Toxicological assessment of tyre-derived compounds: effects of 6PPD-quinone, diphenylguanidine, and mercaptobenzothiazole on Phaeodactylum tricornutum

作者：Henry Ebele Obanya, Fay Couceiro, Alex T. Ford, Francoise Cabada-Blanco · 发表于：Aquatic Toxicology · 年份：2025 · DOI：10.1016/j.aquatox.2025.107457 · 被引用次数：5 · 研究领域：Environmental Toxicology and Ecotoxicology、Toxic Organic Pollutants Impact、Pharmaceutical and Antibiotic Environmental Impacts

Urban runoff and industrial discharges introduce toxic compounds into marine ecosystems, threatening aquatic life and ecosystem functions. This study aimed to assess the acute toxic effects of three widely occurring tyre-derived contaminants (mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and 6PPD-quinone (6PPD-Q)) on the growth of the marine diatom Phaeodactylum tricornutum. Growth inhibition assays were performed following ISO 10,253:2016 guidelines. Among the three compounds tested, DPG was the most toxic (EC50 = 0.101 µg/L), followed closely by MBT (EC50 = 0.212 µg/L). In contrast, 6PPD-Q was comparatively less toxic (EC50 = 4.072 µg/L). The no-observed-effect concentration (NOEC) and lowest-observed-effect concentration (LOEC) for DPG were 0.02 and 0.062 µg/L, respectively, and for MBT were 0.0948 and 0.299 µg/L, indicating high toxicity at environmentally relevant levels. In comparison, 6PPD-Q showed only moderate toxicity (NOEC = 3 µg/L; LOEC = 9 µg/L). Statistical analysis (ANOVA with Tukey's HSD post-hoc) confirmed significant dose-dependent inhibition for each compound (p < 0.001). Notably, at the lowest 6PPD-Q concentrations some replicates exhibited slight growth stimulation (negative inhibition ∼4 %), suggesting a potential hormetic effect. These findings underscore the ecological risks of tyre contaminants, especially in urban coastal areas where environmental concentrations oftern approach or exceed the EC50 and LOEC values found here. To our knowledge, ...