Cold War Legacy: Sub-surface Investigation of Unsaturated Prairie Soil Radiologically Contaminated in 1951

Abstract

An unintentional release of fission products (FPs) from a buried storage tank in 1951 resulted in 6.7 L of liquid, bearing radioactive material, being spilled into unsaturated prairie soil at a depth of 3.7 m. Since then, the site has been undisturbed. In October 2001, boreholes were drilled and soil samples were recovered for analysis. Gamma well logging showed higher than background radiation readings at a depth of 3.5 m (corresponding to the storage container location) and a peak reading at 4.7 m (attributed to the breakthrough curve). The soil was determined to be predominantly lean clay with a silty sand layer between 4.4 and 5.1 m. Future work includes radiochemical analysis, soil column simulation, determination of distribution coefficients and transport modelling.