长江重庆段溶解性有机物的荧光特性分析

利用三维荧光光谱(EEMs),并结合平行因子分析(PARAFAC)及主成分分析(PCA),研究了长江重庆段溶解有机物(DOM)的荧光组分特征及其污染来源,并探讨了荧光强度同溶解性有机碳(DOC)及溶解氧(DO)的相关性.结果表明,PARAFAC模型识别出长江重庆段DOM由2类6个荧光组分组成,即类腐殖质荧光组分C1(350/422 nm)、C4(245,305/395 nm)、C5(260,340/420 nm)、C6(260/480 nm)及类蛋白荧光组分C2(275/300 nm)、C3(227,278/329 nm).在DOM来源组成中,陆源的类腐殖质含量占62.56%,类蛋白物质含量占31.31%.类腐殖质组分的荧光强度同DOC的含量存在明显的线性正相关(r=0.73),类蛋白组分的荧光强度同DO的含量呈明显的线性负相关(r=0.80).EEMs-PARAFAC不仅可以表征长江重庆段DOM的光谱特征,示踪长江重庆段的有机污染程度,还可以为三峡库区水体保护提供依据.

Fluorescence characteristics of dissolved organic matter in the Chongqing section of Yangtze River

Excitation-Emission Matrix spectroscopy(EEMs) combined with Parallel Factor Analysis(PARAFAC) and Principal Component Analysis(PCA) was applied to investigate the fluorescence characteristics and pollution source of dissolved organic matter(DOM) in the Chongqing section of Yangtze River.The results indicated that six fluorescence components were identified by PARAFAC,including four fulic-like components C1(350/422 nm);C4(245,305/395 nm);C5(260,340/420 nm);C6(260/480 nm),and two protein-like components C2(275/300 nm);C3(227,278/329 nm).The contribution rates to the total fluorescence intensity of fulic-like components and protein-like components were 62.56% and 31.31% respectively,suggesting terrestrial sources for DOM.The fluorescence intensity of fulic-like components showed positive linear correlation with the concentration of dissolved organic carbon(DOC).Meanwhile,significantly negative linear correlation was found between the fluorescence intensity of protein-like components and the concentration of dissolved oxygen(DO) in water.The application of EEMs-PARAFAC can not only reveal the DOM characteristic and monitor the variation degree of organic pollution in the Chongqing section of Yangtze River,but also provide evidence for water protection in the Three Gorges Reservoir.