Intensive Spatiotemporal Characterization of the Tire Wear Toxin 6PPD Quinone in Urban Waters

6PPDQ is a tire-derived contaminant toxic to coho salmon
(LC50 = 41–95 ng/L) found widely distributed in
urban environments.
Most monitoring efforts have relied on relatively few discrete samples
collected at select locations across rain events. Early work has revealed
that 6PPDQ concentrations vary widely over time and space, raising
questions about when and where to collect samples. Here, we employ
condensed phase membrane introduction mass spectrometry, a high-throughput
analysis approach to characterize spatiotemporal variability of 6PPDQ
in urban streams. Analytical method detection limits of 0.3–8
ng/L and a duty cycle of 2.5 min/sample enabled high-throughput adaptive
sampling. Temporal sampling revealed dynamic 6PPDQ concentrations,
with significant changes occurring over minutes during peak rainfall.
Spatial variability was characterized at multiple sites along three
watercourses during the first significant precipitation of autumn
2023 on central Vancouver Island, B.C., Canada. Site-specific concentrations
suggest attenuation of 6PPDQ after point source inputs by some combination
of physical (dilution, sorption) or chemical (degradation) processes.
This is the first report of an intensive sampling campaign describing
the spatiotemporal distribution of 6PPDQ, highlighting the need for
careful consideration of sampling strategies to evaluate the risk
and impact of 6PPDQ in urban waterways.