Misha Zvekic

Topic

Advanced Instrumental Approaches to Study the Fate and Distribution of Emerging Chemical Pollutants

Department of Chemistry

Date & location

• Monday, April 22, 2024
• 10:00 A.M.
• Virtual Defence

Examining Committee

Supervisory Committee

• Dr. Erik Krogh, Department of Chemistry, University of Victoria (Supervisor)
• Dr. Chris Gill, Department of Chemistry, UVic (Member)
• Dr. Dennis Hore, Department of Chemistry, UVic (Member)

External Examiner

• Dr. Shira Joudan, Department of Chemistry, University of Alberta

Chair of Oral Examination

• Dr. Marco Cozzi, Department of Economics, UVic

Abstract

As novel chemicals and materials are discovered and manufactured, the concentration and diversity of environmental contaminants increase. The fate and distribution of contaminants depend both on intrinsic chemical properties and extrinsic environmental conditions. When chemicals pollute water, they can leave that environmental compartment via loss to the air, sorption processes (e.g., to soils, plants, microplastics), or accumulation in organisms. Some contaminants persist over long timescales, eventually degrading or transforming. To understand and predict contaminant behaviour, it is key to characterize their physicochemical properties and analyze their environmental partitioning. Here, mass spectrometry (MS) is employed to achieve the sensitivities required to analyze chemicals at environmentally relevant concentrations. A direct MS approach, condensed phase membrane introduction mass spectrometry (CP-MIMS), is used to investigate legacy pollutants such as polycyclic aromatic hydrocarbons (PAHs), and emerging pollutants such as microplastics, nonylphenol, and para-phenylenediamine quinones (PPDQs). Using CP-MIMS, the sorption kinetics (𝑘’_{𝑠𝑜𝑟𝑏}) and thermodynamics (𝐾_OC) between microplastics and chemical contaminants (nonylphenol and PAHs) were analyzed. Plastic and sediment partitioning and aqueous solubility of PPDQs were also characterized. Lastly, chemical partitioning was analyzed in a pregnant sixgill shark (Hexanchus griseus) collected from the Strait of Georgia in 2019. CP-MIMS was initially used and provided important preliminary data that informed the application of appropriate conventional approaches. High resolution mass spectrometry (HRMS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to analyze the concentrations and maternal transfer of perfluoroalkyl substances (PFAS) and heavy metals, respectively, in this unique biological specimen.