Ren Haoyu, Fan Tuantuan, Yao Xin, Ma Feiyang, Liu Li, Ming Junde, Wang Shitong, Zhang Yinghao, Deng Huanguang
School of Geography and Environment, Liaocheng University, Liaocheng 252000, China; College of Water Sciences, Beijing Normal University, Beijing 100875, China.
School of Geography and Environment, Liaocheng University, Liaocheng 252000, China.
Sci Total Environ. 2022 Feb 1;806(Pt 2):150485. doi: 10.1016/j.scitotenv.2021.150485. Epub 2021 Sep 25.
Biodegradation is a key factor determining the properties and metal binding behaviour of dissolved organic matter (DOM). In this study, the contributions of biodegradation to DOM properties and metal binding behaviour in Dongping Lake were explored by using synchronous fluorescence (SF) spectroscopy, two-dimensional correlation spectroscopy (2D-COS) excitation-emission matrix and parallel factor analysis (EEM-PARAFAC). According to the ratio of the fluorescence intensity of different materials to the entire fluorescence intensity (%F), protein-like substances were the main substances of DOM in this lake. The reduction of protein-like substances and the enhancement of humification could be found in the whole lake under the influence of biodegradation. 3 areas (Area A, Area B and Area C) were obtained by principal component analysis (PCA), however, PCA results suggested that DOM properties and sources had some differences in the 3 areas, and DOM bioavailability in Area C was stronger than that in the other 2 areas. With copper (Cu) and lead (Pb) addition, different substances exhibited various affinities to different metal types. The locations of crosspeaks in asynchronous maps illustrated that protein-like substances were more affiliative with Cu, while humic-like substances were bound to Pb earlier. Biodegradation had a conspicuous impact the metal binding ability of DOM in Dongping Lake. The effective quenching constants (LogK) of protein-like substances (protein-like component 2: LogK = 3.85 ± 0.23, LogK = 3.32 ± 0.23) were higher than those of humic-like substances (humic-like component 3: LogK = 3.15 ± 0.02, LogK = 2.93 ± 0.17) for both Cu and Pb before biodegradation. When biodegradation was finished, binding ability of humic-like substances was enhanced from 3.15 ± 0.02 to 3.41 ± 0.10 for DOM-Cu and 2.93 ± 0.17 to 3.79 ± 0.15 for DOM-Pb. On a spatial scale, metal binding ability of DOM in Dongping Lake also changed due to the influence of biodegradation. For both DOM-Cu and DOM-Pb, binding ability in south of Dongping Lake was stronger than that in other areas with the end of biodegradation.
生物降解是决定溶解有机物（DOM）性质和金属结合行为的关键因素。在本研究中，利用同步荧光（SF）光谱、二维相关光谱（2D-COS）激发-发射矩阵和平行因子分析（EEM-PARAFAC），探讨了生物降解对东平湖DOM性质和金属结合行为的影响。根据不同物质的荧光强度与总荧光强度之比（%F），类蛋白物质是该湖泊DOM的主要成分。在生物降解的影响下，整个湖泊中类蛋白物质减少，腐殖化增强。通过主成分分析（PCA）得到3个区域（A区、B区和C区），然而，PCA结果表明，3个区域的DOM性质和来源存在一些差异，C区DOM的生物可利用性强于其他2个区域。添加铜（Cu）和铅（Pb）后，不同物质对不同金属类型表现出不同的亲和力。异步图谱中交叉峰的位置表明，类蛋白物质与Cu的亲和力更强，而类腐殖物质更早地与Pb结合。生物降解对东平湖DOM的金属结合能力有显著影响。生物降解前，类蛋白物质（类蛋白组分2：LogK = 3.85 ± 0.23，LogK = 3.32 ± 0.23）对Cu和Pb的有效猝灭常数（LogK）高于类腐殖物质（类腐殖组分3：LogK = 3.15 ± 0.02，LogK = 2.93 ± 0.17）。生物降解结束后，类腐殖物质对DOM-Cu的结合能力从3.15 ± 0.02提高到3.41 ± 0.10，对DOM-Pb的结合能力从2.93 ± 0.17提高到3.79 ± 0.15。在空间尺度上，由于生物降解的影响，东平湖DOM的金属结合能力也发生了变化。生物降解结束时，东平湖南部DOM对Cu和Pb的结合能力均强于其他区域。
