Institute of Nuclear Minerals, Atomic Energy Research Establishment, Savar, Dhaka-1349, Bangladesh.
The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego, 31-342 Krakow, Poland.
Radiat Prot Dosimetry. 2024 Nov 18;200(19):1918-1925. doi: 10.1093/rpd/ncae201.
Beach sediments are mineral deposits formed through weathering and erosion of either igneous or metamorphic rocks. Among the rock constituent minerals are some natural radionuclides that contribute to ionizing radiation exposure on Earth. Kolatoli and Kuakata are the two major beaches with heavy mineral deposits and important tourist sites in Bangladesh. Natural radioactivity in Kolatoli and Kuakata beach sand deposits along the southern coast of Bangladesh was assessed and compared to identify the sources, causes, and possible environmental impact. Result shows most of the radionuclides have higher activity concentrations than the background level, and the activity varies with the sample locations. The dominant radionuclides were found to be the radionuclides of thorium series i.e. Th-232 and Ra-228 followed by uranium series and K-40. The radioactivity in Kolatoli beach sands was observed to be much higher than Kuakata beach due to the presence of a higher content of heavy minerals i.e. illmenite, rutile, zircon, garnet and monazite. Furthermore, monazite and zircon are the two radioactive minerals that are considered to be the main contributors to the radioactivity in Kolatoli beach sand. These minerals are dominated by the activity of thorium series radionuclides i.e. Th-232 and Ra-228 surpass the activity of all other radionuclides such as U-238, U-234, Th-230, Ra-226, Po-210, and K-40. However, major contribution of radioactivity in Kuakata beach sand comes from uranium series radionuclides such as U-238, U-234, Ra-226, and Po-210. Beach morphology, sedimentological, and geochemical evolution of those minerals might be important areas of further study for the radioactivity monitoring activity in those areas.
海滩沉积物是通过火成岩或变质岩的风化和侵蚀形成的矿物矿床。在岩石组成矿物中，有一些天然放射性核素，它们对地球上的电离辐射暴露有贡献。科拉托利和夸卡塔是孟加拉国两个主要的海滩，拥有丰富的重矿物矿床和重要的旅游景点。评估了孟加拉国南部沿海科拉托利和夸卡塔海滩砂矿床的自然放射性，并进行了比较，以确定来源、原因和可能的环境影响。结果表明，大多数放射性核素的活度浓度都高于背景水平，且活度随样品位置而变化。主要放射性核素是钍系放射性核素，即 Th-232 和 Ra-228，其次是铀系和 K-40。由于重矿物含量较高，如钛铁矿、金红石、锆石、石榴石和独居石，科拉托利海滩砂的放射性比夸卡塔海滩高得多。此外，独居石和锆石是两种放射性矿物，被认为是科拉托利海滩砂放射性的主要贡献者。这些矿物的活动主要受钍系放射性核素的影响，即 Th-232 和 Ra-228 的活动超过了所有其他放射性核素，如 U-238、U-234、Th-230、Ra-226、Po-210 和 K-40。然而，夸卡塔海滩砂的放射性主要来自铀系放射性核素，如 U-238、U-234、Ra-226 和 Po-210。这些矿物的海滩形态、沉积学和地球化学演化可能是这些地区放射性监测活动的进一步研究的重要领域。
