Institute of Geography RAS, Russia; Faculty of Geography, Lomonosov Moscow State University, Russia.
Institute of Geography RAS, Russia; Faculty of Chemistry, Lomonosov Moscow State University, Russia.
J Environ Radioact. 2022 Jul;248:106880. doi: 10.1016/j.jenvrad.2022.106880. Epub 2022 Apr 4.
The purposes of this study are to determine the content and origin of anthropogenic fallout radionuclides (FRN) in soils of Mount Khuko, located in the western sector of the Caucasus Mountains and to assess the possibility to use them for evaluation of sediment redistribution for the alpine grasslands,. The field study was carried out in August 2019 near the top of Mount Khuko, located in the western part of the main Caucasus Mountain Ridge. Integral and incremental soil samples were collected from the different morphological units of the studied area. The content of Cs and Am in soil samples was evaluated using laboratory gamma-spectrometry. A part of samples was selected for Pu isotopes extraction and then alpha-spectrometric analysis. It was established that the Cs contamination of soils in the studied area has at least two sources of origin. The first source is the Cs bomb-derived fallout after the bomb tests in 1950-60th, which is widespread across the globe. The second source is Cs Chernobyl-derived fallout High random variability (Cv = 25-42%) was found within reference sites, located at the undisturbed areas on the local flat interfluves due to high variability of soil characteristics (grain size, density, organic matter content etc.). However minimum spatial variability (range 12,2-14,3 kBq/m) was identified for the mean value of Cs inventories for all 5 reference sites located in the different parts of the studied area. It is difficult to separate individual peaks of the bomb-derived and Chernobyl-derived Cs falloutin sediment sinks with low sedimentation rates. Application Pu as an additional chronological marker allows to identify the origin of above mention peaks in the soils of alpine grasslands and of dry lake bottom.
本研究的目的是确定位于高加索山脉西部的 Khuko 山土壤中人为沉降放射性核素（FRN）的含量和来源，并评估它们在评估高山草原沉积物再分布中的可能性。实地研究于 2019 年 8 月在位于主高加索山脉脊西部的 Khuko 山山顶附近进行。从研究区域的不同形态单元中采集了积分和增量土壤样本。使用实验室伽马光谱法评估了土壤样品中 Cs 和 Am 的含量。选择部分样品进行 Pu 同位素提取，然后进行 alpha 光谱分析。结果表明，研究区域土壤中的 Cs 污染至少有两个来源。第一个来源是 1950-60 年代炸弹试验后全球广泛存在的 Cs 炸弹衍生沉降物。第二个来源是 Cs 切尔诺贝利衍生沉降物。由于土壤特性（粒度、密度、有机质含量等）的高度变异性，在未受干扰的局部平坦分水岭上的参考点发现了高随机性变异性（Cv=25-42%）。然而，对于位于研究区域不同部分的所有 5 个参考点的 Cs 库存平均值，最小空间变异性（范围为 12.2-14.3 kBq/m）被确定。对于沉降速率低的沉积物汇，很难分离出炸弹衍生和切尔诺贝利衍生 Cs 沉降物的单个峰。应用 Pu 作为附加的年代标记，可以识别高山草原土壤和干湖底中上述峰的来源。
