Assessment of natural radioactivity levels in stony sand from Black Stone Beach of Kuantan, the Peninsular Malaysia

Black Stone Beach (or Pantai Batu Hitam) of Kuantan, Malaysia is a windy but unique beach located on the coastal strip, and has become an attraction for tourists from within and outside the country for many years due to its scenic dark rock formations. Considering the radiological safety of human health, a study was conducted to assess the concentrations of naturally occurring radioactive materials in the beach environment. Activity concentrations of primordial radionuclides ²²⁶Ra, ²³²Th, and ⁴⁰K in the stony sand samples collected from the beach area were assessed by using HPGe γ-ray spectrometry. The measured external gamma radiation dose rates and the activity concentrations were found to ranges 22-31 nGy.h^-1 and 9.8 ± 0.6 to 12.4 ± 0.7 Bq.kg^-1, 6.8 ± 0.5 to 8.8 ± 0.6 Bq.kg^-1 and 209 ± 11 to 354 ± 17 Bq.kg^-1 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The mean values of typical radiological indices such as radium equivalent activity (Ra_eq) and annual effective dose were found to be 17.82 Bq.kg^-1 and 10.86 x 10^-3 mSv.year^-1 which were far below the world average values of 370 Bq.kg^-1 and 2.4 mSv.year^-1 set by the UNSCEAR, respectively. Present results served as an important reference for any future radiological study in Kuantan, Malaysia. (authors)