Mixed waste characterization in soil

A pilot program has been initiated at Kirtland AFB, New Mexico to study new methods of environmental characterization and restoration of sites contaminated with potential mixed wastes. The initial program studied four sites whose primary radioactive contaminant was thorium. Geophysical, nuclear, and chemical analyses were performed during the initial phase, with the program currently expanding to include biochemical studies. The entire program was conducted on-site to eliminate public health concerns about hazardous waste movement and to provide a more efficient and effective way to collect and process characterization samples. Chemical analyses showed no significant chemical contamination by metals, semi-volatile organic compounds, and total petroleum hydrocarbons by EPA standards and thus indicated that the soil would not have to be treated as mixed waste. Radioactivity analysis showed a 232Th activity that ranged from background levels to over 1000 pCi/g. Additionally, using dry sieving, a correlation was found between sample radiation content and soil grain size. It is planned to exploit this effect later in the program when site remediation strategies are developed.