Institute of Quality Standard and Monitoring Technology for Agro-products of Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of Quality & Safety Risk Assessment for Agro-products, and Key Laboratory of Testing and Evaluation for Agro-product Safety and Quality (Guangzhou), Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China.
National Key Laboratory of Green Pesticide and Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, South China Agricultural University, Guangzhou 510640, China.
J Agric Food Chem. 2023 Jul 12;71(27):10277-10290. doi: 10.1021/acs.jafc.3c01971. Epub 2023 Jun 28.
As new pesticides are continuously introduced into agricultural systems, it is essential to investigate their environmental behavior and toxicity effects to better evaluate their potential risks. In this study, the degradation kinetics, pathways, and aquatic toxicity of the new fused heterocyclic insecticide pyraquinil in water under different conditions were investigated for the first time. Pyraquinil was classified as an easily degradable pesticide in natural water, and hydrolyzes faster in alkaline conditions and at higher temperatures. The formation trends of the main transformation products (TPs) of pyraquinil were also quantified. Fifteen TPs were identified in water using ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Orbitrap-HRMS) and Compound Discoverer software, which adopted suspect and nontarget screening strategies. Among them, twelve TPs were reported for the first time and 11 TPs were confirmed by synthesis of their standards. The proposed degradation pathways have demonstrated that the 4,5-dihydropyrazolo[1,5-]quinazoline skeleton of pyraquinil is stable enough to retain in its TPs. ECOSAR prediction and laboratory tests showed that pyraquinil was "very toxic" or "toxic" to aquatic organisms, while the toxicities of all of the TPs are substantially lower than that of pyraquinil except for TP484, which was predicted to pose a higher toxicity. The results are important for elucidating the fate and assessing the environmental risks of pyraquinil, and provide guidance for scientific and reasonable use.
随着新的农药不断引入农业系统，研究它们的环境行为和毒性效应至关重要，以便更好地评估它们的潜在风险。在这项研究中，首次研究了新的稠合杂环杀虫剂吡虫啉在不同条件下在水中的降解动力学、途径和水生毒性。吡虫啉在天然水中被归类为易降解农药，在碱性条件下和较高温度下更快水解。还定量了吡虫啉主要转化产物（TPs）的形成趋势。使用超高效液相色谱-四极杆轨道阱高分辨率质谱联用仪（UHPLC-Orbitrap-HRMS）和 Compound Discoverer 软件在水中鉴定了十五种 TPs，采用了可疑和非目标筛选策略。其中，有 12 种 TPs 是首次报道的，有 11 种 TPs 是通过合成其标准品确认的。提出的降解途径表明，吡虫啉的 4,5-二氢吡唑并[1,5-]喹唑啉骨架足够稳定，可以在其 TPs 中保留。ECOSAR 预测和实验室测试表明，吡虫啉对水生生物具有“高毒”或“毒性”，而所有 TPs 的毒性都远低于吡虫啉，除了 TP484，其预测毒性更高。这些结果对于阐明吡虫啉的命运和评估其环境风险非常重要，并为科学合理的使用提供了指导。
