Figueiredo Cátia, Grilo Tiago F, Lopes Clara, Brito Pedro, Caetano Miguel, Raimundo Joana
MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749-016, Lisboa, Portugal; Division of Oceanography and Marine Environment, IPMA - Portuguese Institute for Sea and Atmosphere, Av. Alfredo Magalhães Ramalho, 6, 1495-165 Algés, Portugal; UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Campo Grande 1749-016, Lisboa, Portugal.
J Trace Elem Med Biol. 2022 May;71:126957. doi: 10.1016/j.jtemb.2022.126957. Epub 2022 Feb 23.
Studies dealing with Rare Earth Elements (REE) ecotoxicological behavior are scattered and with potential conflicting results. Climate change impacts on aquatic biota and is known to modify contaminants toxicokinetic. Nevertheless, the current knowledge on the potential interactions between climate change and REE is virtually non-existent. Therefore, we focus our research on La and Gd as representatives of Light and Heavy REE that also are of great environmental concern. Experiments on different mediums (fresh-, brackish- and seawater) were designed to run at present-day and near-future conditions (T°=+4 °C, pH=△-0.4). Sampling was taken at different time scales from minutes to hours for one day. The main challenge was to evaluate the availability of La and Gd under environmental conditions closely related to climate changes scenarios. Furthermore, this study will contribute to the baseline knowledge by which future research towards understanding REE patterns and toxicity will build upon. Lanthanum and Gd behave differently with salinity. Temperature also affects the availability of dissolved La in freshwater. On the other hand, pH reduction causes the decrease of Gd in freshwater. In this medium, concentrations reduce sharply, presumably due to sorption processes or precipitates. In the brackish water experiment only the dissolved La levels in the Warming (T°=+4 °C) and Warming & Acidification (T°=+4 °C, pH=△0.4) diminished significantly through time. Dissolved La and Gd levels in seawater were relatively constant with time. The speciation of both elements is also of great relevance for ecotoxicological experiments. The trivalent free ions (La and Gd) were the most common species in the trials. However, as ionic strength increases, the availability of other complexes rose, which should be subject of great attention for upcoming ecotoxicological studies.
关于稀土元素（REE）生态毒理行为的研究较为分散，结果可能相互矛盾。气候变化对水生生物群有影响，且已知会改变污染物的毒代动力学。然而，目前关于气候变化与稀土元素之间潜在相互作用的知识几乎不存在。因此，我们将研究重点放在镧（La）和钆（Gd）上，它们分别作为轻稀土和重稀土的代表，也是备受环境关注的元素。我们设计了在不同介质（淡水、咸水和海水）中进行的实验，分别在当前和近期条件下（温度=+4°C，pH=△-0.4）进行。在一天内从几分钟到几小时的不同时间尺度上进行采样。主要挑战是评估与气候变化情景密切相关的环境条件下镧和钆的有效性。此外，本研究将有助于建立基线知识，未来关于理解稀土元素模式和毒性的研究将以此为基础。镧和钆在盐度方面表现不同。温度也会影响淡水中溶解态镧的有效性。另一方面，pH值降低会导致淡水中钆的减少。在这种介质中，浓度急剧下降，可能是由于吸附过程或沉淀。在咸水实验中，只有在升温（温度=+4°C）和升温及酸化（温度=+4°C，pH=△0.4）条件下，溶解态镧的水平随时间显著降低。海水中溶解态镧和钆的水平随时间相对恒定。这两种元素的形态对于生态毒理学实验也非常重要。三价自由离子（镧和钆）是试验中最常见的形态。然而，随着离子强度增加，其他络合物的有效性上升，这应成为未来生态毒理学研究的重点关注对象。
