“… Uranium mining, however, adds another dimension of risk because of the potential for exposure to elevated concentrations of radionuclides. Internal exposure to radioactive materials during uranium mining and processing can take place through inhalation, ingestion, or absorption through an open cut or wound. External radiation exposure from beta particles or gamma rays can also present a health risk.

Radiation typically encountered in uranium mining or processing facility operations includes alpha (a), beta (ß), and gamma (?) radiation. All three are types of ionizing radiation—energy in the form of particles or waves that has sufficient force to remove electrons from atoms. Alpha particles consist of two neutrons and two protons, travel only a few centimeters in air, and can cause a high density of ionizations along their path. In some cases, alpha particles can penetrate the dead layer of skin. If radionuclides that decay by alpha emission (e.g., polonium-218, polonium-214) are inhaled, they have the potential to impart a significant dose to the pulmonary epithelium.

The dose of alpha energy delivered by an alpha particle to the DNA in a cell in the respiratory epithelium is fixed and not dependent on concentration or duration of exposure. Although alpha particles can travel only a short distance, they impart a much greater effective dose than beta particles or gamma rays (NRC, 1988, 2008b). The high effective doses from alpha particles, as compared with beta particles or gamma rays, result from their relatively high energies combined with their very short ranges in tissue. Alpha particles are notable among environmental carcinogens because of their potent ability to produce a high proportion of double-strand DNA breaks per particle. Double-strand DNA breaks are more difficult for the body to repair.”

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