Pino-Otín María Rosa, Ballestero Diego, Navarro Enrique, Mainar Ana M, Val Jonatan
Universidad San Jorge, Villanueva de Gállego, 50830 Zaragoza, Spain.
Pyrenean Institute of Ecology, CSIC, Av. Montañana 1005, Zaragoza 50059, Spain.
Sci Total Environ. 2021 Apr 10;764:142820. doi: 10.1016/j.scitotenv.2020.142820. Epub 2020 Oct 16.
Fipronil is a broad-spectrum insecticide whose release in the environment damages many non-target organisms. This study evaluated the toxicity of fipronil at two biological levels using in vivo conditions and environmentally relevant concentrations: the first based on two model organisms (aquatic invertebrate Daphnia magna and the unicellular freshwater alga Chlamydomonas reinhardtii) and a second based on three natural communities (river periphyton and freshwater and soil microbial communities). The physicochemical properties of fipronil make it apparently unstable in the environment, so its behaviour was followed with high performance liquid chromatography (HPLC) under the different test conditions. The most sensitive organism to fipronil was D. magna, with median lethal dose (LC) values from 0.07 to 0.38 mg/L (immobilisation test). Toxicity was not affected by the media used (MOPS or river water), but it increased with temperature. Fipronil produced effects on the photosynthetic activity of C. reinhardtii at 20 °C in MOPS (EC = 2.44 mg/L). The freshwater periphyton presented higher sensitivity to fipronil (photosynthetic yield EC of 0.74 mg/L) in MOPS and there was a time-dependent effect (toxicity increased with time). Toxicity was less evident when periphyton and C. reinhardtii tests were performed in river water, where the solubility of fipronil is poor. Finally, the assessment of the metabolic profiles using Biolog EcoPlates showed that bacteria communities were minimally affected by fipronil. The genetic identification of these communities based on 16S rRNA gene sequencing revealed that many of the taxa are specialists in degrading high molecular weight compounds, including pesticides. This work allows us to better understand the impact of fipronil on the environment at different levels of the food chain and in different environmental conditions, a necessary point given its presence in the environment and the complex behaviour of this compound.
氟虫腈是一种广谱杀虫剂，其在环境中的释放会损害许多非目标生物。本研究使用体内条件和与环境相关的浓度，在两个生物水平上评估了氟虫腈的毒性：第一个基于两种模式生物（水生无脊椎动物大型溞和单细胞淡水藻类莱茵衣藻），第二个基于三个自然群落（河流周丛生物以及淡水和土壤微生物群落）。氟虫腈的物理化学性质使其在环境中明显不稳定，因此在不同测试条件下用高效液相色谱法（HPLC）跟踪其行为。对氟虫腈最敏感的生物是大型溞，其半数致死剂量（LC）值为0.07至0.38mg/L（固定化试验）。毒性不受所用培养基（MOPS或河水）的影响，但会随温度升高而增加。在20°C的MOPS中，氟虫腈对莱茵衣藻的光合活性产生影响（有效浓度EC = 2.44mg/L）。在MOPS中，淡水周丛生物对氟虫腈表现出更高的敏感性（光合产量EC为0.74mg/L），并且存在时间依赖性效应（毒性随时间增加）。当在河水中进行周丛生物和莱茵衣藻测试时，毒性不太明显，因为氟虫腈在河水中的溶解度很差。最后，使用Biolog生态板对代谢谱进行评估表明，细菌群落受氟虫腈的影响最小。基于16S rRNA基因测序对这些群落进行的基因鉴定表明，许多分类群是降解包括农药在内高分子量化合物的专家。鉴于氟虫腈在环境中的存在及其复杂行为，这项工作使我们能够更好地了解其在食物链不同水平和不同环境条件下对环境的影响。
