Uranium and technetium bio-immobilization in intermediate-scale physical models of an in situ bio-barrier.
Uranium and technetium bio-immobilization in intermediate-scale physical models of an in situ bio-barrier.
复制标题
原位生物屏障的中等规模物理模型中的铀和锝生物固定化。
DOI：
10.1021/es060420
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发表时间：
2006
影响因子：
11.4
通讯作者：
J. Istok
中科院分区：
文献类型：
--
作者：
Mandy M. Michalsen;B. Goodman;S. Kelly;K. Kemner;J. Mckinley;J. Stucki;J. Istok
我们调查了长期的影响，乙醇添加对U和Tc的流动性在地下水流经中等规模的柱填充未污染的沉积物。在污染现场的地面上操作的柱作为物理模型的原位生物barrierfor U和Tc从地下水中去除。将含有4微M U和520 pM Tc的地下水泵送通过柱20个月。一个柱接受乙醇的添加以刺激土著微生物的活性;第二个柱不接受乙醇并用作对照。在硫酸盐和Fe（III）还原条件下，模拟柱中U（VI）和Tc（VII）的去除可持续20个月（约189孔体积）。在对照中观察到较少的明显微生物活性和仅少量U（VI）和Tc（VII）的去除。顺序沉淀提取和XANES光谱证实，U（IV）是存在于刺激列，虽然U（IV）也检测到在控制;极低的浓度排除检测Tc（IV）在任何样品中。这些结果提供了额外的证据表明，生物固定可能是有效的去除U和Tc从地下水。然而，生物固定的长期有效性可能会受到水力传导率降低或生物可利用的Fe（III）耗尽的限制。
We investigated the long-term effects of ethanol addition on U and Tc mobility in groundwater flowing through intermediate-scale columns packed with uncontaminated sediments. The columns were operated above-ground at a contaminated field site to serve as physical models of an in situ bio-barrierfor U and Tc removal from groundwater. Groundwater containing 4 microM U and 520 pM Tc was pumped through the columns for 20 months. One column received additions of ethanol to stimulate activity of indigenous microorganisms; a second column received no ethanol and served as a control. U(VI) and Tc(VII) removal was sustained for 20 months (approximately 189 pore volumes) in the stimulated column under sulfate- and Fe(III)-reducing conditions. Less apparent microbial activity and only minor removal of U(VI) and Tc(VII) were observed in the control. Sequential sediment extractions and XANES spectra confirmed that U(IV) was present in the stimulated column, although U(IV) was also detected in the control; extremely low concentrations precluded detection of Tc(IV) in any sample. These results provide additional evidence that bio-immobilization may be effective for removing U and Tc from groundwater. However, long-term effectiveness of bio-immobilization may be limited by hydraulic conductivity reductions or depletion of bioavailable Fe(III).