Releasing Characteristics of Sediment Dissolved Organic Nitrogen (DON) from Erhai Lake and its environmental impact mechanism
SHI Ling-long1,2,3,4, ZHANG Li2,3,4, WANG Sheng-rui2,3,4, DUAN Chang-qun1, LI Wen-zhang2,3, XI Yin2,3, LI Qiu-cai2,3, Xu Ke-chen2,3
1. College of Ecology and Environmental Sciences, Yunnan University, Kunming 650091, 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, Yunnan Kunming 650504, China
The release characteristics of DON in the surface sediments of Erhai Lake were studied by simulation experiment combined with UV-Vis absorbance and fluorescence spectroscopy.Moreover,the environmental influence factors and environment implication of sediment DON were also discussed.The obtained results indicated that:(1) The release kinetics of DON in the surface sediment could be well simulated by first-order kinetics equation.The maximal DON release amount from each area followed the pattern:northern > southern > middle,ranging from 24.387 to 46.949mg/kg.Moreover,the first (maximum within 10min) and the largest releasing components were the protein-like component P(I+Ⅱ,n) and humic-like component P(Ⅲ+V,n)(accounting for approximately 76%) respectively.(2) The DON release amount in sediments of Erhai Lake is relatively small under the overlying water conditions of aerobic (DO=8~10mg/L) and moderate pH (pH=8),and the obvious increase/decrease of pH/DO was considered to promote its releasing amount.(3) The compositional parameters of DON in Erhai sediments was positively correlated with its releasing amount (r=0.813~0.919,P<0.01).The more the substituent DON was contained in the sediment,the greater the molecular weight and aromaticity degree were,and the greater its release amount was.Moreover,the content ratio of protein-like to humic-like substances P(I+Ⅱ,n)/P(Ⅲ+V,n) can also be taken as the indirect indicator of the release amount of sediment DON.The compositional characteristic of sediment DON can reflect its releasing characteristics,that is,the DON release risk of from Erhai sediments can be reflected to some extent.
史玲珑, 张莉, 王圣瑞, 段昌群, 李文章, 席银, 李秋才, 许可宸. 洱海沉积物溶解性有机氮释放及环境影响机制[J]. 中国环境科学, 2017, 37(7): 2715-2722.
SHI Ling-long, ZHANG Li, WANG Sheng-rui, DUAN Chang-qun, LI Wen-zhang, XI Yin, LI Qiu-cai, Xu Ke-chen. Releasing Characteristics of Sediment Dissolved Organic Nitrogen (DON) from Erhai Lake and its environmental impact mechanism. CHINA ENVIRONMENTAL SCIENCECE, 2017, 37(7): 2715-2722.
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