匹里青河夏季有色溶解性有机质(CDOM)分布特征及来源分析

Distribution characteristics and source analysis of chromophoric dissolved organic matter(CDOM) in Piliqing River in summer

对河流有色溶解性有机质(CDOM)光学特性、组成及来源进行研究,有利于更好地了河流水体生态环境,为进一步揭示有色溶解性有机质在河流水体的环境影响特性提供参考.以具有典型西北干旱区流域特征的皮里青河作为研究区域,通过匹里青河河段不同土地利用背景下的33个表层水样的实测数据,对有色溶解性有机质吸收特性、荧光组分、水质参数及它们之间的相关性进行分析,进而对匹里青河CDOM的分布特征、组成特性及来源情况进行研究.结果表明,荒山区及自然植被区只存在类腐殖酸荧光峰,农田密集区及城镇集中区除存在典型的类腐殖峰外,还存在明显的类蛋白荧光峰.平行因子方法解析出类腐殖质组分C1和类色氨酸组分C2两种组分,且三维荧光特征参数揭示出CDOM来源为内外源共同作用,此外,研究表明CDOM组分与总磷、总氮、凯氏氮呈极显著相关性,说明水体中CDOM组分与N、P元素的迁移转化密切相关,主成分分析表明荧光组分与水质来源相同,且CDOM来源受陆源输入更显著.

The research on the optical properties,composition and source of colored dissolved organic matter(CDOM)were straightforwardly beneficial to understand ecological environment of rivers,which provided a reference for further revealing the environmental impact characteristics of CDOM.The study area was the Piliqing River,occupying the watershed characteristics of typical arid area in Northwest of China.The measured data of 33 surface water samples under different land usage backgrounds in the Piliqing River section was used to analyze the absorption characteristics,fluorescent components,water quality parameters and correlations of the CODM.Later,the distribution characteristics,composition characteristics and sources of the CDOM of the Piliqing River were studied.The results showed that only humic acid-like fluorescence peaks existed in barren mountain areas and natural vegetation areas.There were not only typical humus-like peaks,but also obvious protein-like fluorescence peaks in farmland-intensive areas and urban-intensive areas.Two components were separated by parallel factor method,such as humus-like component C1 and tryptophan-like component C2.Moreover,the three-dimensional fluorescence characteristic parameters revealed that CDOM originated from both endogenous and exogenous sources.In addition,CDOM components were highly correlated with TP,TN and TKN,which indicated that the constitution of CDOM was closely related to the migration and transformation of N and P elements in waters.And the principal component analysis showed that the fluorescent component was the same as that of water source,and the CDOM source was more significantly affected by terrestrial landing.