It has been regarded that road-deposited sediment (RDS) is one of the important sinks of anthropogenic pollutants as well as the major source of pollutants in stormwater runoff. However, the role of RDS, as a mediator of pollutants to the stormwater runoff, has not yet been investigated so far. Therefore, in this study, the leaching of dissolved pollutants, especially dissolved organic matter (DOM) from RDS, in synthetic precipitation was investigated. A significant amount of metals, nutrients, dissolved compounds, and DOM was leached. The leaching of DOM during 10 sequential leachings was 1811.3 and 2301.7 mg C/kg for larger (63 μm–2 mm) and smaller (< 63 μm) RDS, respectively. The results of UV/Vis spectroscopy, fluorescence spectroscopy, and size exclusion chromatography showed that the leached DOM was of anthropogenic/abiotic origins with lower molecular weight and humification degree. It is ubiquitous in stormwater runoff and industrial discharges and differs from natural organic matter. The results strongly suggest that RDS is an important mediator transferring anthropogenic pollutants to stormwater runoff. In addition, the removal of RDS, such as sweeping, would significantly reduce the pollutants input to the runoff.

道路沉积物（RDS）被认为是人为污染物的重要汇之一，也是雨水径流污染物的主要来源。然而，迄今为止，RDS 作为污染物对雨水径流的中介作用尚未得到研究。因此，在本研究中，研究了溶解污染物，特别是 RDS 中溶解有机物 (DOM) 在合成沉淀中的浸出。大量金属、养分、溶解化合物和 DOM 被浸出。对于较大 (63 μm–2 mm) 和较小 (< 63 μm) RDS，10 次连续浸出期间 DOM 的浸出量分别为 1811.3 和 2301.7 mg C/kg。紫外/可见光谱、荧光光谱、体积排阻色谱表明浸出的 DOM 是人为/非生物来源，具有较低的分子量和腐殖化程度。它在雨水径流和工业排放中无处不在，与天然有机物不同。结果强烈表明 RDS 是将人为污染物转移到雨水径流的重要介质。此外，清除 RDS，如清扫，将显着减少输入径流的污染物。