State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
Norwegian Institute of Bioeconomy Research (NIBIO), Division Biotechnology and Plant Health, Høgskoleveien 7, 1433 Aas, Norway.
J Hazard Mater. 2021 Sep 15;418:126303. doi: 10.1016/j.jhazmat.2021.126303. Epub 2021 Jun 4.
Difenoconazole is a widely used triazole fungicide that has been frequently detected in the environment, but comprehensive study about its environmental fate and toxicity of potential transformation products (TPs) is still lacking. Here, laboratory experiments were conducted to investigate the degradation kinetics, pathways, and toxicity of transformation products of difenoconazole. 12, 4 and 4 TPs generated by photolysis, hydrolysis and soil degradation were identified via UHPLC-QTOF/MS and the UNIFI software. Four intermediates TP295, TP295A, TP354A and TP387A reported for the first time were confirmed by purchase or synthesis of their standards, and they were further quantified using UHPLC-MS/MS in all tested samples. The main transformation reactions observed for difenoconazole were oxidation, dechlorination and hydroxylation in the environment. ECOSAR prediction and laboratory tests showed that the acute toxicities of four novel TPs on Brachydanio rerio, Daphnia magna and Selenastrum capricornutum are substantially lower than that of difenoconazole, while all the TPs except for TP277C were predicted chronically very toxic to fish, which may pose a potential threat to aquatic ecosystems. The results are important for elucidating the environmental fate of difenoconazole and assessing the environmental risks, and further provide guidance for scientific and reasonable use.
苯醚甲环唑是一种广泛使用的三唑类杀菌剂，在环境中经常被检测到，但关于其环境归宿和潜在转化产物（TPs）的毒性的综合研究仍然缺乏。在这里，进行了实验室实验来研究苯醚甲环唑的降解动力学、途径和转化产物的毒性。通过 UHPLC-QTOF/MS 和 UNIFI 软件，鉴定了光解、水解和土壤降解生成的 12、4 和 4 种转化产物。通过购买或合成其标准品，首次确认了 4 种中间体 TP295、TP295A、TP354A 和 TP387A，并在所有测试样品中进一步使用 UHPLC-MS/MS 进行了定量。苯醚甲环唑在环境中主要的转化反应是氧化、脱氯和羟化。ECOSAR 预测和实验室测试表明，四种新型 TPs 对斑马鱼、大型溞和铜绿微囊藻的急性毒性明显低于苯醚甲环唑，而除 TP277C 以外的所有 TPs 均被预测对鱼类具有慢性高毒性，这可能对水生生态系统构成潜在威胁。这些结果对于阐明苯醚甲环唑的环境归宿和评估环境风险非常重要，并为科学合理的使用提供了指导。
