Liu Dongping, Gao Hongjie, Yu Huibin, Song Yonghui
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; College of Water Sciences, Beijing Normal University, Beijing 100875, PR China.
State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
Water Res. 2022 Dec 1;227:119317. doi: 10.1016/j.watres.2022.119317. Epub 2022 Nov 7.
Dissolved organic matter (DOM) in aquatic environment distinctly affects the behavior and fate of heavy metals via complexation, while the interfacial mechanisms and processes are still lacking in detail. Here, Cu (II) binding characteristics of DOM originated from hilly (NDOM), rural (RDOM) and urban (UDOM) regions in an urbanized river was explored by fluorescence excitation-emission matrix spectroscopy (EEM) combined with principal component coefficients, parallel factor analyses (PARAFAC), moving-window two-dimensional correlation spectroscopy (MW2DCOS) and structural equation modeling (SEM). Eight components were extracted from the titrants through EEM-PARAFAC, i.e., phenol-like substance (C1), tyrosine-like substance (C2), visible tryptophan-like substance (C3), ultraviolet tryptophan-like substance (C4), recent biological production (C5), wastewater-derived organic matter (C6), microbial humic-like substance (C7) and fulvic-like substance (C8). Interestingly, NDOM only contained C1, C3, C5 and C8, while nearly all components were found in RDOM (except for C2) and UDOM (except for C4). The f value of C1 (1.239) in NDOM was much higher than those in RDOM (0.134) and UDOM (0.115), so was of C8. It indicated that phenol-like and fulvic-like derived from autochthonous sources exhibited great binding ratios in the complexation with Cu (II). Moreover, C3 and C5 from UDOM exhibited higher f values (0.591 and 1.983) than those from NDOM and RDOM, suggesting that Cu (II) has a great binding capacity on protein-like from domestic and industrial wastewater. The MW2DCOS revealed that phenol-like and protein-like in NDOM and RDOM were essential for the binding of 160 μmol L Cu (II), whereas fulvic-like in NDOM and UDOM could react significantly with 10 μmol L Cu (II). Based on SEM, Cu (II) concentration had a negative direct effect on the fluorescence intensity of C7 or C8, whereas it showed an indirect positive effect on C7 or C8 through influencing C5, so was C6. It suggested that Cu (II) showed an indirect positive effect on the C8. This study might present a further comprehend of the environmental behaviors of Cu (II) in rivers.
水生环境中的溶解有机物（DOM）通过络合作用显著影响重金属的行为和归宿，而界面机制和过程仍缺乏详细研究。在此，采用荧光激发-发射矩阵光谱（EEM）结合主成分系数、平行因子分析（PARAFAC）、移动窗口二维相关光谱（MW2DCOS）和结构方程模型（SEM），研究了城市化河流中源自丘陵地区（NDOM）、农村地区（RDOM）和城市地区（UDOM）的DOM与铜（II）的结合特性。通过EEM-PARAFAC从滴定剂中提取出8种成分，即酚类物质（C1）、酪氨酸类物质（C2）、可见类色氨酸物质（C3）、紫外类色氨酸物质（C4）、近期生物产物（C5）、废水衍生有机物（C6）、微生物腐殖质类物质（C7）和富里酸类物质（C8）。有趣的是，NDOM仅含有C1、C3、C5和C8，而RDOM（除C2外）和UDOM（除C4外）几乎包含所有成分。NDOM中C1的f值（1.239）远高于RDOM（0.134）和UDOM（0.115），C8也是如此。这表明源自本地源的酚类和富里酸类物质在与铜（II）的络合中表现出很高的结合比例。此外，UDOM中的C3和C5的f值（0.591和1.983）高于NDOM和RDOM，表明铜（II）对生活和工业废水中的类蛋白质具有很强的结合能力。MW2DCOS表明，NDOM和RDOM中的酚类和类蛋白质对160 μmol·L铜（II）的结合至关重要，而NDOM和UDOM中的富里酸类物质能与10 μmol·L铜（II）发生显著反应。基于SEM，铜（II）浓度对C7或C8的荧光强度有负向直接影响，而通过影响C5对C7或C8有间接正向影响，C6也是如此。这表明铜（II）对C8有间接正向影响。本研究可能有助于进一步理解河流中铜（II）的环境行为。
