Bioaccumulation and Biotransformation of BDE-47 Using Zebrafish Eleutheroembryos (Danio rerio).

Polybrominated diphenyl ethers (PBDEs) are well-known endocrine disrupting chemicals (EDCs) identified as organic persistent pollutants (POPs). Their metabolites OH-BDE and MeO-BDE have been reported to be potentially more toxic than the postulated precursor PBDEs. BDE-47 is the one of the most predominant congener of PBDEs in the environment by its high presence on the industrially used mixtures. In this study, the bioaccumulation and biotransformation of BDE-47 into its major metabolites is evaluated using zebrafish (Danio rerio) eleutheroembryos adapting a previously developed alternative method to bioconcentration official guideline OECD 305, which reduces the animal suffering, time and cost. For the simultaneous determination of BDE-47 and its metabolites in larvae and exposure medium and considering the polarity difference of the analytes and the small sample size, the development of an validated analytical method is a clue step to ensure quality results. In this study, an ultrasound-assisted extraction followed by a SPE dispersive clean-up step and GC-MS-μECD with a previous derivatization process was optimized and validated. Bioconcentration factors (BCF) were calculated using first order one-compartment toxicokinetic model. The profiles found show rapid absorption in the first hours of larval development and great bioaccumulative capacity, finding BCF of 7294±899 and 36363±5702 at nominal concentrations of 10 and 1 μg·L -1 , respectively. Metabolization studies show increasing concentrations of the metabolites BDE-28, 2'-OH-BDE-28 and 5-MeO-BDE-47 throughout the exposure time. The results obtained show the feasibility of the method for bioaccumulation and opens the possibility of metabolic studies with zebrafish eleutheroembryos, which is a very underdeveloped field without official testing or regulation. This article is protected by copyright. All rights reserved. Environ Toxicol Chem 2023;00:0-0. © 2023 SETAC.