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 contami nated with potential mixed wastes. The initial program studied four sites w hose primary radioactive contaminant was thorium. Geophysical, nuclear, and chemical analyses were performed duping the initial phase, with the progra m currently expanding to include biochemical studies. The entire program wa s conducted on-site to eliminate public health concerns about hazardous was te movement and to provide a more efficient and effective way to collect an d process characterization samples. Chemical analyses showed no significant chemical contamination by metals, semi-volatile organic compounds, and tot al petroleum hydrocarbons by EPA standards and thus indicated that the soil would not have to be treated as mixed waste. Radioactivity analysis showed a Th-232 activity that ranged from background levels to over 1000 pCi/g. A dditionally, using dry sieving, a correlation was found between sample radi ation content and soil grain size. It is planned to exploit this effect lat er in the program when site remediation strategies ape developed. (C) 1999 Elsevier Science B.V. All rights reserved.