北运河上覆水DOM组分含量特征及对水质的影响

基于三维荧光光谱，紫外-可见光谱技术，对比分析了汛期非汛期北运河通州区域上覆水中溶解性有机物（DOM）的组成、来源及结构特征，建立了上覆水中N和P的含量与DOM组成之间的关系，确定了反映潜在富营养化生态风险的指标.结果表明，北运河通州地区上覆水中DOM含量在9.17~27.78mg/L之间，总体呈现非汛期>汛期，上游>下游，DOM含量时空特征差异显著.汛期DOM分子量与非汛期相比较小，DOM芳香程度汛期低于非汛期；在上游和下游，汛期上覆水DOM A₂₅₃/A₂₀₃大于非汛期.汛期DOM受陆源腐殖质和生物源的共同影响，而非汛期主要受微生物活动的影响.汛期蛋白质类和腐殖质类物质的浓度水平显著低于非汛期，非汛期蛋白质类组分相对占比较多，而汛期腐殖质类组分相对占比较多.在汛期，上覆水DOM中C1、C3、C4组分的最大荧光强度可间接反映北运河富营养化的潜在风险.

Content characteristics of DOM components in overlying water of Beiyun River and its influence on water quality

Based on three-dimensional fluorescence spectroscopy and ultraviolet visible spectroscopy, the composition, source and structural characteristics of dissolved organic matter (DOM) in the overlying water of Tongzhou area of Beiyun River in flood and non-flood season were compared and analyzed, and the relationship between the content of N and P in the overlying water and the composition of DOM was established, The results indicated that the DOM content in the overlying water of Tongzhou area ranged from 9.17mg/L to 27.78mg/L, showing a general trend of non-flood season > flood season, upstream > downstream. The temporal and spatial characteristics of DOM content were significantly different. The molecular weight of DOM in flood season was smaller than that in non-flood season, and the aromatic degree of DOM in flood season was lower than that in non-flood season; the value of DOM A₂₅₃/A₂₀₃ in flood season was higher than that in non-flood season. DOM in flood season was affected by both land-based humus and biological sources, while that in non-flood season was mainly affected by microbial activities. The concentrations of protein and humus in flood season were significantly lower than those in non-flood season. Protein components accounted for more in non-flood season, while humus components accounted for more in flood season. The maximum fluorescence intensity of C1, C3 and C4 in DOM could indirectly reflect the potential risk of eutrophication in Beiyun River.