Zebrafish larvae exposed by tire wear particles leachate and latex paticles leachate (long period, 30 days)

Rubber waste products, such as tire wear particles (TWP) and latex particles (LAP), pose significant environmental risks due to their potential toxicity to aquatic ecosystems. This study systematically evaluates the toxicological effects of leachates from TWP and LAP (10 g/L) on zebrafish embryos (Danio rerio), integrating chemical characterization and toxicological assays to address previous research gaps. Chemical analysis revealed that both leachates contained toxic metals, such as zinc and aluminum, with concentrations exceeding WHO guidelines for drinking water, alongside distinct organic compounds identified via GC-MS, including antioxidants, plasticizers, and accelerators. LAP leachates exhibited significantly higher toxicity compared to TWP leachates, as evidenced by elevated mortality (LC50: 33.34% for LAP), increased malformation rates, delayed hatching, reduced spontaneous movement, heartbeat, and body length. Oxidative stress assays indicated significant disruptions in antioxidant enzyme activity and elevated malondialdehyde (MDA) levels, particularly in the LAP exposure group. Transcriptomic analysis further revealed differential gene expression patterns, with ferroptosis and arachidonic acid metabolism emerging as key pathways in both leachate groups. LAP leachates disrupted broader metabolic and inflammatory processes, while TWP leachates predominantly engaged stress signaling pathway and apoptosis-related pathways. RT-qPCR validation confirmed significant changes in oxidative stress and cardiac-related genes, including the downregulation of tnnt2d and stc1l in LAP-exposed embryos. These findings highlight the heightened embryotoxicity of LAP leachates and the differential impacts of TWP and LAP leachates, emphasizing the urgent need for targeted regulatory oversight to mitigate their ecological risks.