Instituto Del Agua, Universidad de Granada, 18071, Spain.
Instituto Del Agua, Universidad de Granada, 18071, Spain.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111288. doi: 10.1016/j.ecoenv.2020.111288. Epub 2020 Sep 16.
Inactivation by adding different phosphorus (P) adsorbents is one of the most frequently used methods for combating inland water eutrophication. The aim of this work was to assess the toxic effects of novel P adsorbents (magnetic particles, MPs) on the phytoplankton community. An outdoor microcosm experiment, containing lake water and surface sediment from a hypertrophic Mediterranean lake, was carried out following a factorial design (n = 5) with three different treatments: control (C), where no MPs were added; Treatment-Water (T-W) and Treatment-Sediment (T-S). In T-W and T-S treatments, MPs were added on the surface water layer and on the sediment, respectively, to obtain a final concentration of 1.4 g MP L. This concentration was based on both the sedimentary mobile P concentration of the study site and the maximum P adsorption capacity of the MPs, obtained from the literature. After 24 h of contact time, the MPs were removed using a magnetic rake. Physicochemical measurements and biological samples were taken after 24 h of exposure to the MPs and at different time points after such exposure (day 2, 7, 21, 35 and 70). Changes in phytoplankton community such as abundance (biovolume and Chla), species composition and taxonomic groups were assessed, as well as changes in the Shannon-Wiener diversity index. Additionally, the eutrophic metric Algae Group Index (AGI), one of the metrics proposed in the Water Framework Directive, was also calculated. Our results indicate that there is no strong evidence to infer that MPs caused an effect on the phytoplankton community, since no significant differences (GLM test; p > 0.05) were found between controls and treatments in any of the studied variables (phytoplankton taxonomic groups, AGI, Chla concentration, biovolume, diversity and community responses). Accordingly, MPs did not cause any toxic effects on the phytoplankton community of the lake, encouraging the use of MPs in a future whole-lake restoration strategy. However, if the final goal of the restoration plan is to combat nuisance cyanobacteria blooms, higher initial MPs doses or repeated MPs applications are required to achieve a reduction in P concentrations below biological thresholds in order to prevent algal blooms.
添加不同的磷（P）吸附剂失活是治理内陆水体富营养化最常用的方法之一。本研究旨在评估新型 P 吸附剂（磁性颗粒，MPs）对浮游植物群落的毒性影响。采用室外微宇宙实验，以富营养化的地中海湖泊的湖水和表层沉积物为实验材料，采用三因子设计（n=5）进行实验，包括三个处理组：对照组（C），未添加 MPs；处理组-水（T-W）和处理组-沉积物（T-S）。在 T-W 和 T-S 处理组中，分别在水层和沉积物表面添加 MPs，以获得 1.4 g MPs/L 的最终浓度。该浓度基于研究地点的可移动沉积物 P 浓度和文献中获得的 MPs 的最大 P 吸附能力。接触 24 h 后，用磁耙去除 MPs。在暴露于 MPs 24 h 后以及暴露后不同时间点（第 2、7、21、35 和 70 天）采集理化测量值和生物样本。评估了浮游植物群落的变化，如丰度（生物量和 Chla）、物种组成和分类群，以及香农-威纳多样性指数的变化。此外，还计算了富营养化指标藻类群指数（AGI），这是《水框架指令》中提出的指标之一。我们的研究结果表明，没有强有力的证据表明 MPs 对浮游植物群落造成了影响，因为在任何研究变量（浮游植物分类群、AGI、Chla 浓度、生物量、多样性和群落响应）中，对照组和处理组之间均无显著差异（GLM 检验；p＞0.05）。因此， MPs 对湖泊浮游植物群落没有造成任何毒性影响，这鼓励在未来的全湖修复策略中使用 MPs。然而，如果修复计划的最终目标是防治有害蓝藻水华，需要更高的初始 MPs 剂量或重复应用 MPs，以降低 P 浓度，使其低于生物阈值，从而防止藻类水华的发生。
