Colloids Take Plutonium For A Ride

Data collected at one of the world's most contaminated nuclear waste sites show how radionuclides such as plutonium can be transported long distances in groundwater (Science 2006, 314, 638). For years, effluent from the Mayak nuclear waste reprocessing plant near Kyshtym, Russia, flowed into a small lake, contaminating local groundwater. Rodney C. Ewing of the University of Michigan, Ann Arbor, and his U.S., Russian, and French colleagues studied migration of actinides in the groundwater and found that, over 55 years, plutonium and uranium bound to iron oxide colloids have migrated as far as 4 km from the lake. The findings confirm that "colloids can be responsible for long-distance transport," Ewing says. The team notes plutonium and uranium could be transported in a similar way at other sites, such as the proposed Yucca Mountain repository in Nevada.