Wattanavatee Komrit, Krmar Miodrag, Bhongsuwan Tripob
Department of Physics, Prince of Songkla University, Hatyai 90112, Thailand.
Department of Physics, University of Novi Sad, Trg Dositeja Obradovica 4, 21000, Novi Sad, Republic of Serbia.
J Environ Radioact. 2017 Oct;177:113-127. doi: 10.1016/j.jenvrad.2017.06.009. Epub 2017 Jun 20.
The aim of this study was to determine the activity concentrations of natural terrestrial radionuclides (U, Ra, Th and K) and airborne radionuclides (Pb, Pb and Be) in natural terrestrial mosses. The collected moss samples (46) representing 17 species were collected from 17 sampling localities in the National Parks and Wildlife Sanctuaries of Thailand, situated in the mountainous areas between the northern and the southern ends of peninsular Thailand (∼7-12 °N, 99-102 °E). Activity concentrations of radionuclides in the samples were measured using a low background gamma spectrometer. The results revealed non-uniform spatial distributions of all the radionuclides in the study area. Principal component analysis and cluster analysis revealed two distinct origins for the studied radionuclides, and furthermore, the Pearson correlations were strong within Ra, Th, U and K as well as within Pb and Pb, but there was no significant correlation between these two groups. Also Be was uncorrelated to the others, as expected due to different origins of the airborne and terrestrial radionuclides. The radionuclide activities of moss samples varied by moss species, topography, geology, and meteorology of each sampling area. The observed abnormally high concentrations of some radionuclides probably indicate that the concentrations of airborne and terrestrial radionuclides in moss samples were directly related to local geological features of the sampling site, or that high levels of Be were most probably linked with topography and regional NE monsoonal winds from mainland China.
本研究的目的是测定天然陆生苔藓中天然陆生放射性核素（铀、镭、钍和钾）和气载放射性核素（铅、铅和铍）的活度浓度。从泰国国家公园和野生动物保护区的17个采样点收集了代表17个物种的46份苔藓样本，这些采样点位于泰国半岛南北两端之间的山区（北纬约7 - 12°，东经99 - 102°）。使用低本底伽马能谱仪测量样本中放射性核素的活度浓度。结果显示研究区域内所有放射性核素的空间分布不均匀。主成分分析和聚类分析揭示了所研究放射性核素的两个不同来源，此外，镭、钍、铀和钾之间以及铅和铅之间的皮尔逊相关性很强，但这两组之间没有显著相关性。正如预期的那样，由于气载和陆生放射性核素的来源不同，铍与其他元素也不相关。苔藓样本的放射性核素活度因苔藓物种、每个采样区域的地形、地质和气象条件而异。观察到的一些放射性核素异常高浓度可能表明，苔藓样本中气载和陆生放射性核素的浓度与采样点的当地地质特征直接相关，或者高浓度的铍很可能与地形以及来自中国大陆的东北季风有关。
