Natural radioactivity distribution and gamma radiation exposure of beach sands close the granitoids of NE Chalkidiki, Greece

Περίληψη

This study aims to evaluate the activity concentrations of 238U, 226Ra, 232Th, 228Th and 40K along the beaches NE Chalkidiki being adjacent to the local granitoids. These ranged from 9.0-63.0, 11.5-62.9, 10.9-54.5, 11.8-56.6 and 27-828 Bq/kg respectively. The (% wt.) heavy magnetic (HM) (allanite, epidote, amphibole, mica, clinopyroxene, magnetite and pyrite) fraction, the heavy non-magnetic (HNM) (zircon, titanite and apatite) fraction and the total heavy fraction (TH), were correlated with the concentrations of the measured radionuclides in the bulk samples. The measured radionuclides in the beach sands were normalized to the respective values measured in the granitic rocks, which are their most probable parental rocks, so as to provide data upon their enrichment or depletion. The annual effective dose varies between 0.003 and 0.009 mSv y-1 for tourists and from 0.012 to 0.037 mSv y-1 for local people working on the beach.