Characteristics of dissolved organic nitrogen (DON) and relationship with water quanlity in the overlying water of Erhai lake
LI Wen-zhang1,2,3,4, ZHANG Li2,3,4, WANG Sheng-rui1,2,3,4, XIAO Shang-bin1, LI Yan-ping2,3, QIAN Wei-bin2,3,5, LI Qiu-cai2,3,5, XI Yin1,2,3
1. China Three Gorges University, College of Hydraulic & Environmental Engineering, Yichang 443002, China;
2. State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;
3. State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;
4. Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Dali 671000, China;
5. Guilin University of Technology, College of Environmental Science and Engineering, Guilin 541004, China
This study investigated the content and spatial distribution of dissolved organic nitrogen (DON) in the overlying water of Erhai Lake. 3D fluorescence and UV-vis absorbance techniques were utilized to analyse its structure composition characteristics. The relationship between DON characteristics and water quality was also discussed in detail. DON contents in the overlying water ranged from 0.08 to 0.33mg/L (average value of 0.18), with the temporal distribution of the spring > summer > autumn > winter, in the year of 2014. The spatial and vertical DON distributions followed the pattern of southern > northern > middle and middle layer > surface layer > bottom layer, respectively. Besides, DON humification degree in the overlying water of Erhai lake was high, with DON being mainly composed of aliphatic chain instead of carbonyl, carboxyl, hydroxyl substituents and ester content. The BIX and FI values ranged from 0.84 to 1.19(mean value of 0.94) and 1.58 to 1.66 (mean value of 1.63), respectively, indicating that DON in the overlying water of Erhai lake was affected by terrigenous input and biological endogenous metabolism. Additionally, the study exhibited that the humic acid-like substances, which accounted for 61.82% averagely, were the main DON component. The fluorescent components at 0~2m presented the maximum Migration quantity, with the protein-like components (P(I+II,n)) always below 20%. Moreover, DON had a significant positive correlation with DTN in the overlying water of Erhai Lake (R=0.949, P < 0.949), and P(I+II,n)/P(III+V,n) values exhibited a significant positive correlation with TN, DTN and SRP (R=0.467~0.552, P < 0.05). This suggested that the DON content could indirectly reflect Erhai lake water quality to a certain extent. Especially the protein-like substances positively contributed a lot to the maintenance of good water quality, namely the higher the protein-like substance content was, the higher the nitrogen and phosphorus content would be in the overlying water of Lake Erhai.
李文章, 张莉, 王圣瑞, 肖尚斌, 李艳平, 钱伟斌, 李秋材, 席银. 洱海上覆水溶解性有机氮特征及其与湖泊水质关系[J]. 中国环境科学, 2016, 36(6): 1867-1876.
LI Wen-zhang, ZHANG Li, WANG Sheng-rui, XIAO Shang-bin, LI Yan-ping, QIAN Wei-bin, LI Qiu-cai, XI Yin. Characteristics of dissolved organic nitrogen (DON) and relationship with water quanlity in the overlying water of Erhai lake. CHINA ENVIRONMENTAL SCIENCECE, 2016, 36(6): 1867-1876.
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