河流-湖泊系统中溶解有机质的示踪及迁移

应用同步和三维荧光光谱对夏季贵州红枫湖、百花湖河流-湖泊系统的DOM(溶解有机质)进行识别和示踪,重点揭示了人为来源DOM的迁移和影响.结果表明,人为来源DOM比例较大的水体r(287 nm/332 nm)(同步荧光光谱指数)均大于1,r(B/C)(三维荧光光谱指数)较高,287 nm处的同步荧光峰是有机污染物的特征峰.与红枫湖表层水相比,百花湖表层水出现明显的类蛋白荧光峰,且r(287 nm/332 nm)(2.7)远大于红枫湖(0.7),指示百花湖中人为来源ρ(DOM)高于红枫湖.东门桥河向百花湖输送了较多人为来源DOM,但在百花湖水体纵向剖面4 m以下受到的影响较小.经过稀释和净化百花湖出口人为来源的ρ(DOM)已降至较低水平.同步荧光和三维荧光光谱联合可用来识别和示踪水体中人为来源ρ(DOM). 

Tracing the Transport of Dissolved Organic Matter in a River-Lake System

By using synchronous fluorescence spectroscopy and three-dimensional excitation emission matrix(EEM) spectroscopy,dissolved organic matter(DOM) in the Hongfeng and Baihua Lakes in Guizhou Province and their surrounding rivers were identified and traced during summer,with specific focus on the transport and influences of the anthropogenic DOMs.The results showed that the synchronous fluorescence spectroscopy index r(287 nm/332 nm) of the water with high proportion of anthropogenic DOM was larger than 1.The characteristic peak was at about 287 nm,and its EEM spectroscopy index r(B/C) was larger than that of the DOM with low portion of anthropogenic sources.The synchronous fluorescence spectroscopy index r(287 nm/332 nm) of the surface water of Lake Baihua(2.7) was much higher than that of Lake Hongfeng(0.7).There was an obvious protein-like fluorescence peak in the spectroscopy of Lake Baihua,which indicated a higher portion of anthropogenic DOM.The results also demonstrated that a large amount of anthropogenic DOM was transported to Lake Baihua by Dongmenqiao River,and this inflow mainly affected the water layer of 0 m to 4 m depth.After dilution and degradation,ρ(DOM) decreased to a very low level by the time the water was discharged from Lake Baihua.It is useful to combine synchronous fluorescence spectroscopy with three-dimensional excitation emission matrix fluorescence spectroscopy for anthropogenic DOM identification and tracing in river-lake water systems.