<br>四川盆地金沙江上游支流潜流带沉积物中Cr(VI)和硝酸盐的同时自然衰减,Science of the Total Environment

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四川盆地金沙江上游支流潜流带沉积物中Cr(VI)和硝酸盐的同时自然衰减
Science of the Total Environment ( IF 8.2 ) Pub Date : 2024-06-21 , DOI: 10.1016/j.scitotenv.2024.174145
Fen Xu ₁ , Junqin Bao ₁ , Qiang Liu ₁ , Xiaoxia He ₁ , Yaqian Zhou ₁ , Hong Wang ₁ , Jiamin Xing ₂ , Lun Zhou ₃ , Jianfei Yuan ₄

Affiliation

地下水和地表水中六价铬 (Cr(VI)) 和硝酸盐 (NO) 的共存对这两种污染物的自然衰减提出了相当大的挑战，因为它们在自然界中的相互作用仍然存在争议。本研究通过整合 Cr(VI) 还原动力学、NO 转化、微生物群落结构和三速率模型，研究了潜流带 (HZ) 沉积物中 Cr(VI) 和 NO 之间的相互作用。沉积物中 Cr(VI) 和 NO 的同时自然衰减受到其初始浓度和氧化还原条件的显着影响。 NO 略微增强了低浓度 Cr(VI)（37.1 和 96.2 μM）的还原作用，而在高浓度 Cr(VI)（200.0 μM）下观察到抑制作用。然而，除了初始浓度较低的 Cr(VI) (37.1 μM) 和 NO (450 μM) 外，NO 的还原受到 Cr(VI) 的不利影响。有氧条件下Cr(VI)和NO的还原率和效率明显低于厌氧条件。这种现象可归因于O的存在，它降低了沉积物相关的Fe(II)对Cr(VI)和NO的选择性，并引起微生物群落结构的改变，导致NO转化的后续变化。此外，三速率模型代表了一种稳健的方法，用于阐明在存在共污染物（例如不同氧化还原条件下的 NO 污染）的情况下 Cr(VI) 的还原情况。这项研究进一步深入了解了 HZ 内 Cr(VI) 和 NO 之间的相互作用机制，因此有必要考虑 Cr(VI) 的微生物毒性以及 Cr(VI)、NO 和 O 之间的电子竞争。

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Simultaneous natural attenuation of Cr(VI) and nitrate in the hyporheic zone sediments from an upstream tributary of the Jinsha River in the Sichuan Basin

The coexistence of hexavalent chromium (Cr(VI)) and nitrate (NO) in groundwater and surface water presents a considerable challenge for the natural attenuation of these two contaminants because their interactions in nature remain contentious. This study investigated the interplay between Cr(VI) and NO in hyporheic zone (HZ) sediments by integrating Cr(VI) reduction kinetics, NO transformation, microbial community structure, and a three-rate model. The concurrent natural attenuation of Cr(VI) and NO in the sediments was significantly influenced by their initial concentrations and redox conditions. The reduction of low concentrations of Cr(VI) (37.1 and 96.2 μM) was slightly enhanced by NO, while inhibitory effects were observed at high concentrations of Cr(VI) (200.0 μM). However, except for an initial low concentration of Cr(VI) (37.1 μM) and NO (450 μM), the reduction of NO was adversely affected by Cr(VI). The reduction rates and efficiencies of Cr(VI) and NO were noticeably lower under aerobic conditions than under anaerobic conditions. This phenomenon can be attributed to the presence of O, which decreased the selectivity of sediments-associated Fe(II) towards Cr(VI) and NO and induced alterations in the microbial community structure, leading to subsequent changes in NO transformation. Furthermore, the three-rate model represents a robust approach for elucidating the reduction of Cr(VI) in the presence of co-contaminants, such as NO contamination under diverse redox conditions. This study provides further insights into the interaction mechanism between Cr(VI) and NO within the HZ, necessitating the consideration of the microbial toxicity of Cr(VI) and electron competition among Cr(VI), NO, and O.

更新日期：2024-06-21

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