Leachates from tyres induce acute toxicity in fish, influence of tyre type and age

Tyres are an important source of microplastics (so called tyre wear particles (TWP)) and chemicals in the environment. Given their composition and the quantity produced every year, tyres are of particular concern in terms of the effects they could have on species, especially in marine ecosystems. Specifically, it has already been shown that a chemical derived from tyres caused the death of Coho salmon (Oncorhynchus kisutch) in urbanized watersheds. In this work, we evaluated the acute toxicity of leachates obtained from three different tyres (1 new and 2 road-worn tyres) on embryonic and larval stages of marine medaka (Oryzias melastigma). Leachates were obtained from millimetric pieces of cut tyres incubated for 14 days in filtered seawater (25‰). The exposure lasted 12 days with hatching at 10 days and different endpoints were considered: mortality, developmental defects, morphology of eggs and larvae, heartbeats, hatching and larval swimming activity. These experiments revealed a dose-dependent effect of the leachates on early life stages of marine medaka for all endpoints considered with a LOEC obtained with 10 Also see: https://micro2024.sciencesconf.org/559100/document