Work

Integration of nontarget screening and QSAR modeling to identify novel butachlor transformation products of high priority in soil and water environment

Year: 2025

Type: article

Abstract: Butachlor (BTR), a widely used chloroacetanilide herbicide in rice paddies worldwide, has raised concerns due to limited data on its environmental transformation products (TPs) and their ecotoxicological effects. This study systematically investigates BTR’s degradation kinetics, mechanisms, pathways, and ecotoxicity in water and soil through batch tests, integrating Non-Target Screening (NTS) with Quantitative structure-activity relationship (QSAR) modeling. Hydrolysis half-lives (DT50) ranged from 73.2 to 196 days (pH 4-9), while photolysis half-lives were 12.9-18.6 hours, indicating enhanced degradation in alkaline and light-exposed conditions. Soil degradation exhibited DT50 values of 22.3-38 days, with anaerobic conditions slightly accelerating the process. Using UPLC-Q-TOF-MS, ten TPs were identified, including three novel ones, and four (TP191, TP225, TP277, TP293) were confirmed with synthetic standards. A probable transformation mechanism was suggested based on the identified TPs and Density Functional Theory (DFT) based calculations. Key degradation pathways - dechlorination, hydroxylation, dehydrogenation, N-debutoxylation, cyclization, hydrolysis, dehydration and oxidation - were identified. Finally, Ecotoxicity modeling showed certain TPs, particularly TP277, had “extreme” acute toxicity to Daphnia magna, while TP277 and TP293 posed higher chronic toxicity risks to Danio rerio than the parent compound. These findings highlight the ecological risks of BTR TPs and advocate for their inclusion in environmental risk assessments to safeguard aquatic ecosystems.

Source: Environment International

DOI: 10.1016/j.envint.2025.109491

Authors: Feng Chen, Chi Wu, Lan Zhang, Liangang Mao, Lizhen Zhu, Xingang Liu

Institutions: Institute of Plant Protection, Chinese Academy of Agricultural Sciences, State Key Laboratory of Biology of Plant Diseases and Insect Pests

Language: English

Topic: Pesticide and Herbicide Environmental Studies

Subfield: Pollution

Field: Environmental Science

Domain: Physical Sciences

SDG: Clean water and sanitation

Open Access status: gold

Estimated APC paid: $4,750