Exploring the potential of high mass resolution and mass accuracy mass spectrometric techniques to track the environmental metabolism and fate of BFRS : application to the ambient environment

• Main Author: Ganci, Aristide Paolo
• Published: University of Birmingham 2018
• Subjects: GE Environmental Sciences
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.768287

This thesis investigates levels, sources, and transformation products of both legacy BFRs (LBFRs), and several novel BFRs (NBFRs). To accurately target these emerging pollutants in environmental matrices, an analytical method based on liquid chromatography coupled to high resolution mass spectrometry was developed. Sediment samples taken along the River Thames revealed the presence of both legacy and novel compounds, with concentrations of selected NBFRs approaching those of LBFRs. Tentative sources in the industrial area of London were identified, along with the presence of hydroxylated transformation products of polybrominated diphenyl ethers (PBDEs). Further, the employed technique facilitates the precise identification of metabolites and degradation products formed through in vitro and photodegradation studies. This provides valuable insight into the transformation mechanisms of NBFRs, including hydroxylation and debromination reactions. While 2,3,4,5-tetrabromobenzoic acid (TBBA) was the major metabolite of 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH) was biotransformed to monohydroxy- DBE-DBCH and monohydroxy-triDBE-DBCH in trout liver microsomes. Photolysis of investigated NBFRs resulted in the formation of lower brominated species through stepwise reductive debromination as a main pathway. In addition, the use of mass defect plots and bromine isotopic pattern assist in the identification of relevant unknown chemicals within complex mixtures of halogenated compounds in dust and sediment samples.