基于平行因子分析的河流溶解性有机质污染识别与响应

Identification and response to pollution of dissolved organic matter in rivers based on parallel factor analysis

研究Y江流域水体溶解性有机质(DOM)组分及来源对了解Y江水生生态系统至关重要.本研究采用平行因子分析法,通过拉曼及瑞利散射校正和组分提取等对三维荧光光谱矩阵进行处理,并结合常规水质参数,对水体中DOM的三维荧光光谱特征、组分比例、特征参数及荧光特性等进行相关性分析,探究Y江流域水体DOM的组分、来源及空间分布特性.结果表明,Y江干流主要河流断面的COD约有85%的采样点符合Ⅰ类地表水标准,TN约有58%的采样点超过Ⅳ类地表水标准,TP约有85%的采样点符合Ⅲ类地表水标准,NH_(3)-N约有77%的采样点符合Ⅱ类地表水标准.TN和TP为Y江干流的主要污染物,且在下游区域呈升高的趋势,水体存在富营养化的可能.通过PARAFAC分析得出Y江DOM的三组分荧光光谱模型,其中,C1主要由富里酸和腐殖酸类组成,占比56.4%;C2为类陆生腐殖质,占比13.4%;C3为色氨酸类蛋白质组分,占比30.2%.Y江干流地表水DOM具有轻微的腐殖化程度,同时具有明显的自生源特性.外源输入和内源释放是导致该区域地表水水质变化的重要因素.DOM的来源和组成在空间分布上具有显著差异.在上游区域,植被分解和土壤有机质分解等自然过程是该区域DOM形成的主要途径.在中游和下游区域,DOM受到人类活动的影响较大,特别是在下游区域,C3组分含量占DOM的比例较高,这可能是由于城市和工业企业排污等人类活动对DOM的组成造成影响.皮尔逊相关性分析显示,DOM中的组分C1和C3与TN、NH_(3)-N、UV_(254)呈显著正相关(p<0.01),C1组分平均含量最高(56.4%),因此,C1组分可用于该流域水体含氮类物质的动态追踪,从而对Y江富营养变化进行快速、有效的推演.本研究揭示了Y江流域水体DOM的荧光特征和组分来源响应机制,为该流域水质污染识别与监控提供了良好的科学依据.

It is imperative to investigate the composition and source of dissolved organic matter (DOM) in small watersheds to gain a deeper understanding of the aquatic ecosystem of the Y River.In this study,parallel factor analysis was utilized to process the three-dimensional fluorescence spectral matrix,incorporating Raman and Rayleigh scattering correction,component extraction,and integration with traditional water quality parameters.Through correlation analysis of the three-dimensional fluorescence spectral characteristics,component proportions,characteristic parameters,and fluorescence properties of DOM in water bodies,the study explores the components,sources,and spatial distribution characteristics of DOM in the Y River basin.The results indicate that approximately 85%of the sampling points in the main section of the Y River′s mainstream meet Class I surface water standards for COD,about 58%of the sampling points exceed Class IV surface water standards for TN,approximately 85%of the sampling points meet Class III surface water standards for TP,and about 77%of the sampling points meet Class II surface water standards for NH_(3)-N.TN and TP emerge as the primary pollutants in the Y River′s mainstream,demonstrating an increasing trend in the downstream area,hinting at the potential for water eutrophication.Moreover,PARAFAC analysis uncovers three components of the fluorescence spectra of DOM in the Y River:C1mainly comprises fulvic acid and humic acid,accounting for 56.4%,C2 is made up of terrestrial humic substances,accounting for 13.4%,and C3 is composed of tryptophan-like protein components,accounting for 30.2%.The surface water DOM of the Y River displays a mild degree of humification and significant autochthonous characteristics.Both exogenous input and endogenous release are crucial factors contributing to the alterations in water quality in this area.The sources and compositions of DOM exhibit significant spatial differences.In the upstream area,natural processes such as vegetation decomposition and soil organic matter decomposition are the main pathways for DOM formation.Conversely,in the middle and downstream areas,DOM is significantly influenced by human activities.Particularly in the downstream area,the proportion of C3 components in DOM is higher,possibly due to the impact of human activities,such as wastewater discharge from urban and industrial enterprises,on the composition of DOM.Moreover,Pearson correlation analysis shows that components C1 and C3 in DOM are significantly positively correlated with TN,NH_(3)-N,and UV_(254)(p<0.01).Notably,with an average content of 56.4%,C1 components can be used to dynamically track nitrogen-containing substances in the watershed,thereby quickly and effectively deducing eutrophication changes in the Y River.This study offers a comprehensive understanding of the fluorescence characteristics and source response mechanisms of DOM in the Y River watershed,providing a sound scientific basis for the identification and monitoring of water quality pollution in this watershed using Parallel factor analysis.