title: Occurrence, polarity and bioavailability of dissolved organic matter in the Huangpu River, China.
abstract: Dissolved organic matter (DOM) plays an important role in biogeochemical cycles in aquatic ecosystem. To investigate the characteristics of DOM in Huangpu River (the last tributary of the Yangtze River), surface water samples were collected along the river from December 2011 to June, 2013. The concentrations of dissolved organic carbon (DOC), the absorbance and fluorescence spectrum of DOM in water samples were measured. Fluorescent DOM in the Huangpu River was decomposed into four components by the parallel factor analysis (PARAFAC), including one humic-like substance and three protein-like substances. It showed that high spatial variability of DOC concentration was observed in the upstream water compared to the downstream water, and so did the absorbance coefficients of chromophoric dissolved organic matter and the total fluorescence intensities of different PARAFAC components of DOM. Furthermore, there was a large difference between the polarity and bioavailability of DOM in the Huangpu River. Polar compounds dominated tyrosine-like component of fluorescent DOM in all seasons. Tryptophan-like and humic-like substances had more polar fraction in summer and autumn than those in winter, while aromatic protein-like materials had the highest polar fraction in winter. Almost all of fluorescent DOM components were refractory in spring, while less than 20% of fluorescent DOM in average were biodegradable within 4weeks in other seasons. We concluded that the spatial variation in the abundance of DOM in the Huangpu River is mainly affected by the water discharges from the Hangjiahu Plain and the seasonal difference in polarity and bioavailability of DOM is largely determined by its origins.
authors.affiliation: Key laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: dong033407103@163.com.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Dong
authors.affiliation: Key laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Penghui
authors.initials: P
authors.lastname: Li
authors.affiliation: Key laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China. Electronic address: qhhuang@tongji.edu.cn.
authors.forename: Qinghui
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Key laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Soils, Water and Environment Research Institute, Agricultural Research Center, Giza, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Abdelhafez
authors.affiliation: Key laboratory of Yangtze River Water Environment of the Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
mesh_terms: D001682:Biological Availability; D002681:China; D009930:Organic Chemicals / Q000032:analysis* / Q000493:pharmacokinetics; D045483:Rivers / Q000737:chemistry
chemical_list: D009930:Organic Chemicals
keywords: Absorbance coefficients; Bioavailability; Chromophoric dissolved organic matter; Dissolved organic carbon; Fluorescence; Polarity