Abstract
Evolution of trimethylbenzoic acids in the KC-135 aquifer at the former Wurtsmith Air Force Base (WAFB), Oscoda, MI was examined to determine the functionality of trimethylbenzoic acids as key metabolite signatures in the biogeochemical evolution of an aquifer contaminated with JP-4 fuel hydrocarbons. Changes in the composition of trimethylbenzoic acids and the distribution and concentration profiles exhibited by 2,4,6- and 2,3,5-trimethylbenzoic acids temporally and between multilevel wells reflect processes indicative of an actively evolving contaminant plume. The concentration levels of trimethylbenzoic acids were 3-10 orders higher than their tetramethylbenzene precursors, a condition attributed to slow metabolite turnover under sulfidogenic conditions. The observed degradation of tetramethylbenzenes into trimethylbenzoic acids obviates the use of these alkylbenzenes as non-labile tracers for other degradable aromatic hydrocarbons, but provides rare field evidence on the range of high molecular weight alkylbenzenes and isomeric assemblages amenable to anaerobic degradation in situ. The coupling of actual tetramethylbenzene loss with trimethylbenzoic acid production and the general decline in the concentrations of these compounds demonstrate the role of microbially mediated processes in the natural attenuation of hydrocarbons and may be a key indicator in the overall rate of hydrocarbon degradation and the biogeochemical evolution of the KC-135 aquifer.
Original language | English (US) |
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Pages (from-to) | 177-194 |
Number of pages | 18 |
Journal | Journal of Contaminant Hydrology |
Volume | 67 |
Issue number | 1-4 |
DOIs | |
State | Published - Dec 2003 |
Externally published | Yes |
Bibliographical note
Funding Information:This study was funded by a cooperative agreement from the US Environmental Protection Agency and the Department of Defense-Strategic Environmental Research and Development Program (DoD-SERDP) with the University of Michigan National Center for Integrated Bioremediation Research and Development (UM-NCIBRD). The authors thank Charles L. Major, Tony Brown, Dave Jaglowski, and Michael Gerdenich for assistance in field sampling and Briana Sye, Sandy Homola, Tim Baker, Nitin Barad, and Hongming Chen for laboratory assistance. This paper benefited greatly from the reviews of Dr. Peter Adriaens (University of Michigan) and Dr. Paul Bradley (United States Geological Survey) and editorial handling of Dr. David Lerner (University of Sheffield). Scholarship support from Engineering and Science Education Project-Department of Science and Technology (DOST-ESEP), Philippines through Dr. Estrella Alabastro and Dr. Ida Dalmacio of the Philippine Council for Advance Science and Technology Research and Development (PCASTRD) are gratefully acknowledged.
Keywords
- Biodegradation
- Biogeochemistry
- Groundwater
- Intrinsic bioremediation
- Jet fuel hydrocarbons
ASJC Scopus subject areas
- Environmental Chemistry
- Water Science and Technology