CONTRIBUTIONS BY DR. HANS OLAF PFANNKUCH AT THE BEMIDJI, MINNESOTA CRUDE-OIL SPILL RESEARCH SITE

On August 20, 1979, a crude-oil pipeline burst about 19 kilometers northwest of Bemidji, Minnesota spilling about 10,700 barrels of crude oil onto a glacial-outwash deposit. Shortly thereafter, Dr. Hans Olaf Pfannkuch of the University of Minnesota, in collaboration with scientists from the the U.S. Geological Survey and several academic institutions, began research to understand the fate and transport of this known hydrocarbon source through the soil and ground water. Dr. Pfannkuch and his students contributed at least 14 research papers dealing with subjects such as contaminant-source strength and mass-exchange processes at the petroleum-water interface. In Dr. Pfannkuch's initial report on the spill in December 1979 he suggested that, “No extensive propagation of the dissolved oil components beyond the confines of the present site will take place.” Subsequent research at the site over the past 22 years has confirmed his initial assessment. Since 1983, an inter-agency and inter-disciplinary research team has been assessing the physical, chemical, and biological processes controlling the transport and fate of hydrocarbon contaminants in the subsurface at the Bemidji crude-oil spill site. The objective of the project has been to improve the understanding of the mobilization, transport, and fate of crude oil in the shallow subsurface. The collective research at this project site was fundamental to documenting that spreading of crude-oil contamination can be limited by natural attenuation and that anaerobic degradation of hydrocarbons, particularly through iron reduction, is an important process. Results of the research at this site have provided fundamental knowledge, new tools, and new techniques that have been used to guide practical remediation strategies at similar sites worldwide. In helping to initiate this research effort, the efforts of Dr. Pfannkuch have resulted in considerable benefit to the public, in particular persons involved in petroleum pollution and contaminant remediation such as researchers, industry, consultants, regulators, teachers, and students.