PDF(Pubmed)
Abstract：
Labuan, Miri, Kundasang and Raub regions of Malaysia have very different geological formations and settings that could result in different levels of natural radioactivity. Hence, this study determines the influence of different geological formations on radioactivity in these locations using field measurements, petrology and geochemistry. A total of 141 gamma dose rates and 227 beta flux measurements were collected using Polimaster survey meters (PM1405) in these four regions. The gamma dose rate values range from 0.37 to 0.05 µSv/h with a mean value of 0.11 µSv/h. Beta flux values range from 3.46 to 0.12 CPS with a mean value of 0.57 CPS. Mineralogy and elemental composition of the different rock types were analysed using thin-section petrography, XRD, ICP and pXRF methods. Felsic igneous rocks such as syenite and granite have higher natural radioactivity and contain more radionuclide-bearing minerals such as apatite, zircon, allanite, K-feldspar, titanite, muscovite and biotite. Metamorphic rocks have the second highest natural radioactivity and contain fewer radioactive minerals. The natural radioactivity of sedimentary rocks mostly depends on their clay content. The gamma dose rate maps show that igneous and metamorphic regions around Raub have higher radioactivity compared to the sedimentary-dominated regions around Miri and Labuan. Annual effective dose (AED) and excess lifetime cancer risk (ELCR) were calculated to evaluate the potential health risk for inhabitants of these regions. Labuan and Miri are considered to be safe zones with respect to natural radioactivity as the results show little to no risk for the public, compared with the Raub region, which is medium to high risk.
摘要：
Labuan,米里,马来西亚的Kundasang和Raub地区具有非常不同的地质构造和环境，可能导致不同水平的自然放射性。因此，这项研究通过现场测量确定了不同地质构造对这些地点放射性的影响，岩石学和地球化学。在这四个地区，使用Polimaster测量仪（PM1405）共收集了141个γ剂量率和227个β通量测量值。γ剂量率值范围为0.37至0.05µSv/h，平均值为0.11µSv/h。β通量值范围为3.46至0.12CPS,平均值为0.57CPS。使用薄片岩相学分析了不同岩石类型的矿物学和元素组成，XRD,ICP和pXRF方法。正长岩和花岗岩等长岩火成岩具有较高的天然放射性，含有较多的含放射性核素的矿物，如磷灰石，锆石,黄铁矿,钾长石,钛铁矿,白云母和黑云母。变质岩具有第二高的天然放射性，含有较少的放射性矿物。沉积岩的天然放射性主要取决于其粘土含量。伽马剂量率图显示，与美里和纳邦周围的沉积为主的地区相比，拉布周围的火成岩和变质地区具有更高的放射性。计算了年有效剂量（AED）和终生癌症风险（ELCR），以评估这些地区居民的潜在健康风险。Labuan和Miri被认为是天然放射性的安全区，因为结果显示对公众来说几乎没有风险，与Raub地区相比，这是中等到高风险。
