title: Stereoselective transformation of triadimefon to metabolite triadimenol in wheat and soil under field conditions.
abstract: Racemic triadimefon (TF) was applied to wheat and soil at three sites (Beijing, Huaibei, and Zhengzhou in China) under open field conditions. Its enantioselective degradation and stereoselective transformation to the major metabolite, triadimenol (TN), in wheat straw, grain and soil were investigated. At all sites, the degradation of TF enantiomers in straw and soil followed first-order kinetics. In soil from Beijing and Zhengzhou R-(-)-TF was preferentially degraded; however, preferential enantioselective degradations were not recorded in soil from Huaibei or in the straw from all sites. There were noticeable differences in the stereoselective formation of TN stereoisomers in all straw and soil samples. TN diastereomer A with high animal toxicity was preferentially produced via a reductive reaction in straw. In contrast, diastereomer B, was preferential in soil across the experimental period. Different TN concentrations were found in the order of SR-(-)-TN>RR-(+)-TN>RS-(+)-TN>SS-(-)-TN in straw, and RR-(+)-TN>SS-(-)-TN>SR-(-)-TN>RS-(+)-TN in soil. Neither TF nor TN was found in wheat grain at harvest. Because of differences in degradation, formation, and toxicity, the characterization of enantiomers and stereoisomers in this study contributes toward comprehensively assessing the fate and risk of chiral agrochemicals in the environment and food.
authors.affiliation: Institute of Quality Standards & Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Key Laboratory of Agrifood Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
authors.forename: Hongwu
authors.initials: H
authors.lastname: Liang
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Jing
authors.initials: J
authors.lastname: Qiu
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Shuming
authors.initials: S
authors.lastname: Yang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
authors.forename: Lihong
authors.initials: L
authors.lastname: Qiu
mesh_terms: D052918:Environmental Restoration and Remediation; D005659:Fungicides, Industrial / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D010575:Pesticides / Q000032:analysis / Q000737:chemistry*; D018570:Risk Assessment; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry; D013237:Stereoisomerism; D013997:Time Factors; D014230:Triazoles / Q000032:analysis / Q000737:chemistry*; D014908:Triticum / Q000187:drug effects*
chemical_list: D005659:Fungicides, Industrial; D010575:Pesticides; D012989:Soil Pollutants; D014230:Triazoles; C032910:triadimefon
keywords: Soil; Stereoselective transformation; Triadimefon; Triadimenol; Wheat