Assessment of outdoor radiation hazard of natural radionuclides in tourism beach areas

Tourism beaches are main attractions visited by members of the public for leisure and holidays. Knowledge of radiation hazard would enable the radiation risk estimation to be made, and suggest mitigation steps if needed. Surface radiation dose, activity concentration of ²³⁸U, ²³²Th and ⁴⁰K, and radiation hazard index in 18 beaches at eastern, south western and southern coast of Peninsular Malaysia were determined. In-situ surface radiation dose measurements were done using portable radiation survey meter, while gamma-ray activities of sand samples were measured by using gamma-ray spectrometry method. The surface dose rates were found to range between 0.04 to 0.12 μSv hr^-1. Mean activity concentration of ²³⁸U varies between 7.3 to 51.0 Bqkg^-1, ²³²Th between 5.9 and 58.4 Bqkg^-1 while ⁴⁰K between 32.7 and 1293 Bqkg^-1 respectively. The corresponding annual effective dose from these natural radiations ranged between 0.051 and 0.552 mSv/y. This average is way below the average worldwide exposure of 2.4 mSv/y. The external radiation hazard index calculated for the eighteen samples ranged between 0.05 and 0.51. No obvious correlation was observed between in-situ dose measurement with the annual effective dose as well as radiation hazard index.