Center for Urban Waters, Tacoma, WA, 98421, USA.
Department of Civil and Environmental Engineering, University of Washington, Seattle, WA, 98195, USA.
Environ Sci Process Impacts. 2023 May 25;25(5):901-911. doi: 10.1039/d3em00047h.
We here report chemical characteristics relevant to the fate and transport of the recently discovered environmental toxicant 6PPD-quinone (2-((4-methylpentan-2-yl)amino)-5-(phenylamino)cyclohexa-2,5-diene-1,4-dione or "6PPDQ"). 6PPDQ is a transformation product of the tire rubber antioxidant 6PPD that is ubiquitous in roadway environments, including atmospheric particulate matter, soils, runoff, and receiving waters, after dispersal from tire rubber use and wear on roadways. The aqueous solubility and octanol-water partitioning coefficient ( log ) for 6PPDQ were measured to be 38 ± 10 μg L and 4.30 ± 0.02, respectively. Within the context of analytical measurement and laboratory processing, sorption to various laboratory materials was evaluated, indicating that glass was largely inert but loss of 6PPDQ to other materials was common. Aqueous leaching simulations from tire tread wear particles (TWPs) indicated short term release of ∼5.2 μg 6PPDQ per gram TWP over 6 h under flow-through conditions. Aqueous stability tests observed a slight-to-moderate loss of 6PPDQ over 47 days (26 ± 3% loss) for pH 5, 7 and 9. These measured physicochemical properties suggest that 6PPDQ is generally poorly soluble but fairly stable over short time periods in simple aqueous systems. 6PPDQ can also leach readily from TWPs for subsequent environmental transport, posing high potential for adverse effects in local aquatic environments.
我们在此报告与最近发现的环境毒物 6PPD-醌（2-（（4-甲基戊基-2-基）氨基）-5-（苯氨基）环己-2,5-二烯-1,4-二酮或“6PPDQ”）的命运和迁移相关的化学特性。6PPDQ 是轮胎橡胶抗氧化剂 6PPD 的转化产物，在轮胎橡胶使用和道路磨损后从轮胎橡胶中分散出来，普遍存在于道路环境中，包括大气颗粒物、土壤、径流和接收水。6PPDQ 的水溶解度和辛醇-水分配系数（log）分别测量为 38±10μg/L 和 4.30±0.02。在分析测量和实验室处理的背景下，评估了对各种实验室材料的吸附，表明玻璃基本上是惰性的，但 6PPDQ 对其他材料的损失很常见。从轮胎胎面磨损颗粒（TWP）进行的水浸出模拟表明，在流动条件下，每克 TWP 在 6 小时内可释放约 5.2μg 的 6PPDQ。在 47 天的时间内（5 天、7 天和 9 天损失 26±3%），水稳定性测试观察到 6PPDQ 略有至中度损失。这些测量的物理化学性质表明，6PPDQ 在简单的水溶液中通常溶解度较差，但在短时间内相当稳定。6PPDQ 也可以从 TWP 中轻易浸出，随后进行环境迁移，对当地水生环境造成高潜在的不利影响。
