Environmental Radioactivity

Abstract

In this chapter, the sources and occurrence of radioactive isotopes will be discussed, including natural and anthropogenic radioactive isotopes. The occurrence and circulation of radionuclides in different parts of the geosphere (atmosphere, hydrosphere, and lithosphere) and biosphere (plants, animals, and humans) will be shown. The biological effects of the radioactive isotopes will be demonstrated. The dose units characterizing the irradiations and the mechanism of the biological effects (the physical-chemical-biological reaction chain) will be discussed. The importance of radical formation in the biological effects will be emphasized. The sources of the natural background radiation will be listed: the cosmic ray, the cosmogenic and primordial radionuclides, natural radioactivity due to anthropogenic activity, and artificial radioactive isotopes. The dangerous irradiation ranges, including the stochastic, deterministic, somatic, and genetic effects, will be mentioned. Finally, the principles behind radiation protection regulations will be summarized.