Evaluating Community-Level Effects of 6PPD-Quinone in a Natural Boreal Lake Ecosystem

Abstract 6PPD-quinone (6PPD-Q), a transformation product of the tire rubber antioxidant 6PPD, is an emerging contaminant known for its acute toxicity to certain salmonids. However, its potential impacts on aquatic communities remain poorly understood. To address this knowledge gap, 6PPD-Q-spiked limnocorrals were deployed in a natural boreal lake, and water chemistry, phytoplankton, zooplankton, and benthic invertebrate communities were assessed over 28 days following a single pulse exposure (0–100 μg/L) simulating stormwater runoff. Waterborne 6PPD-Q concentrations declined by 80–99% by the end of the study, with no detectable effects on water chemistry or aquatic communities. Temporal changes in chlorophyll-a concentrations and zooplankton abundance were attributed to seasonal dynamics rather than 6PPD-Q exposure, and benthic invertebrate community composition remained unchanged. Concurrently, wild-spawned fathead minnow (Pimephales promelas) embryos were exposed to 6PPD-Q-spiked water collected from the limnocorrals. Larval survival declined significantly at 100 μg/L, with altered hatch timing and sublethal effects including reduced growth, changes in eye, yolk sac, and pericardial areas, and altered energy allocation. These effects occurred at 10.6–22.4 μg/L and above, concentrations that exceed those so far reported in surface waters and stormwater by approximately an order of magnitude. Collectively, this study provides the first field-scale assessment of 6PPD-Q effects on aquatic communities and early life-stage fish. Environmental Significance. This study provides the first field-scale assessment of 6PPD-Q impacts on freshwater communities. While broad aquatic communities appeared resilient to short-term exposure scenarios, early life stages of fish responded at concentrations above those currently reported in the environment, identifying developmental end points that warrant attention when assessing the risks of tire-derived contaminants in freshwater ecosystems.