Assessment of tyre wear particles, tyre associated chemicals and microplastics in the Moreton Bay catchment

Plastics pollution, including tyre wear particles (TWPs), is a rapidly growing global issue, particularly in urban environments, yet there is little information on how these pollutants impact sensitive local catchments, particularly in Australia. This study investigated the Moreton Bay catchment, Australia, to quantify TWPs, conventional microplastics and 15 commonly detected tyre associated chemicals (TACs), including 6PPD-quinone, in water and sediment. TACs were detected in all water samples (3 sites), with total concentrations ranging from 252 to 2043 ng/L, and 6PPD-quinone ranging from < 0.11–0.35 ng/L. In sediments (29 sites), TAC were detected at 24 sites, with total detected concentrations ranging from 0.04 to 311 ng/g dry weight (d.w.), with 6PPD-quinone ranged from < 0.07–3.2 ng/g d.w. TWPs were below the MDL (10 ng/L) in water but were detected in sediments at 12 sites (<0.8–308 µg/g d.w.). Polyethylene dominated sediments (up to 241 µg/g d.w.), whereas polyethylene terephthalate dominated water samples (313–982 µg/L). Spatial patterns showed higher contaminant occurrence in riverine systems compared with the Bay, suggesting that local catchment and depositional conditions may influence contaminant distribution. These findings provide the first quantitative assessment of TWPs and TACs in this region and establish a baseline to inform monitoring and management of tyre-derived pollution in Australian environments.