May 21, 2026: BC Branch: AGM + Special Speaker
Date: Thursday, May 21, 2026 – 12pm-1:30pm PDT
Topic: 6PPD-Quinone and Stormwater Management
Speaker: Dr. Rachel Scholes
Description:
Road runoff contaminants have been broadly implicated in the biological decline of urban aquatic ecosystems. In particular, 6PPD-quinone (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine quinone), the transformation product of a tire rubber antiozonant, is lethal to coho salmon at ng/L concentrations and has been identified as the primary causal toxicant in die-off’s of coho salmon in B.C. and the U.S. Pacific Northwest. This talk will summarize insights from our “Salmonid Toxic Runoff Exposure and Mitigation (STREAM)” project, which aimed to assess the occurrence of 6PPD-quinone in the Lower Mainland of B.C. and the potential for green infrastructure systems to address these contaminants. We conducted field sampling of salmon-bearing streams throughout Metro Vancouver and conducted field tests of bioretention systems and retention ponds to assess 6PPD-quinone removal. We also completed lab-scale batch and column experiments to identify opportunities to enhance contaminant capture in bioretention systems. Together, our findings indicate the widespread occurrence of 6PPD-quinone in urban waters and demonstrate the effectiveness of bioretention systems to capture 6PPD-quinone.
Speaker Bio:
Dr. Rachel Scholes is an Assistant Professor in the Department of Civil Engineering at the University of British Columbia. Her research focuses on trace organic contaminants in aqueous environments, including engineered and nature-based water treatment systems. She earned her M.S. and Ph.D. in Environmental Engineering from the University of California, Berkeley, and a B.S. in Chemical Engineering from Northwestern University, and completed a Fulbright Fellowship at the University of Otago, New Zealand. Prior to joining UBC, she conducted postdoctoral research at the United States Department of Agriculture. As an early-career faculty member, she has been highlighted as an Emerging Investigator by the Royal Society of Chemistry, and was appointed by the Peter Wall Institute for Advanced Studies at UBC as a Catalyst Scholar addressing the Climate and Nature Emergency.
Join us afterwards for the BC Branch Annual General Meeting, where members will review the past year’s activities, receive updates from the executive team, and discuss plans and priorities for the year ahead. All members are encouraged to attend!
