Tire tread particles turn streams toxic For coho salmon in the U.S. Pacific Northwest, returning to spawn in urban and suburban streams can be deadly. Regular acute mortality events are tied, in particular, to stormwater runoff, but the identity of the causative toxicant(s) has not been known. Starting from leachate from new and aged tire tread wear particles, Tian et al. followed toxic fractions through chromatography steps, eventually isolating a single molecule that could induce acute toxicity at threshold concentrations of ∼1 microgram per liter. The compound, called 6PPD-quinone, is an oxidation product of an additive intended to prevent damage to tire rubber from ozone. Measurements from road runoff and immediate receiving waters show concentrations of 6PPD-quinone high enough to account for the acute toxicity events. Science, this issue p. 185 A toxic transformation product of a tire rubber antioxidant explains mortality in salmon exposed to urban stormwater. In U.S. Pacific Northwest coho salmon (Oncorhynchus kisutch), stormwater exposure annually causes unexplained acute mortality when adult salmon migrate to urban creeks to reproduce. By investigating this phenomenon, we identified a highly toxic quinone transformation product of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), a globally ubiquitous tire rubber antioxidant. Retrospective analysis of representative roadway runoff and stormwater-affected creeks of the U.S. West Coast indicated widespread occurrence of 6PPD-quinone (<0.3 to 19 micrograms per liter) at toxic concentrations (median lethal concentration of 0.8 ± 0.16 micrograms per liter). These results reveal unanticipated risks of 6PPD antioxidants to an aquatic species and imply toxicological relevance for dissipated tire rubber residues.

中文翻译：

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一种普遍存在的轮胎橡胶衍生化学物质导致银鲑急性死亡

轮胎胎面颗粒使溪流有毒 对于美国太平洋西北部的银鲑来说，返回城市和郊区溪流产卵可能是致命的。经常发生的急性死亡事件尤其与雨水径流有关，但致病毒物的身份尚不清楚。从新旧轮胎胎面磨损颗粒的渗滤液开始，Tian 等人。通过色谱步骤跟踪有毒组分，最终分离出一个分子，该分子可以在阈值浓度为~1微克/升时引起急性毒性。该化合物称为 6PPD-醌，是一种添加剂的氧化产物，旨在防止臭氧对轮胎橡胶的损害。对道路径流和直接接收水体的测量显示 6PPD-醌的浓度高到足以解释急性毒性事件。科学，本期第 3 页。185 轮胎橡胶抗氧化剂的有毒转化产物解释了暴露于城市雨水中的鲑鱼的死亡率。在美国太平洋西北部银鲑（Oncorhynchus kisutch）中，当成年鲑鱼迁移到城市小溪进行繁殖时，每年暴露在雨水中都会导致无法解释的急性死亡。通过研究这一现象，我们确定了一种全球普遍存在的轮胎橡胶抗氧化剂 N-(1,3-二甲基丁基)-N'-苯基-对苯二胺 (6PPD) 的剧毒醌转化产物。对美国西海岸具有代表性的道路径流和受雨水影响的小溪进行的回顾性分析表明，在有毒浓度（中位致死浓度为 0.8 ± 0.16 微克/升）下广泛存在 6PPD-醌（<0.3 至 19 微克/升）。