• 关键词：沉积物  营养盐  荧光溶解性有机物  空间分布  污染来源

• 基金项目：国家水体污染控制与治理科技重大专项项目（No.2017ZX07102，2017ZX07102-002）

• 杨颖
• 中国科学院生态环境研究中心，水污染控制实验室，北京 100085

• 刘吉宝
• 中国科学院生态环境研究中心，水污染控制实验室，北京 100085

• 魏源送
• 中国科学院生态环境研究中心，水污染控制实验室，北京 100085;中国科学院生态环境研究中心，环境模拟与污染控制国家重点联合实验室，北京 100085;中国科学院大学，北京 100049

• 韩冬青
• 昌平区水务局，北京 102200

• 樊维杰
• 昌平区水务局，北京 102200

• 摘要：以北运河为研究对象，选择干流12个点采集沉积物柱芯，分析上覆水及沉积物中的营养盐空间分布特征，采用单因子污染指数及综合污染指数法对沉积物营养盐污染进行评价；基于沉积物间隙水的三维荧光光谱，采用区域积分法（FRI）对荧光溶解性有机物（FDOM）进行分析，结合3种荧光特征指数进行FDOM溯源分析.结果表明，北运河沉积物上覆水中的TN、TP浓度均值分别为（5.63±1.39） mg·L^-1和（0.71±0.25） mg·L^-1，为地表水劣Ⅴ类；上游沉积物中的营养盐含量较高，中下游显著降低，部分区域在0~5 cm深度上污染较重，大多数采样点无明显污染分层现象；营养盐污染评价结果表明，上游温榆河段表层沉积物为重度污染，中下游多为中度和轻度污染.将沉积物间隙水中的FDOM分为5个荧光组分，其占比排序依次为：Ⅱ色氨酸类蛋白质（33%）> Ⅰ酪氨酸类蛋白质（31%）> Ⅳ溶解性微生物代谢产物（16%）> Ⅲ富里酸类物质（13%）> Ⅴ腐殖酸类物质（7%）.FDOM以类蛋白质物质为主，来源于微生物代谢活动产生的新近自生源组分.通过相关性分析推测，沉积物中的TN可能来源于有机质中的有机氮组分，TP来源于陆源输入，与陆源输入的植物残体分解有关.

• Abstract：This study investigated the spatial distribution of nutrients in overlying water and sediments of the main stream in North Canal Basin according to 12 sampling points. The pollution level of nutrients was evaluated by using single factor contamination index and comprehensive pollution index methods. Furthermore， three-dimensional fluorescence spectroscopy was performed to characterize the fluorescently dissolved organic matter （FDOM） components in the interstitial water of sediment. The fluorescence regional integration （FRI） was used to quantitatively analyze the FDOM component in interstitial water， and the traceability analysis of FDOM was performed according to the calculation of three fluorescence indexes. Results showed that the average concentrations of TN and TP in the overlying water of North Canal Basin were （5.63±1.39） mg·L^-1 and （0.71±0.25） mg·L^-1， respectively， which were inferior to Grade V of surface water standard from China. The nutrient content in the sediments of upstream reaches was high， and decreased along with the middle and downstream reaches. In the depth direction， depth of 0~5 cm of few sediments were heavily polluted， and the sediments from most sampling points had no obvious stratification of pollution. The results of nutrient evaluation indicated that the surface sediments in the upper reaches （Wenyu River） were heavily polluted， and the sediments in midstream and the downstream reaches were moderately and lightly polluted. The FDOM in the interstitial water of sediment was divided into 5 fluorescent components， the order of their proportions was： tryptophan protein （zone Ⅱ， 33%）> tyrosine protein （zone I， 31%）> soluble microbial metabolites （zone Ⅳ， 16%）> Fulvic Acids （zone Ⅲ， 13%）> Humic Acids （zone Ⅴ， 7%）. Protein-like substances were the main component， which was from the newly autogenic components produced by microorganisms. Based on correlation analysis， it was speculated that the sources of TN and TP in the sediments were similar， TN was related to the organic nitrogen component in the organic matter and TP was from the terrestrial input related to the decomposition of plants.

• Key words：sediment  nutrients  fluorescent dissolved organic matter （FDOM）  spatial distribution  pollution source

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