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首页> 外文期刊>Environmental Science & Technology >Monitoring Tc Dynamics in a Bioreduced Sediment: An Investigation with Gamma Camera Imaging of ~(99m)Tc-Pertechnetate and ~(99m)Tc- DTPA
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Monitoring Tc Dynamics in a Bioreduced Sediment: An Investigation with Gamma Camera Imaging of ~(99m)Tc-Pertechnetate and ~(99m)Tc- DTPA

机译：监测生物还原沉积物中的Tc动力学：〜（99m）Tc-高tech酸酯和〜（99m）Tc-DTPA的伽马相机成像技术的研究

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摘要

We demonstrate the utility of nuclear medical imaging technologies and a readily available radiotracer, [~(99m)Tc]TcO_4~-, for the noninvasive monitoring of Fe(n) production in acetate-stimulated sediments from Old Rifle, CO, USA. Microcosms consisting of sediment in artificial groundwater media amended with acetate were probed by repeated injection of radiotracer over three weeks. Gamma camera imaging was used to noninvasiveiy quantify the rate and extent of [~(99m)Tc]TcO_4~- partitioning from solution to sediment Aqueous Fe(Ⅱ) and sediment-associated Fe(Ⅱ) were also measured and correlated with the observed tracer behavior. For each injection of tracer, curves of ~(99m)Tc concentration in solution vs time were fitted to an analytic function that accounts for both the observed rate of sedimentation as well as the rate of ~(99m)Tc association with the sediment The rate and extent of ~(99m)Tc association with the biostimulated sediment correlated well with the production of Fe(Ⅱ), and a mechanism of [~(99m)Tc]TcO_4~- reduction via reaction with surface-bound Fe(Ⅱ) to form an immobile Tc(IV) species was inferred. After three weeks of bioreduction, a subset of microcosms was aerated in order to reoxidize the Fe(Ⅱ) to Fe(Ⅲ), which also destroyed the afflnity of the [~(99m)Tc]TcO_4~- for the sediments. However, within 3 days postoxidation, the rate of Tc(Ⅶ) reduction was faster than immediately before oxidation implying a rapid return to more extensive bioreduction. Furthermore, aeration soon after a tracer injection showed that sediment-bound Tc(Ⅳ) is rapidly resolubilized to Tc(Ⅶ). In contrast to the [~(99m)Tc]TcO_4~-, a second commercially available tracer, [~(99m)Tc]TcO_4~- (diethylenetriaminepentaacetic acid), had minimal association with sediment in both controls and biostimulated sediments. These experiments show the promise of [~(99m)Tc]TcO_4~- and Tc-DTPA as noninvasive imaging probes for a redox-sensitive radiotracer and a conservative flow tracer, respectively.
机译：我们展示了核医学成像技术的实用性和现成的放射性示踪剂[〜（99m）Tc] TcO_4〜-，用于无创地监测来自美国科罗拉多州Old Rifle的醋酸盐刺激沉积物中Fe（n）生产。通过在三周内重复注入放射性示踪剂来探测由人工地下水介质中的沉积物组成的微观世界，这些沉积物用乙酸盐修正。使用伽马相机成像对[〜（99m）Tc] TcO_4〜-从溶液分配至沉积物的速率和程度进行无创定量。还测量了Fe（Ⅱ）和与沉积物相关的Fe（Ⅱ）并与观察到的示踪剂相关联行为。对于每次示踪剂注入，溶液中〜（99m）Tc浓度随时间变化的曲线均拟合到一个分析函数，该函数既考虑了观测到的沉降速率，又考虑了〜（99m）Tc与沉积物的关联速率。 〜（99m）Tc与生物刺激沉积物缔合的程度和程度与Fe（Ⅱ）的产生密切相关，以及[〜（99m）Tc] TcO_4〜-通过与表面结合的Fe（Ⅱ）反应还原的机理形成一个固定的Tc（IV）物种。经过三周的生物还原后，为了将Fe（Ⅱ）重新氧化为Fe（Ⅲ），对微观世界进行了充氧，这也破坏了[〜（99m）Tc] TcO_4〜-对沉积物的亲和力。但是，在氧化后3天之内，Tc（Ⅶ）的还原速率比氧化前快，这意味着迅速恢复到更广泛的生物还原。此外，示踪剂注入后不久的曝气表明，与沉积物结合的Tc（Ⅳ）迅速溶解为Tc（Ⅶ）。与[〜（99m）Tc] TcO_4-相反，第二种商用示踪剂[〜（99m）Tc] TcO_4-（二亚乙基三胺五乙酸）与对照和生物刺激沉积物中的沉积物缔合最小。这些实验表明，[〜（99m）Tc] TcO_4〜-和Tc-DTPA有望分别用作氧化还原敏感放射性示踪剂和保守流动示踪剂的无创成像探针。

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  • 来源
    《Environmental Science & Technology》 |2012年第22期|12583-12590|共8页
  • 作者

    Nicholas T. Vandehey; James P. ONeil; Aaron J. Slowey; Rostyslav Boutchko; Jennifer L. Druhan; William W. Moses; Peter S. Nico;

  • 作者单位

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

    Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California, USA;

  • 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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  • 正文语种 eng
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