Distribution of natural radioactivity and assessment of radioactive dose of Western Anatolian plutons, Turkey

The distribution of Ra-226, Th-232, and K-40 in 70 granite samples obtained from 13 Western Anatolian plutons (Turkey) was measured by using.-ray spectroscopy. The activities of the measured radionuclides varied up to 259 Bq kg(-1) for Ra-226, up to 241 Bq kg(-1) for Th-232, and up to 2518 Bq kg(-1) for K-40, with mean values of 66 (+/- 44), 90 (+/- 47), and 1097 (+/- 410) Bq kg(-1), respectively, which are smaller than the mean values given for granites worldwide. The mean value of the increase on the external.-radiation effective dose rate is 0.21 (+/- 0.09) mSv year(-1), varying by <1 mSv year(-1). The mean value of the internal a-radiation was 0.15 (+/- 0.10) mSv year(-1), varying <0.5 mSv year(-1). Most of the samples cause an increase to both the external and internal dose by <30%, which is smaller than the permitted limit. Therefore, there is no radiological risk from the usage of the samples studied as decorative and ornamental building materials.