Answer to Question #616 Submitted to "Ask the Experts"

Q

How does a nuclear power plant release ⁹⁰Sr into the environment? I have been hearing about recent increases in childhood leukemia rates as shown by "The Tooth Fairy Project" testing of children living near nuclear power plants. The correlation seems to be high. Where can I find more information?

A

Nuclear power plants can release tiny amounts of ⁹⁰Sr in their waste water. However, these discharges are monitored by the plants and closely regulated by the US Nuclear Regulatory Commission. Radiation doses to the public from all nuclear plant sources, including ⁹⁰Sr, are a small fraction of the dose received from natural background radiation.

A definitive study on cancer in populations living near nuclear facilities was published by the National Cancer Institute, a governmental organization within the US Department of Health and Human Services. Their fact sheet on the report "No Excess Mortality Risk Found in Counties with Nuclear Facilities" states the following: A National Cancer Institute (NCI) survey published in the Journal of the American Medical Association, 20 March 1991, showed no general increased risk of death from cancer for people living in 107 US counties containing or closely adjacent to 62 nuclear facilities. The facilities in the survey had all begun operation before 1982. Included were 52 commercial nuclear power plants, 9 Department of Energy research and weapons plants, and 1 commercial fuel reprocessing plant. The survey examined deaths from 16 types of cancer including leukemia. In the counties with nuclear facilities, cancer death rates before and after the startup of the facilities were compared with cancer rates in 292 similar counties without nuclear facilities (control counties).

The NCI survey showed that, in comparison with the control counties, some of the study counties had higher rates of certain cancers and some had lower rates, either before or after the facilities came into service. None of the differences that were observed could be linked with the presence of nuclear facilities. "From the data at hand, there was no convincing evidence of any increased risk of death from any of the cancers we surveyed due to living near nuclear facilities," said John Boice, ScD, who was chief of NCI's Radiation Epidemiology Branch at the time of the survey. He cautioned, however, that the counties may be too large to detect risks present only in limited areas around the plants. "No study can prove the absence of an effect," said Dr. Boice, "but if any excess cancer risk due to radiation pollution is present in counties with nuclear facilities, the risk is too small to be detected by the methods used." The reader is urged to read the full fact sheet, which can be found at http://cis.nci.nih.gov/fact/3_11.htm. The fact sheet includes more details of the study, a series of questions and answers, and sources for more information.

Tom Gesell
Department of Physics
Idaho State University