The role of natural radioactivity as a tracer of the sedimentary dynamic in Las Canteras beach

Abstract

In this master thesis, the natural radioactivity has been studied in order to evaluate the spatial and temporal variability of the sand of one the most important beaches in Gran Canaria island, Las Canteras. For this purpose, the activity concentration of 226Ra, 232Th, 40K and 210Pbxc has been analyzed in space and time as well as its radiological impacts. The external gamma dose rate does not seem to change with time and it does not indicate any radiological risk on the beach either. For spatial variability, a Cluster Analysis and a Principal Component Analysis were performed, resulting in a new division of the beach with three zones influenced by the structure of the natural offshore rocky bar presented in the area of the different sampling points. In addition, a correlation analysis between the radionuclides and different non-parametric variables were studied, showing that the composition of the samples also influences on the distribution of radionuclides along the beach. Finally, the results of the temporal analysis suggest a transport of sediments from the area with higher activity of the beach to the zone that presents lower activity.