Radioactivity level and the measurement of soil gas radon concentration in Dikili geothermal area, Turkey

The natural radioactivity level and the radon concentration of soil were measured at four important geothermal area located in Dikili geothermal region, Turkey. The natural radionuclide content of soil samples were measured by NaI(Tl) gamma spectrometer system and the soil radon concentration were determined using Kodak-Pethe LR-115 Type II Solid State Nuclear Track Detectors (SSNTD). The aim of the study was to investigate the seasonal variation of the radon concentration as well as evaluate the health hazards related to natural activity if any. It was found that the radon concentration of soil gas in the study area ranged from 98-8594 Bq m-3 with an average value of 1920 Bq m-3. The highest radon concentration observed in summer and the lowest concentration measured in winter. The average activity concentrations of 238U, 232Th and 40K were found to be 28.7, 17.6 and 579.2 Bq kg-1, respectively. Towards this, annual effective doses from these radionuclides determined and analyzed. The calculated dose values are not very high and don’t exceed the radioprotection standards suggested by international agencies.