Delineation of subsurface hydrocarbon contamination at a former hydrogenation plant using spectral induced polarization imaging
Broadband spectral induced polarization (SIP) measurements were conducted at a former hydrogenation plant in Zeitz (NE Germany) to investigate the potential of SIP imaging to delineate areas with different BTEX (benzene, toluene, ethylbenzene, and xylene) concentrations. Conductivity images reveal a...
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Published in | Journal of contaminant hydrology Vol. 136-137; pp. 131 - 144 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Kidlington
Elsevier B.V
01.08.2012
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Broadband spectral induced polarization (SIP) measurements were conducted at a former hydrogenation plant in Zeitz (NE Germany) to investigate the potential of SIP imaging to delineate areas with different BTEX (benzene, toluene, ethylbenzene, and xylene) concentrations. Conductivity images reveal a poor correlation with the distribution of contaminants; whereas phase images exhibit two main anomalies: low phase shift values (<5 mrad) for locations with high BTEX concentrations, including the occurrence of free-phase product (BTEX concentrations >1.7g/l), and higher phase values for lower BTEX concentrations. Moreover, the spectral response of the areas with high BTEX concentration and free-phase products reveals a flattened spectrum in the low frequencies (<40Hz), while areas with lower BTEX concentrations exhibit a response characterized by a frequency peak. The SIP response was modelled using a Debye decomposition to compute images of the median relaxation-time. Consistent with laboratory studies, we observed an increase in the relaxation-time associated with an increase in BTEX concentrations. Measurements were also collected in the time domain (TDIP), revealing imaging results consistent with those obtained for frequency domain (SIP) measurements. Results presented here demonstrate the potential of the SIP imaging method to discriminate source and plume of dissolved contaminants at BTEX contaminated sites.
► Characterization of BTEX contaminated sites with spectral induced polarization imaging. ► Discrimination of source zone and plume of dissolved contaminants at the field scale. ► Comparison of time domain and frequency domain induced polarization imaging results. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0169-7722 1873-6009 |
DOI: | 10.1016/j.jconhyd.2012.06.001 |