College of Resources and Environment, Chengdu University of Information Technology, Chengdu 610225, China.
Key Laboratory of Urban Stormwater System and Water Environment, Ministry of Education, Beijing University of Civil Engineering and Architecture, Beijing 100044, China.
Ecotoxicol Environ Saf. 2021 May;214:112064. doi: 10.1016/j.ecoenv.2021.112064. Epub 2021 Mar 7.
Hydrophyte decomposition caused large amounts of dissolved organic matter (DOM) to enter aquatic environment that influence the migration and transformation of heavy metals (HMs). Six hydrophytes with five dry weight gradients (DWG) were used for the decomposition experiments. The results showed that protein-like materials occupy relatively high content in the hydrophyte-derived DOM. The binding properties of DOM-Cu(II) have been explored by using two-dimensional correlation spectroscopy (2D-COS) in conjunction with synchronous fluorescence spectroscopy (SFS) and log-transformed SFS. The weak signals of binding site can be amplified by the log-transformed 2D-COS analysis. Herein, more binding sites can be identified by the log-transformed 2D-COS analysis. The results reveal that tryptophan-like materials show a preferential sequence of binding Cu(II) in the hydrophyte-derived DOM with a relatively low DWG and sediment DOM, and fulvic-like substances indicate a preferential sequence of binding Cu(II) in the hydrophyte-derived DOM with a relatively high DWG. Meanwhile, the results of binding parameters indicate that the log K is the range of 3.61-4.25, 4.33-4.74, 4.59-4.97, 3.91-4.41, and 4.14-4.78 for D1-D5, respectively, suggesting that hydrophyte decomposition can change the binding affinity between DOM components and Cu(II). The complexes of fluorescent components with Cu(II) showed a high log K value at long wavelength (e.g. humic-like substances), and a relatively low fluorescent ligand proportion (f%) at shorter wavelength in the hydrophyte-derived DOM. However, the log K is the range of 3.08-4.31, 4.09-4.45, 3.93-4.35, 4.39-4.75, and 3.95-4.36 for C1-C5, separately. Protein-like substances with Cu(II) showed a relatively high log K value with the exception of C4. The log-transformed 2D-COS can be an analytical tool to understand the binding heterogeneity of DOM with HMs. The study can provide a guide for managing and controlling the effects of hydrophyte decomposition.
水生植物分解会导致大量溶解有机物 (DOM) 进入水生环境，从而影响重金属 (HM) 的迁移和转化。使用 6 种具有五个干重梯度 (DWG) 的水生植物进行分解实验。结果表明，蛋白质类物质在水生植物衍生 DOM 中占有相对较高的含量。通过二维相关光谱 (2D-COS) 结合同步荧光光谱 (SFS) 和对数变换 SFS 研究了 DOM-Cu(II) 的结合特性。对数变换 2D-COS 分析可以放大结合位点的弱信号。在这里，对数变换 2D-COS 分析可以识别更多的结合位点。结果表明，在低 DWG 水生植物衍生 DOM 和沉积物 DOM 中，色氨酸类物质优先与 Cu(II)结合，富里酸类物质优先与 Cu(II)结合在相对较高 DWG 的水生植物衍生 DOM 中。同时，结合参数的结果表明，log K 的范围分别为 3.61-4.25、4.33-4.74、4.59-4.97、3.91-4.41 和 4.14-4.78，用于 D1-D5，表明水生植物分解可以改变 DOM 成分与 Cu(II)之间的结合亲和力。在水生植物衍生 DOM 中，与 Cu(II)形成复合物的荧光成分具有较高的 log K 值（例如腐殖质类物质），而在较短波长处的相对荧光配体比例（f%）较低。然而，log K 的范围分别为 3.08-4.31、4.09-4.45、3.93-4.35、4.39-4.75 和 3.95-4.36，用于 C1-C5。与 Cu(II)形成复合物的蛋白质类物质除 C4 外均具有较高的 log K 值。对数变换 2D-COS 可以作为一种分析工具，用于理解 DOM 与 HM 的结合异质性。该研究可为管理和控制水生植物分解的影响提供指导。
