Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Key Laboratory of Land Surface Pattern and Simulation, Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Chemosphere. 2019 Feb;217:851-857. doi: 10.1016/j.chemosphere.2018.11.060. Epub 2018 Nov 11.
Geochemical distribution of trace elements in sediments could reflect the impact of anthropogenic activities on environmental changes in aquatic ecosystems. In this study, rare earth elements (REEs) were used as geochemical tracers to study the environmental processes in a complex and dynamic aquatic environment. Both surface and core sediment samples were collected from Poyang Lake, the largest freshwater lake located in the middle-low region of the Yangtze River. Sediment samples were analyzed for their respective REE spatial distributions, fractionation, and co-occurrence patterns. The inner relationships and geochemistry characters of REEs were assessed by geostatistics and co-occurrence network analysis. Results indicated that total REE concentrations in the sediments from Poyang Lake ranged from 145.1 to 351.1 μg g, with an average concentration of 254.0 μg g. Light rare earth element (LREE, La - Sm) enrichment was evident in all sediment samples, indicating the effects of river-lake interactions and the contributions from terrestrial inputs. The negative Ce and Eu anomalies were found in most sediment samples, indicating the differentiation between Ce, Eu, and other REEs in the processes of sediment transportation and deposition. Collectively, the identification of the major contamination sources of REEs in sediment, analyzed by the patterns of the co-occurrence networks and REE fractionation, revealed that the REEs in sediments from Poyang Lake originated both natural and anthropogenic sources and were disturbed by the impact of anthropogenic activities.
沉积物中微量元素的地球化学分布可以反映人为活动对水生态系统环境变化的影响。在这项研究中，稀土元素（REEs）被用作地球化学示踪剂，以研究复杂和动态水生态环境中的环境过程。本研究从长江中下游最大的淡水湖鄱阳湖采集了表层和柱状沉积物样品，用于研究 REE 在沉积物中的空间分布、分馏和共现模式。通过地质统计学和共现网络分析评估了 REE 之间的内在关系和地球化学特征。结果表明，鄱阳湖沉积物中总 REE 浓度范围为 145.1-351.1μg/g，平均值为 254.0μg/g。所有沉积物样品均表现出轻稀土元素（LREE，La-Sm）的富集，表明了河湖相互作用的影响和陆地输入的贡献。大多数沉积物样品中发现了 Ce 和 Eu 的负异常，表明在沉积物搬运和沉积过程中 Ce、Eu 和其他 REE 之间存在分异。总的来说，通过共现网络模式和 REE 分馏分析，确定了沉积物中 REE 的主要污染来源，结果表明鄱阳湖沉积物中的 REE 既有自然来源也有人为来源，并且受到人为活动的影响。
