Departamento de Medio Ambiente, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Consejo Superior de Investigaciones Científicas (CSIC), Madrid, 28040, Spain.
Departamento de Química Analítica, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid, 28040, Spain.
Environ Res. 2024 Mar 15;245:118072. doi: 10.1016/j.envres.2023.118072. Epub 2023 Dec 28.
Fish acute toxicity tests are commonly used in aquatic environmental risk assessments, being required in different international substances regulations. A general trend in the toxicity testing of nanomaterials (NMs) has been to use standardized aquatic toxicity tests. However, as these tests were primarily developed for soluble chemical, issues regarding particle dissolution, agglomeration or sedimentation during the time of exposure are not considered when reporting the toxicity of NMs. The aim of this study was to characterize the NM behaviour throughout the fish acute test and to provide criteria to assay the toxicity of nine NMs based on TiO, ZnO, SiO, BaSO, bentonite, and carbon nanotubes, on rainbow trout following OECD Test Guideline (TG) nº203. Our results showed the importance of conducting a preliminary test (without fish) when working with NMs. They provide valuable information on, sample monitoring, agglomeration, sedimentation, dissolution, actual concentrations of NMs, needed to design the test. Among the NMs tested, only bentonite nanoparticles were stable during the 96-h pre-test and test in aquarium water. In contrast, the remaining NMs exhibited considerable loss and sedimentation within the first 24 h. The high sedimentation observed for almost all NMs highlights the need of consistently measuring the concentrations throughout the entire duration of the fish acute toxicity test to make reliable concentration-response relationships. Notable differences emerged in LC50 values when using actual concentrations as nominal concentrations overestimated concentrations by up to 85.6%. Among all NMs tested, only ZnO NMs were toxic to rainbow trout. A flow chart was specifically developed for OECD TG 203, aiding users in making informed decisions regarding the selection of test systems and necessary modifications to ensure accurate, reliable, and reusable toxicity data. Our findings might contribute to the harmonization of TG 203 improving result reproducibility and interpretability and supporting the development of read-across and QSAR models.
鱼类急性毒性试验常用于水生环境风险评估，不同的国际物质法规都有要求。纳米材料（NMs）毒性测试的一个总体趋势是使用标准化的水生毒性测试。然而，由于这些测试主要是为可溶性化学物质开发的，因此在报告 NMs 的毒性时，没有考虑到颗粒在暴露期间的溶解、团聚或沉淀问题。本研究的目的是在鱼类急性试验过程中对 NM 行为进行表征，并提供基于 TiO2、ZnO、SiO2、BaSO4、膨润土和碳纳米管的 9 种 NM 毒性测试的标准，采用 OECD 测试指南（TG） nº203 对虹鳟鱼进行测试。我们的研究结果表明，在使用 NMs 时进行初步测试（无鱼）非常重要。这些结果为样品监测、团聚、沉淀、溶解、实际 NM 浓度提供了有价值的信息，这些信息对于设计测试非常必要。在所测试的 NMs 中，只有膨润土纳米颗粒在 96 小时预测试和水族馆水中测试期间是稳定的。相比之下，其余的 NMs 在最初的 24 小时内就出现了大量的损失和沉淀。几乎所有 NMs 都存在高沉降，这突出表明需要在鱼类急性毒性试验的整个过程中始终测量浓度，以建立可靠的浓度-反应关系。当使用实际浓度作为名义浓度时，LC50 值会出现显著差异，实际浓度最高可高估 85.6%。在所测试的所有 NMs 中，只有 ZnO NMs 对虹鳟鱼有毒。特别为 OECD TG 203 开发了一个流程图，帮助用户在选择测试系统和必要的修改方面做出明智的决策，以确保准确、可靠和可重复使用的毒性数据。我们的研究结果可能有助于 TG 203 的协调，提高结果的可重复性和可解释性，并支持基于相似物质的预测和定量结构-活性关系模型的发展。
