Publisher © Czech Geological Survey, ISSN: 2336-5757 (online), 0514-8057 (print)
Natural radionuclides and 137Cs activity in dam sediments of the Brno Dam
AbstractThe concentrations of natural radioactive elements (K, U and Th) and 137Cs in bottom sediments of the Brno Dam (on the Svratka River) have been determined by gamma-ray spectrometry. Natural radioactivity of studied sediments is relativelly low and corresponds to natural radioactivity of the main rocks of accumulation area of watershed. In bottom sediments of the Brno Dam a horizon strongly contaminated by radiocesium coming from radioactive fall-out due to an accident of the atomic reactor of the Chernobyl power station in 1986 year was encountered. Activity of 137Cs in this horizon achieves as much as 309 Bq.kg-1. The Brno Dam water is now let out so the water level is ten metres lower and water stream is eroding bottom dam sediments. Sediments with extremely high concentration of 137Cs are in this way redeposited into streams below the Brno Dam and they can represent a certain environmental risk.