Methane oxidation in a crude oil contaminated aquifer: Delineation of aerobic reactions at the plume fringes
| Autor: | Julie D. Kirshtein, Richard T. Amos, Barbara A. Bekins, Geoffrey N. Delin, David W. Blowes, Isabelle M. Cozzarelli |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Water table
Minnesota Aquifer Polymerase Chain Reaction Redox Cluster Analysis Environmental Chemistry Petroleum Pollution Anaerobiosis Groundwater Water Science and Technology geography geography.geographical_feature_category Chemistry DNA Groundwater recharge Contamination Aerobiosis Plume Oxygen Petroleum Isotopes of carbon Environmental chemistry Methylococcaceae Multivariate Analysis Anaerobic oxidation of methane Gases Methane Oxidation-Reduction Water Pollutants Chemical Environmental Monitoring |
| Zdroj: | Journal of Contaminant Hydrology. 125:13-25 |
| ISSN: | 0169-7722 |
| DOI: | 10.1016/j.jconhyd.2011.04.003 |
| Popis: | High resolution direct-push profiling over short vertical distances was used to investigate CH 4 attenuation in a petroleum contaminated aquifer near Bemidji, Minnesota. The contaminant plume was delineated using dissolved gases, redox sensitive components, major ions, carbon isotope ratios in CH 4 and CO 2 , and the presence of methanotrophic bacteria. Sharp redox gradients were observed near the water table. Shifts in δ 13 C CH4 from an average of − 57.6‰ (± 1.7‰) in the methanogenic zone to − 39.6‰ (± 8.7‰) at 105 m downgradient, strongly suggest CH 4 attenuation through microbially mediated degradation. In the downgradient zone the aerobic/anaerobic transition is up to 0.5 m below the water table suggesting that transport of O 2 across the water table is leading to aerobic degradation of CH 4 at this interface. Dissolved N 2 concentrations that exceeded those expected for water in equilibrium with the atmosphere indicated bubble entrapment followed by preferential stripping of O 2 through aerobic degradation of CH 4 or other hydrocarbons. Multivariate and cluster analysis were used to distinguish between areas of significant bubble entrapment and areas where other processes such as the infiltration of O 2 rich recharge water were important O 2 transport mechanisms. |
| Databáze: | OpenAIRE |
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