Microplastics and Tire Wear Particles in Urban Stormwater: Abundance, Characteristics, and Potential Mitigation Strategies

Limited research exists on microplastics(MPs) and tirewear particles (TWPs) in stormwater. This study reports on the abundanceof MPs and TWPs in stormwater in Australia and mitigation strategiesto reduce MP pollution. Stormwater has been identified as a pathway for microplastics(MPs),including tire wear particles (TWPs), into aquatic habitats. Our knowledgeof the abundance of MPs in urban stormwater and potential strategiesto control MPs in stormwater is still limited. In this study, stormwatersamples were collected from microlitter capture devices (inlet andoutlet) during rain events. Sediment samples were collected from thematerial captured in the device and from the inlet and outlet of aconstructed stormwater wetland. MP (>25 & mu;m) concentrationinstormwater varied across different locations ranging from 3.8 to 59MPs/L in raw and 1.8 to 32 MPs/L in treated stormwater, demonstratinga decrease after passage through the device (35-88% removal).TWPs comprised & SIM;95% of all particles, followed by polypropylene(PP) and poly(ethylene terephthalate) (PET). The concentration ofTWPs ranged from 2.5 to 58 TWPs/L and 1450 to 4740 TWPs/kg in stormwaterand sediment, respectively. A higher abundance of MPs was found inthe sediment at the inlet of the constructed wetland compared to theoutlet, indicating a potential role of wetlands in removing MPs fromstormwater. These findings suggest that both constructed wetlandsand microlitter capture devices can mitigate the transport of MPsfrom stormwater to the receiving waterways.