Source apportionment of chiral persistent organic pollutants

• Author / Creator

  Asher, Brian Justin

• This thesis explores the fate of chiral compounds in the environment, with a focus on the utility of enantiomer measurements for elucidating pollutant sources. The enantiomer distributions of several chiral polychlorinated biphenyls (PCBs) were measured in the water column of the Hudson River Estuary, and the atmosphere above it, to provide evidence for the relative contribution of fresh versus historical sources. Racemic distributions were observed in air for all chiral congeners detected, but nonracemic distributions for PCB 95 occurred throughout the water column. The results suggest that the source of this congener, and potentially other congeners, to the local aquatic food web is weathered historical contamination. In contrast, the source of PCBs to the local atmosphere is likely fresh releases from the surrounding dense urban centre. The choice of peak integration technique and its effect on the measurement of chiral contaminants was studied. The common valley drop method was shown to bias calculated enantiomer fractions to a greater extent than a deconvolution method. Typical biases when using the valley drop method were shown to have a dramatic effect on environmental calculations that employ the enantiomer fraction. The enantiomer distributions and concentrations of PCBs in soil and air were determined in the region surrounding a hazardous waste incinerator in Alberta, Canada. Concentrations and homologue patterns showed that the incinerator was the primary source of PCBs to the region. Enantiomer distributions in air were largely racemic, yet nonracemic signatures were observed in soil. This data suggests that atmospheric PCBs in the region likely originate from recent emissions from the incinerator, and not revolatilization of historically deposited contaminants from soil. By examining concentrations, as well as isomer and enantiomer distributions of perfluorooctane sulfonate (PFOS) in several aquatic species, the impact of precursor compounds on concentrations of PFOS in the aquatic food web of Lake Ontario was deduced. Racemic distributions were observed in some forage fish, but nonracemic distributions were observed in invertebrate species as well as lake trout. Since the biotransformation of precursors to PFOS is known to be enantioselective, the observed nonracemic signatures in some aquatic species points to an influence of precursors on the local aquatic organisms body burdens of PFOS.

• Subjects / Keywords

  • Source apportionment
  • Polychlorinated biphenyls
  • Perfluorooctane sulfonate

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R34M1P

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.