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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Effects of selected radioactive substances

Radioactive substances interact with the human body, each with its specific way which depends on occurrance and physical properties. Based on examples for selected substances, this interaction is explained.



Plutonium (Pu) is a heavy metal with the atomic number 94. For the human body it is chemically toxic as some other heavy metals like lead and mercury. Additionally, plutonium is radioactive, which means that its various isotopes emit radiation during decay. The half-life of plutonium isotopes is rather long, for example for plutonium-239, it takes 24,110 years until half of the atomic nuclei have decayed. During radioactive decay, mainly alpha radiation is emitted and - to a far lesser extent - also gamma radiation.



The physical and chemical properties of uranium are described. In principle, there are two health effects of uranium to be considered: health effects due to the metal properties of uranium (chemotoxic effects) and health effects due to radiation properties of uranium (radiotoxic effects).



Polonium-210 is the most common isotope of polonium in nature. It is formed as the last radioactive chain link in the radioactive decay chain of uranium-238. The total natural occurrence of polonium is extremely low. Polonium-210 has a physical half-life of 138 days. It emits alpha particles during its radioactive decay to lead-206. Radioactive polonium poses a health hazard only if the radionuclide is taken in by the body through food or drinking water, through breathing (inhalation) or if it enters the body through open wounds in the skin for example.

Drawing of a house with three persons and radon in the ambient air

Health effects of radon

Radon can accumulate in the ambient air of closed rooms. Particularly harmful are its short-lived progeny which can deposit in the respiratory tract. Alpha radiation that accrues during decay can promote lung cancer. According to statistical risk calculations, nearly 1,900 deaths yearly are due to indoor radon in Germany. Within the European Union, 20,000 deaths yearly can be attributed to indoor radon.

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