摘要
选取徒骇河聊城河段的2个典型市控断面——李凤桃与老南镇断面进行表层水样采集,利用紫外可见吸收光谱和三维荧光光谱等多种光谱分析手段,并结合超滤技术及荧光淬灭实验,探究不同季节和不同分子量(<0.7μm、0.7μm~1kDa、<1k Da)DOM的特征差异及其与重金属(Cu^(2+))相互作用的机制.结果表明,李凤桃SUVA254值(0.33±0.01)显著高于老南镇(0.30±0.01)(P<0.05),表明老南镇分布着更多的小分子和非芳香性物质.研究基于EEM-PARAFAC共识别出了5个组分,包括3个类腐殖质组分(C1、C2、C4)和2个类蛋白质组分(C3、C5),其中类腐殖质组分在两断面的DOM中占主导地位.老南镇DOM总荧光强度(F_(max))高于李凤桃,且两断面溶解性有机碳(DOC)主要储存在低分子量DOM(<1kDa)中.在DOM与Cu^(2+)的结合过程中,二维相关光谱(2D-COS)表明老南镇和李凤桃断面DOM类腐殖质优先与Cu^(2+)络合;分馏后,两断面DOM的结合序列发生了变化(类蛋白质优先与Cu^(2+)发生络合).此外,在两断面DOM中,高分子量组分(除C1和C4外)具有较高的金属结合能力(log KCu:(3.08±0.08)~(3.62±0.02)).
Surface water samples were collected from two municipally monitored sections of the Tuhai River in Liaocheng—Li Fengtao and Lao Nanzhen—and analyzed using a combination of spectroscopic techniques,including ultraviolet-visible(UV-Vis)absorption and three-dimensional excitation-emission matrix(EEM)fluorescence spectroscopy,supplemented by ultrafiltration fractionation and fluorescence-quenching experiments to comprehensively characterize dissolved organic matter(DOM).The study investigated seasonal variations in DOM composition across three molecular weight fractions(<0.7μm,0.7μm~1kDa,and<1kDa)and explored the underlying mechanisms of DOM-Cu^(2+)complexation.The specific ultraviolet absorbance at 254nm(SUVA254)was significantly higher at Li Fengtao(0.33±0.01)than at Lao Nanzhen(0.30±0.01)(P<0.05),suggesting a higher proportion of smaller,non-aromatic molecules at the latter site.Parallel factor analysis(PARAFAC)of EEM data identified five fluorescent components,including three humic-like(C1,C2,C4)and two protein-like(C3,C5)substances,with humic-like constituents dominating at both locations.Total fluorescence intensity(Fmax)was higher at Lao Nanzhen,and dissolved organic carbon(DOC)was primarily concentrated in the<1kDa fraction at both sites.Two-dimensional correlation spectroscopy(2D-COS)analysis demonstrated that humic-like components preferentially bound to Cu^(2+)in the unfractionated DOM samples from both locations.However,after ultrafiltration fractionation,the binding sequence shifted,with protein-like components becoming the dominant Cu^(2+)-binding constituents.Furthermore,high-molecular-weight fractions(excluding C1and C4)from both sites exhibited relatively strong metal-binding capacities,as evidenced by their conditional stability constants(logKCu:(3.08±0.08)to(3.62±0.02)).
作者
王珊珊
桑冬玲
刘强
姚昕
孙赵利
张家政
张晨
李婷婷
WANG Shan-shan;SANG Dong-ling;LIU Qiang;YAO Xin;SUN Zhao-li;ZHANG Jia-zheng;ZHANG Chen;LI Ting-ting(School of Geography and Environment,Liaocheng University,Liaocheng 252059,China;Shandong Liaocheng Ecological and Environmental Monitoring Center,Liaocheng 252000,China)
出处
《中国环境科学》
北大核心
2025年第8期4398-4409,共12页
China Environmental Science
基金
山东省自然科学基金资助项目(ZR2024MD114,ZR2020QE234)
国家自然科学基金资助项目(41977322)。
关键词
DOM
分子量
铜
荧光淬灭
金属结合能力
DOM
molecular weight
Cu2+
fluorescence quenching
metal-binding ability
