title: Characteristics and sources analysis of riverine chromophoric dissolved organic matter in Liaohe River, China.
abstract: Chromophoric dissolved organic matter (CDOM) in riverine systems can be affected by environmental conditions and land-use, and thus could provide important information regarding human activities in surrounding landscapes. The optical properties of water samples collected at 42 locations across the Liaohe River (LHR, China) watershed were examined using UV-Vis and fluorescence spectroscopy to determine CDOM characteristics, composition and sources. Total nitrogen (TN) and total phosphorus (TP) concentrations at all sampling sites exceeded the GB3838-2002 (national quality standards for surface waters, China) standard for Class V waters of 2.0 mg N/L and 0.4 mg P/L respectively, while trophic state index (TSIM) indicated that all the sites investigated were mesotrophic, 64% of which were eutrophic at the same time. Redundancy analysis showed that total suspended matter (TSM), dissolved organic carbon (DOC), and turbidity had a strong correlation with CDOM, while the other parameters (Chl a, TN, TP and TSIM) exhibited weak correlations with CDOM absorption. High spectral slope values and low SUVA254 (the specific UV absorption) values indicated that CDOM in the LHR was primarily comprised of low molecular weight organic substances. Analysis of excitation-emission matrices contour plots showed that CDOM in water samples collected from upstream locations exhibited fulvic-acid-like characteristics whereas protein-like substances were most likely predominant in samples collected in estuarine areas and downstream from large cities. These patterns were interpreted as indicative of water pollution from urban and industrial activities in several downstream sections of the LHR watershed.
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com; Key Research Institute of Yellow River Civilization and Sustainable Development & Collaborative Innovation Center on Yellow River Civilization of Henan Province, Henan University, Kaifeng, Henan, China.
authors.forename: Tiantian
authors.initials: T
authors.lastname: Shao
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Kaishan
authors.initials: K
authors.lastname: Song
authors.affiliation: Department of Earth Sciences, Indiana University-Purdue University, Indianapolis, IN, USA.
authors.forename: Pierre-Andre
authors.initials: PA
authors.lastname: Jacinthe
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Jia
authors.initials: J
authors.lastname: Du
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Ying
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, No. 85 Minglun Road, Shunhe Hui District, Kaifeng, Changchun 475001, China E-mail: songks1106@163.com.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Bai
mesh_terms: D002681:China; D009584:Nitrogen / Q000032:analysis; D009930:Organic Chemicals / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D009930:Organic Chemicals; D010758:Phosphorus; D009584:Nitrogen