Monitoring in situ biodegradation of benzene and toluene by stable carbon isotope fractionation

Vieth, Andrea; Kästner, Matthias; Schirmer, Mario; Weiß, Holger; Gödeke, Stefan; Meckenstock, Rainer U.; Richnow, Hans H.

doi:10.1002/etc.5620240108

Cited by 64 publications

(76 citation statements)

References 40 publications

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“…Sulfate concentrations decreased significantly concomitant to 34 S/ 32 S isotope fractionation in the highly contaminated zones, confirming microbial sulfate reduction as the dominant electron-accepting process (Fischer et al 2004;Vieth et al 2005). This was further corroborated by assessment of oxygen and sulfur isotope fractionation of sulfate during anaerobic toluene and benzene degradation by sulfate-reducing bacteria in enrichment cultures obtained from the Zeitz aquifer, and column experiments operated under near in situ conditions with Zeitz groundwater (Knöller et al 2006;2008).…”

Section: Hydrogeochemistry and Degradation Conditionssupporting

confidence: 64%

“…4 is reliable, particularly for BTEX contaminants (Mancini et al 2002;Meckenstock et al 2002;Fischer et al 2004;Griebler et al 2004;Vieth et al 2005). However, it is of limited value for contaminants such as tert-butyl alcohol (TBA), TCE, DCE, and VC, which can be both substrates and metabolites .…”

Section: Sequential Transformation Patternsmentioning

confidence: 96%

“…A detailed description of the hydrogeology and hydrochemistry of the contaminated aquifer is given by Fischer et al (2004), Vieth et al (2005), and Schirmer et al (2006). Briefly, BTEX exceeded concentrations of 900 mg L −1 in the source area, with benzene and toluene concentrations up to 850 and 50 mg L −1 , respectively, and ethyl benzene and xylenes concentrations typically lower than 3 mg L −1 .…”

Section: Hydrogeochemistry and Degradation Conditionsmentioning

confidence: 99%

“…Briefly, BTEX exceeded concentrations of 900 mg L −1 in the source area, with benzene and toluene concentrations up to 850 and 50 mg L −1 , respectively, and ethyl benzene and xylenes concentrations typically lower than 3 mg L −1 . Groundwater samples were taken from multi-level sampling wells covering the entire area of the approximately 350 m long BTEX plume with two potential main source zones in the upper aquifer (Fischer et al 2004(Fischer et al , 2007Vieth et al 2005). The distribution of contaminants, electron acceptors, and mineralization products along the flow path was determined in order to characterize the predominant BTEX biodegradation conditions.…”

Section: Hydrogeochemistry and Degradation Conditionsmentioning

confidence: 99%

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Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers

Braeckevelt

Fischer

Kästner

2012

Appl Microbiol Biotechnol

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Microbial processes govern the fate of organic contaminants in aquifers to a major extent. Therefore, the evaluation of in situ biodegradation is essential for the implementation of Natural Attenuation (NA) concepts in groundwater management. Laboratory degradation experiments and biogeochemical approaches are often biased and provide only indirect evidence of in situ degradation potential. Compound-Specific Isotope Analysis (CSIA) is at present among the most promising tools for assessment of the in situ contaminant degradation within aquifers. One- and two-dimensional (2D) CSIA provides qualitative and quantitative information on in situ contaminant transformation; it is applicable for proving in situ degradation and characterizing degradation conditions and reaction mechanisms. However, field application of CSIA is challenging due to a number of influencing factors, namely those affecting the observed isotope fractionation during biodegradation (e.g., non-isotope-fractionating rate-limiting steps, limited bioavailability), potential isotope effects caused by processes other than biodegradation (e.g., sorption, volatilization, diffusion), as well as non-isotope-fractionating physical processes such as dispersion and dilution. This mini-review aims at guiding practical users towards the sound interpretation of CSIA field data for the characterization of in situ contaminant degradation. It focuses on the relevance of various constraints and influencing factors in CSIA field applications and provides advice on when and how to account for these constraints. We first evaluate factors that can influence isotope fractionation during biodegradation, as well as potential isotope-fractionating and non-isotope-fractionating physical processes governing observed isotope fractionation in the field. Finally, the potentials of the CSIA approach for site characterization and the proper ways to account for various constraints are illustrated by means of a comprehensive CSIA field study at the benzene, toluene, ethylbenzene, and xylene (BTEX)-contaminated site Zeitz.

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Section: Hydrogeochemistry and Degradation Conditionssupporting

confidence: 64%

Section: Sequential Transformation Patternsmentioning

confidence: 96%

Section: Hydrogeochemistry and Degradation Conditionsmentioning

confidence: 99%

Section: Hydrogeochemistry and Degradation Conditionsmentioning

confidence: 99%

See 2 more Smart Citations

Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers

Braeckevelt

Fischer

Kästner

2012

Appl Microbiol Biotechnol

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“…CSIA has been used to study the fate of various groundwater pollutants, such as monoaromatic and polyaromatic hydrocarbons (Blum et al, 2009;Vieth et al, 2005;Griebler et al, 2004), MTBE (Kolhatkar et al, 2002;Zwank et al, 2005), chlorinated ethenes Sherwood Lollar et al, 2000), perchlorate (Sturchio et al, 2012), nitrate (Deutsch et al, 2006;Ging et al, 1996;Seiler, 2005;Zhang et al, 2012), and chromium (VI) (Wanner et al, 2012a). However, except for the identification of nitrate sources, it has so far not been used to examine diffuse pollution at the catchment scale.…”

Section: S R Lutz Et Al: Potential Use Of Csia In River Monitoringmentioning

confidence: 99%

A model-based assessment of the potential use of compound-specific stable isotope analysis in river monitoring of diffuse pesticide pollution

Lutz

Meerveld

Waterloo

et al. 2013

Hydrol. Earth Syst. Sci.

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Abstract. Compound-specific stable isotope analysis (CSIA) has, in combination with model-assisted interpretation, proven to be a valuable approach to quantify the extent of organic contaminant degradation in groundwater systems. CSIA data may also provide insights into the origin and transformation of diffuse pollutants, such as pesticides and nitrate, at the catchment scale. While CSIA methods for pesticides have increasingly become available, they have not yet been deployed to interpret isotope data of pesticides in surface water. We applied a coupled subsurface-surface reactive transport model (HydroGeoSphere) at the hillslope scale to investigate the usefulness of CSIA in the assessment of pesticide degradation. We simulated the transport and transformation of a pesticide in a hypothetical but realistic twodimensional hillslope transect. The steady-state model results illustrate a strong increase of isotope ratios at the hillslope outlet, which resulted from degradation and long travel times through the hillslope during average hydrological conditions. In contrast, following an extreme rainfall event that induced overland flow, the simulated isotope ratios dropped to the values of soil water in the pesticide application area. These results suggest that CSIA can help to identify rainfallrunoff events that entail significant pesticide transport to the stream via surface runoff. Simulations with daily rainfall and evapotranspiration data and one pesticide application per year resulted in small seasonal variations of concentrations and isotope ratios at the hillslope outlet, which fell within the uncertainty range of current CSIA methods. This implies a good reliability of in-stream isotope data in the absence of transport via surface runoff or other fast transport routes, since the time of measurement appears to be of minor importance for the assessment of pesticide degradation. The analysis of simulated isotope ratios also allowed quantification of the contribution of two different reaction pathways (aerobic and anaerobic) to overall degradation, which gave further insight into the transport routes in the modelled system. The simulations supported the use of the commonly applied Rayleigh equation for the interpretation of CSIA data, since this led to an underestimation of the real extent of degradation of less than 12 % at the hillslope outlet. Overall, this study emphasizes the applicability and usefulness of CSIA in the assessment of diffuse river pollution, and represents a first step towards a theoretical framework for the interpretation of CSIA data in agricultural catchments.

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Assessment of Microbial In Situ Activity in Contaminated Aquifers

Kästner

Fischer

Nijenhuis

et al. 2006

Engineering in Life Sciences

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Microbial ecologists and environmental engineers share the interest in identifying the key microorganisms responsible for compound turnover in the environment and in estimating the respective transformation rates. For the successful application of Natural Attenuation processes, a reliable assessment of the in situ turnover of a contaminant in an aquifer is essential. Here, we review and present new details of two recently developed approaches concerning the assessment of in situ biodegradation: (i) determination of biodegradation caused by microbial metabolism in a contamination plume by stable isotope fractionation analysis (SIFA) and (ii) determination of the actual degradation under the respective environmental conditions in the aquifer by using in situ microcosms (BACTRAPS®) amended with 13C‐labeled substrates as tracer compounds. Based on stable isotope fractionation analysis, the degradation occurring under anoxic biogeochemical conditions at a respective site can be calculated for the entire plume. This has been shown for benzene and toluene at the Zeitz site and partly for chlorobenzene at the Bitterfeld site. By use of the in situ microcosm approach with 13C‐labeled compounds, the microbial in situ degradation under strictly anaerobic conditions could be proven for benzene and toluene in Zeitz and for chlorobenzene in Bitterfeld. The transformation of 13C‐carbon of the labeled substrate into microbial fatty acids confirmed the assimilation of the pollutant resulting in the formation of biomass. In addition, metabolites such as benzylsuccinic acid were found in the toluene‐amended microcosms indicating anaerobic degradation of toluene. This result corresponds to the geochemical conditions found at the field site and therefore, the microcosm approach with 13C‐labeled compounds can be used to assign the predominant in situ degradation pathways in a contaminated aquifer. Since fatty acids profiles alone are often too unspecific for a community analysis at species level, the composition of the microbial communities was analyzed by genetic profiling and sequencing of partial 16S rRNA genes PCR‐amplified from total DNA extracted directly from the microcosms. Sequences retrieved from the microcosms indicated a dominance of not yet cultivated bacteria. Several sequences were phylogenetically closely related to sequences of bacteria known to be iron and sulfate reducers, typically found at sites polluted with BTEX and/or mineral oil. The results show that the current methods for monitoring microbial in situ activity at present stage are valuable tools for improving environmental control of compound turnover and will speed up engineering approaches.

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Monitoring in situ biodegradation of benzene and toluene by stable carbon isotope fractionation

Cited by 64 publications

References 40 publications

Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers

Field applicability of Compound-Specific Isotope Analysis (CSIA) for characterization and quantification of in situ contaminant degradation in aquifers

A model-based assessment of the potential use of compound-specific stable isotope analysis in river monitoring of diffuse pesticide pollution

Assessment of Microbial In Situ Activity in Contaminated Aquifers

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