Hexamethoxymethyl-melamine (HMMM) is used as a crosslinking agent in resins and plastics and in the manufacture of tires. In the present study, surface water samples were collected from two rivers adjacent to high traffic highways in the Greater Toronto Area in Ontario, Canada. Composite samples collected from the Don River and Highland Creek during rain events and a period of rapid snowmelt were preconcentrated using solid phase extraction and analyzed using liquid chromatography with high-resolution mass spectrometry. Elevated concentrations (> 1 µg/L) of HMMM were detected in surface waters during rain events in October of 2019 and during snow melt in early March of 2020. There were lower average concentrations of HMMM detected during rain events in the winter and spring of 2020. Temporal profiles of changes in the concentrations of HMMM in composite samples collected every 3 h during a rain event in October 2019 closely corresponded to the hydrograph profiles at the sampling sites, with the HMMM concentrations peaking > 6 h after the peak in water levels. This work contributes to the literature showing that HMMM is a ubiquitous contaminant of urban watersheds and that runoff from roads is a vector for the transport of this compound into urban surface waters.

六甲氧基甲基三聚氰胺 (HMMM) 用作树脂和塑料以及轮胎制造中的交联剂。在本研究中，地表水样本是从加拿大安大略省大多伦多地区交通繁忙的高速公路附近的两条河流中采集的。在降雨事件和一段快速融雪期间从当河和高地溪收集的复合样品使用固相萃取进行预浓缩，并使用液相色谱和高分辨率质谱进行分析。在 2019 年 10 月的降雨事件和 2020 年 3 月上旬的融雪期间，在地表水中检测到 HMMM 的浓度升高（> 1 µg/L）。在冬季和春季的降雨事件中检测到的 HMMM 平均浓度较低2020 年。2019 年 10 月降雨事件期间每 3 小时采集一次的复合样品中 HMMM 浓度变化的时间剖面与采样点的水位线剖面密切对应，HMMM 浓度在水位达到峰值后 > 6 小时达到峰值。这项工作有助于文献表明 HMMM 是城市流域中普遍存在的污染物，道路径流是该化合物进入城市地表水的载体。