Identification of metabolites generated in the biotransformation process by the Danio rerio (zebrafish) exposed to the fungicide tebuconazole

Abstract

Tebuconazole is a triazole fungicide widely used in agricultural crops for control of multiple fungal, mainly foliar and soil-borne diseases. Due to its intense use, this pesticide has been detected on aquatic matrices in different countries, which makes it necessary to identify metabolites capable to be used in its exposure monitoring. The aim of this work was to evaluate tebuconazole metabolites in zebrafish water tanks using liquid chromatography coupled to a high-resolution mass spectrometer (LCHRMS) to highlight analytical targets to monitor tebuconazole exposure in aquatic environments. Two Phase I metabolites, TEB-OH and TEB-COOH, and one Phase II metabolite, TEB-S, were identified. Target metabolomics pointed TEB-S as the most important metabolite for discrimination between treatment and negative control group and potential surrogate for detection and monitoring of tebuconazole exposure in aquatic environments. To the best of our knowledge, this is the first study to suggest the sulphation of tebuconazole (TEB-S) by zebrafish metabolism. Moreover, the use of water samples proved to be a promising approach when compared to the usual biological matrices (e.g. plasma) for evaluating the exposure of aquatic animals to tebuconazole because it is a clean and easy to obtain matrix. Water samples presented a higher concentration of metabolites when compared to plasma samples. The results suggest the applicability of this assay model for the identification of potential biomarkers for monitoring the presence of xenobiotics in water.