Credit: SLAC National Accelerator Laboratory
A new field project, led by SLAC researchers and the DOE Office of Legacy Management, is using X-ray techniques to target long-lived groundwater contamination (large dark brown area) at former uranium ore processing sites in the floodplains of the upper Colorado River basin. The visible signs of ore processing, tailings piles and contaminated buildings, were cleaned up in the 1990s, and scientists expected that remaining uranium in the ground should have been flushed out into nearby rivers by now (yellow arrow). However, recent estimates predict that contamination will persist for a long period of time, in some cases longer than 100 years. The goal of this new study is to determine why uranium persists in groundwater; scientists will test the hypothesis that buried zones of organic material (dark brown horizontal stripes) store uranium and release it into the water. Samples are being collected in drilling operations and will be analyzed at SLAC’s X-ray facility SSRL.