Presented on April 25, 2024, at the 2024 Emerging Contaminants in the Environment Conference by Sara Nedrich - Environmental Toxicologist at The Dow Chemical Co.
Abstract: 6PPD-quinone, an environmental contaminant released from tire-wear particles, is acutely toxic to salmonid species with low (ng/L) exposures resulting in rapid onset of mortality. An investigation of 6PPD-quinone in surface waters was undertaken in a salmon-supporting urban watershed (Grand River). Hourly composite samples from the Grand River and its tributaries showed a maximum concentration of 18 ng/L 6PPD-quinone following a 2.1-inch storm event. A separate investigation has also been completed to assess source contribution of 6PPD-quinone from newly constructed conventional asphalt and tire rubber asphalt roads in 2022. Runoff was collected from a road paved with four different pavement structures and assessed for 6PPD-quinone release following storm events at the time of installation and after one-year of aging and traffic in 2023. Results show differences in stormwater runoff, with the greatest concentrations of 6PPD-quinone associated with the combination of tire rubber and polytransoctenamer rubber (TOR) (29 ng/L) equal to traditional asphalt (28 ng/L) greater than rubber modified overlay (15 ng/L) greater than asphalt overlay with tire rubber sub-base (ND, less than 10 ng/L). Runoff of 6PPD-quinone was higher after one year of aging with limited detections at initial installation. Additional monitoring studies are being proposed to further assess 6PPD-quinone in urban salmonid habitat.
