Monitoring oxidation of chlorinated ethenes by permanganate in groundwater using stable isotopes: Laboratory and field studies
Monitoring oxidation of chlorinated ethenes by permanganate in groundwater using stable isotopes: Laboratory and field studies
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DOI：
10.1021/es020073d
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发表时间：
2003-02-15
影响因子：
11.4
通讯作者：
Diao, X
中科院分区：
文献类型：
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作者：
Hunkeler, D;Aravena, R;Diao, X
注入过氧化氢越来越多地用于就地销毁地下水中的氯化乙烯。本实验室和现场研究表明，碳同位素分析可以发挥的作用，在评估高锰酸盐氧化三氯乙烯（TCE）。在实验室实验中，在TCE氧化过程中观察到强烈的碳同位素分馏，初始KMnO 4浓度在67和1250 mg/L之间时具有相似的同位素富集因子（-25.1至-26.8 ‰）。在现场，一个单一的高锰酸盐注入事件进行了桑迪含水层与TCE作为致密的非水液体（DNAPL）污染。注入后，在距离注入点4 m处观察到富集的δ（13）C值高达+204%，Cl-浓度升高。在更远的地方，Cl-增加而TCE的δ（13）C没有任何变化，表明Cl-不是本地产生的，而是迁移到采样点。除了最接近注入点的取样位置外，Δ（13）C再次反弹至初始Δ（13）C，这可能是由于DNAPL的溶解。同位素质量平衡计算使得有可能确定TCE氧化在反弹阶段继续发生的区域。该研究表明，δ（13）C值可用于评估TCE氧化和溶解之间的动态，并定位仅从Cl-分布无法识别的氯化乙烯氧化带。
Permanganate injection is increasingly applied for in situ destruction of chlorinated ethenes in groundwater. This laboratory and field study demonstrates the roles that carbon isotope analysis can play in the assessment of oxidation of trichloroethene (TCE) by permanganate. In laboratory experiments a strong carbon isotope fractionation was observed during oxidation of TCE with similar isotopic enrichment factors (-25.1 to -26.8 parts per thousand) for initial KMnO4 concentrations between 67 and 1250 mg/L. At the field site, a single permanganate injection episode was conducted in a sandy aquifer contaminated with TCE as dense nonaqueous liquid (DNAPL). After injection, enriched delta(13)C values of up to +204% and elevated Cl- concentrations were observed at distances of up to 4 m from the injection point. Farther away, the Cl- increased without any change in delta(13)C of TCE suggesting that Cl- was not produced locally but migrated to the sampling point. Except for the closest sampling location to the injection point, the delta(13)C rebounded to the initial delta(13)C again, likely due to dissolution of DNAPL. Isotope mass balance calculations made it possible to identify zones where TCE oxidation continued to occur during the rebound phase. The study indicates that delta(13)C values can be used to assess the dynamics between TCE oxidation and dissolution and to locate zones of oxidation of chlorinated ethenes that cannot be identified from the Cl- distribution alone.