派河及其支流溶解性有机质分子组成特征

Molecular Signatures of Dissolved Organic Matter in the Paihe River and Its Tributaries

溶解性有机质(DOM)是水生生态系统中的重要组成部分,派河作为“引江济淮”清水廊道工程江淮段的唯一输水通道,其DOM分子层面的组成信息和特性尚不明确.利用静电场轨道阱高分辨质谱技术对派河及其支流(光明大堰河)DOM分子进行表征,并且利用皮尔逊(Pearson)相关性分析和主成分分析(PCA)研究两条河流DOM的分子组成信息、特性和来源间的关系.结果表明,派河DOM的相对分子质量与含氧量相对较低;光明大堰河DOM分子的相对分子质量、芳香性和不饱和度相对较高.从元素组成和化合物组成看,两条河流主要以CHO类化合物和来源于陆地植物的木质素与单宁化合物为主,DOM分子均受到陆源DOM的强烈影响,派河DOM中还存在较高百分比CHOS类、蛋白质和脂质化合物.结合Pearson相关性分析和PCA分析结果,派河DOM还受到生活污水与污水处理厂尾水汇入、城市化进程加剧和微生物活动的影响.结果可为派河流域DOM时空组成变动研究提供详细资料,并为派河清水廊道工程提供技术支撑.

Dissolved organic matter(DOM)is an abundant and critical component of aquatic ecosystems,participating in many physicochemical and biogeochemical processes.The Paihe River is the only inflow river in the Jianghuai section of“Yangtze-Huaihe water diversion”clear water gallery project;however,its DOM molecular composition information and characteristics are still unclear.In this study,the molecular characterization of DOM in the Paihe River and Guangming Dayan River was determined using Orbitrap mass spectrometry.The Pearson’s correlation and principal component analysis(PCA)were used to study the relationship between molecular composition information,characteristics,and sources of DOM in two rivers.The results showed that the molecular weight and oxygen content of DOM molecules in the Paihe River were relatively low;the molecular weight,aromaticity,and unsaturation of DOM molecules in the Guangming Dayan River were relatively high.From the element composition and compound composition of the two rivers’DOM,both rivers were mainly composed of CHO-compounds,lignin,and tannins derived from land plants,which indicates that both rivers were severely affected by terrestrial input.There were high percentages of CHOS,protein,and lipid compounds of DOM in the Paihe River.According to the results of the Pearson’s correlation and PCA analyses,the DOM molecules of the Paihe River were also influenced by wastewater from sewage treatment plants,urbanization processes,and microbial activity.Molecular composition information and characteristics of DOM can provide a detailed reference to improve the theoretical support for the Paihe River clear water gallery project.