Chen Zhao-Yu, Li Si-Yue
Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2021 Jan 8;42(1):195-203. doi: 10.13227/j.hjkx.202004201.
The urbanization process of the Three Gorges Reservoir area (TGRA) shows important impacts on the formation, migration, and transportation of dissolved organic matter (DOM) in rivers. In this study, a high-urbanized river (Taohuaxi) and low-urbanized river (Pulihe) in the TGRA were selected and water samples were collected in spring (April) and summer (August) to analyze the seasonal and spatial characteristics of DOM in the rivers using UV-Vis absorption spectroscopy and three-dimensional fluorescence spectroscopy. The DOC, (the spectral slope of the short wavelength range), (spectral slope ratio), BIX (recent autochthonous contribution), and Fn(280) (relative importance of protein-like substances) of the Taohuaxi and Pulihe Rivers were higher in summer (August) than in spring (April), and CDOM concentration, CDOM/DOC, SUVA (aromatic structure), SUVA (hydrophobic component), E3/E4 (proportion of fulvic acid), (the spectral slope of the long wavelength range), and HIX (the degree of humification) were higher in spring than in summer. The overall averages of the DOC, CDOM concentration, , Fn (280), BIX, and FI were higher in the high-urbanized Taohuaxi River than the low-urbanized Pulihe River, whilst the CDOM/DOC, SUVA, and SUVA were lower in the Taohuaxi River. With the increase of urbanization along the water flow pathways, SUVA and SUVA gradually decreased, while Fn (280) gradually increased. The humus source (FI) of the two rivers in spring and summer is mixed and includes terrigenous and biological sources (plankton and algae) but is mostly endogenous. Furthermore, DOM is characterized by a moderately recent autochthonous contribution. Our study implies a large impact of urbanization on the composition and sources of DOM.
三峡库区（TGRA）的城市化进程对河流中溶解有机物（DOM）的形成、迁移和输运具有重要影响。本研究选取了三峡库区一条高度城市化的河流（桃花溪）和一条低度城市化的河流（蒲里河），于春季（4月）和夏季（8月）采集水样，采用紫外可见吸收光谱和三维荧光光谱分析河流中DOM的季节和空间特征。桃花溪和蒲里河的溶解有机碳（DOC）、（短波范围光谱斜率）、（光谱斜率比）、BIX（近期本地贡献）和Fn(280)（类蛋白物质相对重要性）在夏季（8月）高于春季（4月），而有色溶解有机物（CDOM）浓度、CDOM/DOC、SUVA（芳香结构）、SUVA（疏水成分）、E3/E4（富里酸比例）、（长波范围光谱斜率）和HIX（腐殖化程度）在春季高于夏季。高度城市化的桃花溪中DOC、CDOM浓度、、Fn(280)、BIX和FI的总体平均值高于低度城市化的蒲里河，而桃花溪中的CDOM/DOC、SUVA和SUVA较低。随着沿水流路径城市化程度的增加，SUVA和SUVA逐渐降低，而Fn(280)逐渐增加。两条河流春夏季腐殖质来源（FI）混合，包括陆源和生物源（浮游生物和藻类），但以内源为主。此外，DOM的特征是近期本地贡献适中。我们的研究表明城市化对DOM的组成和来源有很大影响。
