Characterization of organic‐contaminated ground by a combination of electromagnetic mapping and direct‐push in situ measurements. Issue 5 (1st December 2013)

• Record Type: Journal Article
• Authors: Mitsuhata, Yuji; Ando, Dai; Imasato, Takehiko; Takagi, Kazushige
• Is Part Of: Near surface geophysics. Volume 12:Issue 5(2014)
• Page Start: 613
• Page End: 622
• Publication Date: 2013-12-01
• Subjects: Earth (Planet) -- Surface -- Periodicals; Geophysics -- Technique -- Periodicals; Engineering geology -- Periodicals; Geophysics -- Periodicals; Planets -- Surfaces; Engineering geology; Geophysics -- Technique; Geophysics; Earth (Planet); Periodicals; 550
• DOI: 10.3997/1873-0604.2014015
• Languages: English
• ISSNs: 1569-4445

Abstract

ABSTRACT: Contamination of soil and groundwater by synthetic volatile organic compounds (VOCs) and hydrocarbons has recently raised public concern. Geophysical techniques are frequently used to characterize contaminated sites and to specify subsurface contaminant plumes in Europe and America, but there have been very few such surveys in Japan. Electromagnetic (EM) induction mapping was applied to investigate a contaminated site on reclaimed land near a harbour in central Japan. The use of EM mapping enabled efficient coverage of a study area in the site and imaging of the subsurface resistivity distribution down to approximately 10 m. In situ direct‐push membrane interface probe (MIP) and electrical conductivity (EC) in situ measurements were also performed as more direct sensing techniques, and the results were compared with soil core samples. The results suggest that the first and second conductive zones mapped by this investigation correspond to clayey soil zones that act as barriers to prevent the infiltration of contaminants. In addition, the in situ MIP measurements and laboratory analyses indicate multiple occurrences of contamination by VOCs and oil. Although EM mapping was not able to clearly specify a contaminant plume, it was demonstrated as a useful technique to delineate the infiltration pathways of contaminants by illustrating the subsurface distributions of clayey zones. In addition, the combination of direct‐push in situ measurements and EM mapping is demonstrated as an essential characterization strategy to verify the interpreted resistivity structure and to determine the relationship between the heterogeneous resistivity and contaminant distribution.