Blum, Philipp
Hunkeler, Daniel
Weede, Matthias
Beyer, Christof
Grathwohl, Peter
Morasch, Barbara
Quantification of biodegradation for o-xylene and naphthalene using first order decay models, Michaelis-Menten kinetics and stable carbon isotopes
Journal Of Contaminant Hydrology
Journal Of Contaminant Hydrology
Journal Of Contaminant Hydrology
Journal Of Contaminant Hydrology
105
Natural attenuation
Redox zones
Contaminant Plume
Compound-specific isotope analysis (CSIA)
Rate constants
Polyaromatic hydrocarbons (PAH)
Btex
In-Situ Degradation
Air-Force-Base
Natural Attenuation
Aromatic-Hydrocarbons
Contaminated Aquifer
Intrinsic Bioremediation
Rayleigh Equation
Monoaromatic Hydrocarbons
Anaerobic Degradation
Bacterial-Degradation
2009
2009
At a former wood preservation plant severely contaminated with coal tar oil, in situ bulk attenuation and biodegradation rate constants for several monoaromatic (BTEX) and polyaromatic hydrocarbons (PAH) were determined using (1) classical first order decay models, (2) Michaelis-Menten degradation kinetics (MM), and (3) stable carbon isotopes, for o-xylene and naphthalene. The first order bulk attenuation rate constant for o-xylene was calculated to be 0.0025 d(-1) and a novel stable isotope-based first order model, which also accounted for the respective redox conditions, resulted in a slightly smaller biodegradation rate constant of 0.0019 d(-1). Based on MM-kinetics, the o-xylene concentration decreased with a maximum rate of k(max)=0.1 mu g/L/d. The bulk attenuation rate constant of naphthalene retrieved from the classical first order decay model was 0.0038 d(-1). The stable isotope-based biodegradation rate constant of 0.0027 d(-1) was smaller in the reduced zone, while residual naphthalene in the oxic part of the plume further downgradient was degraded at a higher rate of 0.0038 d(-1). With MM-kinetics a maximum degradation rate of k(max)=12 mu g/L/d was determined. Although best fits were obtained by MM-kinetics, we consider the carbon stable isotope-based approach more appropriate as it is specific for biodegradation (not overall attenuation) and at the same time accounts for the dominant electron-accepting process. For o-xylene a field based isotope enrichment factor epsilon(field) of - 1.4 could be determined using the Rayleigh model, which closely matched values from laboratory studies of o-xylene degradation under sulfate-reducing conditions. (C) 2008 Elsevier B.V. All rights reserved.
Journal Of Contaminant Hydrology
Journal Articles
10.1016/j.jconhyd.2008.11.009