Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium E-mail:
IHE Institute for Water Education, 2601 DA Delft, The Netherlands.
Water Sci Technol. 2020 May;81(9):1852-1862. doi: 10.2166/wst.2020.214.
The kinetics of Se uptake and toxicity to Lemna were studied over a period of 14 days of exposure to Se(IV) or Se(VI). The growth of Lemna stopped immediately after exposure to 5.0 mg/L of Se(IV) or Se(VI). The content of chlorophyll and phaeopigments of Lemna exposed to 5.0 mg/L of Se(IV) was two to three times less than in the control after 3 d exposure. Lemna took up Se rapidly within the first 3 d. The Se content in Lemna along with the exposure time fitted well the two-compartment and the hyperbolic model, which demonstrates that the mechanism of Se(IV) and Se(VI) uptake in Lemna is not only through passive diffusion, but also through other processes such as ion channel proteins or transporters. The kinetic bioconcentration factors (BCFs) were 231 and 42 for 0.5 mg/L Se(IV) and Se(VI) exposure, respectively. The uptake rate of Lemna reached 263 mg/kg/d and 28 mg/kg/d in the Se(IV) and Se(VI) treatments, respectively. This study showed that Se(IV) has a faster accumulation rate than Se(VI), but a higher toxicity, indicating Lemna could be a good candidate to remove Se(IV) from water, producing Se-enriched biomass which may eventually also be considered for use as Se-enriched feed supplement or fertilizer.
在暴露于 Se(IV)或 Se(VI)的 14 天期间，研究了 Se 的吸收动力学和对浮萍的毒性。浮萍在暴露于 5.0 mg/L 的 Se(IV)或 Se(VI)后立即停止生长。暴露于 5.0 mg/L 的 Se(IV)的浮萍中的叶绿素和类胡萝卜素含量在 3 d 暴露后比对照少了两到三倍。浮萍在最初的 3 d 内迅速吸收 Se。浮萍中的 Se 含量随暴露时间的变化很好地符合双室模型和双曲线模型，这表明 Se(IV)和 Se(VI)在浮萍中的吸收机制不仅通过被动扩散，还通过离子通道蛋白或转运体等其他过程。动力学生物浓缩因子（BCF）分别为 0.5 mg/L Se(IV)和 Se(VI)暴露时的 231 和 42。浮萍在 Se(IV)和 Se(VI)处理中的吸收速率分别达到 263 和 28 mg/kg/d。本研究表明，Se(IV)的积累速度比 Se(VI)快，但毒性更高，这表明浮萍可能是一种从水中去除 Se(IV)的良好候选物，产生富含 Se 的生物量，最终也可能被考虑用作富含 Se 的饲料补充剂或肥料。
