城市雨水管网沉积物不同分子量溶解性有机质空间分布及光谱特征

采用超滤法、紫外-可见吸收光谱和三维荧光光谱分析法研究了北京市西城区4个典型功能区(居民区、文教区、交通区、商业区)雨水管网表层沉积物中不同分子量溶解性有机质(DOM)的分布特征和光谱特性。结果表明:雨水管网沉积物DOM以小分子量组分为主,约占整体水平的60%~70%。通过分析还发现,沉积物中小分子量(小于3k Da)DOM主要是类蛋白物质,而腐殖类物质主要集中在DOM的大分子量(大于10k Da)区域,微生物活动对小分子量DOM贡献作用显著,由此可见,DOM的分子组成和结构特性在一定程度上可以作为雨水管网沉积物DOM主成分和来源的衡量指标。4个功能区DOM腐殖化水平较低,表现出随分子量增大DOM腐殖化程度升高的规律。

Spatial Distribution and Spectral Characteristics of Dissolved Organic Matter with Different Molecular Weight in Urban Rainwater Sewer Sediment

Ultrafiltration technique, UV-Visible and excitation-emission matrix (EEM) fluorescence was used to investigate the distribution and fluorescence properties of different molecular weight dissolved organic matter (DOM) in the surface sediment from rainwater sewer of four regions (residential, campus, traffic, business) in Xicheng district, Beijing. The results indicated that the small molecular weight DOM showed great dominance in sewer sediment and approximately accounts 60%-70% of the total. Besides, small molecular weight DOM (<3k Da) is mainly composed of protein-like substances and shows strong autochthonous component character, however, humic-like substances shows great dominance in the big molecular weight DOM (>10k Da), microbial activities had made contribution to sediment DOM, hence the molecular composition and structure of DOM could be utilized to investigate the main components and sources of dissolved organic matter in rainwater sewer sediment. The surface sediment DOM of these four regions exhibits lower humification level, and the humification level of DOM increased with the molecular weight increased.