Propriétés électriques des sols contaminés par des hydrocarbures pétroliers: étude en laboratoire

In many worldwide cities, urban development has reached the fringes of old industrial areas, whereas industrial downsizing has produced a significant number of Brownfield. These are often orphan sites contaminated with various pollutants which still remain undeveloped even after several decades of abandonment. In recent years, urban Brownfield started to be considered as been beneficial occasions for urban land redevelopment, however, it was recognized that their remediation and reuse slows down urban sprawl as well as their environmental impacts. Hence, there is a growing need to assess the environmental quality of these sites. The environmental assessment of urban Brownfield is difficult due to their large physical and chemical heterogeneity. One of the most promising methods to characterize these urban sites (heterogeneous fill) that are often contaminated by pollutants after more than a century of industrialization is the induced polarization (IP). In this project, the potential of this method to detect contaminated soil with fresh oil is investigated by doing laboratory measurements. During the first phase of this project, an exhaustive study is conducted on the different geophysical auscultation methods to characterize heterogeneous fill. This study includes the method of electrical resistivity and induced polarization to characterize the contaminated soil. After the study is completed, these methods analyze the electrical properties such as resistivity and chargeability. The chemical and physical properties will be tested on laboratory samples (sand and till) obtained from a Montreal urban Brownfield. The electrical resistivity and chargeability are in principle susceptible to the soil mineral composition, grain size, water content, pore fluid chemistry, metal content and the degree of hydrocarbons presence. Finally it will be possible to assess the IP sensitivity to hydrocarbon concentration (detection level) and in general the effectiveness of the induced polarization method to evaluate the electrical, physical and chemical behaviour of the urban fills (heterogeneous).