The radiological evaluation of uranium, radium and radon in metallic and thermo-metallic springs in Ikaria Island, the eastern Aegean Sea, Greece

摘要

The natural alpha and gamma-emitters ~(238)U, ~(226)Ra and ~(222)Rn were analysed in geothermal springs on Ikaria Island situated in the eastern Aegean Sea. The obtained results were evaluated in relation to the radiological regime of the wider area. The exposure dose rates in a network surrounding the island, and the committed effective doses to the human population due to potable spring water are also reported. Although, the measured concentrations of ~(238)U, ~(226)Ra and ~(222)Rn in spring water fall in the range of values reported in the literature, in general, they are higher if compared to other Greek regions. Elevated concentrations of ~(238)U, Ra, ~(222)Rn were found occasionally, whereas evaporation of spring water during treatment procedures in spa installations have resulted in ~(238)U enrichment. Higher concentrations of ~(238)U and Ra were observed in the hot springs. As the surrounding materials present elevated concentrations of the considered radionuclides, the metallic and thermo-metallic springs influence the ambient areas, acting as radionuclide carriers. In terms of the radiological risk, humans might suffer a limited influence from internal alpha-radiation due to systematic water consumption, whereas the concentration of uranium in one spring in terms of ecotoxicity was above the protective boundary level with regard to the predicted no-effect concentration (PNEC) values set for the protection of aquatic biota.