Natural radioactivity distribution and gammaradiation exposure of beach sands close to Kavalapluton, Greece

This study aims to evaluate the activity concentrationsof U, Ra, Th, Th and K along thebeaches of Kavala being adjacent to the rock-types of theKavala pluton. These ranged from 14–940, 16–1710, 26–4547, 27–4488 and 194–1307 Bq/kg respectively, representingthe highest values of natural radioactivity measuredin sediments of Greece. The (%wt.) heavy magnetic (HM)(allanite, amphibole, mica, clinopyroxene, magnetite andhematite) fraction, the heavy non-magnetic (HNM) (monazite,zircon, titanite and apatite) fraction and the totalheavy fraction (TH), were correlated with the concentrationsof the measured radionuclides in the bulk samples.The heavy fractions seem to control the activity concentrationsof U and 232Th of all the samples, showingsome local differences in the main U and Th mineralcarrier. The measured radionuclides in the beach sandswere normalized to the respective values measured in thegranitic rocks, which are their most probable parentalrocks, so as to provide data upon their enrichment or depletion.The annual equivalent dose varies between 0.01and 0.35 mSv y for tourists and from 0.03 to 1.48 mSv y for local people working on the beach.