The effects of the parasiticide ivermectin were assessed in plankton-dominated indoor microcosms. Ivermectin was applied once at concentrations of 30, 100, 300, 1000, 3000, and 10,000 ng/l. The half-life (dissipation time 50%; DT50) of ivermectin in the water phase ranged from 1.1 to 8.3 days. The lowest NOECcommunity that could be derived on an isolated sampling from the microcosm study by means of multivariate techniques was 100 ng/l. The most sensitive species in the microcosm study were the cladocerans Ceriodaphnia sp. (no observed effect concentration, NOEC = 30 ng/l) and Chydorus sphaericus (NOEC = 100 ng/l). The amphipod Gammarus pulex was less sensitive to ivermectin, showing consistent statistically significant reductions at the 1000-ng/l treatment level. Copepoda taxa decreased directly after application of ivermectin in the highest treatment but had already recovered at day 20 posttreatment. Indirect effects (e.g., increase of rotifers, increased primary production) were observed at the highest treatment level starting only on day 13 of the exposure phase. Cladocera showed the highest sensitivity to ivermectin in both standard laboratory toxicity tests as well as in the microcosm study. This study demonstrates that simple plankton-dominated test systems for assessing the effects of ivermectin can produce results similar to those obtained with large complex outdoor systems.
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机译:在以浮游生物为主的室内缩影中评估了杀寄生虫伊维菌素的作用。伊维菌素以30、100、300、1000、3000和10,000 ng / l的浓度施用一次。伊维菌素在水相中的半衰期(耗散时间为50%; DT50)为1.1至8.3天。可以通过多变量技术从微观研究中分离出的样本中获得的最低NOEC社区为100ng / l。在缩影研究中最敏感的物种是枝角cl Ceriodaphnia sp.。 (未观察到作用浓度,NOEC = 30 ng / l)和球形乳突球菌(NOEC = 100 ng / l)。两栖动物伽玛鲁氏菌对伊维菌素较不敏感,在治疗水平为1000 ng / l时显示出一致的统计学显着降低。在最高治疗中使用伊维菌素后,足类的分类直接减少,但在治疗后第20天已经恢复。仅在暴露期的第13天才开始在最高治疗水平上观察到间接作用(例如,轮虫增加,初级产量增加)。在标准实验室毒性测试和微观研究中,克拉多菌对伊维菌素均表现出最高的敏感性。这项研究表明,用于评估伊维菌素作用的简单浮游生物为主的测试系统所产生的结果与大型复杂室外系统所获得的结果相似。
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