The role of Fe(III) heterogeneity in controlling bioremediation of petroleum contaminated aquifers

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Authors:Spain, Jackson M.; Schreiber, Madeline
Author Affiliations:Primary:
Virginia Polytechnic Institute & State University, Blacksburg, VA, United States
Volume Title:Geological Society of America, 2001 annual meeting
Source:Abstracts with Programs - Geological Society of America, 33(6), p.364; Geological Society of America, 2001 annual meeting, Boston, MA, Nov. 1-10, 2001. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592
Publication Date:2001
Note:In English
Summary:Thermodynamic theory predicts that microorganisms will utilize terminal electron accepting processes (TEAPs) sequentially, beginning with the process that yields the highest amount of energy, but field studies often document an apparent overlap of TEAP byproducts (e.g. Fe(II), CH4). There are several possible explanations for this observed overlap, including downgradient transport of Fe(II) and methane, use of vertically averaged data from wells screened over more than one TEAP, or simultaneous utilization of multiple electron acceptors occurring in microenvironments, or small pockets of microbial activity. In this study, we are testing the hypothesis that microenvironments of Fe(III) and CO2 utilization are created by heterogeneities in Fe(III) concentration and bioavailability. The heterogeneous nature of most soils and sediments allows for the possibility of small pockets of TEAPs that are different from the bulk TEAP. Sediment cores, collected from a petroleum-contaminated site, were used to inoculate batch microcosms. Microenvironment formation is being controlled by the addition of sand-sized glass beads coated with Fe(III)-oxides. In one group of microcosms, the beads form a continuous layer on top of the sediment; the other group contains beads mixed throughout the sediment. In order to examine how microbes are utilizing solid phase iron coupled to BTEX oxidation, samples will be analyzed using scanning electron microscopy (SEM) and electron microprobe techniques in correlation with iron mineral extraction. Results of this research will provide better understanding of whether microbes utilize TEAPs sequentially or simultaneously. This will allow for more accurate quantification of contaminant mass loss in the field, which will result in better numerical models for bioremediation designs, enabling more effective management of petroleum-contaminated sites.
Subjects:Aquifers; Aromatic hydrocarbons; Bioavailability; Bioremediation; BTEX; Controls; Cores; Electron probe data; Experimental studies; Ferric iron; Geochemistry; Ground water; Heterogeneity; Hydrocarbons; Iron; Metals; Organic compounds; Oxidation; Petroleum products; Pollution; Remediation; Sediments; SEM data; Soils; Electron receptors; TEAPs; Terminal electron accepting processes
Record ID:2003008845
Copyright Information:GeoRef, Copyright 2018 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
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