Ponton Dominic E, Graves Stephanie D, Fortin Claude, Janz David, Amyot Marc, Schiavon Michela
GRIL, Université de Montréal, Département des Sciences Biologiques, Montreal, QC H2V 0B3, Canada.
University of Saskatchewan, Toxicology Graduate Program, Saskatoon, SK S7N 5B3, Canada.
Plants (Basel). 2020 Apr 19;9(4):528. doi: 10.3390/plants9040528.
Selenium (Se) uptake by primary producers is the most variable and important step in determining Se concentrations at higher trophic levels in aquatic food webs. We gathered data available about the Se bioaccumulation at the base of aquatic food webs and analyzed its relationship with Se concentrations in water. This important dataset was separated into lotic and lentic systems to provide a reliable model to estimate Se in primary producers from aqueous exposure. We observed that lentic systems had higher organic selenium and selenite concentrations than in lotic systems and selenate concentrations were higher in lotic environments. Selenium uptake by algae is mostly driven by Se concentrations, speciation and competition with other anions, and is as well influenced by pH. Based on Se species uptake by algae in the laboratory, we proposed an accurate mechanistic model of competition between sulfate and inorganic Se species at algal uptake sites. Intracellular Se transformations and incorporation into selenoproteins as well as the mechanisms through which Se can induce toxicity in algae has also been reviewed. We provided a new tool for risk assessment strategies to better predict accumulation in primary consumers and consequently to higher trophic levels, and we identified some research needs that could fill knowledge gaps.
初级生产者对硒（Se）的摄取是决定水生食物网中较高营养级硒浓度最具变化且最为重要的步骤。我们收集了关于水生食物网底部硒生物累积的现有数据，并分析了其与水中硒浓度的关系。这个重要的数据集被分为流水系统和静水系统，以提供一个可靠的模型，用于根据水体暴露情况估算初级生产者中的硒含量。我们观察到，静水系统中的有机硒和亚硒酸盐浓度高于流水系统，而流水环境中的硒酸盐浓度更高。藻类对硒的摄取主要受硒浓度、形态以及与其他阴离子的竞争驱动，同时也受pH值影响。基于实验室中藻类对硒形态的摄取情况，我们提出了一个准确的藻类摄取位点上硫酸盐与无机硒形态之间竞争的机理模型。还综述了细胞内硒的转化、硒掺入硒蛋白的过程以及硒在藻类中诱导毒性的机制。我们为风险评估策略提供了一种新工具，以便更好地预测初级消费者中的累积情况，并进而预测更高营养级中的累积情况，同时我们还确定了一些可以填补知识空白的研究需求。
