Hu Bin, Wang Peifang, Wang Chao, Qian Jin, Hou Jun, Cui Xiaoai, Zhang Nannan
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, China.
Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, China.
Chemosphere. 2017 Dec;188:424-433. doi: 10.1016/j.chemosphere.2017.09.023. Epub 2017 Sep 7.
Excitation-emission matrix fluorescence spectroscopy combined with parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation spectroscopy (2D-COS) were applied to evaluate the effects of anthropogenic impoundment on the characteristics of dissolved organic matter (DOM) and its heavy metal binding affinity. Three field-sampling cruises conducted in Hongze Lake from 2015 to 2016 were classified as early impoundment and late impoundment cruises according to the hydrological conditions. Five fluorescence components were derived from EEM-PARAFAC, including three humic-like components (C1C3) and two protein-like components (C4 and C5). The results show a higher dissolved organic carbon concentration, humification degree, molecular size, and level of terrestrial humic-like substances (C1C3) for early impoundment DOM compared with late impoundment DOM, which were derived from the relatively high inflow discharges present before impoundment. Meanwhile, the relatively high autochthonous contribution and level of protein-like substances found in late impoundment DOM suggested that anthropogenic impoundment can influence the DOM composition in Hongze Lake. Increases in the binding affinities (log K) of humic-like substances (C1 and C3) and decreases in the log K of tryptophan-like substances (C4) were observed during the impoundment period. Additionally, 2D-COS results suggested that the preferential Cu(II) binding ligands in early and late impoundment DOM were tryptophan- (C4) and humic-like (C1) substances, respectively. These results indicated that impoundment-derived DOM composition alteration can decrease the bioavailability and toxicity of Cu in Hongze Lake. The results reported here will improve the understanding of DOM and heavy metal cycling in impoundment lakes.
采用激发-发射矩阵荧光光谱结合平行因子分析（EEM-PARAFAC）和二维相关光谱（2D-COS）来评估人为蓄水对溶解有机物（DOM）特性及其与重金属结合亲和力的影响。根据水文条件，将2015年至2016年在洪泽湖进行的三次野外采样航次分为蓄水早期和蓄水后期航次。通过EEM-PARAFAC得到了五个荧光组分，包括三个类腐殖质组分（C1-C3）和两个类蛋白质组分（C4和C5）。结果表明，与蓄水后期DOM相比，蓄水早期DOM的溶解有机碳浓度、腐殖化程度、分子大小和陆地类腐殖质物质（C1-C3）水平更高，这是由于蓄水前存在相对较高的入流排放。同时，蓄水后期DOM中较高的自生源贡献和类蛋白质物质水平表明，人为蓄水会影响洪泽湖的DOM组成。在蓄水期间，观察到类腐殖质物质（C1和C3）的结合亲和力（log K）增加，而类色氨酸物质（C4）的log K降低。此外，2D-COS结果表明，蓄水早期和后期DOM中优先与Cu（II）结合的配体分别是色氨酸（C4）和类腐殖质（C1）物质。这些结果表明，蓄水导致的DOM组成变化会降低洪泽湖中Cu的生物有效性和毒性。本文报道的结果将有助于增进对蓄水湖泊中DOM和重金属循环的理解。
