Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia
2018
Khandaker, Mayeen Uddin | Asaduzzaman, Khandoker | Sulaiman, Abdullah Fadil Bin | Bradley, D.A. | Isinkaye, Matthew Omoniyi
Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide ⁴⁰K and the natural-series indicator radionuclides ²²⁶Ra and ²³²Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of ²²⁶Ra, ²³²Th and ⁴⁰K from 451±9 to 2411±65Bqkg⁻¹ (mean of 1478Bqkg⁻¹); 232±4 to 1272±35Bqkg⁻¹ (mean of 718Bqkg⁻¹) and 61±6 to 136±7Bqkg⁻¹ (mean of 103Bqkg⁻¹) respectively. Conversely, in white sands the respective values for ²²⁶Ra and ²³²Th were appreciably lower, at 8.3±0.5 to 13.7±1.4Bqkg⁻¹ (mean of 9.8Bqkg⁻¹) and 4.5±0.7 to 9.4±1.0Bqkg⁻¹ (mean of 5.9Bqkg⁻¹); ⁴⁰K activities differed insubstantially from that in black sands, at 85±4 to 133±7Bqkg⁻¹ with a mean of 102Bqkg⁻¹. The mean activity concentrations of ²²⁶Ra and ²³²Th in black sands are comparable with that of high background areas elsewhere in the world. The heavy minerals content gives rise to elevated ²²⁶Ra and ²³²Th activity concentrations in all of black sand samples. Evaluation of the various radiological risk parameters points to values which in some cases could be in excess of recommendations providing for safe living and working. Statistical analysis examines correlations between the origins of the radionuclides, also identifying and classifying the radiological parameters. Present results may help to form an interest in rare-earth resources for the electronics industry, power generation and the viability of nuclear fuels cycle resources.
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