Where does radioiodine come from?
Radioactive iodines (radioiodines such as 131I) are byproducts of the fission of uranium atoms. They can be produced during the operation of nuclear power plants and during the detonation of nuclear weapons. Radioiodine is not likely to be produced in significant amounts by atomic bombs, spent nuclear fuel, or dirty bombs.
Pathways of Exposure
People can be exposed to radioiodine that has been released into the environment by:
Inhalation of Contaminated Air
Radioiodine in the gaseous state can be inhaled into the lungs where it can dissolve and enter the blood. The blood then circulates through the body, including the thyroid gland.
Ingestion of Contaminated Food or Milk
The ability of radioiodine to exist in a particulate form or as a solution in water makes it possible for it to contaminate drinking water, soil, and plants used as food. Radioiodine on pasture grasses or on feed for cattle can contaminate their milk.
*It is very unlikely that contaminated foods would be a major source of exposure in the United States because of existing food guidelines and emergency procedures.
