Searching for geophysical signatures of microbial activity at a hydrocarbon contaminated site

We report a geophysical investigation at a former wood treatment facility that used creosote oil in the treatment process. Creosote is a DNAPL (Dense Non-Aqueous Phase Liquid) and previous studies have detected this contaminant in groundwater samples from the site. Two spill locations are known. At one of these two locations we analyzed core samples using magnetic laboratory procedures such as magnetic susceptibility, thermomagnetic curves and environmagnetic parameters measurements. The magnetic analysis indicates an increase of ultrafine magnetic particles around the water table, a magnetic signature of microbial induced mineralization. At the other location, prior to a future drilling campaign, we used resistivity (ER) and induced polarization (IP) surface methods, to identify the contaminant impact on the soil and groundwater. The results show the spill zone locations, and possibly zones of different oil contents in the subsurface.