Geophysical Monitoring of Coupled Microbial and Geochemical Processes During Stimulated Subsurface Bioremediation
Understanding how microorganisms alter their physical and chemical environment during bioremediation is hindered by our inability to resolve subsurface microbial activity with high spatial resolution. Here we demonstrate the use of a minimally invasive geophysical technique to monitor stimulated microbial activity during acetate amendment in an aquifer near Rifle, Colorado. During electrical induced polarization (IP) measurements, spatiotemporal variations in the phase response between imposed electric current and the resultant electric field correlated with changes in groundwater geochemistry accompanying stimulated iron and sulfate reduction and sulfide mineral precipitation. The magnitude of the phase response varied with measurement frequency (0.125 and 1 Hz) andwasdependent upon the dominant metabolic process. The spectral effect was corroborated using a biostimulated column experiment containing Rifle sediments and groundwater. Fluids and sediments recovered from regions exhibiting an anomalous phase response were enriched in Fe(II), dissolved sulfide, and cell-associated FeS nanoparticles. The accumulation of mineral precipitates and electroactive ions altered the ability of pore fluids to conduct electrical charge, accounting for the anomalous IP response and revealing the usefulness of multifrequency IP measurements for monitoring mineralogical and geochemical changes accompanying stimulated subsurface bioremediation.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 965580
- Report Number(s):
- PNNL-SA-68077; 6902a; KP1504010; TRN: US0903653
- Journal Information:
- Environmental Science & Technology, 43(17):6717–6723, Vol. 43, Issue 17; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACETATES
AQUIFERS
BIOREMEDIATION
ELECTRIC CURRENTS
ELECTRIC FIELDS
GEOCHEMISTRY
IRON
MICROORGANISMS
MONITORING
MONITORS
POLARIZATION
PRECIPITATION
SEDIMENTS
SPATIAL RESOLUTION
SULFATES
SULFIDE MINERALS
Geophysical monitoring
bioremediation
uranium
spectral induced potential
Environmental Molecular Sciences Laboratory