State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, 73 East Beijing Road, Nanjing 210008, China; State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Xianlin Campus, Nanjing University, Nanjing 210023, China.
Ecotoxicol Environ Saf. 2013 Dec;98:266-72. doi: 10.1016/j.ecoenv.2013.09.008. Epub 2013 Sep 27.
Dissolved organic matter (DOM) affects the toxicity, mobility and bioavailability of metals in aquatic environment. In this study, the interactions between two metals of environmental concern [Cu(II) and Fe(III)] with DOM in a euthrophic algae-rich lake (Lake Taihu, China), including dissolved natural organic matter (NOM) and algal extracellular polymeric substance (EPS), were studied using fluorescence excitation-emission matrix (EEM) quenching titration combined with parallel factor (PARAFAC) analysis. Obvious protein-like peaks were detected in algal EPS matrix, while both protein- and humic-like peaks can be found in NOM. PARAFAC analysis identified four fluorescent components, including one humic-, one tryptophan- and two tyrosine-like components, from 114 EEM samples. It was shown that fluorescent tyrosine- (log K(M) > 5.21) and humic-like substances (log K(M) > 4.84) in NOM fraction exhibited higher metal binding capacities than those in EPS matrix, while algal EPS was characterized with a high metal-tryptophan-like substances affinity (log K(M) > 5.08). Moreover, for the eutrophic algae-rich lakes, fluorescent tryptophan- and humic-like substances were responsible for Cu transportation, whereas the mobility of Fe would be related with the tyrosine-like substances. The results facilitate a further insight into the biogeochemical behaviors of metals in eutrophic algae-rich ecosystems as well as other related aquatic environments.
溶解有机质（DOM）会影响金属在水生环境中的毒性、迁移性和生物利用度。在这项研究中，使用荧光激发-发射矩阵（EEM）猝灭滴定结合平行因子（PARAFAC）分析，研究了两种环境关注金属（Cu（II）和 Fe（III））与富营养化藻类湖（中国太湖）中的 DOM 之间的相互作用，包括溶解天然有机质（NOM）和藻细胞外聚合物物质（EPS）。在藻 EPS 基质中检测到明显的蛋白质样峰，而在 NOM 中可以同时检测到蛋白质样和腐殖质样峰。PARAFAC 分析从 114 个 EEM 样品中鉴定出了四个荧光组分，包括一个腐殖质样、一个色氨酸样和两个酪氨酸样组分。结果表明，NOM 部分中的荧光酪氨酸样（log K（M）> 5.21）和腐殖质样物质（log K（M）> 4.84）比 EPS 基质具有更高的金属结合能力，而藻 EPS 则具有高金属-色氨酸样物质亲和力（log K（M）> 5.08）。此外，对于富营养化藻类丰富的湖泊，荧光色氨酸样和腐殖质样物质负责 Cu 的运输，而 Fe 的迁移性则与酪氨酸样物质有关。这些结果有助于进一步了解富营养化藻类丰富的生态系统以及其他相关水生环境中金属的生物地球化学行为。
