Natural radioactivity and metal contamination of river sediments in the Calabria region, south of Italy

摘要

River sediments from eight different sites of the coast of Calabria, south of Italy, were sampled to determine natural radioactivity and metal concentrations, in order to assess any possible radiological hazard, the level of contamination and the possible anthropogenic impact in the area. Gamma and X-ray fluorescence (XRF) spectrometry were employed and results of this study show that the mean activity concentrations of radium (in secular equilibrium with uranium) ranged from 15.1 Bq/kg to 26.7 Bq/kg, that of thorium from 21.8 Bq/kg to 48.3 Bq/kg and that of potassium from 541.3 Bq/kg to 1452.2 Bq/kg. In terms of mean mass concentrations, XRF analysis revealed that uranium was lower than 1.5 ppm (minimum detectable value), thorium ranged from 6.1 ppm to 10.3 ppm while potassium ranged from 2.5% to 4.4%. The degree of sediment contaminations were computed using an enrichment factor (EF) and geoaccumulation index (I-geo) for some potential hazardous elements. Results suggested that enrichment factor and geoaccumulation values of Pb and Mn were greatest among the studied metals. The study revealed that on the basis of computed indexes, the eight investigated rivers can be classified as no polluted ones.