Xia Hui, Yan Zhiquan, Huang Kui, Wang Bangchi, Li Tonghuan, Chen Qunfeng
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China; Ministry of Education Engineering Research Center of Water Resource Comprehensive Utilization in Cold and Arid Regions, 730070, China; Key Laboratory of Yellow River Water Environment in Gansu Province, Lanzhou 730070, China.
School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
J Contam Hydrol. 2025 Sep;274:104641. doi: 10.1016/j.jconhyd.2025.104641. Epub 2025 Jun 7.
Organic matter in floodplain soils undergoes complex leaching dynamics during stormwater runoff, directly impacting the water environmental quality of river basin. This study explored the leaching behavior of dissolved organic matter (DOM) and particulate organic matter (POM) in soils from the upper Yellow River floodplain through simulated rainfall experiments. The results showed that DOM and POM were extensively released into the initial rainfall phase (0-20 min), followed by a gradual decline and stabilization in leaching rates. Tryptophan-like substances dominate in the DOM, contributing 45 %-55 % of the total DOM released, while humic substances exhibited a delayed release pattern. POM release was significantly affected by particle size, with smaller particles predominant in the early runoff and larger particles becoming more prominent after 25 min. Two-dimensional correlation spectroscopy (2D-COS) of POM revealed a sequential shift in functional groups, following the order: alcohols > aliphatic compounds > carboxylic acids > esters/ketones > aromatic compounds. Polysaccharides and aliphatic compounds were found to leach preferentially during runoff. Additionally, a transformation between DOM and POM was observed, with larger POM particles gradually converting into DOM, thereby influencing the physicochemical characteristics of the runoff. This study highlights distinct differences in the leaching behavior of DOM and POM during rainfall events, with protein-like and aliphatic compounds showing faster release rates, and smaller particles being more readily mobilized into runoff.
洪泛区土壤中的有机物在雨水径流过程中经历复杂的淋溶动态，直接影响流域的水环境质量。本研究通过模拟降雨实验，探讨了黄河上游洪泛区土壤中溶解有机物（DOM）和颗粒有机物（POM）的淋溶行为。结果表明，DOM和POM在降雨初期阶段（0-20分钟）大量释放，随后淋溶速率逐渐下降并趋于稳定。DOM中以类色氨酸物质为主，占总释放DOM的45%-55%，而腐殖质呈现延迟释放模式。POM的释放受颗粒大小显著影响，较小颗粒在径流初期占主导，25分钟后较大颗粒变得更加突出。POM的二维相关光谱（2D-COS）显示官能团依次发生变化，顺序为：醇类>脂肪族化合物>羧酸>酯/酮类>芳香族化合物。发现多糖和脂肪族化合物在径流过程中优先淋溶。此外，还观察到DOM和POM之间的转化，较大的POM颗粒逐渐转化为DOM，从而影响径流的物理化学特征。本研究突出了降雨事件中DOM和POM淋溶行为的明显差异，蛋白质类和脂肪族化合物释放速率更快，较小颗粒更容易进入径流。
