沣河洪水过程溶解有机物的荧光特征及来源分析研究

Fluorescence and source of dissolved organic matter during storm flows in the Fenghe River

利用三维荧光光谱技术对陕西西安境内的沣河秦渡镇水文站和高桥水文站的暴雨期间洪水过程的溶解有机物进行研究,讨论了荧光溶解有机物的来源、组成、分子结构等特征.结果表明强降水带来了更多荧光溶解有机物,表现为冲刷效应,洪水过程河流溶解有机物的荧光峰主要以代表陆源有机物的类富里酸荧光为主,类蛋白荧光较弱或没有检测出,表明人为污染影响较小.结构特征为腐化程度高、芳香性大,以大分子的有机物为主.春季首次强降水冲刷的有机物结构成分较为复杂,点源污染稀释作用和水库泄洪作用对洪水过程有机物的浓度、组成、结构等变化特征也有很大影响.

Three-dimensional excitation emission matrix fluorescence spectroscopy (3DEEM)was used to characterize fluorescence properties of dissolved organic matter during storm flows at Qinduzhen Hydrological Station and Gaoqiao Hydrological Station in the Fenghe River of Xi’an,Shaanxi Province.Storm flows brought more fluorescence of dissolved organic matter,possibly due to a flushing effect.Fluorescence in storm flows was dominantly fulvic-like representing terrestrial inputs, but protein-like fluorescence was weak or not detected,suggesting weaker influence from pollution. Dissolved organic matter showed high degree of corruption,aromaticity and organic macromolecules.Dissolved organic matter was structured more complex due to a spring first flush effect.Dilution of point source pollution and releasing flood waters from upstream reservoirs also had considerable impact on concentration,composition and structure of dissolved organic matter in storm flows.