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Charting the hidden force at street corners
There's
a steadily growing conviction among some researchers that electromagnetic
fields can promote bad things — cancer, miscarriages, depression, Lou
Gehrig's disease and, possibly, Alzheimer's disease. But there's
all-too-scanty knowledge of how much exposure people get in the course of a
day.
To help bridge this knowledge gap, Magda Havas,
who teaches in the Faculty of Environmental and Resource Studies at Trent
University in Peterborough, has taken readings on the main streets of 60
Ontario communities ranging in size from Toronto (2.3 million people) to
Burk's Falls (1,000).
She found that 49 of the communities (82 per
cent) had readings above the level that is associated with childhood
leukemia. The worst of all the communities, by far, was Kingston, followed
by Oshawa, London, Peterborough, and Toronto.
Burk's Falls had the lowest readings, followed
by Cambridge, Newmarket, Madoc, Perth and Bradford.
Pinpointing sources is important, because it
is the accumulated exposure, collected at different places from different
sources during the course of a day, that determines health impacts.
Havas is quick to point out there is no proof,
as yet, that electromagnetic fields directly cause illnesses. But there is
plenty of evidence showing they are associated with illnesses and can
promote them.
Her work on Main Street, Ontario, should be a
wake-up call to public utilities and other businesses generating
electromagnetic fields, such as banks and cellphone companies, which one day
could face lawsuits from people claiming compensation for impaired health.
No doubt aware of potential liability, the
California Public Utilities Commission ordered a study eight years ago on
the effects of electromagnetic fields. Slated to cost $11.2 million, it is
the most extensive study ever done and is about to be released. According to
the London Sunday Times, the study will suggest hundreds of thousands of
people may be at risk.
The strength of magnetic fields is measured in
milliGauss (mG), after the German mathematician Karl Friedrich Gauss
(1777-1855). According to federal government guidelines in Canada, a
cumulative, 24-hour exposure of up to 1,000 milliGauss is safe.
However, Havas says, this guideline is
ridiculous. Studies have established that a 24-hour exposure in the range of
2-4 mG doubles the incidence of childhood leukemia. A daily exposure of 16
mG has been shown to triple the risk of miscarriage during the first 10
weeks of pregnancy. When breast cancer cells are exposed to 12 mG, their
growth rate increases.
To put this in context, kitchen appliances,
measured at a distance of 30 centimetres, can run from 0.1 to 30 mG. In
offices, photocopy machines emit up to 4 mG, fluorescent lights up to 3 mG
and computer terminals up to 0.6 mG. Power drills can generate up to 4 mG
and power saws up to 30 mG.
In Kingston, Havas monitored 36 street corners
on Princess St. between Division and Ontario Sts. Her mean reading was 47 mG.
In Toronto, the mean reading for 108 street corners on Yonge St. between
Bloor and Front Sts. was 19.2 mG. In Oshawa, the mean on Simcoe St. was 29.5
mG; in London on Dundas St., 22.9 mG; and in Peterborough on George St.,
20.8 mG.
That's not good news for sidewalk cafes,
street vendors, couriers and people living over stores. Her study is
published in The Science Of The Total Environment 298 (2002) at pages
183-206. An excellent review of studies on electromagnetic fields can be
found at
http://www.powerlinefacts.com/EMF.htm.
The study is good news in terms of raising
awareness — and that's crucial to any health issue.
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