Natural Radionuclides in the Building Materials From the Region of The Small Carpathians
Research Papers. Faculty of Materials Science and Technology. Slovak University of Technology in Trnava
Distribution of radionuclides in the main rock types: granodiorites, biotite-gneisses, black shale and amphibolites at the locality Pezinok -Kolársky vrch was studied in samples from two boreholes. Concentrations of 238 U, 232 Th and 40 K in the samples were analysed by gamma spectroscopy (concentrations of 238 U were 0.091 -37.800 mg/kg, 232 Th 0.534 -13.234 mg/kg, 40 K 0.116 -5.162 mg/kg). The highest average 238 U concentration was in black shale, highest average 232 Th concentration in
... ncentration in granodiorite and highest average 40 K concentration in granodiorite. Activities of 238 U were determined within the range of 1.092 -48.960 Bq/kg (with exception of one anomalous value -453.6 Bq/kg), activities of 232 Th within the range of 2.189 -54.298 Bq/kg and activities of 40 K within the range of 30.933 -1,376.499 Bq/kg. The source of 238 U and 232 Th (and partially also of 40 K) is in the granodiorite intrusion. During the metamorphic process, Uranium was mobilised to the black shales. The concentrations and consequently the total activities of 238 U, 232 Th and 40 K in the studied rock samples exceed the permitted limit values for building materials. It is possible to recommend their utilisation only for external purposes.