National Crude Oil Spill Fate and Natural Attenuation Research Site near Bemidji Minnesota

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The primary focus of the science team at the site is to improve the understanding of the mobilization, attenuation, transport, fate, potential health effects, and remediation of petroleum in the subsurface through collaborative research, peer-reviewed publications, presentations, data, and educational activities.

The objective of the project is to improve the understanding of the mobilization, transport, and fate of crude oil in the shallow subsurface. The U.S. Geological Survey Toxic Substances Hydrology Program began an interdisciplinary research project in 1983 at the site of a crude-oil spill near Bemidji, Minnesota. Research is conducted by scientists from the U.S. Geological Survey and from several academic institutions. Currently we have four primary research objectives: (1)characterizing the nature, toxicity and prevalence of partial transformation products emanating from the crude oil source, (2) evaluating the secondary impacts [such as arsenic cycling] of biodegradation, (3) understanding the timeframe of natural attenuation of petroleum hydrocarbon source zones, and (4) developing field tools, methods, and data that support evaluations of environmental health effects of natural attenuation of crude oil. 

fact sheet describing results from the Bemidji research site is available.

The spill occurred in 1979 when a pipeline transporting crude oil broke. After cleanup efforts were completed in 1980, about 400,000 liters of oil remained in the unsaturated zone and near the water table. This continues to be a source of contaminants to a shallow outwash aquifer. The oil is moving as a separate fluid phase, as dissolved petroleum constituents in ground water, and as vapors in the unsaturated zone. Native microbes are converting the petroleum derivatives into carbon dioxide, methane, and other biodegradation products.

Lessons learned decades after an oil spill faded from headlines

 

Lessons learned decades after an oil spill faded from headlines

(Public domain.)

Cross section master

(Public domain.)