Geng Yuehan, Lv Jingjie, Tian Yaoyu, Ma Xin, Hua Rimao, Fang Liancheng
Anhui Provincial Key Laboratory of Hazardous Factors and Risk Control of Agri-food Quality Safety, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China.
Anhui Provincial Key Laboratory of Hazardous Factors and Risk Control of Agri-food Quality Safety, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute of Ecological Environmental Protection and Pollution Remediation Engineering, Anhui Agricultural University, Hefei, Anhui 230036, China; Joint Research Center for Food Nutrition and Health of IHM, Anhui Agricultural University, Hefei, Anhui 230036, China.
Pestic Biochem Physiol. 2025 Nov;214:106612. doi: 10.1016/j.pestbp.2025.106612. Epub 2025 Aug 5.
Neonicotinoid insecticides residuals pose a threat to aquatic ecosystems and human health. Imidaclothiz, as a novel neonicotinoid pesticide, the metabolic mechanisms in aquatic environments was unclear. This study investigated the degradation characteristics of imidaclothiz in both pure and actual water, and analyzed the photodegradation and hydrolysis metabolites of imidaclothiz in aquatic environments and assessed their toxicity. The hydrolysis of imidaclothiz was not affected by temperature, pH, and metal ions. In non-sterilized Tai Lake water, the half-life of imidaclothiz were 72-187 d, with biodegradation being the primary process. Additionally, lighting was the key factor to influencing the degradation of imidaclothiz in aquatic environment. Electron Spin Resonance (ESR) results indicated that O and ·OH played crucial roles in the photodegradation of imidaclothiz. Density functional theory (DFT) calculations revealed that the maximum electrostatic potential of the imidaclothiz molecule was located at the electron-donating group (-NH-) on the oxadiazole ring, making it more prone to oxidation reactions. High-resolution mass spectrometry (HRMS) was employed to identify the photolysis and hydrolysis products of imidaclothiz. Toxicity assessment revealed that the oxidized metabolite M217 of imidaclothiz exhibited higher toxicity to aquatic organisms than the parent compound. Meanwhile, both imidaclothiz and its photodegradation and hydrolysis products posed noteworthy chronic toxicity to fish, daphnid and green algae. These finding provided theoretical guidance for the risk assessment and safe use of imidaclothiz.
新烟碱类杀虫剂残留对水生生态系统和人类健康构成威胁。吡虫啉噻嗪，作为一种新型新烟碱类农药，其在水生环境中的代谢机制尚不清楚。本研究调查了吡虫啉噻嗪在纯水和实际水体中的降解特性，分析了其在水生环境中的光降解和水解代谢产物，并评估了它们的毒性。吡虫啉噻嗪的水解不受温度、pH值和金属离子的影响。在未灭菌的太湖水体中，吡虫啉噻嗪的半衰期为72 - 187天，生物降解是主要过程。此外，光照是影响吡虫啉噻嗪在水生环境中降解的关键因素。电子自旋共振（ESR）结果表明，O和·OH在吡虫啉噻嗪的光降解中起关键作用。密度泛函理论（DFT）计算表明，吡虫啉噻嗪分子的最大静电势位于恶二唑环上的供电子基团（-NH-）处，使其更易发生氧化反应。采用高分辨质谱（HRMS）鉴定吡虫啉噻嗪的光解和水解产物。毒性评估表明，吡虫啉噻嗪的氧化代谢产物M217对水生生物的毒性高于母体化合物。同时，吡虫啉噻嗪及其光降解和水解产物对鱼类、水蚤和绿藻均具有显著的慢性毒性。这些发现为吡虫啉噻嗪的风险评估和安全使用提供了理论指导。
