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Carbon and hydrogen isotope fractionation of benzene during biodegradation under sulfate‐reducing conditions: a laboratory to field site approach
Author(s) -
Fischer Anko,
Gehre Matthias,
Breitfeld Jana,
Richnow HansHermann,
Vogt Carsten
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4049
Subject(s) - chemistry , microcosm , benzene , sulfate , biodegradation , environmental chemistry , isotope fractionation , fractionation , isotope analysis , hydrogen , carbon fibers , chromatography , organic chemistry , ecology , materials science , composite number , composite material , biology
The microbial carbon and hydrogen isotope fractionation of benzene under sulfate‐reducing conditions was investigated within systems of increasing complexity: (i) batch laboratory microcosms, (ii) a groundwater‐percolated column system, and (iii) an aquifer transect. Recent molecular biological studies indicate that, at least in the laboratory microcosms and the column system, benzene is degraded by similar bacterial communities. Carbon and hydrogen enrichment factors ( ε C , ε H ) obtained from laboratory microcosms and from the column study varied significantly although experiments were performed under similar redox and temperature conditions. Thus, enrichment factors for only a single element could not be used to distinguish benzene degradation under sulfate‐reducing conditions from other redox conditions. In contrast, using correlation of changes of hydrogen vs. carbon isotope ratios (Λ = Δ δ 2 H/Δ δ 13 C), similar Λ‐values were derived for the benzene biodegradation under sulfate‐reducing conditions in all three experimental systems (Λ laboratory microcosms = 23 ± 5, Λ column = 28 ± 3, Λ aquifer = 24 ± 2), showing the robustness of the two‐dimensional compound‐specific stable isotope analysis (2D‐CSIA) for elucidating distinct biodegradation pathways. Comparing carbon and hydrogen isotope fractionation data from recent studies, an overlap in Λ‐values was observed for benzene biodegradation under sulfate‐reducing (Λ = 23 ± 5 to Λ = 29 ± 3) and methanogenic (Λ = 28 ± 1 to Λ = 39 ± 5) conditions, indicating a similar initial benzene reaction mechanism for both electron‐acceptor conditions. Copyright © 2009 John Wiley & Sons, Ltd.