Journal article
Biogeochemical and Isotopic Gradients in a BTEX/PAH Contaminant Plume: Model-Based Interpretation of a High-Resolution Field Data Set
CSIRO Land and Water, Private Bag No. 5, Wembley WA 6913, Australia, School of Earth and Environment, University of Western Australia, Crawley, Western Australia, Helmholtz Zentrum München, Institute of Groundwater Ecology, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany, Centre for Applied Geosciences, University of Tübingen, Sigwartstrasse 10, 72076 Tübingen, Germany, and Department of Environmental Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
A high spatial resolution data set documenting carbon and sulfur isotope fractionation at a tar oil-contaminated, sulfate-reducing field site was analyzed with a reactive transport model. Within a comprehensive numerical model, the study links the distinctive observed isotope depth profiles with the degradation of various monoaromatic and polycyclic aromatic hydrocarbon compounds (BTEX/PAHs) under sulfate-reducing conditions.
In the numerical model, microbial dynamics were simulated explicitly and isotope fractionation was directly linked to the differential microbial uptake of lighter and heavier carbon isotopes during microbial growth. Measured depth profiles from a multilevel sampling well with high spatial resolution served as key constraints for the parametrization of the model simulations.
The results of the numerical simulations illustrate particularly well the evolution of the isotope signature of toluene, which is the most rapidly degrading compound and the most important reductant at the site. The resulting depth profiles at the observation well show distinct differences between the small isotopic enrichment in the contaminant plume core and the much stronger enrichment of up to 3.3‰ at the plume fringes.
Language: | English |
---|---|
Publisher: | American Chemical Society |
Year: | 2009 |
Pages: | 8206-8212 |
ISSN: | 15205851 and 0013936x |
Types: | Journal article |
DOI: | 10.1021/es901142a |