Radioactive contamination
Radionuclides, also called radioisotopes, are chemical species whose nuclei are unstable and dissipate excess energy by spontaneously emitting ionising radiation. For pollution monitoring, alpha particles (helium nuclei), beta particles (electrons) and gamma photons are detected in the energy range tens of keV (kiloelectron volt) to MeV (megaelectron volt). Their activity is measured mainly using semiconductor and scintillation detectors, as well as ionisation chambers.
Natural radionuclides are not the product of human activity and can be found throughout the environment. Natural radionuclides are divided into five main categories:
- Radionuclides induced in Earth's atmosphere by cosmic rays
- Nonchain primordial radionuclides
- Uranium-238 chain radionuclides
- Thorium-232 chain radionuclides
- Uranium-235 chain radionuclides
Artificial radionuclides are the product of human activity and their occurrence in the environment is undesirable. Populations must be protected against dangers arising from artificial pollutant radionuclides therefore the monitoring of the air, water and soil is of highest importance.
Despite the regulations, the main potential sources of environmental contamination by radionuclides can be:
- Nuclear accidents in nuclear facilities and the spread of radionuclides into the environment.
- Radiological incidents in workplaces with radioactive substances.
- Insufficient measures against the penetration of wastes into the environment from waste repositories.
- The use of nuclear weapons.