Characterization of tire-derived nanocomposites: an overlooked component of road runoff entering aquatic ecosystems

초록

Tire wear particles (TWPs) make up most of road debris entering waterways and release a diverse array of pollutants as they break down. Yet the nanoparticle fraction responsible for the toxicity of these leachates has remained unidentified. Here we show that TWPs immersed in either deionized or saline water release ZnO-based nanoparticles wrapped in carbon black (CB) within a few days, even without any weathering. The quantity of Zn leaching and chemical surface properties of these nanoparticles differ between the two types of water. The combined presence of NaCl and lower pH enhances metal release and promotes surface oxidation of the leached nanoparticles. While Zn leaching from TWPs is well documented, the co-release of ZnO and silica encapsulated with CB reveals an unintended consequence of incorporating nanoscale fillers into modern tire formulations. These findings demonstrate a previously overlooked class of tire-derived leachate nanocomposites entering aquatic environments, altering potential ecotoxicity.

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