Anaerobic degradation of benzene and other aromatic hydrocarbons in a tar-derived plume: Nitrate versus iron reducing conditions
van Leeuwen, Johan A.; Gerritse, Jan; Hartog, Niels; Ertl, Siegmund; Parsons, John R.; Hassanizadeh, S. Majid
(2022) Journal of Contaminant Hydrology, volume 248, pp. 1 - 13
(Article)
Abstract
The anaerobic degradation of aromatic hydrocarbons in a plume originating from a Pintsch gas tar-DNAPL zone was investigated using molecular, isotopic- and microbial analyses. Benzene concentrations diminished at the relatively small meter scale dimensions of the nitrate reducing plume fringe. The ratio of benzene to toluene, ethylbenzene, xylenes and naphthalene
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(BTEXN) in the fringe zone compared to the plume zone, indicated relatively more loss of benzene in the fringe zone than TEXN. This was substantiated by changes in relative concentrations of BTEXN, and multi-element compound specific isotope analysis for δ2H and δ13C. This was supported by the presence of (abcA) genes, indicating the presumed benzene carboxylase enzyme in the nitrate-reducing plume fringe. Biodegradation of most hydrocarbon contaminants at iron reducing conditions in the plume core, appears to be quantitatively of greater significance due to the large volume of the plume core, rather than relatively faster biodegradation under nitrate reducing conditions at the smaller volume of the plume fringe. Contaminant concentration reductions by biodegradation processes were shown to vary distinctively between the source, plume (both iron-reducing) and fringe (nitrate-reducing) zones of the plume. High anaerobic microbial activity was detected in the plume zone as well as in the dense non aqueous phase liquid (DNAPL) containing source zone. Biodegradation of most, if not all, other water-soluble Pintsch gas tar aromatic hydrocarbon contaminants occur at the relatively large dimensions of the anoxic plume core. The highest diversity and concentrations of metabolites were detected in the iron-reducing plume core, where the sum of parent compounds of aromatic hydrocarbons was greater than 10 mg/L. The relatively high concentrations of metabolites suggest a hot spot for anaerobic degradation in the core of the plume downgradient but relatively close to the DNAPL containing source zone.
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Keywords: Aromatic hydrocarbons, Benzene carboxylase genes, BTEX, Manufactured gas plant, Metabolites, Natural attenuation, Stable isotope fractionation, Tar, Taverne, Environmental Chemistry, Water Science and Technology
ISSN: 0169-7722
Publisher: Elsevier
Note: Funding Information: This work was financially supported by SBNS , Foundation of Dutch Railways for soil remediation. We acknowledge Antoine Booms, Gerhard Winter, Roy Goossen, Patrick Broekhuizen from Aveco de Bondt, and Andre Cinjee from Deltares, for sharing their site knowledge, site access and assistance in the field. Special thanks to Fredericke Hannes and Rick Helmus for their support in the laboratory and guidance to interns Thomas Wagner, Olaf Brock, Merijn van Logtenstijn and Panos Panagiotis on metabolite and qPCR analysis. Also, we like to thank the reviewers for their constructive and detailed comments while reviewing. Also, we like to thank the reviewers for their constructive and detailed comments while reviewing the manuscript. Funding Information: This work was financially supported by SBNS, Foundation of Dutch Railways for soil remediation. We acknowledge Antoine Booms, Gerhard Winter, Roy Goossen, Patrick Broekhuizen from Aveco de Bondt, and Andre Cinjee from Deltares, for sharing their site knowledge, site access and assistance in the field. Special thanks to Fredericke Hannes and Rick Helmus for their support in the laboratory and guidance to interns Thomas Wagner, Olaf Brock, Merijn van Logtenstijn and Panos Panagiotis on metabolite and qPCR analysis. Also, we like to thank the reviewers for their constructive and detailed comments while reviewing. Also, we like to thank the reviewers for their constructive and detailed comments while reviewing the manuscript. Publisher Copyright: © 2022
(Peer reviewed)