Assessment of gamma dose rates around Istanbul (Turkey)

Natural radionuclide activity concentrations in surface soils of Istanbul have been measured using gamma spectroscopy. The activity concentrations of the radionuclides in soils are directly relevant to outdoor exposure. The natural gamma radioactivity of the terrestrial radionuclides in soil samples and the gamma-absorbed dose rates of these radionuclides in air were calculated throughout different areas of Istanbul. The average activity concentrations of 238U, 232Th and 40K were found to be 21, 37 and 342 Bq kg−1, respectively. The average outdoor gamma dose rate in air at 1 m above ground was determined as 65 nGy h−1. Using the data obtained in this study the average annual effective dose equivalent for a person living in Istanbul was found to be about 80 μSv.