Contamination (radioactivity)
In radiation protection, contamination ( Latin contaminatus , defected ) is the contamination of people and the environment with radioactive substances . Occasionally radiation is used synonymously ; " Radiation " can also mean radiation damage , regardless of contamination.
The removal of contamination is called decontamination .
Regulations in Germany
The German Radiation Protection Ordinance regulates the handling, acquisition and storage of radioactive substances as well as their dosage and limit values.
"The purpose of this ordinance is to regulate the principles and requirements for precautionary and protective measures to protect people and the environment from the harmful effects of ionizing radiation, which apply to the use and effects of radioactive substances and ionizing radiation of civilizational and natural origin."
Criteria in the Nuclear Safety Officer and Reporting Ordinance (AtSMV) define when a reportable incident occurs.
"Events that meet the reporting criteria listed in Annexes 1 to 5 are subject to reporting."
Point 1.3 in Appendices 1 to 5 defines limit values for contamination that require reporting of an incident.
Detection of contamination
Contamination detection devices are available to detect possible contamination . Contamination of a point, for example a part of the skin, is assumed, for example, if the device measures more than three times the zero rate occurring in the environment .
hazards
To protect people and the environment, contamination must be avoided at all costs. Due to the high longevity of some radionuclides, their ionizing radiation and possibly toxicity, radioactive substances can be dangerous for very long periods of time ( danger of radioactivity ) and must therefore be stored safely ( radioactive waste ).
Biological effect
Humans can be exposed to potentially fatal radiation, both external and internal ( incorporation by ingestion or inhalation). Immediate decontamination is necessary. The biological effect of internally deposited radionuclides depend strongly on the activity and biodistribution and erosion rate of the radionuclide, which in turn depends on its chemical form. The biological effect can also depend on the chemical toxicity (see plutonium ) of the underlying material, regardless of its radioactivity. Some radionuclides are usually distributed throughout the body and can be broken down quickly, as is the case with tritium water. However, some organs accumulate certain elements and their radionuclides, which can lead to significantly lower degradation rates. For example, depending on the supply of iodine , the thyroid accumulates a high concentration of iodine. This percentage can be reduced significantly with iodine blockade .
Causes of Contamination
Radioactive contamination is usually the result of a leak or an accident during the manufacture or use of radionuclides (radioisotopes). Contamination can come from radioactive gases, liquids or particles. Examples:
- Incidents in nuclear power plants ( incidents in European nuclear facilities , incidents in German nuclear facilities , accidents in nuclear facilities )
- Contamination can not be completely ruled out in nuclear medicine and should be detected as early as possible through the use of contamination monitors . The contaminated area should be demarcated in order to avoid the spread of radioactive substances and thus the contamination of other people and objects. Appropriate decontamination measures are intended to minimize radiation exposure for those affected and, in particular, the risk of the substances being incorporated . Auxiliary and responsible persons (in Germany the radiation protection officer ) should be called in. Suitable measures to avoid contamination are the use of protective clothing ( e.g. doctor's coat ), disposable gloves and overshoes . Direct contact with excretions ( blood , urine , feces , sweat , saliva , vomit ) from patients after nuclear medicine examinations and especially nuclear medicine therapy should be avoided.
- Nuclear fallout is the distribution of radioactive material through a nuclear explosion (e.g. atomic bombs dropped on Hiroshima and Nagasaki , nuclear weapons tests )
- Contamination of water or air during the reprocessing of nuclear fuel
decontamination
Depending on the form of the radioactive contamination and the substances involved, this can be more or less completely eliminated. Whether surface contamination of a building or device can be removed through professional washing or only through removal and removal depends on whether the radioactive substances collect on surfaces such as walls and floors or penetrate into the ground. Gaseous contamination, such as radon, can be counteracted by ventilation, which raises the question of the source of the gases or aerosols. Another possibility is the temporal storage until the dose rate has dropped to acceptable values. In any case, the rules of radiation protection must be observed.
In the case of externally contaminated people, an attempt is first made to separate the contamination from the body by removing clothing.
After ingestion (swallowing) or inhalation (inhalation) of radioactive material, the body must be supported in excreting these substances again. For example, Berlin blue is administered in cesium poisoning .
See also
Individual evidence
- ↑ The little Stowasser. Latin-German school dictionary. Munich 1971 p. 135
- ↑ Keyword "Radiation" in the Roche Lexicon Medicine, 5th edition ( online )
- ↑ https://www.gesetze-im-internet.de/atsmv/BJNR017660992.html
- ↑ Fire brigade regulations for 500 units in NBC operation, 2012
- ↑ J. Kretschko and U. Wellner: Dosimetry and radiation protection. In: U. Büll et al .: Nuclear Medicine. Georg Thieme Verlag, Stuttgart and New York 2001 ISBN 3-13-128123-5 p. 156
- ^ W. Sunshine. A. Bockisch: Radiation protection. In: T. Kuwert et al .: Nuclear Medicine. Georg Thieme Verlag, Stuttgart and New York 2008 ISBN 978-3-13-118504-4 p. 66