Norwegian University of Life Sciences, Center of Excellence in Environmental Radioactivity (CERAD), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, 1433 Ås, Norway.
Norwegian University of Life Sciences, Center of Excellence in Environmental Radioactivity (CERAD), Faculty of Environmental Sciences and Natural Resource Management, P.O. Box 5003, 1433 Ås, Norway.
J Environ Radioact. 2020 Aug;219:106273. doi: 10.1016/j.jenvrad.2020.106273. Epub 2020 Apr 27.
In this study we performed microscopic characterization of mineral particles that were collected in the thorium-rich Fen Complex in Norway and identified and isolated based on autoradiography in function of their radioactivity. For this we combined information obtained with X-ray absorption μ-CT, μ-XRF and μ-XRD, both in bi- and in three-dimensional (tomographic) mode. We demonstrate that radionuclides and metals are heterogeneously distributed both within soil samples and within individual Th-enriched aggregates, which are characterised as low-density mineral bulk particles with high density material inclusions, where Th as well as several metals are highly concentrated. For these sites, it is important to take into account how these inhomogeneous distributions could affect the overall environmental behaviour of Th and progeny upon weathering due to human or environmental factors. Moreover, the estimated size of the Th-containing inclusions as determined in this work represents information of importance for the characterization of radionuclides and toxic metals exposure, as well as for assessing the viability of mining for Th and rare-earth metals in the Fen Complex and the associated environmental impact.
在这项研究中，我们对在挪威富含钍的芬恩复合体中收集的矿物颗粒进行了微观特征描述，并根据其放射性进行了识别和分离。为此，我们结合了 X 射线吸收 μ-CT、μ-XRF 和 μ-XRD 的信息，包括二维和三维（层析）模式。我们证明，放射性核素和金属在土壤样品和单个富钍聚集物内均呈不均匀分布，这些聚集物的特征是低密度矿物整体颗粒，高密度物质包含物，其中钍以及几种金属高度集中。对于这些地点，重要的是要考虑到由于人为或环境因素，这些不均匀分布可能会如何影响风化过程中钍及其后代的整体环境行为。此外，本工作中确定的含钍包含物的估计尺寸代表了对放射性核素和有毒金属暴露特征描述、评估在芬恩复合体开采钍和稀土金属的可行性以及相关环境影响的重要信息。
