ABSTRACT
The results of the low-background gamma-spectrometric measurements of sediments from three Western Carpathian mountain rivers during a three year term (2006-2009) are presented. These sediments are dynamic and very informative for environmental monitoring of a large watershed. Distances between the river sample points were 10-20 km and the total change of the altitude was 200-400 m. The proposed sampling scheme allows to investigate the changes of seasonal and spatial distributions of the radionuclides in sediment. The statistical correlations between the sampling points, the water level of the river and the contents of natural or anthropogenic radionuclides in sediment were studied. The effect of the intensive leaching of radionuclides from sediments during the flood season is shown and this can be considered as the principal self-purification mechanism.
