Past documented laboratory measurements have shown movement of petroleum hydrocarbons to the freezing front in contaminated freezing soils. The mechanisms that are, in part, responsible for the increased contaminant concentration at the freezing front are illustrated in this study with a mass-balance model. Results from this quantitative analysis show that this concentration increase is due to exclusion of petroleum hydrocarbon from the crystalline ice structure and from physical displacement of liquid petroleum hydrocarbon from the pore space as water freezes and expands into ice. Consequences of this process in relation to contaminant migration in freezing soils through time are discussed.

Knowledge of how contaminants spread through frozen ground is required to better protect water quality and environmental health. This study investigates the effect of pore ice on vertical and lateral movement of a petroleum product in coarsegrained soils. Time lapse photography is used to track diesel product migrating through two-dimensional flumes packed with wetted soil frozen to 5 ı C. Results from these flow studies indicate that the presence of pore ice blocks pore space, causing increased lateral movement of petroleum, creates preferential pathways resulting in increased petroleum penetration depths, and can restrict infiltration of petroleum into soils with high ice saturations.