Yu Xiao-Qin, Cui Yang, Chen Hui-Min, Zhu Jun-Yu, Li Yu-Yang, Guo Yan-Ni, Zhou Yong-Qiang, Han Long-Fei
College of Geographic Sciences, Hunan Normal University, Changsha 410081, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Huan Jing Ke Xue. 2021 Aug 8;42(8):3719-3729. doi: 10.13227/j.hjkx.202011193.
In the past few decades, China's rapid industrial activities and urbanization processes have greatly impacted the urban surface water ecosystem. The changes in the quality of urban surface water directly affect the supply and carbon cycling of urban waters. We collected 50 water samples from urban rivers, lakes, and reservoirs in the city of Changchun in June 2020. Three-dimensional fluorescence spectroscopy coupled with parallel factor analysis (EEMs-PARAFAC) was used to unravel the optical characteristics, composition, and sources of chromophoric dissolved organic matter (CDOM). Our results indicated that the mean concentration of DOC is significantly higher in urban rivers than in reservoirs (-test, <0.05), and the mean UV absorption coefficient of CDOM of urban rivers is significantly larger than that of park lakes and reservoirs (-test, <0.05), indicating that urban rivers have the highest concentration of CDOM. The spectral slope of CDOM absorption and the spectral slope ratio were shown to be higher in park lakes than in reservoirs, and even higher than in urban rivers (-test, <0.001). Three fluorescent components were obtained using PARAFAC, namely terrestrial human-like (C1), microbial human-like (C2) and tryptophan-like (C3) components. The mean fluorescence intensity of C1-C3 was significantly higher in urban rivers than in both the park lakes and reservoirs (-test, <0.005), and the mean fluorescence intensity of C1 in the reservoir water body was significantly higher than that of C2 and C3 (-test, <0.005), indicating that the discharge of municipal wastewater likely contributes significantly to the CDOM pool of urban rivers in Changchun, and the contribution percentages of highly bio-labile protein-like components to the CDOM pool in these waters are high. Urban wastewater treatment should be strengthened to effectively protect water quality, as well as the economic, environmental, and ecological functions of urban waters in Changchun City.
在过去几十年中，中国快速的工业活动和城市化进程对城市地表水生态系统产生了巨大影响。城市地表水水质的变化直接影响城市水体的供应和碳循环。2020年6月，我们从长春市的城市河流、湖泊和水库中采集了50个水样。采用三维荧光光谱结合平行因子分析（EEMs-PARAFAC）来解析发色溶解有机物（CDOM）的光学特性、组成和来源。我们的结果表明，城市河流中溶解性有机碳（DOC）的平均浓度显著高于水库（t检验，P<0.05），城市河流中CDOM的平均紫外吸收系数显著大于公园湖泊和水库（t检验，P<0.05），表明城市河流中CDOM浓度最高。公园湖泊中CDOM吸收光谱斜率和光谱斜率比高于水库，甚至高于城市河流（t检验，P<0.001）。使用PARAFAC获得了三种荧光组分，即类陆源腐殖质（C1）、类微生物腐殖质（C2）和类色氨酸（C3）组分。城市河流中C1-C3的平均荧光强度显著高于公园湖泊和水库（t检验，P<0.005），水库水体中C1的平均荧光强度显著高于C2和C3（t检验，P<0.005），表明城市生活污水排放可能对长春市城市河流的CDOM库有显著贡献，且这些水体中高生物活性的类蛋白质组分对CDOM库的贡献百分比很高。应加强城市污水处理，以有效保护长春市城市水体的水质以及经济、环境和生态功能。
