Ni Lixiao, Su Lili, Li Shiyin, Wang Peifang, Li Dandan, Ye Xiang, Li Yi, Li Yong, Li Yiping, Wang Chao
Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, School of Environment, Hohai University, Nanjing, China.
Department of Environmental Science and Engineering, School of Geography Science, Nanjing Normal University, Nanjing, China.
Environ Toxicol Chem. 2017 Jul;36(7):1856-1863. doi: 10.1002/etc.3728. Epub 2017 Feb 23.
The present study examines the uptake of the heavy metal cadmium (Cd) by Microcystis aeruginosa in the presence of dissolved organic matter (DOM) from different origins. The DOM used in the present study were extracted from soil, sediment taken from Meiliang Bay at Taihu Lake, and from M. aeruginosa cultured in the laboratory. The 3 different DOM samples were characterized using ultraviolet-visible absorption spectroscopy and Fourier transform infrared spectroscopy. The excitation-emission matrix (EEM) fluorescence spectroscopy was used to characterize the interactions of DOM with Cd . The results showed that all types of DOM extracted from the 3 sources in the present study exhibited aliphatic and aromatic characteristics and contained hydroxyls, carbonyls, phenols, carboxyls, carbohydrates, amines, and ethers. Humic acids and fulvic acids proved to be the major components of DOM. The sediment DOM had the highest degrees of aromatization and humification among the samples. The results also showed that sediment and soil DOM samples had lower molecular weights than M. aeruginosa DOM. The DOM could react with Cd by complexing to alter Cd speciation. When exposed to Cd, EEM fluorescence intensities of all 3 DOM types had a significant decrease, and the intracellular Cd content improved with increasing Cd concentrations. The addition of DOM greatly enhanced Cd uptake by M. aeruginosa compared with the control group. Environ Toxicol Chem 2017;36:1856-1863. © 2017 SETAC.
本研究考察了在存在不同来源溶解有机物（DOM）的情况下，铜绿微囊藻对重金属镉（Cd）的吸收情况。本研究中使用的DOM分别从土壤、太湖梅梁湾沉积物以及实验室培养的铜绿微囊藻中提取。采用紫外可见吸收光谱和傅里叶变换红外光谱对这3种不同的DOM样品进行表征。利用激发发射矩阵（EEM）荧光光谱表征DOM与Cd的相互作用。结果表明，本研究从3种来源提取的所有类型的DOM均表现出脂肪族和芳香族特征，且含有羟基、羰基、酚类、羧基、碳水化合物、胺类和醚类。腐殖酸和富里酸被证明是DOM的主要成分。沉积物DOM在样品中具有最高的芳构化和腐殖化程度。结果还表明，沉积物和土壤DOM样品的分子量低于铜绿微囊藻DOM。DOM可通过络合与Cd发生反应，从而改变Cd的形态。当暴露于Cd时，所有3种DOM类型的EEM荧光强度均显著降低，且细胞内Cd含量随Cd浓度增加而提高。与对照组相比，添加DOM极大地增强了铜绿微囊藻对Cd的吸收。《环境毒理学与化学》2017年；36：1856 - 1863。© 2017 SETAC。
