Integrative approach to delineate natural attenuation of chlorinated benzenes in anoxic aquifers.
Biodegradation of chlorobenzenes was assessed at an anoxic aquifer by combining hydrogeochemistry and stable isotope analyses. In situ microcosm analysis evidenced microbial assimilation of chlorobenzene (MCB) derived carbon and laboratory investigations asserted mineralization of MCB at low rates. Sequential dehalogenation of chlorinated benzenes may affect the isotope signature of single chlorobenzene species due to simultaneous depletion and enrichment of (13)C, which complicates the evaluation of degradation. Therefore, the compound-specific isotope analysis was interpreted based on an isotope balance. The enrichment of the cumulative isotope composition of all chlorobenzenes indicated in situ biodegradation. Additionally, the relationship between hydrogeochemistry and degradation activity was investigated by principal component analysis underlining variable hydrogeochemical conditions associated with degradation activity at the plume scale. Although the complexity of the field site did not allow straightforward assessment of natural attenuation processes, the application of an integrative approach appeared relevant to characterize the in situ biodegradation potential.
Stelzer
Nicole
N
Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
Imfeld
Gwenaël
G
Thullner
Martin
M
Lehmann
Jürgen
J
Poser
Alexander
A
Richnow
Hans-H
HH
Nijenhuis
Ivonne
I
D001673:Biodegradation, Environmental; D002247:Carbon Isotopes / Q000032:analysis; D002722:Chlorobenzenes / Q000032:analysis / Q000737:chemistry*; D004463:Ecology / Q000379:methods / Q000706:statistics & numerical data; D005858:Germany; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis*
D002247:Carbon Isotopes; D002722:Chlorobenzenes; D014874:Water Pollutants, Chemical