Toxicity of tire rubber-derived pollutants 6PPD-quinone and 4-tert-octylphenol on marine plankton

The impacts of tire wear particles and their associated chemicals on the aquatic systems are a major environmental concern. In this study, we investigated the acute toxicity of two pollutants derived from tire rubber, 6PPD-quinone and 4-tert-octylphenol, on marine plankton. Specifically, we determined the acute effects of these pollutants on various organisms within the plankton food web: the microalgae Rhodomonas salina, the adult copepod Acartia tonsa, and the early life stages of the echinoderms Arbacia lixula and Paracentrotus lividus and the fish Sparus aurata. Exposure to 6PPD-quinone did not affect the microalgae growth, copepod survival, or fish embryo viability after 48 h of exposure at concentrations up to 1000 µgL^-1. However, 6PPD-quinone significantly inhibited the growth of early developmental stages of both echinoderm species, with median effective concentrations of 7 and 8 µgL^-1. Conversely, 4-tert-octylphenol was toxic to all studied organisms, with median lethal and effective concentrations ranging from 21 to 79 µgL^-1 depending on the species and endpoints. The most sensitive planktonic organisms to 4-tert-octylphenol were echinoderm embryos and copepods, which exhibited negative effects at concentrations as low as 1 and 25 µgL^-1, respectively. Our results demonstrate that acute exposure to 6PPD-quinone and 4-tert-octylphenol can cause harmful effects on key planktonic organisms at environmentally relevant concentrations. Overall, our findings highlight the need for develop ecologically safer tire rubber additives and reduce traffic-related tire particle emissions to mitigate their entry and potential impacts on aquatic ecosystems.