Distinguishing the Properties and Sources of the Dissolved Organic Matter in Karst Reservoir Water During Winter Using Three-Dimensional Fluorescence Spectrum Technology:A Case Study in Wulixia Reservoir of Guangxi Province

Abstract

In recent years, the fluorescence spectrum technology has been widely applied to study the physical and chemical properties of dissolved organic matter (DOM) in natural water. In order to reveal the properties of the dissolved organic matter in reservoir water, the three-dimensional fluorescence spectrum and the parallel factor analysis were used to determine the properties of DOM and its sources in the Wulixia reservoir during the winter of 2016. Moreover, the chemical characteristics of water and the relative proportion of DOM fluorescent components were estimated. Results show that:① Ca2+ and HCO3- are the main cations and anions in the Wulixia reservoir during winter. The water is mainly controlled by the carbonate balance system and dissolved organic carbon (DOC) accounted for about 91% of total organic carbon (TOC). ③ DOM from the Wulixia reservoir can be divided into three components:fulvic acid, humic acid, and tryptophan. ③ The parameters, fluorescence index, humification index, biological index, and freshness index show the existence of DOM in the Wulixia reservoir. Microorganisms have a significant effect on DOM composition.