Abstract

Brominated flame retardants (BFRs) are a large class of highly persistent and bioaccumulative chemicals with the potential for adverse effects in wildlife exposed to them. This thesis investigated the distribution of polybrominated diphenyl ethers (PBDEs) and several nonPBDE halogenated FRs (HFRs) throughout maternal herring gull tissues (adipose, liver, muscle, red blood cells, plasma) and their eggs (yolk and albumen), and estimated the extent of their in ovo depuration. Methoxylated polybrominated diphenoxybenzenes (MeO-PB-DiPhOBzs) are a class of what are believed to be degradation byproducts recently discovered in herring gull egg homogenate samples collected as part of the annual Great Lakes Herring Gull Monitoring Program. MeO-PB-DiPhOBz tissue distributions and in ovo transfer rates were similarly determined and compared to PBDEs and non-PBDE HFRs. This thesis also conducted a systematic literature review on the metabolism of BFRs in wildlife species, with a focus on emerging and novel (E/N)BFRs. Deficiencies in in vitro assay quality control and assurance practices were highlighted, as well as a paucity in studies conducted on E/NBFRs with most focused on legacy BFRs (i.e., PBDEs and hexabromocyclododecanes). The unmethoxylated form of MeO-PBDiPhOBzs are reported here for the first time in any environmental medium, present in soil collected from Channel Shelter Island (CSI), Lake Huron. MeO-PB-DiPhOBzs were also measured in the soil and herring gull regurgitant collected on CSI, suggesting that they are bioaccumulative contaminants to which the gulls are exposed, rather than metabolic products produced within them. Lastly, novel in silico methodologies were developed and evaluated to model the CYP-mediated biotransformation of MeO-PB-DiPhOBzs. Five distinct potential binding modes of the CYP3A4-MeO-PB-DiPhOBz complex were predicted, while CYP1A binding modes were limited likely due to their strong preference for coplanar ligands.