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Topic

Spatial and Temporal Characterization of 6PPD-Q in Urban Waters Using Condensed Phase Membrane Introduction Mass Spectrometry

Department of Chemistry

Date & location

• Monday, January 12, 2026
• 1:30 P.M.
• Virtual Defence

Examining Committee

Supervisory Committee

• Dr. Erik Krogh, Department of Chemistry, ӣ��Ӱ�� (Supervisor)
• Dr. Christopher Gill, Department of Chemistry, UVic (Member)

External Examiner

• Dr. Rachel Scholes, Department of Civil Engineering, University of British Columbia

Chair of Oral Examination

• Dr. LJ Slovin, School of Child and Youth Care, UVic

Abstract

In 2020, 6PPD-Q (a p-phenylene diamine quinone) was identified as the contaminant associated with urban runoff mortality syndrome, with acute toxicity in the low ng/L range. The quinone compound is an ozonation product of an antioxidant, 6PPD, used to extend the life of rubber products, including tires. 6PPD-Q has been widely detected in aquatic ecosystems, atmospheric particulate matter, and biological samples (including humans). Characterizing environmental risk and developing mitigation strategies for this toxicant requires an understanding of rain-driven pulses of road runoff and stormwater into receiving environments. The ubiquity of tire-derived contaminants and the inherently dynamic nature of their release to the environment requires rapid and scalable detection methods. This thesis applies condensed-phase membrane introduction mass spectrometry (CP-MIMS) for environmental surveillance of this emerging contaminant. CP-MIMS has previously been applied for several pollutants such as polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids (NAs) in oil sands process water, and commercial sunscreen UV filters in recreational waters. This direct mass spectrometry method has been adapted to provide trace level 6PPD-Q analysis. Method selectivity is provided through tandem MS, analytical duty cycles are only 2.5-minute/sample, and 1 ng/L limits of detection shows sensitivity. This allowed for the spatiotemporal studies of the pollutant’s distribution in Nanaimo, BC, a medium sized city on Vancouver Island at the meter – kilometer spatial scale, and minute – hour time scales. Characterizing the concentrations of 6PPD-Q has implications for understanding the in-stream exposure durations for vulnerable species such as coho salmon. Lastly, rain-driven pulses of 6PPD-Q were measured continuously in real-time and on-site using a mobile lab outfitted with a field-operable CP-MIMS system for the first time.