Natural radioactivity in major rivers of Kelantan state, Malaysia

Assessment of natural radionuclides (238U, 232Th, and 40K) and terrestrial gamma radiation dose rates (TGRD) in major rivers of Kelantan states, Malaysia were conducted. Measurements were carried out using a portable [NaI(TI)] micro roentgen (μR) survey meter and inductively coupled plasma mass spectrometer (ICP-MS) for in situ TGRD and the activity concentrations of 238U, 232Th, and 40K in water samples, respectively. The mean TGRD was found to be 312.98 nGy h-1 and from water samples analyzed, the mean activity concentrations of 238U, 232Th, and 40K was found to be 13.31 mBq L-1, 4.39 mBq L-1 and 1118.72 mBq L-1 which were about 3 times and slightly higher than the world average values of 5 mBq L-1 and 3 mBq L-1 respectively