Kitty litter has been one of the most effective methods of cleaning up in the history of humankind--sopping up moveable messes and sequestering them. Using a naturally forming mineral as their kitty litter, researchers at the Department of Energy's Idaho National Engineering and Environmental Laboratory are working on a way to sop up a radioactive element and immobilize it until the element's radioactivity is spent.
Funded by DOE's Environmental Management Science Program, the researchers are trying to trap strontium-90 and other similar elements in calcite. INEEL geochemist Robert W. Smith leads the multi-university collaboration that includes INEEL microbiologist Rick S. Colwell, University of Toronto geomicrobiologist F. Grant Ferris, INEEL analytical chemist Jani Ingram, and Portland State University microbiologist Anna-Louise Reysenbach. Together, the researchers received a 3-year, $0.9 million grant that was announced by Under Secretary of Energy Ernest Moniz today. The award was part of a larger $25 million grant for 31 projects at 20 universities and eight DOE laboratories.
Strontium-90 is a radioactive element produced in nuclear reactors. In the past decades, some waste disposal methods have left pockets of low-level radioactive contamination in the vadose zone (the region between the surface and the groundwater) and in the groundwater. The vadose zone under INEEL ranges from 100 feet to 600 feet deep. Getting pollutants out of the subsurface is difficult to do with engineering efforts.
Strontium and similar elements can migrate through the vadose zone and aquifer, said Smith. With the radioactive strontium-90 trapped in the calcite crystal, however, it will be unable to move and will be effectively removed from the groundwater.
All radioactive elements eventually decay to inert elements, and Strontium-90
will take 300 years to decay away to nothingness. "If we can retain it, tie it
up for that length of time," said Smith, "and if we d
Contact: Mary Beckman
DOE/Idaho National Laboratory