Abstract

The concentration and composition of natural organic matter (NOM) dissolved in river water are greatly affected by the soil properties of different land types in the adjacent catchments. As an important source, forest soils supply a considerable amount of NOM to rivers through runoff during rainfall. With its properties of reacting with chlorine during drinking water disinfection process to form carcinogenic byproducts and competing with synthetic organic chemicals for adsorption in drinking water treatment, better understanding of the characteristics of NOM is important [1,2]. NOM is a mixture of a wide range of complicated constituents. Consisted mainly of humid and fulvic acids, NOM possesses different physicochemical properties in many aspects, such as molecular size, hydrophobicity and electric charge density. The content and composition of NOM in a river is not only associated with the soil types in its catchment but also affected by the pH of rainwater that contacts with the soils and carries NOM constituents into aquatic environment [3]. This study was performed to investigate the physicochemical characteristics of NOM released to Kani River from one of the major soil types distributed in its catchment. The investigation was based on specific ultraviolet absorbance (SUVA), fluorescence excitation emission matrix (EEM) and molecular weight distribution (MW).