RAPID MIGRATION OFA LARGE HYDROCARBON PLUME IN SAPROLITE

Two subsurface hydrocarbon plumes recently originated under a commercial fuel tank farm in northern Virginia. The total loss was about 200,000 gallons of mostly diesel fuel, but included jet-A fuel and gasoline. Chemical and physical evidence suggests that the longer plume, about 1,000 meters in length, moved its entire length in less than 5 years. It has been estimated that natural bioremediation would require about 2,500 years to reduce the contamination to remediation endpoints, and enhanced bioremediation would take about 200 years. Citizen groups and local regulatory officials initally requested remediation by total plume excavation which would take only about 5 years. However, remediation by excavation would require removal of many expensive homes and a commercial district, neither of which were present when the tank farm was constructed almost 40 years ago. US-EPA approved settlement arrangements required that the company that was responsible for the spill has to purchase all the impacted homes owned by occupants who wish to sell, and the company has to develop and maintain remediation efforts, until appropriate regulatory agencies are satisfied.