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Sun, F. ; Mellage, A.* ; Gharasoo, M. ; Melsbach, A. ; Cao, X. ; Zimmermann, R. ; Griebler, C.* ; Thullner, M.* ; Cirpka, O.A.* ; Elsner, M.

Mass-transfer-limited biodegradation at low concentrations-evidence from reactive transport modeling of isotope profiles in a bench-scale aquifer.

Environ. Sci. Technol. 55, 7386-7397 (2021)
Verlagsversion Forschungsdaten DOI PMC
Open Access Gold (Paid Option)
Creative Commons Lizenzvertrag
Organic contaminant degradation by suspended bacteria in chemostats has shown that isotope fractionation decreases dramatically when pollutant concentrations fall below the (half-saturation) Monod constant. This masked isotope fractionation implies that membrane transfer is slow relative to the enzyme turnover at μg L-1 substrate levels. Analogous evidence of mass transfer as a bottleneck for biodegradation in aquifer settings, where microbes are attached to the sediment, is lacking. A quasi-two-dimensional flow-through sediment microcosm/tank system enabled us to study the aerobic degradation of 2,6-dichlorobenzamide (BAM), while collecting sufficient samples at the outlet for compound-specific isotope analysis. By feeding an anoxic BAM solution through the center inlet port and dissolved oxygen (DO) above and below, strong transverse concentration cross-gradients of BAM and DO yielded zones of low (μg L-1) steady-state concentrations. We were able to simulate the profiles of concentrations and isotope ratios of the contaminant plume using a reactive transport model that accounted for a mass-transfer limitation into bacterial cells, where apparent isotope enrichment factors *ε decreased strongly below concentrations around 600 μg/L BAM. For the biodegradation of organic micropollutants, mass transfer into the cell emerges as a bottleneck, specifically at low (μg L-1) concentrations. Neglecting this effect when interpreting isotope ratios at field sites may lead to a significant underestimation of biodegradation.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
Schlagwörter 2,6-dichlorobenzamide ; Csia ; Gc-irms ; Bioavailability ; Flow-through System ; Reactive-transport Model; Pollutant 2,6-dichlorobenzamide Bam; Bacterial Sulfate Reduction; Metabolite 2,6-dichlorobenzamide; Stable Carbon; Bioavailability Restrictions; Anaerobic Biodegradation; Chlorinated Hydrocarbons; Fractionation Analysis; Bioreactive Transport; Herbicide Dichlobenil
ISSN (print) / ISBN 0013-936X
e-ISSN 1520-5851
Zeitschrift Environmental Science & Technology
Quellenangaben Band: 55, Heft: 11, Seiten: 7386-7397 Artikelnummer: , Supplement: ,
Verlag ACS
Verlagsort Washington, DC
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Institute of Groundwater Ecology (IGOE)
Cooperation Group Comprehensive Molecular Analytics (CMA)
Förderungen ERC