Characteristics of dissolved organic matter content in urban rivers under different environmental impact zones: A case study of China’s Tuo River

Abstract

Although urbanization has significant effects on the landscape around the rivers, there are few studies on the fluorescence characteristics of dissolved organic matter (DOM) in watersheds under different landscape models. Therefore, in this study the optical properties of DOM in the same river under different environmental impact zones as the research object, by fluorescence excitation-emission matrix (EEM) combine with the parallel factor analysis (PARAFAC) method and mathematical statistics to research the tourist, residential and agricultural impact. The results show that agriculture has a significant effect on the concentrations of total nitrogen (TN) and chemical oxygen demand (COD) in the surface water; terrestrial humic-like and two protein-like component were derived using the PARAFAC modeling on sample fluorescence spectra, and significant differences fluorescent components in a river under different environmental impact zones. Fluorescence index analysis showed that autochthonous was the main sources of DOM. Correlation and principal component analysis (PCA) were applied to assess the relationships of fluorescent components, fluorescent indices, and water quality parameters. It revealed agricultural non-point source and the impact of human activities on the watershed.