Evaluation of radiological risks due to natural radioactivity around Lynas Advanced Material Plant environment, Kuantan, Pahang, Malaysia

Understanding the public awareness concerning the Lynas Advanced Material Plant (LAMP), an Australian rare earths processing plant located in Malaysia, a radiological study in soil and water samples collected at random surrounding the LAMP environment was undertaken using HPGe gamma-ray spectrometry. The mean soil activities for Ra-226, Th-232, and K-40 were found to be 6.56 +/- 0.20, 10.62 +/- 0.42, and 41.02 +/- 0.67 Bq/kg, respectively, while for water samples were 0.33 +/- 0.05, 0.18 +/- 0.04, and 4.72 +/- 0.29 Bq/l, respectively. The studied areas show typical local level of radioactivity from natural background radiation. The mean gamma absorbed dose rate in soils at 1 m above the ground was found to be 11.16 nGy/h. Assuming a 20 % outdoor occupancy factor, the corresponding annual effective dose showed a mean value of 0.014 mSv year(-1), significantly lower than the worldwide average value of 0.07 mSv year(-1) for the annual outdoor effective dose as reported by UNSCEAR (2000). Some other representative radiation indices such as activity utilization index (AUI), H (ex), H (in), excess lifetime cancer risk (ELCR), and annual gonadal dose equivalent (AGDE) were derived and also compared with the world average values. Statistical analysis performed on the obtained data showed a strong positive correlation between the radiological variables and Ra-226 and Th-232.