The influence of particle size on radionuclide activity concentrations in Tejo River sediments

Sediment samples from Tejo River were analyzed for ²²⁸Ra, ²²⁶Ra, ¹³⁷Cs and ⁴⁰K by HPGe gamma spectrometry. The activity concentration data were statistically analyzed. The activity concentrations values were in the range of about two orders of magnitude for each radionuclide. The influence of the particle size on the radionuclide concentrations was observed. The different environmental origins of the radionuclides ²²⁸Ra, ²²⁶Ra, ¹³⁷Cs and ⁴⁰K, in the sediments were demonstrated through correlation analysis. Cluster analysis showed a close relationship between ²²⁸Ra and ²²⁶Ra and a different behavior for ⁴⁰K. The data obtained in this study provides useful information on the background radioactivity of the studied area and can be further used for radiological mapping of the Tejo River. - Highlights: • Sediment samples were analyzed for ²²⁸Ra, ²²⁶Ra, ⁴⁰K and ¹³⁷Cs by gamma spectrometry. • Radionuclide activity concentrations are dependent on the sediment particle size. • Correlation analysis demonstrates the different origins of the radionuclides. • Cluster analysis has distinguished two different groups: ²²⁸Ra, ²²⁶Ra and ⁴⁰K