State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, People's Republic of China.
School of Science, Centre for Marine Ecosystems Research, Edith Cowan University, Joondalup, WA, 6027, Australia.
Environ Sci Pollut Res Int. 2019 Sep;26(27):27872-27887. doi: 10.1007/s11356-019-05993-3. Epub 2019 Jul 25.
Mosses can be used as biomonitors to monitor radionuclide deposition and heavy metal pollution in cities, forests, and grasslands. The aims of this work were to determine the activity concentrations of natural (Po, Pb or Pb (excess Pb is defined as the activity of Pb minus the activity of Ra), Be, K, Ra, U, and Th) and anthropogenic radionuclides (Cs) in moss body profiles and in situ underlying soils of moss samples and to assess/determine the distribution features and accumulation of these radionuclides. Activity concentrations of radionuclides in the samples were measured using a low-background gamma spectrometer and a low-background alpha spectrometer. Consistent with their source, the studied radionuclides in the moss samples and underlying soils were divided according to the principal component analysis (PCA) results into an airborne group (Po, Pb (Pb), Be, and Cs) and a terrestrial group (K, U, Ra, and Th). The activity concentrations of Po and Pb in moss body profiles were mainly concentrated in the stems-rhizoid parts, in which we measured some of the highest Po and Pb levels compared to the results in the literature. Be mainly accumulated in the leaves-stem parts. Different positive correlations were observed between Po and Pb and between Be and Pb, which indicated that the uptake mechanisms of Po, Pb, and Be by moss plants were different, to some extent. Cs was detected only in some moss samples, and the fraction of Cs in the underlying soils was much lower than that in the moss, suggesting that mosses were protecting the underlying soils from further pollution. Except for K, the terrestrial radionuclide (U, Ra, and Th) content in mosses was predominantly at low levels, which indicated not only the inability of mosses to use those elements for metabolic purposes but also the rather poor capability of mosses to directly mobilize, absorb, and transport elements (U, Ra, or Th) not dissolved in water.
苔藓可以作为生物监测器，用于监测城市、森林和草原中的放射性核素沉积和重金属污染。本工作的目的是确定苔藓体组织和原位苔藓样品下垫土中天然（Po、Pb 或 Pb（过剩 Pb 定义为 Pb 的活度减去 Ra 的活度）、Be、K、Ra、U 和 Th）和人为放射性核素（Cs）的活度浓度，并评估/确定这些放射性核素的分布特征和积累情况。使用低本底伽马谱仪和低本底 alpha 谱仪测量样品中放射性核素的活度浓度。根据主成分分析（PCA）结果，研究中的苔藓样品和下垫土中的放射性核素与它们的来源一致，分为气载组（Po、Pb（Pb）、Be 和 Cs）和陆源组（K、U、Ra 和 Th）。Po 和 Pb 在苔藓体组织中的活度浓度主要集中在茎-根状部分，与文献中的结果相比，我们在这些部位测量到了一些最高的 Po 和 Pb 水平。Be 主要积累在叶-茎部分。Po 和 Pb 之间以及 Be 和 Pb 之间观察到不同的正相关，这表明苔藓植物对 Po、Pb 和 Be 的吸收机制在某种程度上是不同的。Cs 仅在一些苔藓样品中被检测到，而 Cs 在下层土壤中的分数远低于苔藓中的分数，这表明苔藓在保护下层土壤免受进一步污染。除了 K 之外，苔藓中的陆源放射性核素（U、Ra 和 Th）含量主要处于低水平，这不仅表明苔藓不能将这些元素用于代谢目的，而且还表明苔藓直接动员、吸收和运输水不溶元素（U、Ra 或 Th）的能力较差。
