滇池流域入湖河流溶解性有机质的分布及来源

Analysis of distribution characteristics and source of dissolved organic matter in the rivers that flow into the Dianchi Lake Basin

基于三维荧光光谱和平行因子分析方法,探究了2018年滇池流域主要入湖河流丰水期和枯水期水体溶解性有机质(DOM)组成,并结合主成分分析和多元线性回归分析对河流中DOM各荧光组分的相对贡献进行了定量分析.结果表明:入滇河流水体DOM包含5种荧光组分,分别为类腐殖质荧光组分C1、C3、C5和类蛋白色氨酸荧光组分C2、C4,且5种荧光组分之间具有同源性,污染严重河流水体DOM的荧光强度相对较高;荧光指数、自生源指数、腐殖化指数综合表明,入滇河流水体DOM的内源特性较强,自生源特征明显,生物可利用性较高,腐质化程度低,分子结构不稳定.主成分分析和多元线性回归分析结果显示:枯水期DOM的荧光组分中类腐殖物质的平均贡献率占30.1%,类蛋白色氨酸物质的平均贡献率占69.9%;丰水期DOM组分中类腐殖物质的平均贡献率占54.3%,类蛋白色氨酸物质的平均贡献率占45.7%.

The fluorescence components were examined for the DOM in the rivers flowing into Dianchi Lake over the high and low water periods in 2018 using excitation emission matrix fluorescence spectroscopy-parallel factor analysis technique. Principal component analysis was used to study the relative contribution of each DOM component.The DOM was composed by humic-like substances(C1, C3, C5), protein-like and tryptophan-like substances(C2, C4). These components had the same source, and the fluorescence response in contaminated rivers was stronger than that in clean rivers. Fluorescence, biological and humification indices collectively indicated that the DOM in the rivers mainly originated from endogenous sources with high biological availability and low humification degree. Principal component analysis and multivariate linear regression analysis show that the contributions of humus-like substances to the DOM during the low-and the high-flow seasons account for 30.1% and 54.3%, and the contributions of protein-and tryptophan-like substances to the DOM are 69.9% and 45.7% in the two seasons, respectively.