By Richard Ingram
New studies in the United Kingdom and in the United States have found alarming confirmation of increased leukaemia caused by exposure to levels of nuclear radiation previously considered safe.
Two studies were published in the British Medical Journal on March 26. One, by Dr J.A. Cartwright, confirms the findings of Professor M.J. Gardner, published in February 1990. Gardner found an association between childhood leukaemias and radiation exposure of the fathers working at the Sellafield reactor prior to the conception of their children.
The other study, by J.D. Urquhart of childhood leukaemia around the Dounreay nuclear plant in Scotland, found a positive association between time spent playing on beaches around Dounreay and subsequent development of leukaemia. Urquhart explicitly states that his study does not contradict Gardner's findings, but argues that it points to the importance of both occupational and environmental exposures in childhood leukaemia.
In the United States, a study published on March 20 in the Journal of the American Medical Association found excess leukaemia deaths among workers at the Oak Ridge National Laboratory nuclear weapons production plant.
The study found that leukaemia deaths were 63% higher than expected among white male workers hired between 1943 and 1972, after a longer follow-up period of study. All cancer deaths were 30 higher than expected among workers of all races and both sexes, hired during that period and employed for more than 30 days.
"This study suggests that the long-term exposure to low doses of ionising radiation may produce risks of excess leukaemia and other cancers that are far greater than would be predicted by data on high-dose, short-term exposures like those at Hiroshima and Nagasaki", said H. Jack Geiger, MD, co-director of the Physicians for Social Responsibility Task Force on the Health Risks of Nuclear Weapons Production.
The Oak Ridge workforce had been studied before with no findings of increased risk, but only through 1977. In the new study, the researchers tracked down all deaths through 1984. It was in the additional seven years that the increased risk became apparent.