摘要：Understanding the quantity and quality of sediment dissolved organic matter (DOM) in river is critical for explaining and semi-quantifying the exports of DOM in fluvial ecosystem. In the present study, surface sediment samples were collected from different outfalls of the Nanfei River, an important urban river in Chaohu Lake Basin, China. Fluorescence and ultraviolet-visible absorption spectrums were used to analyze the components and characteristics of surface sediment DOM. The results showed that four fluorescent components were resolved by analyzing the three dimensional fluorescence spectrum matrix data of the DOM from fluvial sediments with the PARAFAC model. Humic-like substances are the main component, and microbiological degradation is the primary source, these results indicated that microorganisms played an important role in the formation of DOM in the sediments. For different types of outfalls, sediment DOM from the rainwater outfalls has a low value of dissolved organic carbon (DOC) and proteinoid; and sediment DOM from rainwater, sewage outfalls and tributaries outfalls have more microbiological degradation components. The fluorescence index (FI) is sensitive enough to indicate both the different types of outfalls and the microbiological degradation components of humic-like substances. The spectral slope ratio from 275 nm to 295 nm (S275-295) has a certain relationship with the microbiological degradation components, and S350-400 increases when the proteinoid component becomes larger. The difference of DOM quantity between different types of outfalls suggests that foreign water has intensive effects on sediment DOM fractions in the urban fluvial system, and the spectral fingerprint of DOM acts as a proxy for revealing the origins and formation processes in the sediment.
