Researchers use bacteria to reduce uranium to safe levels: "'Toxic uranium is often found in groundwater at places where uranium was either mined or enriched to make weapons,' said Craig Criddle, a professor of civil and environmental engineering at Stanford. 'This uranium-contaminated water can migrate into surface waters, where it becomes a threat to organisms and water supplies. Excavation of contaminated soil or pumping and treating the water are prohibitively expensive and lead to additional disposal issues. An alternative is to stimulate naturally occurring subsurface microorganisms that can convert the dissolved uranium into a solid form that is not susceptible to transport by water.'

For the past six years, a research team at Stanford headed by Criddle has worked with a research team at the Oak Ridge National Laboratory (ORNL) in Tennessee headed by Phil Jardine, a soil chemist and distinguished research staff scientist there, to develop a possible solution to the problem. The group's strategy took groundwater that originally contained more than 1,000 times the drinking-water regulatory limit for uranium and brought concentrations down to the limit. The technique and its early results are described in a pair of papers to appear June 15 in the journal Environmental Science and Technology, a publication of the American Chemical Society. The papers were published online on May 13."