引黄水源水库平--丰水期有色可溶性有机物(CDOM)的来源、组成及差异分析

Variation analysis of source and composition of CDOM in a source water reservoir of Yellow River diversion project during normal and wet seasons

为探究引黄水源水库——门楼水库平水期和丰水期有色可溶性有机物(CDOM)的组成特征、来源及差异,运用紫外可见光谱技术(UV-vis)和三维荧光光谱(EEMs)技术,结合平行因子分析法(PARAFAC)分析2022年5月(平水期)和2022年7月(丰水期)有色可溶性有机物含量及组分变化。研究结果表明:PARAFAC识别出2类荧光组分,分别是C1(Ex=355 nm,Em=476 nm,类腐殖质组分)和组分C2(Ex=225 nm,Em=320 nm,类蛋白组分);丰水期CDOM组分荧光强度显著高于平水期。CDOM光谱参数表明,门楼水库水体处于中营养状态,水体CDOM受新生内源和外源输入共同影响,以自生源为主;水库CDOM具有相对分子量小、腐殖化程度较弱的特点。丰水期水库富营养化水平和CDOM相对浓度低于平水期;丰水期CDOM疏水性组分比例和芳香化程度高于平水期。水质理化指标、CDOM组分和光谱参数相关性分析结果表明SUVA_(260)和SUVA_(280)与DOC呈显著负相关,说明紫外可见光谱参数在一定程度上可以用来估算DOC的浓度;Chl.a浓度作为表征浮游植物生物量的指标,与DOC、a_(254)呈显著正相关。研究揭示了门楼水库水体CDOM的荧光特征、组分来源响应机制和水期差异,为进一步探究CDOM在引黄水源水库的环境行为特性、对水体富营养化的贡献以及对其它污染物环境行为的影响等提供基础资料。

In order to investigate the characteristics,sources and variations in the composition of chromophoric dissolved organic matter(CDOM)during the normal and rainy seasons in the reservoir of the Yellow River Diversion Source Reservoir-Menlou Reservoir,UV-vis and EEMs techniques combined with PARAFAC were used to analyse the changes in CDOM content and components in May 2022(normal season)and July 2022(rainy season).The results of the study showed that PARAFAC identified 2 types of fluorescent fractions,C1(Ex=355 nm,Em=476 nm,humus-like fraction)and C2(Ex=225 nm,Em=320 nm,protein-like fraction).The fluorescence intensity of the CDOM fraction was significantly higher in wet seasons than in normal seasons.The spectral parameters of CDOM indicated that the water body of Menlou Reservoir was in a mesotrophic state,and the CDOM of the water body was mainly autogenous due to the combined effects of endogenous and exogenous inputs.The reservoir CDOM was characterized by low relative molecular weight and low humification.The levels of eutrophication and the relative concentrations of CDOM in the reservoir were lower in the wet season than in the normal season,and the proportion of hydrophobic components and the degree of aromatization of CDOM were higher than in the normal season.Correlation analysis of water physical and chemical indicators,CDOM components and spectral parameters showed that SUVA_(260) and SUVA_(280) were significantly negatively correlated with DOC,indicating that UV-Vis spectral parameters could be used to estimate the concentration of DOC to some extent;Chl.a concentration,as an indicator characterizing phytoplankton biomass,was significantly and positively correlated with DOC,a_(254).The study revealed the fluorescence characteristics,component source response mechanism and water period variation of CDOM in the water body of Menlou Reservoir,providing basic data for further investigation of the environmental behavior characteristics of CDOM in the Yellow River Diversion Water Source Reservoir,its contribution to water eutrophication and its influence on the environmental behavior of other pollutants.