ENVIRONMENT

The residue of fear after Chernobyl

Brian D. Johnson June 2 1986
ENVIRONMENT

The residue of fear after Chernobyl

Brian D. Johnson June 2 1986

The residue of fear after Chernobyl

ENVIRONMENT

Every afternoon after a rainfall, 40-year-old Bill Walker visits a fenced-off lot behind his Ottawa office and retrieves a plastic bag holding a sample of fresh rainwater. He then tests the water in a laboratory to determine how much nuclear fallout is still in the local atmosphere after the April 26 explosion at a Soviet nuclear reactor in the Ukraine. Walker is a technician at the radiation and medical devices bureau of the federal health and welfare

department, which receives samples of rain and air from 28 monitoring stations across Canada. Usually the bureau performs the tests once or twice a month. But since the accident occurred at the Chernobyl plant, the “becquerel” index has added an esoteric dimension to the national weather picture. A becquerel is a measure of radiation signifying the decay of one atomic nucleus per second. And after cross-country readings last week, Ottawa told Canadians it was safe to drink rainwater again.

In France, five maintenance workers were contaminated last week when a pipe containing radioactive fluid overflowed at a nuclear reprocessing plant. Officials said the men were unharmed. But the accident—combined with a new report of a serious accident at another French reactor in 1984—heightened the controversy surrounding France’s nucle-

ar program, which uses 40 reactors to generate 65 per cent of the nation’s electricity. Meanwhile in Vienna, the International Atomic Energy Agency (IAEA), a United Nations advisory organization, held an emergency meeting last week to discuss the Chernobyl disaster. The agency’s 35-nation board agreed to draw up binding accords requiring members to notify and assist each other quickly after a nuclear accident. Said IAEA chief Hans Blix of Sweden: “I fear the general

public will no longer believe any contention that the risk of severe accident is so small as to be almost negligible.”

Soviet delegates at the IAEA undertook to present a detailed report on Chernobyl sometime this summer. And by week’s end, the actual death toll from the accident stood at 15—two in the initial explosion and 13 others from radiation over the past month. But U.S. experts said that the fallout may have severe long-term effects on many more people in the Soviet Union, Eastern Europe and Scandinavia. Two physicists—Washington-based Thomas Cochran of the Natural Resources Defense Council and Frank von Hippel of Princeton University in New Jersey—said that over the next few decades the accident could cause as many as 64,000 cancer cases and more than 10,000 deaths. But they emphasized that their estimates

were inexact. Said Cochran: “We know a tremendous amount about the health effects of radiation, but very little about quantifying the effects at low doses.” Exposure to small amounts of radiation may cause cancer many years later, but a heavy dose can obliterate the body’s bone marrow in a matter of weeks—crippling the immune system. In Moscow’s Hospital Number 6, the leading Soviet centre for the treatment of blood disorders such as leukemia, an

international team of doctors led by Los Angeles bone-marrow specialist Dr. Robert Gale has been performing bonemarrow transplants on some of the 35 workers exposed to intense radiation. Gale and his colleagues have been treating such victims as reactor technicians and security guards from the plant 100 km north of Kiev since May 2. Said Gale: “This is the first event of this kind. It is unprecedented to have so many transplants going on simultaneously. There is no place in the world that could handle something like this alone.” Bone marrow is the primary source of blood cells and immune-defence cells. When the bone marrow’s ability to produce billions of blood

cells each day is impaired, the body gradually loses its protection against infection and hemorrhaging. The marrow transplant procedure is relatively simple-specialists draw marrow from a donor’s pelvic bones and inject it into the recipients’ bloodstream. Then the new marrow travels to the bones to replace the patient’s damaged marrow. A successful transplant depends on an almost-perfect match between donor and recipient tissues, otherwise the body will reject the transplant. The best donors are usually siblings, and one Chernobyl victim died after his sister refused to serve as a donor. Reported Gale: “She said she didn’t want to go under general anesthesia and that her brother was going to die anyway.”

The effects of high-level radiation were brutally obvious to the specialists working in the brown-brick hospital on

the outskirts of Moscow. The most seriously affected of the 204 Chernobyl victims receiving treatment there had burnt skin and degenerated intestines as well as destroyed marrow. But the more widespread low-level radiation which emanated from the crippled reactor and spread around the world represents a more insidious threat because scientists do not agree on the amount of radiation the body can absorb without ill effects. According to Canadian government standards, the recommended limit is 70 becquerels per kilogram for food produce and 10 becquerels per litre for drinking water and milk.

By contrast, equivalent U.S standards range from 300 to 550 becquerels for milk and food—dropping to 50 becquerels per litre for infant food. On May 10,

two weeks after the nuclear accident at Chernobyl, tests of Canadian rainwater peaked at 68 becquerels per litre at one site in Vancouver. Still, radiation officials estimate that humans naturally attain a level of about 4,000 becquerels mainly from potassium in food, as well as from radium in soil and from sunlight. Declared radiation bureau scientist Roger Eaton in Ottawa: “Because our body is being assaulted by radiation all the time, it is difficult to say how much is too much.”

While heavy rains have cleared the air across most of Canada and washed away most of the fallout, Eaton said the tests would continue for at least another two weeks—“until we are confident that the event has passed.” As well, federal officials said they plan to

perform difficult and time-consuming tests on milk for strontium 90, a radioactive isotope which collects in the bones and attacks the mechanism for producing the healthy white blood cells necessary to prevent leukemia. But Eaton expects to find isotope levels well below Canadian safety limits. Still, there are an estimated 212 large nuclear reactors operating in 26 countries around the world, and the rising death toll and increased monitoring prompted by a single malfunctioning unit in the Soviet Union are grim reminders of the potential dangers of nuclear power.

BRIAN JOHNSON

NORA UNDERWOOD

JULIA BENNETT