College of Food Safety, Guizhou Medical University, Guiyang, 550025, China; Key Laboratory of Environmental Pollution Monitoring and Disease Control, Guizhou Medical University, Guiyang, 550025, China.
Guangxi Subtropical Crops Research Institute, Guangxi, Nanning, 530001, China.
Chemosphere. 2019 Jul;226:782-790. doi: 10.1016/j.chemosphere.2019.03.183. Epub 2019 Apr 2.
Etoxazole is a newly registered and widely used acaricide. However, its metabolites were not fully understood and might exhibit similar or even higher toxicity than parent compound. Therefore, in this study, the metabolites of etoxazole in citrus, soil and earthworms were firstly identified by an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS). Four potential metabolites in citrus, 11 in soil, and 8 in earthworms were determined. These metabolites were then further structural elucidated based on the fragment pathways, and accurate mass measurement. The distributions of etoxazole and its main metabolites (M1, M2, M3, M4 and M5) which were identified as the dehydrogenation, hydrolysis, oxidation products of etoxazole (M0) were also monitored in citrus, soil and earthworms at different exposure periods. The 45 days exposure experiment showed that M0 gradually decreased in citrus and soil samples by 80% and 28% of the initial amounts, respectively. In earthworm samples, M0 accumulated in the bodies of the worms during 24 days exposure and then decreased with time. The dissipation rate of etoxazole were citrus > earthworms > soil. Concentrations of M1 and M3 in soil were found continuously increased with time during the experimental period. Moreover, the persistence of M1 in earthworm samples was also observed. Great attention should be paid to these two compounds due to their potential risks to both environmental and human health.
恶唑烷是一种新注册并广泛使用的杀螨剂。然而，其代谢物尚未完全了解，可能表现出与母体化合物相似甚至更高的毒性。因此，在本研究中，首次通过超高效液相色谱-四极杆飞行时间质谱（UPLC-QTOF/MS）鉴定了恶唑烷在柑橘、土壤和蚯蚓中的代谢物。在柑橘中确定了 4 种潜在代谢物，在土壤中确定了 11 种，在蚯蚓中确定了 8 种。然后根据碎片途径和精确质量测量进一步结构阐明这些代谢物。在不同暴露期内，还监测了恶唑烷及其主要代谢物（M1、M2、M3、M4 和 M5）在柑橘、土壤和蚯蚓中的分布，这些代谢物被鉴定为恶唑烷（M0）的脱氢、水解和氧化产物。45 天暴露实验表明，M0 在柑橘和土壤样品中分别逐渐减少了 80%和 28%。在蚯蚓样品中，M0 在 24 天暴露期间在蚯蚓体内积累，然后随时间减少。恶唑烷在柑橘中的消解速率大于在蚯蚓中的消解速率大于在土壤中的消解速率。土壤中 M1 和 M3 的浓度在实验期间随时间不断增加。此外，还观察到 M1 在蚯蚓样品中的持久性。由于这两种化合物对环境和人类健康都存在潜在风险，因此应予以高度关注。
