State Key Laboratory of Marine Environmental Science of China (Xiamen University), College of the Environment and Ecology, Xiamen University, Xiamen, 361102, People's Republic of China.
Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.
Environ Sci Pollut Res Int. 2017 Mar;24(7):6461-6471. doi: 10.1007/s11356-016-8250-4. Epub 2017 Jan 10.
The environmental behaviour and the bioavailability of polycyclic aromatic hydrocarbons (PAHs) are strongly affected by dissolved organic matter (DOM) in aquatic environments. In this study, we investigated the dynamics of the bioavailability and character of the intracellular DOM (IDOM) from Microcystis aeruginosa (M. aeruginosa-IDOM) during 10 days oxic and anoxic incubations by spectroscopy. Subsequently, the binding affinity of pyrene with the initial/altered M. aeruginosa-IDOM was estimated by fluorescence quenching method. The incubation results indicated that changes in dissolved organic carbon (DOC) concentration and selected spectral descriptors of the M. aeruginosa-IDOM under oxic condition were different from those of anoxic condition. The microbial transformation of the M. aeruginosa-IDOM resulted in an enhancement of the organic carbon-normalized binding coefficient (K ) of pyrene in both oxic and anoxic treatments. Moreover, only for the oxic condition, Pearson correlation analysis demonstrated that aromaticity (specific UV absorbance at 254 nm, SUVA), humification degree (humification index, HIX) and the percent distribution of humic-like component 2 (%C2) presented significantly positive correlations with the pyrene K , while the percent distribution of protein-like component 1 (%C1) exhibited a negative correlation with the K . However, no significant correlation was observed between any spectral descriptor and the K under anoxic condition. This result suggested that the binding affinity of pyrene may be primarily influenced by the altered M. aeruginosa-IDOM characteristics associated with the biological transformation. Hence, our results provided potential evidence for resolving the inconsistency in the relationships between DOM characteristics and the binding affinities of PAHs.
多环芳烃（PAHs）的环境行为和生物可利用性受水生态系统中溶解有机物质（DOM）的强烈影响。在这项研究中，我们通过光谱法研究了铜绿微囊藻（M. aeruginosa-IDOM）的生物可利用性和细胞内 DOM（IDOM）特征在 10 天好氧和缺氧培养过程中的动态。随后，通过荧光猝灭法估计芘与初始/改变的 M. aeruginosa-IDOM 的结合亲和力。培养结果表明，在好氧条件下，溶解有机碳（DOC）浓度和 M. aeruginosa-IDOM 的选定光谱描述符的变化与缺氧条件下的变化不同。M. aeruginosa-IDOM 的微生物转化导致在好氧和缺氧处理中，芘的有机碳归一化结合系数（K）增强。此外，仅在好氧条件下，Pearson 相关分析表明，芳香度（254nm 处的特定紫外吸光度，SUVA）、腐殖化程度（腐殖化指数，HIX）和腐殖质样组分 2 的百分比分布（%C2）与芘的 K 呈显著正相关，而蛋白质样组分 1 的百分比分布（%C1）与 K 呈负相关。然而，在缺氧条件下，没有观察到任何光谱描述符与 K 之间存在显著相关性。该结果表明，芘的结合亲和力可能主要受与生物转化相关的改变的 M. aeruginosa-IDOM 特性的影响。因此，我们的结果为解决 DOM 特性与 PAHs 结合亲和力之间的不一致关系提供了潜在证据。
