Uptake of organic contaminants from car tire microplastics in Arctic marine species

Car tire particles represent an important environmental challenge that is difficult to alleviate. The particles stem from abrasion during driving, so-called tire wear particles (TWPs), down-cycled end-oflife tire crumb rubber (CR) granulate that is used widely as low-cost infill on sports fields, or degradation products from discarded tires. The material contains a variety of additives and chemical residues from the manufacturing process, including metals, especially high concentrations of zinc, polycyclic aromatic hydrocarbons (PAHs), and benzothiazoles (Halsband et al., 2020), but also paraphenylenediaminesb (PPDs) and numerous other organic chemicals. In urbanized areas, TWPs arebemitted from vehicles, while CR is dispersed from artificial sports fields and other urban surfaces to the environment. This suggests that particulate and chemical runoff to coastal systems is likely and represents a route of exposure to marine organisms. In the Arctic, even small human settlements can represent local sources of TWPs and CR granulate emissions. Here, we summarize recent experimental studies examining the responses of different marine animals to tire rubber particle or leachate exposure, focusing on toxicity and the uptake kinetics of tire-related organic chemicals into organs and tissues. We present data for different ecological functional groups relevant to the Arctic, including copepods, shrimps, crabs, and fish, representing different body sizes, marine habitats, and feeding modes, and thus varying exposure scenarios. Our findings from GC-HRMS SIM chromatography demonstrate that several tire additives are taken up into tissues. Although the available data indicates many tire-derived organic chemicals do not seem to bioaccumulate, mapping of tire rubber particle and chemical distributions in Arctic coastal systems, dose-response toxicity testing and risk assessments of environmental concentrations are warranted, also with a view to potential trophic transfer within the Arctic marine food chain.