IDENTIFICATION OF UNKNOWN TEBUCONAZOLE TRANSFORMATION PRODUCTS IN SOIL BY ENHANCED SUSPECT SCREENING ANALYSIS

K. ROCCO, M. COQUERY, C. MARGOUM

Aquatic Chemistry Team (LAMA), UR RiverLy, INRAE, Villeurbanne, France

Tebuconazole, a triazole-class fungicide, has been registered and used in Europe for over 20 years. Its environmental transformation products (TPs) are among the most studied for a fungicide, with over 50 TPs detected in the last decade. However, most previous studies focused on the identification of tebuconazole TPs in soils, after solvent extraction. In order to study the potential mobility of tebuconazole TPs from agricultural watersheds to waterbodies, we proposed here an enhanced suspect screening analysis of TPs applied after two soil extraction methods. Soils from the same vineyard watershed in the Beaujolais region of France were exposed to tebuconazole in a 120-day laboratory degradation experiment. Extractions of tebuconazole and its TPs from soils was carried out by a soft water extraction, mimicking a mobile fraction, followed by a pressurized liquid extraction, for a thorough extraction. Both extracts were analyzed by Liquid Chromatography coupled to High Resolution Mass Spectrometry (LC-HRMS). Target and suspect screening analyses were performed to follow either the dissipation of the tebuconazole or the apparition of its TPs over exposure time. An enhanced database was created by combining results of *in-silico* prediction tools with literature data. This database of 291 potential tebuconazole TPs was used for suspect screening on the sample extracts. Over 30 tebuconazole TPs were detected, including TPs discovered for the first time. Different TPs were identified depending on the type of soil extraction, with more compounds detected for solvent extractions than water extractions. *In-silico* predictions using EPISuite and ECOSAR softwares were applied on suspected TPs in order to characterize their physicochemical properties and estimate their potential ecotoxicity. This original identification approach of tebuconazole TPs in soils, and their potential mobility to waterbodies, provides additional insight of the environmental fate of tebuconazole.