Carbon and hydrogen isotopic fractionation during biodegradation of methyl tert-butyl ether.
Carbon and hydrogen isotopic fractionation during biodegradation of methyl tert-butyl ether.
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DOI：
10.1021/es011135n
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发表时间：
2002-05
影响因子：
11.4
通讯作者：
J. R. Gray;G. Lacrampe-Couloume;D. Gandhi;K. Scow;Ryan D. Wilson;D. Mackay;B. S. Lollar
中科院分区：
文献类型：
--
作者：
J. R. Gray;G. Lacrampe-Couloume;D. Gandhi;K. Scow;Ryan D. Wilson;D. Mackay;B. S. Lollar
研究了细菌纯培养物（PM 1）和范登堡空军基地（VAFB）混合菌群对甲基叔丁基醚（MTBE）好氧生物降解过程中碳、氢同位素分馏的影响，以评价稳定碳、氢同位素分析作为生物降解指标的相对优势。在99.7%的生物降解率下，残留MTBE中的碳同位素富集高达8.1/1000。碳分馏在PM 1和VAFB实验中是可重复的，在PM 1实验中，重复样品的富集因子（λ）相似，为-2.0/1000 +/- 0.1/1000至-2.4/1000 +/- 0.3/1000，在PM 1实验中，重复样品的富集因子（λ）相似，为-1.5/1000 +/-0.1/1000至-1.8/1000 +/- 0.1/1000。在VAFB实验中重复1000。对于PM 1纯培养物，氢同位素分馏具有高度可重复性，重复样品的δ值为-33/1000 +/- 5/1000至-37/1000 +/- 4/1000。在VAFB微观世界中，重复样品瓶的Δ λ值的变异性更大，测量值为-29/1000 +/- 4/1000和-66/1000 +/- 3/1000。尽管存在这种变异性，但在90%生物降解时，氢同位素分馏总是导致残留甲基叔丁基醚的2 H富集>80/1000。可再现的碳分馏表明，化合物特定的碳同位素分析可用于估计在污染场地的生物降解程度。相反，大量的氢同位素分馏记录在生物降解过程中的甲基叔丁基醚表明，化合物特定的氢同位素分析提供了最确凿的手段，确定在污染场地的原位生物降解。
Carbon and hydrogen isotopic fractionation during aerobic biodegradation of MTBE by a bacterial pure culture (PM1) and a mixed consortia from Vandenberg Air Force Base (VAFB) were studied in order to assess the relative merits of stable carbon versus hydrogen isotopic analysis as an indicator of biodegradation. Carbon isotopic enrichment in residual MTBE of up to 8.1/1000 was observed at 99.7% biodegradation. Carbon fractionation was reproducible in the PM1 and VAFB experiments, yielding similar enrichment factors (epsilon) of -2.0/1000 +/- 0.1/1000 to -2.4/1000 +/- 0.3/1000 for replicates in the PM1 experiment and -1.5/1000 +/- 0.1/1000 to -1.8/1000 +/- 0.1/1000 for replicates in the VAFB experiment. Hydrogen isotopic fractionation was highly reproducible for the PM1 pure cultures, with epsilon values of -33/1000 +/- 5/1000 to -37/1000 +/- 4/1000 for replicate samples. In the VAFB microcosms, there was considerably more variability in epsilon values, with values of -29/1000 +/- 4/1000 and -66/1000 +/- 3/1000 measured for duplicate sample bottles. Despite this variability, hydrogen isotopic fractionation always resulted in 2H enrichment of the residual MTBE of >80/1000 at 90% biodegradation. The reproducible carbon fractionation suggests that compound-specific carbon isotope analysis may be used to estimate the extent of biodegradation at contaminated sites. Conversely, the large hydrogen isotopic fractionation documented during biodegradation of MTBE suggests that compound-specific hydrogen isotope analysis offers the most conclusive means of identifying in-situ biodegradation at contaminated sites.