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Subsurface fate of spilled petroleum hydrocarbons in continuous permafrost

Abstract:

Accidental releases of approximately 2000 m3 of fuel have resulted in subsurface contamination adjacent to Imikpuk Lake, a drinking-water source near Barrow, AK. This paper presents a conceptual model of the distribution and transport of subsurface free-phase hydrocarbons at this site. The mean annual temperature in Barrow is −13 °C, and average monthly temperatures exceed 0 °C only during the months of June, July, and August. As a result, the region is underlain by areally continuous permafrost that extends to depths of up to 300 m and constrains subsurface hydrologic processes to a shallow zone that temporarily thaws each summer. During the 1993 and 1994 thaw seasons, the measured depth of thaw varied across the site from approximately 0.5 to 2 m. However, exploratory borings in 1995 showed that free-phase hydrocarbons were present at depths greater than 3 m, indicating that permafrost at this …