The Fluorescent Properties of Dissolved Organic Matter and Assessment of Total Nitrogen in Overlying Water with Different Dissolved Oxygen Conditions
ZHANG Hua1,2, WANG Kuan1,2, SONG Jian1,2*, ZHANG Yong1,2, HUANG Ming1,2, HUANG Jian1,2, ZHU Jing1,2, HUANG Shan1,2, WANG Meng1,2
1. School of Environment and Energy Engineering, Anhui Jianzhu University, Hefei 230601, China 2. Key Laboratory of Anhui Province of Water Pollution Control and Wastewater Reuse, Anhui Jianzhu University, Hefei 230601, China
Abstract：This paper used excitation-emission matrix spectroscopy (EEMs) to probe the fluorescence properties of dissolved organic matter (DOM) in the overlying water with different dissolved oxygen (DO) conditions, investigating the relationship between protein-like fluorescence intensity and total nitrogen concentration. The resulting fluorescence spectra revealed three protein-like components (high-excitation wavelength tyrosine, low-excitation wavelength tyrosine, low-excitation wavelength tryptophan) and two fulvic-like components (ultraviolet fulvic-like components, visible fulvic-like components) in the overlying water. Moreover, the protein-like components were dominant in the overlying water’s DOM. The fluorescence intensity of the protein-like components decreased significantly after aeration. Two of the protein-like components—the low-excitation wavelength tyrosine and the low-excitation wavelength tryptophan—were more susceptible to degradation by microorganisms within the degradable organic matter with respect to the high-excitation wavelength tyrosine. In contrast, the ultraviolet and visible fulvic-like fluorescence intensity increased along with increasing DO concentration, indicating that the fulvic-like components were part of the refractory organics. The fluorescence indices of the DOM in the overlying water were between 1.65~1.80, suggesting that the sources of the DOM were related to terrigenous sediments and microbial metabolic processes, with the primary source being the contribution from microbial metabolism. The fluorescence indices increased along with DO growth, which showed that microbial biomass and microbial activity gradually increased with increasing DO while microbial metabolism also improved, which also increased the biogenic components in the overlying water. The fluorescence intensity of the high-excitation wavelength tyrosine peak A showed a good linear relationship with the total nitrogen concentration at higher DO concentrations of 2.5, 3.5, and 5.5 mg·L-1, with r2 being 0.956, 0.946, and 0.953, respectively. This study demonstrated that excitation-emission matrix spectroscopy can distinguish the transformation characteristics of the DOM and identify the linear relationship between the fluorescence intensity of the high-excitation wavelength tyrosine peak A and total nitrogen concentration, thus providing a quick and effective technique and theoretical support for river water monitoring and water restoration.
张 华1,2，王 宽1,2，宋 箭1,2*，张 勇1,2，黄 明1,2，黄 健1,2，朱 菁1,2，黄 珊1,2，王 萌1,2 . 不同溶解氧水平上覆水中DOM荧光特性及总氮含量评估 [J]. 光谱学与光谱分析, 2016, 36(03): 890-895.
ZHANG Hua1,2, WANG Kuan1,2, SONG Jian1,2*, ZHANG Yong1,2, HUANG Ming1,2, HUANG Jian1,2, ZHU Jing1,2, HUANG Shan1,2, WANG Meng1,2. The Fluorescent Properties of Dissolved Organic Matter and Assessment of Total Nitrogen in Overlying Water with Different Dissolved Oxygen Conditions. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(03): 890-895.
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