- Electricity and Cancer
The missing link?
-
- A University team led by Professor Denis
Henshaw in the Department of Physics has
discovered more evidence of the
importance of electric fields as a
possible cause of cancer. Professor
Henshaw revealed the team's latest
research results in a paper published in
the International Journal of Radiation
Biology (Vol.69:1, p.25-38, 1996).
-
- Professor Henshaw and his team found that
electromagnetic or EM fields had been
shown to concentrate naturally occurring
water droplets in the air (aerosols).
Aerosols, his previous work had shown,
contained the radioactive decay products
of radon gas. Radon gas is a natural,
colourless, odourless gas that emerges
from rocks in many parts of Britain.
-
- Professor Henshaw said that only standard
physics was involved in explaining this
process. It was not contentious. But of
course if EM fields concentrated radon in
aerosols they also must concentrate other
harmful substances, including
carcinogenic or cancer-causing agents.
His latest research had implications in
this area.
-
- Such concentrations, he said, might
explain the apparent link between EM
fields (such as those around power lines)
and enhanced cancer risks that had shown
by epidemiological studies. He said that,
given that pathogenic agents were
concentrated, there should be no
objection to a causal link between EM
fields and the incidence of cancer.
-
- Experimental evidence collected by
Henshaw and his team indicates that 1) a
likelihood of higher exposure to radon
decay product aerosols exists near major
sources of EM fields. 2) Since the
effects have been produced by means of an
applied mains potential but with no
current flowing, this means that the
effects are due to the electric field
rather than the magnetic field component
of the electromagnetic field. 3) The
exposure to radon decay products is of
special interest in view of the
geographical links that have been seen
between domestic radon exposure and the
incidence of childhood leukaemia,
childhood brain tumours and other
childhood cancers, the same cancers that
have been linked to EM field exposure. 4)
Aerosols such as airborne chemical
pollutants when falling near a power line
will be deflected towards the line.
Scientists at the University of Bergen in
Norway have found evidence of a higher
number of several pollutants under power
lines. 5) Airborne bacteria may also be
attracted by electric fields.
-
- In summary, Dr. Henshaw expects
"power frequency electric fields to
attract aerosols of all types: natural
radioactive aerosols, non-radioactive
chemical pollutant aerosols, bacteria,
viruses and airborne fungi."
-
- As reported in Microwave News (May/June
1996, p.18-19), researchers in the U.K.
and the U.S. have raised strong
objections to Dr. Henshaw's research
findings.
-
- Four members of the U.K.National
Radiological Protection Board wrote in
the May 96 issue of the Journal that it
"seems most unlikely" that
electric fields could have the effect
reported by Henshaw. "The overall
effect of the mechanisms considered by
Henshaw et al, would be expected, if
anything, to reduce slightly the activity
of radon decay products deposited in the
lung and hence reduce the dose to the
lung and other tissues."
-
- Henshaw replied to this criticism by
stating, "Our measurements of
increased airborne activity near a large
source of EMFs lead directly to increased
dose to all body organs via
inhalation".
-
- Dr. Larry Toburen of East Carolina
University in Greenville, North Carolina
wrote in the Lancet (April20, 1996)
"I am inclined to discount the
electric fields-radon proposal"
Toburen, who is project director of the
NAS/NRC report (see Page 1), argued that
lung cancer, which is associated with
radon exposure,"has not been
detected in excess in people living near
power lines."
-
- Toburen, who appears to follow the
NRC/NAS tendency for selective memory,
must not be aware of a letter published
in the April 15,1996 American Journal of
Epidemiology, by Dr Thomas Erren of the
University of California School of Public
Health. Dr. Erren cited five studies
showing associations between lung cancer
and EMF exposures. They are three
occupational studies- by a Swedish team,
John Hopkins University and McGill
University, which all found an
association between lung cancer and EMFs
and two residential studies, one from the
U.K. and one from the U.S.
-
- Dr Erren wrote that given that lung
cancer is multifactorial, "a (co)
carcinogenic potential of electromagnetic
fields cannot be refuted at this time a
link of [EMFs] to this malignancy would
have considerable public health
relevance." (Microwave News,
May/June 1996, p.18-19)
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