The Radiation and Nuclear Safety Authority (STUK) detected radioactive isotope of cobalt (Co-60) in a surface air particle sample collected in Imatra between 20 November and 7 December 2023. The sample also contained slightly more of the radioactive isotope of cesium 137 (Cs-137) than normal. Concentrations were too small to be of significance to the environment or humans.
The concentration of cobalt-60 was 0.2 microbecquerels per cubic metre of air and that of cesium-137 was 1.9. in the sample collected at the end of November and the beginning of December Cesium-137 was also detected in a sample collected between 13 and 20 November, from which the concentration was determined to be 5.4 microbecquerels per cubic meter. Allso this concentration is insignificant environment and humans.
The cobalt isotope 60 is used in industrial measuring instruments and research, for example. It is also generated in connection with the operation of nuclear facilities.
Cesium-137 is commonly found in particle samples collected from the air. Radioactive caesium resulting from nuclear weapon testing in the atmosphere in the 1960s and the 1986 Chernobyl nuclear power plant accident is still present in Finnish nature. However, the cesium-137 concentration in the December sample from Imatra was higher than normal, so at least some of it probably comes from another source.
The origin of the radioactive substances detected in Imatra is not known, and very often the source of such low radioactivity concentrations remains obscure.
Nine observations of four events in 2023
Radioactive substances caused by human activity are occasionally caught in the filters of STUK's monitoring stations. Four events were observed during 2023. There were a total of nine observations, as some of the events were detected at several monitoring stations. No observation caused any reason to assume that they would have been due to such a release of radioactive substances that would be significant from the point of view of the environment or human health.
STUK monitors the levels of radioactive substances in outdoor air at eight localities in Finland. Particle samplers vacuum up large amounts of air, causing particles in the air to remain on the samplers’ filters. The filters can then be used to measure the activity concentration of radioactive substances and determine which radioactive substances are involved. The method allows the detectinon of even very low concentrations of radioactive substances.
Mediaservice
Puh: 010 850 47611
