interpret the textual
products of scientific investigation?
A: Just as law has its “legalese” and requires
interpretation by experienced lawyers, science also needs to be interpreted. A
simple statement made with great care by a scientist is not always interpreted
properly by the public. For example, in
1994, Ontario Hydro released a document based on a recently completed study on
cancer rates among their electric utility workers.
They stated, and I quote:
1. No association was observed between
occupational exposure to EMF and cancer overall among electric utility workers.
2. The study results indicated no association between most
cancers, including lymphoma, male breast cancer and melanoma, and exposure to
magnetic fields.
3. The Analysis did show a statistically significant
association between cumulative exposure to magnetic fields and a rare form of
adult leukaemia: acute non-lymphoid
leukaemia and a sub-type acute myeloid leukaemia.
4. According to the study authors, this did not provide
definitive evidence of a causal association.
5.
These results are
compatible with the findings of previous studies that demonstrated associations
between EMF exposure and leukaemia, and as such cannot be ignored.
6. Further research will be required, however, to determine
causal association.
Interpretation:
The first statement is generic. It includes smokers with lung cancers (for
example) and this can skew the results.
No respectable scientist has stated that EMF are associated with ALL
forms of cancer. Hence this statement
is true but is somewhat misleading as though it is refuting a scientifically
held view, which it is not.
The second statement begins to focus on
the cancers that have been associated in other studies with EMF exposure. It found no statistically significant
association for the cancers listed.
The third statement focuses on one type
of cancer that has been associated with cumulative exposure to magnetic
fields. Now we have a specific cancer
(a rare form of adult leukaemia) and a specific type of exposure (cumulative
magnetic fields).
The fourth statement is misleading.
Epidemiological studies are not intended
to provide “definitive evidence of a causal association”. Someone who doesn’t understand that
distinction will think that “yes while there is an association it is NOT
causal” and this is an incorrect interpretation of that statement.
The fifth and sixth statements are
straight forward. Laboratory studies
are needed to address the final statement dealing with causality.
Q: What is the evidence that childhood
cancers are linked with power frequency magnetic fields in the home?
A: The
first person to examine this question was Nancy Wertheimer. Wertheimer noticed
that many of the children who had died of cancer in Denver Colorado lived in
homes that were located near power lines and transformers. At that time studies from the former Soviet
Union began to appear reporting that men exposed to high voltages in switch
yards were experiencing health problems.
She wondered if there was a link between the cancers she was observing
and the electromagnetic fields generated by power lines. Ed Leeper provided her with a surrogate
measurement, the wire code that was based on the distance from power lines and
on the thickness and number of conductors (wires) distributing
electricity. Their results, which
appeared in the American Journal of Epidemiology (1979), reported an increased
incidence of childhood leukemia, lymphomas, and nervous system tumors for
children exposed to very high current configuration (VHCC) corresponding to 2.5
mG.
This was a revolutionary study. Up to that point power frequency (60 Hertz)
electromagnetic fields were assumed to be benign.
More than a dozen studies have been conducted in
different countries to test the Wertheimer and Leeper hypothesis. About half of them found a statistically
significant association between childhood cancers and exposure to magnetic fields.
The key findings from these studies are as
follows:
1.
Of
the three childhood cancers (leukemias, lymphomas, nervous system tumors),
leukemias are the ones found to be most often associated with magnetic field
exposure. [Note that the same cancers
as well as breast cancer are frequently reported in the occupational
epidemiological studies of EMF exposure.]
2.
Children
under the age of 14 and especially children under the age of 6 are the most
sensitive presumably due to their rapid growth (Green et al. 1999).
3.
Critical
distances appear to be approximately 50 m (150 feet) from a power line
4.
Critical
magnetic fields are at or above 2 mG.
5.
Daytime
spot measurements give the lowest odds ratios (ratio of observed to expected
number of cases) while median night measurements give the highest. Hence the bedroom is deemed to be the most
important environment in terms of electromagnetic hygiene for children.
Two studies concerned with the health effects of
electromagnetic fields have just been released this month (March 2001). One of the studies, conducted by the eminent
epidemiologist Sir Richard Doll, who was the epidemiologist linking lung cancer
with cigarette smoking in the 1960s and who has been critical of the findings
of power line studies, now admits an
association of increased risk of childhood leukemia with elevated magnetic
fields. This study is important because
it is the first official statement
from a major health organization in the UK, the National Radiation Protection
Board, associating childhood cancer and power frequency (50 Hertz) magnetic
fields. The report is carefully worded
and is intended to minimize concern. It
down plays the number of children who are likely to die from leukemia because
of their exposure to power lines.
The second study, from Germany by Joachim Schuz
and colleagues (2001), has gone even further.
In this study they report a statistically significant association, with
an odds ratio of 3.2, (3.2 fold increased risk) between childhood leukemia and
magnetic field exposure during the night. Since children spend 8 or more hours each
day sleeping, the bedroom becomes a very important environment in terms of
electromagnetic hygiene. Reducing
electromagnetic fields in the bedroom reduces the overall exposure and thus the
risk of leukemia.
Q: How do you interpret the studies that
do not show a statistically significant association with electromagnetic fields
and childhood cancers?
A: There
are several reasons why this might be the case.
1. Laboratory studies have shown that
electromagnetic fields at power frequencies
(60 Hertz) do not initiate cancer but rather promote
cancer or the growth of cancerous cells already in the body. Therefore, electromagnetic fields from power
lines will not induce leukemia but will promote the growth of leukemia (and
presumably other forms of cancer) that already exists in the body.
If these electromagnetic fields promote cancer then the
cancerous cells have to be present before they can be promoted. Hence some studies show an increased
incidence of leukemia, others of lymphomas, others of brain tumors and still
others of breast cancer. These results
are not inconsistent if electromagnetic fields are acting as cancer promoters.
2. Furthermore, in some epidemiological studies the average exposure did not
reach 2 mG which has been identified as a critical limit for children (e.g.
Fulton et al. 1980, mean high current value was 1.8 mG). In these studies you would not expect to
find an increased incidents since the magnetic field level was not sufficiently
high.
3. Also, in some studies very few children
were exposed to the high fields (above 2 mG).
For statistical significance of a cancer that has a low frequency we
often need a large sample size. If the sample
size is too small, the results will not be statistically significant because of
a lack of statistical power. One way to
overcome the small sample size is to combine several studies in a
meta-analysis. This has been done and
those studies show a small (in terms of population) but statistically
significant increase in the risk of childhood cancers. I might add that this risk is small from a
population perspective but it is not small for the parents who lose a child to
leukemia.
4. Also, we lack information on “real”
exposure. All of our measurements are
based on a short sampling time or surrogate measurements such as wire
codes. The longest time most
individuals are measured for their magnetic field exposure is 24 hours. Can you
image determining your likelihood of getting skin cancer from the sun
based on your exposure to the sun during a 24-hour period taken at random? The fact that so many studies are showing a
statistically significant association is remarkable and disturbing.
5. And finally, we have no “zero” exposure,
no true controls because everyone who uses electricity is exposed to
electromagnetic fields. Using
cigarettes as an analogy what we are comparing in these studies is the
2-pack-a-day cigarette smoker with the 2-cigarette-a-day smoker. We do not have non-smokers who are not
exposed to second hand smoke for our controls.
Q: What are the sources of
electromagnetic fields within the home?
A: Within the home there are three potentially important
sources of electromagnetic fields. They
include appliances, indoor wiring and outdoor wiring. Individuals can do much to reduce their exposure from appliances
and indoor wiring but can do little if the primary source of the magnetic field
is the outdoor wiring.
Based on childhood epidemiological studies the
bedroom is a particularly important environment. Bedroom electromagnetic fields
can be reduced in a number of ways and can go far in promoting electromagnetic
hygiene. Electric alarm clocks, radios
and baby monitors can be moved away from the bed. Electric blankets can be unplugged once they warm up a bed. Beds can be moved away from panel or fuse
boxes and electric heaters. Electric
heating coils in ceilings and floors generate high magnetic fields. These fields can be reduced by turning down
the night-time thermostat. Some older
homes have knob and tube wiring that can also generate high magnetic fields and
in other homes an improperly balanced return current can produce high magnetic
fields. Although costly, an electrician
can update the wiring to current wire codes and can balance the return current
and thus reduce magnetic fields associated with indoor wiring. Hence, there is much that individuals can do
to reduce their exposure.
The problem is that individuals have no way of
reducing electromagnetic fields in a home if the primary source is from power
lines run by public utilities.
Q:
Do you have any final comments
you would like to make?
A: Yes.
To protect the most vulnerable individuals in our
population, namely children under the age of 14, magnetic fields need to be
kept below 2 mG, especially in the bedroom (but also in other environments
where children spend their time, schools for example). This recommendation is specific and
enforceable. We have similar standards for drinking water that are set to
protect the most vulnerable individuals in the population. Since individuals cannot alter their
electromagnetic environment if the primary source is from power lines, it is up
to public policy makers to minimize this type of exposure. If this recommendation of 2 mG or less
became part of public policy and was enforced, it would significantly improve
the electromagnetic environment in which we all live.
Thank you for listening.