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

Abstract

Abstract This study aims to evaluate the activity concentrationsof 238U, 226Ra, 232Th, 228Th and 40K 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 238U and 232Th of all the samples, showingsome local differences in the main 238U and 232Th 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−1 for tourists and from 0.03 to 1.48 mSv y−1for local people working on the beach.