Lousberg Joëlle, Hanfland Jost, Kosak Lena Alix, Eilebrecht Sebastian, Ringbeck Benedikt, Schlich Karsten
Fraunhofer Institute for Molecular Biology and Applied Ecology, Schmallenberg, Germany.
Environ Toxicol Chem. 2024 Dec;43(12):2589-2600. doi: 10.1002/etc.5983. Epub 2024 Aug 27.
Maintaining constant exposure concentrations during ecotoxicological studies while testing rapidly degradable substances is a challenge. To achieve stable concentrations during exposure, flow-through systems are used. To assess the impact of substances on higher aquatic plants, the 14-day macrophyte water-sediment Myriophyllum spicatum growth inhibition test (Organisation for Economic Co-operation and Development [OECD, 2014a] test guideline 239) only includes a static or a semistatic test design. The main aim of our study was to investigate the applicability of a flow-through system for M. spicatum. The standard OECD test design was miniaturized, and a flow-through system with spill-over was developed to achieve stable exposure concentrations of a rapidly degrading substance. The main endpoints were total shoot length and fresh and dry weight. Photosynthetic activity was used as an endpoint for the identification of early effects using the noninvasive Image-Producing Pulse Amplitude Modulation (IMAGING-PAM) procedure. Atorvastatin (AV; fast degrading) and bentazone (BT; photosynthesis inhibitor) were used as model substances to observe differences of the effect concentration depending on the test design. At higher exposure levels of AV, stronger necrosis combined with lower effect concentrations was observed in the flow-through test compared with the semistatic test, indicating the applicability of the flow-through test for evaluating degradable substances. The test with BT demonstrated a concentration-dependent decrease in the photosynthetic yield (Y(II)) from day 3 onward even before macroscopically visible changes occurred. Our results show that the flow-through system in the macrophyte growth inhibition test (OECD test guideline 239; 2014a) is a suitable alternative when one is testing rapidly degradable substances such as AV. In addition, we showed that photosynthetic yield can serve as a supplementary endpoint, when one is testing substances with photosynthesis inhibition as a mode of action. Environ Toxicol Chem 2024;43:2589-2600. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
在生态毒理学研究中，对快速降解物质进行测试时，保持恒定的暴露浓度是一项挑战。为了在暴露期间实现稳定的浓度，人们使用了流通系统。为了评估物质对高等水生植物的影响，为期14天的大型植物水-沉积物狐尾藻生长抑制试验（经济合作与发展组织[经合组织，2014a]试验准则239）仅包括静态或半静态试验设计。我们研究的主要目的是调查流通系统对狐尾藻的适用性。对经合组织标准试验设计进行了小型化，并开发了一种带有溢流的流通系统，以实现快速降解物质的稳定暴露浓度。主要终点是总茎长以及鲜重和干重。光合活性被用作使用非侵入性成像脉冲幅度调制（IMAGING-PAM）程序识别早期效应的终点。阿托伐他汀（AV；快速降解）和苯达松（BT；光合作用抑制剂）被用作模型物质，以观察根据试验设计效应浓度的差异。在较高的AV暴露水平下，与半静态试验相比，流通试验中观察到更强的坏死以及更低的效应浓度，这表明流通试验适用于评估可降解物质。BT试验表明，从第3天起，即使在宏观可见变化出现之前，光合产量（Y(II)）也呈现浓度依赖性下降。我们的结果表明，在大型植物生长抑制试验（经合组织试验准则239；2014a）中，当测试像AV这样的快速降解物质时，流通系统是一种合适的替代方法。此外，我们还表明，当测试以光合作用抑制为作用方式的物质时，光合产量可作为一个补充终点。《环境毒理学与化学》2024年；43:2589 - 2600。© 2024作者。《环境毒理学与化学》由威利期刊有限责任公司代表SETAC出版。
