Investigating Influence of Hydrological Regime on Organic Matters Characteristic in a Korean Watershed

Sangsoo Baek,Kyung Cho,Junho Jeon,Jongkwan Park,Hyuk Lee

doi:10.3390/w11030512

Abstract

Source tracking of dissolved organic matter (DOM) is important to manage water quality in rivers. However, it is difficult to find the source of this DOM because various DOMs can be added from the river watershed. Moreover, the DOM composition can be changed due to environmental conditions. This study investigated the change of organic matter characteristics in the Taewha River of Ulsan City, Korea, before and after rainfall. A Soil and Water Assessment Tool (SWAT) was used to simulate water flow from various sources, and dissolved organic matter characterization was conducted in terms of molecular size distribution, hydrophobicity, fluorescence excitation and emission, and molecular composition. From the results, it was found that lateral flow transported hydrophobic and large-molecule organic matter after rainfall. According to the orbitrap mass spectrometer analysis, the major molecular compound of the DOM was lignin. Coupling the SWAT model with organic matter characterization was an effective approach to find sources of DOM in river.

Highlights

Dissolved organic matter (DOM) plays an important role in aquatic environments
The calibrated Soil and Water Assessment Tool (SWAT) model showed an acceptable performance during calibration and validation periods because the Nash-Sutcliffe Efficiency coefficient (NSE) values were greater than 0.5 for both periods
We could the dissolved organic matter (DOM) movement behavior in the river depending on surface runoff, lateral flow, and ground interpret the DOM movement behavior in the river depending on surface runoff, lateral flow, and water

Summary

Introduction

Dissolved organic matter (DOM) plays an important role in aquatic environments. It can be a nutrient source for microorganisms and a carrier for heavy metals and pollutants [1,2,3]. Terrestrial DOM, originating from plant litter and soil humus, contains mostly carbohydrates and lignin while autochthonous DOM, derived from algae and macrophyte, has a relatively high percentage of protein [8,9]. Characteristics of DOM cannot be classified into two groups (terrestrial and autochthonous) because DOM is affected by various environmental factors such as source material, microbial community, and temperature [10,11,12]

Results

Discussion

Conclusion