- Mains power electric
fields implicated in childhood leukemia
cases
-
- The June issue of the European Journal of
Cancer Prevention featured a paper,
Measured Electric Fields in the Bed
places of Leukemic Children by Roger
Coghill, John Steward and Alasdair
Philips, which showed a dose-response
relationship between a child's mains
frequency electric field exposure and the
incidence of childhood leukemia. To quote
from the author's 'Poster', printed in
Powerwatch Technical Supplement, No.1,
March 1996:
-
- "Though nine of eleven studies of
childhood cancer subtypes in relation to
power frequency field generating and
transmission equipment have uncovered
positive associations, surprisingly the
only three studies actually measuring
magnetic field levels do not support
anything like so strong an association as
that observed with surrogate measures
(e.g.wiring codes,distance etc.). The two
negative studies (funded partly by power
utilities) were subsequently admitted by
their authors to be flawed.
-
- At ELF frequencies both electric and
magnetic components of the
electromagnetic wave are inevitably
present, but no fixed relation exists
between them (as is with higher
frequencies) since such fields are in the
near field of the wave (length some 6000
km.). Accordingly any ELF study measuring
the magnetic component can say nothing
about its associated electric field.
-
- Nevertheless, no study of childhood
cancer to date has measured electric
fields in relation to childhood cancer,
except as partial spot measurements in
room centres. Indeed the AC electric
field has been largely disregarded in
recent studies, since it varies with
voltage not load, is easily shielded, and
instruments are not readily available.
-
- On the other hand, whereas the magnetic
field is a locally variable exposure
source, all domestic electrical wiring if
live is a source of continuous electric
field exposure, through locally within
any room the level can vary up to
tenfold. Moreover many animal and
cellular studies point to the electric
component as the active parameter in
biological effects. Arguably therefore
the principal place of domestic exposure
to ELF electric fields is in the
bedplace, and this may vary markedly from
home to home, sources being not only
derived from powerlines but also from
proximal electric appliances or house
wiring.
-
- Against this background we aimed to
measure the electric field continuously
over a 24 hour period in the actual
bedplace of children with leukemia, and
compare these levels with those of
controls, to see if the cases were being
exposed to higher electric fields than
normal.
-
- As with other studies, no clear pattern
of association with magnetic fields was
found. The electric component however
showed a statistically significant
dose-response relationship between cases
and relative risk factor
-
- Conclusion:
- Chronic exposure of children to the ELF
electric component merits further
epidemiological study."
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