应用多元统计研究城市河流沉积物孔隙水中DOM紫外光谱特征

Application of multivariable analysis to study UV-Visble spectra properties of dissolved organic matter from sediment pore water in an urban river

应用紫外-可见光吸收光谱研究白塔堡河丰水期沉积物孔隙水中水溶性有机物（DOM）的来源、结构及腐殖化程度.采集白塔堡河干流13个沉积物孔隙水样品,分析DOM紫外光谱特性,推演出9个紫外光谱指数（SUVA254、E2/E4、E4/E6、E2/E3、S275~295、S350~400、A2/A1、A3/A1和A3/A2）,研究DOM的组成与结构特征,评价DOM的腐殖化水平.白塔堡河沉积物孔隙水中DOM组成、机构及腐殖化水平呈现沿农村河段向城镇与城市河段递变,农村河段DOM分子量大于城镇与城市河段的,农村河段的DOM分子的聚合度、芳化度、腐殖化水平高于城镇与城市河段的,而DOM中富里酸的含量沿农村河段向城镇与城市河段增加.A2/A1、A3/A1和A3/A2和其它6个指标呈负相关,表明DOM的腐殖化水平随着A2/A1、A3/A1和A3/A2的值增大而升高,而随着其它指标的增大而降低.A2/A1、A3/A1和A3/A2更加精确地评价DOM腐殖化水平,辨识不同采样点DOM腐殖化进程.

UV-Visble spectra were used to analyze structural compositions,identify sources and assess humification level of dissolved organic matter（ DOM） extracted from sediment pore water in Baitabuhe River during high-flow period. Thirteen sediment pore water samples were collected from mainstream of the river,and DOM UV spectra of sediment pore water were comprehensively analyzed. Nine indices（ SUVA254,E2/E4,E4/E6,E2/E3,S275-295,S350 ~ 400,A2/A1,A3/A1and A3/A2） were deduced. These indices indicated structural compositions and assessed humification level of DOM.Humification level of DOM in the rural region was different from the urban region,and it was obviously higher in the urban region than that in the rural region. A2/A1,A3/A1and A3/A2showed negative correlations with other indices,indicating that humification degree increased with increases in A2/A1,A3/A1and A3/A2but decreased with increases in other indices. Moreover A2/A1,A3/A1and A3/A2were accuracy indices to completely assesshumification level of DOM and discriminate humification process of the samples.