Charting the hidden force at street corners

Electromagnetic 5

There’s a steadily growing conviction that electromagnetic fields can promote bad things — cancer, miscarriages, depression, Lou Gehrig’s disease, and possibly Alzheimer’s disease.

But there’s still an all-too-scanty knowledge of how much exposure people get in the course of a day.

To help lessen 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 Burks Falls (1,000).

She found that 49 of the communities (82 per cent) had readings above the level that is associated with childhood leukemia. And that the worst of all the communities, by far, was Kingston. Next, in order of high readings, were Oshawa, London, Peterborough, and Toronto.

Burks 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 that, as yet, there is no proof that electromagnetic fields directly cause illnesses. But there is plenty of evidence showing that they are associated with illnesses and can actively promote them.

Her work on main street Ontario should be a wakeup call to public utilities and other businesses generating electromagnetic fields, such as banks and cell phone 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 (Canadian), it is the most extensive study ever done, and is about to be released. Researchers interviewed by the London Sunday Times have said 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 Carl Friederich Gauss (1777-1855). According to federal government guidelines in Canada, a cumulative, 24-hour exposure of up to 1,000 milliGauss is safe.

However, says Havas, 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. And 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. And in the workshop, 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. it was 22.9 mG; and in Peterborough on George St. it was 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. And an excellent review of studies on electromagnetic fields can be found at

The study is good news in terms of raising awareness — and that’s crucial to any health issue.

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