School of Science, Constructor University, Campus Ring 1, 28759, Bremen, Germany.
School of Science, Constructor University, Campus Ring 1, 28759, Bremen, Germany.
Chemosphere. 2024 Sep;364:143069. doi: 10.1016/j.chemosphere.2024.143069. Epub 2024 Aug 9.
Mussels are commonly used as bioarchives in environmental monitoring, yet the impact of vital effects on the trace element or isotope ratios used as biogeochemical proxies is often only ill constrained. A prime example of such trace elements are the Rare Earth elements and Yttrium (REY) which have become (micro)contaminants in freshwater systems worldwide. We here report on the distribution of REY in different soft tissues and in the shells of freshwater bivalve A. anatina, commonly known as "duck mussel", from the Danube River in Hungary and the Vistula River in Poland. Both rivers are contaminated with anthropogenic Gd from contrast agents used in magnetic resonance imaging (MRI). Regardless of the mussels' origin, all of their compartments show very similar shale-normalised REY patterns. None of the samples show any anthropogenic Gd anomaly, implying that in freshwater anthropogenic Gd from MRI contrast agents is either not bioavailable or that REY from ambient river water are insignificant for the REY budget of freshwater mussels. Compared to ambient water, the bivalves bioaccumulate the REY with preferential uptake of Ce and of light REY over heavy REY. However, REY concentrations in mussels are similar to or lower than those in their potential food source, with minor fractionation along the REY series besides slight preferential uptake of La and Y. Comparison of shells and tissues reveals the systematic oxidative decoupling of Ce from its REY neighbours, probably due to the presence of Ce(IV) solution-complexes in the mussels' extrapallial fluid. Despite possible REY fractionation during their initial uptake, vital effects do not impose any major control on REY fractionation during REY transfer within the mussels or during formation of their shells. Mussel shells may, therefore, conveniently be used for environmental monitoring of REY without major disturbance from vital effects.
贻贝通常被用作环境监测的生物档案，但生命效应对痕量元素或同位素比值作为生物地球化学示踪剂的影响通常仅受到有限的约束。此类痕量元素的一个主要例子是稀土元素和钇（REY），它们已成为全球淡水系统中的（微）污染物。我们在此报告了不同软组织和淡水双壳类贻贝 A. anatina 壳中 REY 的分布，A. anatina 在匈牙利的多瑙河和波兰的维斯瓦河被广泛称为“鸭贻贝”。这两条河流都受到磁共振成像（MRI）中使用的造影剂产生的人为 Gd 的污染。无论贻贝的来源如何，它们所有的隔室都显示出非常相似的页岩归一化 REY 模式。没有一个样本显示出任何人为 Gd 异常，这意味着在淡水中，MRI 造影剂中的人为 Gd 要么不可生物利用，要么环境河水中的 REY 对淡水贻贝的 REY 预算没有意义。与环境水相比，双壳类动物通过优先摄取 Ce 和轻 REY 而不是重 REY 来生物积累 REY。然而，贻贝中的 REY 浓度与它们的潜在食物来源相似或更低，除了沿 REY 系列略有优先摄取 La 和 Y 之外，还存在轻微的分馏。壳和组织的比较表明，Ce 与其 REY 邻居的系统氧化解耦可能是由于贻贝外套膜外液中存在 Ce(IV)溶液配合物。尽管在最初摄取过程中可能会发生 REY 分馏，但生命效应不会对贻贝内 REY 转移过程或贻贝壳形成过程中的 REY 分馏施加任何主要控制。因此，贻贝壳可以方便地用于 REY 的环境监测，而不会受到生命效应的重大干扰。
