| Summary: | 碩士 === 國立屏東科技大學 === 環境工程與科學系所 === 101 === In the recent years, dissolved organic matter (DOM) has been getting more and more attention, as it plays a key role in biogeochemical cycles. Hydrophobic organic compound (HOC) sorption on DOM affects the distribution, transportation, and biological toxicity of HOCs in the environment. In this study, the water sample’s DOM was measured with a UV/Vis spectrometer and fluorescence spectrometer to examine the properties of the DOM. The result shows that the humification degree of the DOM decreased at an air-exposure treatment unit but increased after vegetation treatment in a unit in the WanDan wetland. The hydraulic retention time (HRT) played an important role in changing the properties of the DOM at a longer HRT and a higher humification degree.
In the LungLuanTan wetland, the humification degree of the DOM samples was not significantly different at individual sampling sites. However, the degree of humification in the surface water samples was higher than the sample taken from a 0.6 m depth.
The DOMs were separated into high, middle, and low molecular weight solutions. The middle-weight solutions had a higher degree of humification than the other two WanDan wetland samples. The DOMs were also separated with a chemical method into a hydrophilic fraction (HPI), a hydrophobic acid (HPO), and a Transphilic Acid (TPI-A). The HPO solutions had the highest degree of humification in the two wetlands.
The wavelength of humic acid-like and fulvic acid-like material increased at long HRT in the DOM fluorescent peaks. This is called a red shift and indicates that a high HRT promoted a high degree of humification in the DOM samples. The correlation analysis showed that indices A250 and humification index (HIX) had significant positive correlation in the WanDan wetland DOM samples. The indices of A250 and SUVA254 had significant positive correlation in the LungLuanTan wetland. The indices of A250 and SUVA254 are directly proportional to the degree of humification
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