HCAMS room 124
Abstract
Identifying chemical fingerprints to track tire wear particle (TWP) pollution in watersheds
Recently, the contaminant 6PPD-quinone (6PPDQ), an oxidative transformation product of the antioxidant 6PPD, was found in road runoff and was determined to be the cause of coho salmon fish kills occurring in the Pacific Northwest. As tire tread wears down, tire wear particles (TWPs) are formed and release 6PPD, which is transformed into 6PPDQ. Brook, rainbow, and lake trout are other fish species that are sensitive to 6PPDQ and are important for Minnesota recreation, culture, and economy. However, knowledge of TWP pollution abundance and the effects of environmental exposure on tire-derived organic pollutant (TDOP) release and transformation in aquatic systems is limited. The aim of this project was to improve the understanding of environmental conditions that lead to the release and influence the fate of TDOPs from TWPs in order to evaluate TWP pollution transport mechanisms in watersheds. The impacts of environmental exposure were investigated to determine if TDOP leaching is enhanced and if these factors contribute to TDOP presence in watersheds, which may impact fish species. We characterized TDOP detections to use as potential chemical indicators of TWP pollution and measured concentrations through suspect screening methods from a wide range of representative TWPs to give insight into the influence of environmental exposure (objective 1). We analyzed TDOP concentrations under environmentally relevant conditions to understand its influence on TWP leaching behavior and TDOP transformation that may occur in aquatic systems (objective 2). Lastly, we measured TWP and TDOP concentrations in a stream to determine their environmental fate, transport, and abundance in an aquatic system (objective 3). Representative model TWPs were leached in methanol to detect TDOPs under a variety of environmental exposure times. In addition, TWPs were leached in water under environmentally relevant conditions with and without NOM under irradiated and dark conditions to understand leaching and transformation. Results highlighted the effectiveness of suspect screening methods to detect TDOPs and that environmental exposure influences the fate of TDOPs. Light and dark conditions with NOM affect the transformation and persistence of TDOPs. Lastly, we collected suspended sediment and water samples over one field season to evaluate TDOP and TWP presence in an urban Minnesota stream. Both TDOPs and TWPs were detected, which suggests ongoing TWP pollution through environmental exposure mechanisms, partitioning processes, and runoff. These results will help inform management, agencies, and organizations on how to address TWP pollution in Minnesota streams to protect fish species and water resources.