Spectral characteristics and sources of rainstorms dissolved organic matter in Zhoucun Reservoir during flood season

Abstract

运用三维荧光光谱（EEMs）技术结合平行因子分析法（PARAFAC），对周村水库夏季两场暴雨不同降雨历时以及分子量的溶解有机物光谱特征和来源进行分析.结果表明：周村水库不同暴雨荧光光谱中出现了5种组分，分别为类腐殖质（C1、C2）、可见区富里酸（C3）和类蛋白（C4、C5）；相关性分析显示C1与C2、C3、C4以及C5具有显著的相关性，C2与C3具有显著的相关性，C3与C4以及C5具有显著的相关性；同一分子量下的雨水有机质总荧光强度以及各组分荧光强度随着降雨历时的增加均呈下降趋势，并且在各个历时和分子量间差异明显；同一降雨历时下，第一场暴雨总荧光强度随着分子量的减少而增加，第二场暴雨总荧光强度随着分子量的减少而减少；两场暴雨都呈现自生源的特征，其中第一场暴雨具有以陆源输入为主的特征；组分C1和C3与水质参数硝态氮、氨氮、总氮以及有机碳呈显著相关性.通过对暴雨在不同降雨历时以及分子量DOM光谱特征研究，可以进一步分析水库外源输入的天然有机质特征，为水库水质管理提供技术支持.;Based on the three dimensional fluorescence spectra (EEMs) technology combined with the parallel factor analysis (PARAFAC), the spectral characteristics and sources analysis of dissolved organic matter of two rainstorms were investigated for different rainfall duration and molecular weight organic carbon in Zhoucun Reservoir. Two humic-like substances (C1, C2), one fulvic-like substance (C3) and two protein-like substance (C4, C5) were identified by PARAFAC model, and there exhibited significantly correlation coefficient in C1 & C2/C3/C4/C5, C2 & C3 and C3 & C4/C5, respectively. For the same molecular weight organic carbon, total dissolved organic matter (DOM) fluorescence intensity and the fluorescence intensity of each component showed a decreasing trend with the increase of rainfall duration and exhibited significantly differences distribution in two rainstorms. For the same rainfall duration, the total fluorescence intensity of the first rainstorm increased with the decrease of molecular weight organic carbon, while the total fluorescence intensity of the second rainstorm decreased with the decrease of molecular weight. The two rainstorms water both exhibited strong autochthonous component characteristics and first rainstorm exhibited strong terrestrial input characteristic; C1 and C3 exhibited significantly correlation coefficient with nitrate, ammonia, total nitrogen and organic carbon. From all the results, the study could supply a strong support for the managers of Zhoucun Reservoir to explore the DOM characteristic of rainstorm in the future.