EMF & CHILDHOOD LEUKEMIA:
: :
That’s the title of an article in
EC&M,
September, 2006. Just when we thought it was “safe to come out
of the woods,” more studies, focused on children, are being
done. The article’s introduction states that “Decades of
research have studied possible effects of exposure to electric
and magnetic fields. While the great majority of studies have
shown no link between EMF and a variety of maladies, several
key epidemiologic studies have caused expert scientific panels
to conclude that there is indeed a statistically significant
association between power-frequency magnetic fields and the
development of childhood leukemia. Nevertheless, laboratory
confirmation and a convincing explanation of the nature of this
link have eluded researchers and health theorists for some
years.”
The Electric Power Research
Institute of Palo Alto, CA is addressing two issues. Following
is an attempted synopsis by the editor. It is not definitive
and interested readers are advised to read the original article.
The EPRI addresses the
possibility that the link between magnetic fields and childhood
leukemia is a product of artifact in study design. This
could mean that there is no causal basis at all, that the
problem may be “selection bias. However, the second hypothesis
“…explores the possibility that an unrecognized exposure,
contact current, is the active agent that has operated behind
the scenes, with magnetic fields at center stage.”
The second concept relates
to current “…that flows within a person when two locations on
that person’s body are in contact with electrically conductive
surfaces at different electrical potentials or voltages.”
(Those of us familiar with grounding of devices, boxes, conduits
and even building structures should understand the reference to
potential difference.) As I understand it, we should and do try
to negate the difference, using proper and sometimes redundant
grounding procedures. Some of us have seen first hand the
damage (and unsafe conditions) rendered by improper or faulty
grounding procedures.
As for the scenario for a
child’s exposure to contact current, the suspect is a bathtub:
Electrical services are grounded to the (cold) water pipe. As a
result, a small neutral-to- earth voltage, probably less than 1
volt, will appear on the water pipe. According to the article,
the voltage arises from household currents returning via the
water pipe back to the sub station, or from nearby sources of
magnetic fields, such as overhead transmission lines or heavily
loaded distribution primaries. “This voltage will extend across
all contiguous elements of the water system, including the metal
water fixtures in a bathtub, sink or shower. If the drainpipe
sunk into the earth…is also made of metal, a bathing child,
touching the faucet or water stream will receive a contact
current into the arm and through the body… The current pathway
includes the bone marrow (the site of leukemia development),
with the highest dose expected in the thinnest extremities,
where the current densities must be the greatest—that is, in the
lower arm and hand. Also notes is that the voltage exposure is
imperceptible, even to a small child.
The research has accelerated
from “plausibility stage” to hypothesis testing,” by means of a
multidisciplinary study. EPRI began research in 2006 at UC San
Francisco to develop a genetically engineered mouse to model the
pathological events that lead to leukemia in children. This
model will eventually be tested with current exposures. It
appears that results of these efforts will emerge within the
next five years.
For more
specifics, please read the article. |
