College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China; State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China.
Sci Total Environ. 2021 Jul 10;777:146127. doi: 10.1016/j.scitotenv.2021.146127. Epub 2021 Mar 1.
Dissolved organic matter (DOM) in sediments of polluted rivers significantly contributes to oxygen consumption and river blackening and odorization. However, the chemodiversity of DOM at different depths or river reaches is poorly known. Here, we studied the storage and molecular-level signatures of water-extractable organic matter (WEOM) in the sediment column (0-100 cm) of the upper, middle, and lower mainstream of Maozhou River (a polluted river in Shenzhen, China, with 40 years of urbanization) using optical spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. The sediment WEOM level increased from upstream to downstream. The relative abundances of sulfur-containing surfactants in all sediment WEOM were higher than those previously reported for surface water DOM. The WEOM in surface sediment had higher aromaticity, molecular size, and nominal oxidation state of carbon and greater signals from anthropogenic inputs than did deep sediment at the upper and middle mainstream sites. However, these characteristics varied little between surface and deep sediments at the lower mainstream site, probably due to intensive surface water and pore water interactions. The sediment WEOM at 0-40 cm in the middle mainstream showed a greater anthropogenic signature (e.g., more surfactant and dissolved black carbon contributions) than any other sediment. We demonstrate strong anthropogenic impacts on the surface sediment over decades of urbanization.
污染河流沉积物中的溶解有机物质（DOM）是耗氧和导致河流变黑发臭的主要原因。然而，对于不同深度或不同河段 DOM 的化学多样性却知之甚少。本研究采用光学光谱和傅里叶变换离子回旋共振质谱联用技术，研究了中国深圳具有 40 年城市化历史的茅洲河上游、中游和下游主流段（0-100cm）沉积物柱中可提取水相有机物质（WEOM）的储存和分子水平特征。结果表明，沉积物 WEOM 水平从上游到下游逐渐增加。所有沉积物 WEOM 中的含硫表面活性剂的相对丰度均高于以前报道的地表水 DOM。与上游和中游主流段的深层沉积物相比，表层沉积物 WEOM 的芳香度、分子量、碳的名义氧化态以及人为输入的信号更高。然而，下游主流段的表层和深层沉积物之间这些特征的差异很小，这可能是由于地表水和孔隙水之间的强烈相互作用所致。中游主流段 0-40cm 沉积物的人为特征（如更多的表面活性剂和溶解黑碳贡献）比其他任何沉积物都更为明显。本研究证明了数十年城市化进程对表层沉积物的强烈人为影响。
