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Fallout from Nuclear Weapons Tests and Cancer Risks

Exposures 50 years ago still have health implications today that will continue into the future

Steven Simon, André Bouville, Charles Land

Historical Background

Figure 2. Primary atmospheric nuclear weapons test sites...Click to Enlarge Image

The first test explosion of a nuclear weapon, Trinity, was on a steel tower in south-central New Mexico on July 16, 1945. Following that test, nuclear bombs were dropped on Hiroshima and Nagasaki, Japan, in August of 1945. In 1949, the Soviet Union conducted its first test at a site near Semipalatinsk, Kazakhstan. The U.S., the Soviet Union and the United Kingdom continued testing nuclear weapons in the atmosphere until 1963, when a limited test ban treaty was signed. France and China, countries that were not signatories to the 1963 treaty, undertook atmospheric testing from 1960 through 1974 and 1964 through 1980, respectively. Altogether, 504 devices were exploded at 13 primary testing sites, yielding the equivalent explosive power of 440 megatons of TNT (see Figure 2).

The earliest concern about health effects from exposure to fallout focused on possible genetic alterations among offspring of the exposed. However, heritable effects of radiation exposure have not been observed from decades of follow-up studies of populations exposed either to medical x rays or to the direct gamma radiation received by survivors of the Hiroshima and Nagasaki bombs. Rather, such studies have demonstrated radiation-related risks of leukemia and thyroid cancer within a decade after exposure, followed by increased risks of other solid tumors in later years. Studies of populations exposed to radioactive fallout also point to increased cancer risk as the primary late health effect of exposure. As studies of biological samples (including bone, thyroid glands and other tissues) have been undertaken, it has become increasingly clear that specific radionuclides in fallout are implicated in fallout-related cancers and other late effects.

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