Vegetable Oil and Molasses Prove Helpful at the Hanford Cleanup

Researchers working at the Hanford site in Washington state are attempting to clean up contaminated groundwater at the former nuclear production complex by injecting vegetable oil into it. Eighty square miles of groundwater in the area exceed federal safety levels for drinking water, and the areas near the Columbia River have levels of carcinogenic hexavalent chromium that threaten salmon and other wildlife. Last year, researchers injected 5,000 gallons of molasses mixed with 200,000 gallons of water into a test well, with positive results. But they say that vegetable oil, on which native bacteria feed, may last longer — perhaps continuing to feed bacteria for seven years, while a molasses injection must be repeated every two years. The technique has been used at other clean-up sites, including the Hinkley, California, site that was the subject of the film “Erin Brockovich.”