水源水库沉积物及其上覆水DOM光谱特征

Spectral characteristics of dissolved organic matter in sediment and overlying water of water source reservoir

为探究水源水库溶解性有机质(DOM)组成结构及来源,以深圳市茜坑水库为例,采用紫外-可见光谱技术(UV-Vis)并结合平行因子分析法三维荧光光谱技术(EEMs-PARAFAC)对水库表层沉积物及其上覆水的DOM光谱特征进行分析.结果表明:PARAFAC识别出3类荧光组分,分别是C1(E_(x)/E_(m)=270/304nm,类蛋白),C2(E_(x)/E_(m)=285,235/360nm,类蛋白)和C3(E_(x)/E_(m)=270,340/442nm,类腐殖质).荧光特征指数表明茜坑水库沉积物及其上覆水DOM受新生内源和陆源输入共同影响,但主要以内源为主.表层沉积物中的类蛋白质浓度和类腐殖质浓度均远高于上覆水体,表层沉积物可能向上覆水体释放小分子DOM.紫外可见光谱与三维荧光表征结果一致,表层沉积物DOM分子量、腐殖化程度、芳香性和疏水性均低于上覆水.相关性分析表明,上覆水C1组分与C2组分相关性显著(P<0.05),表明其存在同源性.通过对茜坑水库沉积物及其上覆水DOM光谱特征的研究,可进一步分析水库有机质污染特征.

To explore the composition and source of dissolved organic matter(DOM) in water source reservoir, the Shenzhen Xikeng Reservoir was taken as an example, using ultraviolet-visible spectroscopy(UV-Vis) combined with parallel factor analysis three-dimensional fluorescence spectroscopy(EEMs-PARAFAC) analyzed the DOM spectral characteristics of the surface sediments of the reservoir and its overlying water. The results showed that: PARAFAC had identified three types of fluorescent components,namely C1(E_(x)/E_(m) =270/304 nm, protein-like), C2(E_(x)/E_(m)=285,235/360 nm, protein-like) and C3(E_(x)/E_(m)=270,340/442 nm, humus-like).The fluorescence characteristic index indicated that the sediments of the Xikeng Reservoir and the DOM of the overlying water were affected by both the new endogenous and terrestrial inputs, but mainly endogenous. The protein-like concentration and humus-like concentration in the surface sediments were much higher than the overlying water, and the surface sediments might release small molecules of DOM. The UV-vis spectrum and three-dimensional fluorescence characterization results were consistent, and the DOM molecular weight, degree of humification, aromaticity and hydrophobicity of the surface sediments were all lower than that of the overlying water. Correlation analysis showed that the C1 and C2 components of the overlying water were significantly correlated(P<0.05), and there was homology between them. The study of the DOM spectral characteristics of the sediments of the Xikeng Reservoir and its overlying water can further analyze the characteristics of the organic matter pollution of the reservoir.