Hydrogen Isotopic Enrichment:  An Indicator of Biodegradation at a Petroleum Hydrocarbon Contaminated Field Site

Mancini, Silvia; Lacrampe-Couloume, Georges; Jonker, Hendrikus; Breukelen, Boris M. van; Groen, J.; Volkering, F.; Lollar, Barbara Sherwood

doi:10.1021/es011253a

Cited by 103 publications

(107 citation statements)

References 36 publications

(90 reference statements)

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“…The general feasibility of such an approach has been demonstrated in a number of studies (71,(97)(98)(99)(100)(101)(102)(103) and is discussed in a comprehensive recent review by Meckenstock et al (24). Here we focus primarily on the aspect how insight about transformation pathways can aid in choosing the appropriate isotopic enrichment factor ( bulk) that is needed to quantify the extent of in situ transformation according to eq 8.…”

Section: Consequences For the Assessment Of Isotope Fractionation In mentioning

confidence: 99%

A New Concept Linking Observable Stable Isotope Fractionation to Transformation Pathways of Organic Pollutants

Elsner

Zwank

Hunkeler

et al. 2005

Environ. Sci. Technol.

510

803

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Measuring stable isotope fractionation of carbon, hydrogen, and other elements by Compound Specific Isotope Analysis (CSIA) is a new, innovative approach to assess organic pollutant degradation in the environment. Central to this concept is the Rayleigh equation which relates degradation-induced decreases in concentrations directly to concomitant changes in bulk () average over the whole compound) isotope ratios. The extent of in situ transformation may therefore be inferred from measured isotope ratios in field samples, provided that an appropriate enrichment factor ( bulk ) is known. This bulk value, however, is usually only valid for a specific compound and for specific degradation conditions. Therefore, a direct comparison of bulk values for different compounds and for different types of reactions has in general not been feasible. In addition, it is often uncertain how robust and reproducible bulk values are and how confidently they can be used to quantify contaminant degradation in the field. To improve this situation and to achieve a more in-depth understanding, this critical review aims to relate fundamental insight about kinetic isotope effects (KIE) found in the physico(bio)chemical literature to apparent kinetic isotope effects (AKIE) derived from bulk values reported in environmentally oriented studies. Starting from basic rate laws, a quite general derivation of the Rayleigh equation is given, resulting in a novel set of simple equations that take into account the effects of (1) nonreacting positions and (2) intramolecular competition and that lead to position-specific AKIE values rather than bulk enrichment factors. Reevaluation of existing bulk literature values result in consistent ranges of AKIE values that generally are in good agreement with previously published data in the (bio)-chemical literature and are typical of certain degradation reactions (subscripts C and H indicate values for carbon and hydrogen): AKIE C ) 1.01-1.03 and AKIE H ) 2-23 for oxidation of C-H bonds; AKIE C ) 1.03-1.07 for S N 2-

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Section: Consequences For the Assessment Of Isotope Fractionation In mentioning

confidence: 99%

A New Concept Linking Observable Stable Isotope Fractionation to Transformation Pathways of Organic Pollutants

Elsner

Zwank

Hunkeler

et al. 2005

Environ. Sci. Technol.

510

803

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“…Throughout the experiment, aqueous and medium controls were run for ␦ 13 C on alternate days and had a carbon isotopic reproducibility of Ϯ0.2‰ of the mean of all controls. Daily reproducibility for replicate injections of a single control bottle was always Ͻ0.3‰; however, the total error reported for each sample is Ϯ0.5‰ to incorporate both accuracy and reproducibility (14,37,49). Benzene ␦ 2 H values were determined with a continuous flow mass spectrometry system consisting of a Hewlett-Packard 6890 GC interfaced with a pyrolysis oven in line with a Finnigan Mat Delta plus XL isotope ratio mass spectrometer.…”

Section: Enrichment Culturesmentioning

confidence: 99%

“…Daily reproducibility of replicate injections of a single control bottle was always Ͻ3‰. However, the total error reported for each sample is Ϯ5 ‰, incorporating both accuracy and reproducibility (21,37,55).…”

Section: Enrichment Culturesmentioning

confidence: 99%

Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

Mancini

Ulrich²,

Lacrampe-Couloume

et al. 2003

Appl Environ Microbiol

Self Cite

160

143

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Compound-specific isotope analysis has the potential to distinguish physical from biological attenuation processes in the subsurface. In this study, carbon and hydrogen isotopic fractionation effects during biodegradation of benzene under anaerobic conditions with different terminal-electron-accepting processes are reported for the first time. Different enrichment factors () for carbon (range of ؊1.9 to ؊3.6‰) and hydrogen (range of ؊29 to ؊79‰) fractionation were observed during biodegradation of benzene under nitratereducing, sulfate-reducing, and methanogenic conditions. These differences are not related to differences in initial biomass or in rates of biodegradation. Carbon isotopic enrichment factors for anaerobic benzene biodegradation in this study are comparable to those previously published for aerobic benzene biodegradation. In contrast, hydrogen enrichment factors determined for anaerobic benzene biodegradation are significantly larger than those previously published for benzene biodegradation under aerobic conditions. A fundamental difference in the previously proposed initial step of aerobic versus proposed anaerobic biodegradation pathways may account for these differences in hydrogen isotopic fractionation. Potentially, C-H bond breakage in the initial step of the anaerobic benzene biodegradation pathway may account for the large fractionation observed compared to that in aerobic benzene biodegradation. Despite some differences in reported enrichment factors between cultures with different terminal-electron-accepting processes, carbon and hydrogen isotope analysis has the potential to provide direct evidence of anaerobic biodegradation of benzene in the field.

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“…Usually intrinsic biodegradation by indigenous microbial populations is the key process for contaminant elimination and methods are required to demonstrate its efficacy. In groundwater studies, compound-specific isotope analysis (CSIA) has been used increasingly to demonstrate in situ biodegradation of various types of organic contaminants (Kelley et al, 1997;Sturchio et al, 1998;Hunkeler et al, 1999;Sherwood Lollar et al, 2001;Kolhatkar et al, 2002;Mancini et al, 2002;Meckenstock et al, 2002;Song et al, 2002;Kirtland et al, 2003;Richnow et al, 2003a,b;Chu et al, 2004;Griebler et al, 2004;Steinbach et al, 2004;Hunkeler et al, 2005;Morrill et al, 2005). In contrast, only a few studies have investigated the use of CSIA in the unsaturated zone (Stehmeier et al, 1999;Kirtland et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Carbon isotope fractionation during aerobic biodegradation of n-alkanes and aromatic compounds in unsaturated sand

Bouchard

Hunkeler

Höhener

2008

Organic Geochemistry

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Microcosm experiments were conducted to quantify carbon isotope fractionation during aerobic biodegradation of n-alkanes (from C 3 to C 10 ) and monoaromatic hydrocarbons in unsaturated alluvial sand. In single compound experiments with n-alkanes, the largest enrichment factor was obtained for propane (À10.8 ± 0.7‰). The magnitude of the enrichment factor decreased with increasing number of carbon atoms from propane to n-decane (À0.2 ± 0.1‰). This trend can partly be explained by the decreasing probability that a 13 C is located at the reacting site in the molecule with increasing chain length. After correcting for the presence of non-reacting positions, a chain length dependence of the calculated apparent isotope effect persisted. This observation suggests that transport and binding steps before the actual reaction step become increasingly rate limiting with increasing chain length. For aromatic compounds tested individually, the enrichment factor was the largest (À1.4 ± 0.1‰) for benzene (B), followed by toluene (T) (À0.8 ± 0.1‰) and m-xylene (X) (À0.6 ± 0.1‰). Enrichment factors for BTX were systematically smaller than for n-alkanes with equivalent number of carbons, which is likely related to different biodegradation mechanisms. The study demonstrates that significant carbon isotope fractionation occurs during aerobic biodegradation of n-alkanes and aromatic compounds under unsaturated conditions and that the magnitude of isotope enrichment is linked to molecule size and molecule structure.

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Hydrogen Isotopic Enrichment: An Indicator of Biodegradation at a Petroleum Hydrocarbon Contaminated Field Site

Cited by 103 publications

References 36 publications

A New Concept Linking Observable Stable Isotope Fractionation to Transformation Pathways of Organic Pollutants

A New Concept Linking Observable Stable Isotope Fractionation to Transformation Pathways of Organic Pollutants

Carbon and Hydrogen Isotopic Fractionation during Anaerobic Biodegradation of Benzene

Carbon isotope fractionation during aerobic biodegradation of n-alkanes and aromatic compounds in unsaturated sand

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