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首页> 外文期刊>Environmental Science & Technology >Geochemical Production of Reactive Oxygen Species From Biogeochemically Reduced Fe
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Geochemical Production of Reactive Oxygen Species From Biogeochemically Reduced Fe

机译：生物地球化学还原铁的地球化学生产活性氧

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摘要

The photochemical reduction of Fe(Ⅲ) complexes to Fe(Ⅱ) is a well-known initiation step for the production of reactive oxygen species (ROS) in sunlit waters. Here we show a geochemical mechanism for the same in dark environments based on the tidally driven, episodic movement of anoxic groundwaters through oxidized, Fe(Ⅲ) rich sediments. Sediment samples were collected from the top 5 cm of sediment in a saline tidal creek in the estuary at Murrell's Inlet, South Carolina and characterized with respect to total Fe, acid volatile sulfides, and organic carbon content. These sediments were air-dried, resuspended in aerated solution, then exposed to aqueous sulfide at a range of concentrations chosen to replicate the conditions characteristic of a tidal cycle, beginning with low tide. No detectable ROS production occurred from this process in the dark until sulfide was added. Sulfide addition resulted in the rapid production of hydrogen peroxide, with maximum concentrations of 3.85 μM. The mechanism of hydrogen peroxide production was tested using a simplified three factor representation of the system based on hydrogen sulfide, Fe(Ⅱ) and Fe(Ⅲ). The resulting predictive model for maximum hydrogen peroxide agreed with measured hydrogen peroxide in field-derived samples at the 95％ level of confidence, although with a persistent negative bias suggesting a minor undiscovered peroxide source in sediments.
机译：Fe（Ⅲ）配合物的光化学还原为Fe（Ⅱ）是在阳光照射的水中产生活性氧（ROS）的众所周知的引发步骤。在这里，我们根据潮汐驱动的，缺氧的地下水通过氧化的，富含Fe（Ⅲ）的沉积物的间歇性运动，展示了在黑暗环境中相同的地球化学机理。在南卡罗来纳州Murrell's Inlet的河口一条盐水潮汐小溪中，从沉积物顶部5厘米处收集沉积物样品，并对总铁，酸性挥发性硫化物和有机碳含量进行表征。将这些沉积物风干，重悬于充气溶液中，然后以一定的浓度范围暴露于硫化水溶液中，该浓度范围应从低潮开始复制潮汐周期的特征条件。在添加硫化物之前，在黑暗中此过程未发生可检测的ROS产生。硫化物的添加导致过氧化氢的快速产生，最大浓度为3.85μM。使用基于硫化氢，Fe（Ⅱ）和Fe（Ⅲ）的系统的简化三因子表示法测试了过氧化氢的产生机理。最终的最大过氧化氢预测模型与现场衍生样品中测得的过氧化氢在95％置信水平上相吻合，尽管存在持续的负偏差表明沉积物中微量未发现过氧化物源。

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  • 来源
    《Environmental Science & Technology》 |2014年第7期|3815-3821|共7页
  • 作者

    Sarah A. Murphy; Benson M. Solomon; Shengnan Meng; Justin M. Copeland; Timothy J. Shaw; John L. Ferry;

  • 作者单位

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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