| Summary: | Degree: Doctor of Philosophy Abstract: This thesis discusses the fate of individual enantiomers and isomers of organohalogen compounds (OHCs) in the environment and the development of analytical methods to facilitate such determinations. A novel proof of principle anion attachment atmospheric pressure photoionization (AA-APPI) method was developed. Minimal matrix effects, increased sensitivity and lower limits of detection were found in sediment extracts spiked with hexabromocyclododecane (HBCD) compared to atmospheric pressure photoionization. AA-APPI offers a simple means of further extending the range of compounds ionizable by photoionization, while maintaining minimal matrix effects. Enantiomer fractions (EFs) of chiral OHCs were determined in the blood and eggs of glaucous gulls from Svalbard, Norway, to determine the enantioselectivity of OHC maternal transfer. No differences were found between the EFs for any analyte in female gulls compared to those found in egg yolk. This indicates that processes involved in the maternal transfer of OHCs to eggs do not modulate the stereochemical ratio between enantiomers. EFs of polychlorinated biphenyl (PCB) atropisomers were determined in the sediment and biota from an estuary heavily contaminated with highly chlorinated PCB congeners. Non-racemic EFs were found in sediment, likely the result of microbial dechlorination. EFs in grass shrimp mirrored those of sediment, but non-racemic EFs in fish species and bottlenose dolphins were likely a result of both uptake of non-racemic proportions of PCBs from the diet and enantioselective biotransformation. OHC EFs were investigated in captive sledge dogs fed OHC-polluted minke whale blubber, to gain greater understanding of the biotransformation capacity of a model polar bear surrogate species. Sledge dogs biotransformed OHCs enantioselectively, and the comparative enantiomer-specific biotransformation capacity showed similar and contrasting results based on individual compounds/congeners. The isomer-specific fate of ...
|
|---|