College of Environmental Science and Engineering, Hunan University, Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China.
College of Environmental Science and Engineering, Hunan University, Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, China; Hunan Provincial Key Laboratory for Eco-environmental Changes and Carbon Sequestration of the Dongting Lake Basin, School of Geographical Sciences, Institute of Interdisciplinary Studies, Hunan Normal University, Changsha 410081, China.
J Environ Sci (China). 2025 Apr;150:645-656. doi: 10.1016/j.jes.2024.03.055. Epub 2024 Apr 6.
China's lakes are plagued by cadmium (Cd) pollution. Dissolved organic matter (DOM) significantly regulates Cd(II) transport properties at the sediment-water interface. Understanding the effects of different DOM components on the transportation properties of Cd(II) at the sediment-water interface is essential. In this study, typical DOM from different sources was selected to study Cd(II) mobility at the sediment-water interface. Results showed that terrestrial-derived DOM (fulvic acids, FA) and autochthonous-derived DOM (α-amylase, B1) inhibit Cd(II) sequestration by sediments (42.5% and 5.8%, respectively), while anthropogenic-derived DOM (sodium dodecyl benzene sulfonate, SDBS) increased the Cd(II) adsorption capacity by sediments by 2.8%. Fluorescence quenching coupling with parallel factor analysis (EEM-PARAFAC) was used to characterize different DOM components. The results showed that FA contains three kinds of components (C1, C3: protein-like components, C2: humic-like components); SDBS contains two kinds of components (C1, C2: protein-like components); B1 contains three kinds of components (C1, C2: protein-like components, C3: humic-like components).Three complex reaction models were used to characterize the ability of Cd(II) complex with DOM, and it was found that the humic-like component could hardly be complex with Cd(II). Accordingly, humic-like components compete for Cd(II) adsorption sites on the sediment surface and inhibit Cd(II) adsorption from sediments. Fourier transform infrared spectroscopy (FTIR) of the sediment surface before and after Cd(II) addition was analyzed and proved the competitive adsorption theory. This study provides a better understanding of the Cd(II) mobilization behavior at the sediment-water interface and indicates that the input of humic-like DOM will increase the bioavailability of Cd.
中国的湖泊深受镉（Cd）污染问题困扰。溶解有机质（DOM）在沉积物-水界面显著调节 Cd(II)的传输性质。理解不同 DOM 成分对沉积物-水界面 Cd(II)传输性质的影响至关重要。在这项研究中，选择了来自不同来源的典型 DOM 来研究 Cd(II)在沉积物-水界面的迁移性。结果表明，陆地来源的 DOM（富里酸，FA）和自生源 DOM（α-淀粉酶，B1）分别抑制了 42.5%和 5.8%的 Cd(II)被沉积物固定，而人为来源的 DOM（十二烷基苯磺酸钠，SDBS）则使沉积物对 Cd(II)的吸附能力增加了 2.8%。荧光猝灭结合平行因子分析（EEM-PARAFAC）用于表征不同的 DOM 成分。结果表明，FA 含有三种成分（C1、C3：类蛋白成分，C2：类腐殖质成分）；SDBS 含有两种成分（C1、C2：类蛋白成分）；B1 含有三种成分（C1、C2：类蛋白成分，C3：类腐殖质成分）。使用三种复杂的反应模型来表征 Cd(II)与 DOM 的络合能力，发现类腐殖质成分几乎不能与 Cd(II)络合。因此，类腐殖质成分会与 Cd(II)竞争吸附在沉积物表面的吸附位点，并抑制 Cd(II)从沉积物中的吸附。对 Cd(II)添加前后沉积物表面的傅里叶变换红外光谱（FTIR）进行了分析，并验证了竞争吸附理论。本研究提供了对沉积物-水界面 Cd(II)迁移行为的更好理解，并表明类腐殖质 DOM 的输入会增加 Cd 的生物可利用性。
