Natural radioactivity and associated radiation hazards in soil of Kelantan, Malaysia

Abstract

Radiological effects due to external and internal exposure to natural radiation associated with the natural radionuclides 226Ra, 232Th, and 40K in soil of Kelantan, Malaysia was carried out. Terrestrial gamma radiation dose rates (TGRD) measurement was carried out using a portable [NaI(TI)] micro roentgen (µR) survey meter and hyper purity germanium (HPGe) detector for the activity concentrations of 226Ra, 232Th, and 40K in soil samples. The mean TGRD was found to be 209 nGy h−1 and from soil samples analyzed, the mean activity concentrations of 226Ra, 232Th, and 40K were found to be 82 Bq kg−1, 123 Bq kg−1, and 643 Bq kg−1 respectively, which were both about 3 times higher than the Malaysian average as reported by UNSCEAR 2000. The mean radium equivalent (Raeq), absorbed dose rates (D), annual effective dose (H), annual gonadal dose equivalent (AGDE) as well as external and internal radiation hazard index (Hex), which were the indicators of radiological health hazards, were found to be 307 Bq kg−1, 139 nGy h−1, 0.22 mSv y−1, 969.422 µSv y−1, 0.653 and 1.05, respectively.