呼伦湖水体溶解性有机物荧光特征及来源分析

呼伦湖是我国北方生态安全屏障的重要组成部分，为探究呼伦湖水体中有机物的组成及来源，利用三维荧光光谱（EEMs）结合平行因子（PARAFAC）分析技术进行溶解性有机物（DOM）荧光特征及来源研究。结果表明：呼伦湖DOM中含有3种荧光组分，分别为类色氨酸（C1）、类腐殖酸（C2）和类富里酸（C3）；平水期、丰水期和枯水期的C2和C3荧光强度占比约70%，表明呼伦湖水体DOM以腐殖质类物质为主，其中不同水期生态补水工程入湖口的C2和C3荧光强度均高于其他区域；平水期、丰水期和枯水期的荧光指数、生物指数和腐殖化指数平均值分别为1.50~1.54、0.85~1.00和4.12~4.68，表明呼伦湖DOM由陆源和自生源混合组成，具有明显的自生源特征；水质监测数据表明，2021年呼伦湖平水期、丰水期和枯水期水质均为GB 3838—2002《地表水环境质量标准》劣Ⅴ类，其中平水期和丰水期的BOD₅平均值高于枯水期，而平水期总有机碳平均浓度高于丰水期和枯水期；不同水期C2和C3的荧光强度均呈显著正相关，表明DOM中组分C2和C3的产生及来源具有一致性。

Fluorescence characteristics and sources of dissolved organic matter in Hulun Lake

Hulun Lake is an important component part of the northern ecological security barrier in China. To study the components and sources of organic matter in Hulun Lake, the three-dimensional excitation-emission matrix spectra (EEMs) and parallel factor (PARAFAC) analysis techniques were used to analyze the fluorescence characteristics of dissolved organic matter (DOM) and its sources. The results showed that three fluorescent components were obtained in DOM using EEM-PARAFAC, namely tryptophan-like substances (C1), humic-like substances (C2) and fulvic-like substances (C3). The total proportion of C2 and C3 fluorescence intensity accounted for about 70%, showing that the humic-like substances were the main part of DOM in the water of Hulun Lake during the normal, wet and dry seasons. The fluorescence intensity of C2 and C3 in the inlet of the ecological supplement channel was higher than that in other regions in different seasons. The average value of the fluorescence index, the biological source index and the humification index of DOM in Hulun Lake were 1.50-1.54, 0.85-1.00 and 4.12-4.68, respectively, during the normal, wet and dry seasons, indicating that DOM of Hulun Lake came from land sources and autogenous sources with autogenous source characteristics. According to the monitoring data, the water quality of Hulun Lake exceeded Class Ⅴ of Environmental Quality Standards of Surface Water (GB 3838-2002) during the normal, wet and dry seasons in 2021. The average concentration of BOD5 in the normal and wet seasons was higher than that in the dry season in 2021. At the same time, the average concentration of the total organic matter in the normal season was higher than that in the wet and dry seasons. The results of the redundancy analysis showed that C2 was significantly and positively correlated with C3, indicating that the production and source of C2 were consistent with C3 in DOM.