Sources of Contamination
Radioactive contamination is typically the result of a spill or accident during the production, or use of, radionuclides (radioisotopes); these have unstable nuclei which are subject to radioactive decay.
Less typically, nuclear fallout is the distribution of radioactive contamination by a nuclear explosion. The amount of radioactive material released in an accident is called the source term.
Contamination may occur from radioactive gases, liquids or particles. For example, if a radionuclide used in nuclear medicine is spilled (accidentally or, as in the case of the Goiânia incident, through ignorance), the material could be spread by people as they walk around. Radioactive contamination may also be an inevitable result of certain processes, such as the release of radioactive xenon in nuclear fuel reprocessing. In cases that radioactive material cannot be contained, it may be diluted to safe concentrations. For a discussion of environmental contamination by alpha emitters please see actinides in the environment.
Contamination does not include residual radioactive material remaining at a site after the completion of decommissioning. Therefore, radioactive material in sealed and designated containers is not properly referred to as contamination, although the units of measurement might be the same.
Read more about this topic: Radioactive Contamination
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