Abstract：
Dissolved organic matter (DOM) transported by inflowing rivers can considerably contribute to the organic loadings of lakes. The current study characterized the DOM properties and source apportionment in the inflowing rivers of Dianchi Lake, the sixth largest freshwater lake in China suffering from organic pollution, during the rainy season by using spectroscopic and carbon stable isotope techniques, and the regulation role of land use was assessed. The results showed that land use (urbanized, agricultural, or mixed) largely affected DOM properties. Greater concentrations and fluorescence intensities of DOM with low aromaticity and dominant autochthonous sources were observed in the urban rivers than in the agricultural rivers. The proportion of humic-like substances increased, while that of tryptophan-like matter decreased from upstream to downstream of two main urban rivers. DOM in the agricultural rivers was characterized by more amounts of aromatic humic-like substances with dominant allochthonous sources compared to that in the urban rivers. Stable isotope analysis showed that the decomposition of macrophytes and input of terrestrial sources from C3 plant-dominated soil and sewage were the major DOM origins in the rivers. The positive linear relationship between the chemical oxygen demand (COD) concentration and fluorescence intensities of terrigenous DOM components implied the necessity of controlling exogenous inputs to alleviate organic pollution in the Dianchi Lake.
摘要：
流入河流运输的溶解有机物（DOM）可以极大地增加湖泊的有机负荷。目前的研究描述了滇池流入河流的DOM性质和来源分配，中国第六大淡水湖受到有机污染，在雨季，通过使用光谱和碳稳定同位素技术，并评估了土地利用的调节作用。结果表明，土地利用(城市化，农业,或混合)很大程度上影响了DOM属性。与农业河流相比，在城市河流中观察到具有低芳香性和主要自生源的DOM的浓度和荧光强度更高。腐殖质样物质的比例增加，而色氨酸样物质的含量从两条主要城市河流的上游向下游减少。与城市河流相比，农业河流中的DOM的特征是更多的芳香腐殖质样物质，具有主要的异源来源。稳定同位素分析表明，大型植物的分解和C3植物为主的土壤和污水的陆源输入是河流中主要的DOM来源。陆源DOM组分的化学需氧量（COD）浓度与荧光强度之间的正线性关系表明，必须控制外源输入以减轻滇池的有机污染。
