利用UV-vis及EEMs对比冬季完全混合下两个不同特征水库溶解性有机物的光学特性

结合紫外吸收光谱(UV-vis)与三维荧光光谱技术(EEMs),并利用平行因子分析的方法,对两个混合型水库(周村水库和金盆水库)水体中DOM的来源及差异性进行了分析.结果显示,两个水库水体均存在3个荧光组分,分别为长波类腐殖质(350/460 nm)、可见类富里酸(335/410 nm)和类蛋白(260,285/360 nm).但是两水库水体的DOM荧光强度及组分构成比例均存在显著差异(P0.01),两个水库均以类腐殖质为主,但相比金盆水库,周村水库水体中类腐殖质含量相对较低,类蛋白含量较高.周村水库DOM组分间的相关性大于金盆水库,表明后者的DOM来源更为复杂.通过荧光指数FI,自生源指标BIX,腐殖化指标HIX以及新鲜度指数(β∶α)综合对比表明:冬季,在径流量小的情况下,以耕地、畜牧、居民用地为主,沉积物内源污染严重的周村水库水体的DOM以自生源为主;沿岸以森林生态系统为主的金盆水库的DOM则来自混合输入.结果表明混合型水库水文条件及沿岸生态环境特征是决定DOM来源与特征的关键因素之一.

Optical Characteristics of Dissolved Organic Matter from Two Different Full Mixed Reservoirs in Winter Based on UV-vis and EEMs

The differences in the resource and characteristics of DOM between Zhoucun Reservoir and Jinpen Reservoir were studied by fluorescence ultraviolet-visible (UV-vis) and excitation-emission matrix spectra combined with parallel analysis (EEMs-PARAFAC). The results showed that three fluorescent components were identified by PARAFAC model in Zhoucun Reservoir and Jinpen Reservoir, including long wave humus-like component (C1: 350/460 nm), visible fulvic-like (C2: 335/410 nm) and protein-like (C3: 260,285/360 nm). However, the fluorescence intensity and the relative proportions of DOM exhibited significant difference (P<0.01) in two reservoirs. Moreover, the concentration of protein-like component in Zhoucun Reservoir was higher than that in Jinpen Reservoir, while the concentration of humus-like component presented the opposite trend. Based on the comparison of fluorescence index, biological index, humification index and the freshness index, the DOM of Zhoucun Reservoir where the land-use type was cultivated, livestock and residential, the internal pollution of sediments was serious, indicating a strong autochthonous component and aquatic bacterial origin, whereas the DOM of Jinpen Reservoir dominated by forest system had a higher terrigenous contribution in winter. From all the results, hydrological conditions of the reservoir and the characteristics of coastal ecological environment were important factors to influence the DOM sources and characteristics.