HEALTH

Tension in the air

Looking for electrical links with leukemia

DIANE BRADY August 6 1990
HEALTH

Tension in the air

Looking for electrical links with leukemia

DIANE BRADY August 6 1990

Tension in the air

Looking for electrical links with leukemia

HEALTH

Ever since American and European cities began using electric lights to illuminate their streets in the late 19th century, electricity has served as a relatively cheap and clean way to deliver power to many homes and industries. But in the past, some scientists have expressed concern that the electromagnetic fields produced by the flow of electric currents in power lines or household appliances might be harmful to people. Studies carried out in the United States during the past two decades have produced some evidence linking exposure to electrical fields and high rates of brain cancer and leukemia among electrical workers and among children living near high-current power lines. Now, a major study to be launched this fall in Canada, with federal support, will attempt to determine whether there is any real evidence that electromagnetic fields can in fact cause leukemia in children.

The five-year, $800,000 study, which will involve 800 randomly selected Canadian children, is being sponsored by Health and Welfare Canada, the Canadian Electrical Association, which represents the nation’s major electricpower utilities, and the Electric Power Research Institute in Palo Alto, Calif. Research-

ers in Vancouver, Victoria, Edmonton, Calgary, Regina, Winnipeg and Montreal will monitor the exposure to electromagnetic fields among 400 children diagnosed with leukemia, a sometimes fatal form of cancer that attacks blood cells and affects about four in every 100,000 children under 14. A second group of 400 children who do not have leukemia will also take part in the study.

During the study, children in both groups will wear dosimeters, cigarette packagesized devices that measure electromagnetic exposure every minute, during a 48hour period. Mary McBride, an epidemiologist who studies potential causes and patterns of disease with the British Columbia Cancer Agency, and a chief investigator in the study, said that it is the first time that personal dosimeters have been used in the testing. In the past, investigators relied on indirect spot measurements to determine links between electromag-

netic fields and cancer rates. The study, said McBride, “is unique because we’ll actually measure an individual’s exposure instead of guessing.” Researchers say that the study will provide answers to questions raised 11 years ago by Nancy Wertheimer of the University of Colorado Medical Center in Denver, who studied a group of 688 children, half of whom had cancer, including 155 with leukemia, and estimated the strength of electromagnetic fields around their homes. Wertheimer, now retired, concluded that the children with cancer lived “unduly often” in homes near power g lines, including secondary 2j power lines that carried elec| tricity to groups of houses, g Still, the epidemiologist said s that she had no proof that the íe presence of power lines s caused high cancer rates.

The suspicion that electrical fields might be a cause of serious illness has led to protests over the location of electrical power lines in some communities. Coleen Aikens organized one such protest in Leitches Creek, N.S., 456 km northeast of Halifax. Aikens, the mother of three children ranging in age from seven months to six years, organized a group of residents who, in April, asked the Nova Scotia Power Corp. to change the proposed route of power lines that would have passed within 500 feet of homes in the community. “They shouldn’t put people at risk when the jury is still out,” said Aikens. “We can’t backtrack when our children have already been exposed.” Over the past four years, similar concerns have led residents to organize in other communities, including Bridlewood, Ont., and Sherbrooke, Que. Said Margaret Murphy, a spokeswoman for the Nova Scotia environment department: “We’re hearing a lot of concern from people about power lines, but we don’t see any policies or studies we can really look to for guidance.”

Although electrical power lines are visible targets, experts say that all electrically operated machines and appliances produce electromagnetic fields. Indeed, an ordinary kitchen stove or family television set can produce a stronger electromagnetic field than electrical power lines. But Ed Leeper, a Colorado physicist who worked with Wertheimer on the 1979 study, said that the strength of the field drops off quickly from the source, “less than a a metre from most household g appliances, and on up to 20 or z 50 or even 100 metres from m large overhead power lines.”

While no one knows how exposure to electrical fields might cause cancer, McBride said that in experiments, electrical fields have produced some cellular changes in laboratory animals.

For her part, Wertheimer says that studies so far have not found any adverse effects on people from short-term exposure to strong electromagnetic fields, such as those generated by household stoves. But she said that some links between prolonged exposure to electrical

fields and miscarriages among women were found in a 1989 study carried out in Oregon and Colorado. That study pointed to an association between miscarriages and the use of electric blankets, electrically heated water beds and some types of ceiling cable electrical heating.

Still, many scientists say that much more

research is needed to determine whether there is any link at all between electrical fields and illness. Said Claire Infante-Rivard, who teaches epidemiology at Montreal’s McGill University: “We probably have thousands of studies on cholesterol and heart disease, but we still don’t know everything about that. For electromagnetism, we have only a few studies, so it’s much too early to tell.”

Meanwhile, some major utilities have launched their own studies. In January this

year, the giant provincially owned power corporation, Ontario Hydro, commissioned a study by Anthony Miller, who teaches preventive medicine at the University of Toronto. He will investigate the suspected links between childhood leukemia and electromagnetic exposure. At the same time, Ontario Hydro has joined

with Hydro Quebec and Health and Welfare Canada to sponsor a three-year, $ 1.3-million study to determine the effects of electromagnetic fields on the development of brain cancer and leukemia in laboratory animals.

In the meantime, officials of provincial power utilities say that they doubt that electrical fields are harmful to health. Said Larry Boudreau, representing N.B. Power, the New Brunswick utilities commission: “We’ll continue to monitor the latest studies, even though there’s nothing really there to suggest strong links.” Some observers criticize the fact that the utilities, which would have the most to lose if power lines are found to be a health hazard, are a major source of funding and guidance for research in the field. Said David Poch, a Toronto environmental lawyer and author of Radiation Alert, a 1985 book that includes a chapter on the dangers of power lines: “One wonders why we’re leaving it to the fox to guard the hen house.”

o Still, Maria Stuchly, a reo search scientist with Health g and Welfare Canada in Otta9 wa, says that utility compa3 nies, as well as their custom$ ers, are “honestly interested 9 in getting scientifically sound P answers.” In Washington, § last week, the House of Rep| resentatives began hearings 5 to consider a bill, proposed by New Jersey Democrat Frank

Pallone, to set up a federal

research program on electromagnetic fields. In Canada, the federally supported study may provide the first conclusive answers to the disturbing issues that have been raised about electromagnetic fields.

DIANE BRADY