An Overview of Radiation and Health
October 31, 2012
Three basic principles need to shape our consideration of radiation exposure.
First, there is no “safe” or non–harmful level of radiation.
Second, we are all exposed to radiation: background radiation, with which we evolved, and medical radiation, which may be necessary and life saving as decided and controlled by the patient and physician.
Finally, there is another form of exposure which has been thrust upon the world since the advent of the nuclear age. This occurs with the release of radiation throughout the nuclear fuel cycle, nuclear weapons use and testing, and the “controlled” and catastrophic releases of long-lived radionuclides from the nuclear power industry. This is quite a different issue; this radiation is not “natural” and should not be included as acceptable “background.”
The trend through the nuclear age has been toward the general recognition that there is no “safe” or “harmless” dose of radiation. The National Research Council of the National Academies, in a comprehensive report entitled “Health Risks from Exposure to Low Levels of Ionizing Radiation,” BIER VII, recognizes that radiation exposure has a linear relationship to the development of cancer. There is no level of exposure below which there is no risk.
Yet even in the 1970’s the risks of radiation were still being discovered. At that time, it was common medical practice to x-ray pregnant women during labor to see if the pelvis was “adequate,” a procedure, incidentally, that was absolutely worthless from a medical point-of-view. Dr. Alice Stewart did seminal work which revealed that even one x-ray in utero increased a fetus’s chances of getting leukemia later in life. Today, physicians no longer perform x-rays on pregnant women unless absolutely necessary.
Most of the data on the effects of radiation exposure are derived from studies of the survivors of the bombings of Hiroshima and Nagasaki, from intentional medical irradiation, and from a few high-dose accidents. The Hiroshima exposure was a one-time dose largely composed of gamma and x-rays, since the bombs were exploded high in the air, producing very little fallout. This is very different from the releases from nuclear testing, and from accidents at Kyshtym, Chernobyl, and Fukushima, which have irretrievably released into the environment long-lived radionuclides such as cesium-137, strontium-90 and plutonium-239, which will continue to expose living creatures to radiation for hundreds to thousands of years.
It is simply unknown what will be the distant health consequences to humankind of these very long-lived radionuclides in the global environment. Evidence to date is that consequences are likely to be cumulative as the contamination accumulates. Einstein’s prophetic words are still relevant: “The splitting of the atom has changed everything save our mode of thinking. Thus we drift toward unparalleled catastrophe.”