Abstract:

To understand the characteristics and the sources of the dissolved organic matter (DOM) in Three Gorges Reservoir，taking Xiaojiang River backwater area as the research object，threedimensional fluorescence spectroscopy was measured and analyzed. The relationship between fluorescence intensity and DOC，CODMn or chlorophyll a was studied. The results showed that: three major peaks，humuslike fluorescence peak A，proteinlike fluorescence peaks B and C appeared on the threedimensional fluorescence spectroscopy；the DOM fluorescence intensity was well related with DOC and CODMn，indicating that fluorescence dissolved organic matter content can reflect both the organic carbon content and the organic matter content by oxidation in the water in August，during the nonalgae bloom outbreak period，fluorescence intensity had a poor correlation with chlorophyll a，indicating that phytoplankton was not the main source of the fluorescent substances. Based on the comprehensive analysis，it can be inferred that both internal pollution sources and external pollution sources existed in the Xiaojiang River backwater area，and the contribution of the external pollution sources to the fluorescence dissolved organic matter was bigger than the internal pollution sources.