title: Noninvasive characterization of the Trecate (Italy) crude-oil contaminated site: links between contamination and geophysical signals.
abstract: The characterization of contaminated sites can benefit from the supplementation of direct investigations with a set of less invasive and more extensive measurements. A combination of geophysical methods and direct push techniques for contaminated land characterization has been proposed within the EU FP7 project ModelPROBE and the affiliated project SoilCAM. In this paper, we present results of the investigations conducted at the Trecate field site (NW Italy), which was affected in 1994 by crude oil contamination. The less invasive investigations include ground-penetrating radar (GPR), electrical resistivity tomography (ERT), and electromagnetic induction (EMI) surveys, together with direct push sampling and soil electrical conductivity (EC) logs. Many of the geophysical measurements were conducted in time-lapse mode in order to separate static and dynamic signals, the latter being linked to strong seasonal changes in water table elevations. The main challenge was to extract significant geophysical signals linked to contamination from the mix of geological and hydrological signals present at the site. The most significant aspects of this characterization are: (a) the geometrical link between the distribution of contamination and the site's heterogeneity, with particular regard to the presence of less permeable layers, as evidenced by the extensive surface geophysical measurements; and (b) the link between contamination and specific geophysical signals, particularly evident from cross-hole measurements. The extensive work conducted at the Trecate site shows how a combination of direct (e.g., chemical) and indirect (e.g., geophysical) investigations can lead to a comprehensive and solid understanding of a contaminated site's mechanisms.
authors.affiliation: Dipartimento di Geoscienze, Università di Padova, Padova, Italy, giorgio.cassiani@unipd.it.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Cassiani
authors.forename: Andrew
authors.initials: A
authors.lastname: Binley
authors.forename: Andreas
authors.initials: A
authors.lastname: Kemna
authors.forename: Markus
authors.initials: M
authors.lastname: Wehrer
authors.forename: Adrian Flores
authors.initials: AF
authors.lastname: Orozco
authors.forename: Rita
authors.initials: R
authors.lastname: Deiana
authors.forename: Jacopo
authors.initials: J
authors.lastname: Boaga
authors.forename: Matteo
authors.initials: M
authors.lastname: Rossi
authors.forename: Peter
authors.initials: P
authors.lastname: Dietrich
authors.forename: Ulrike
authors.initials: U
authors.lastname: Werban
authors.forename: Ludwig
authors.initials: L
authors.lastname: Zschornack
authors.forename: Alberto
authors.initials: A
authors.lastname: Godio
authors.forename: Arash
authors.initials: A
authors.lastname: JafarGandomi
authors.forename: Gian Piero
authors.initials: GP
authors.lastname: Deidda
mesh_terms: D004553:Electric Conductivity; D004560:Electricity; D055593:Geological Phenomena; D005844:Geology; D007558:Italy; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution / Q000032:analysis*; D012987:Soil / Q000737:chemistry*
chemical_list: D010578:Petroleum; D012987:Soil