Relationship between redox potential and pH on RDX transformation in soil-water slurries

The presence of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in surface so il, the vadose zone, and ground water can present serious environmental pro blems. The processes governing the release and transformation of RDX into s oils and the aquatic environment are not well understood. The objective of this study was to determine the effects of differing environmental conditio ns as reflected by redox potential and pH on the fate of RDX in soil. Labor atory investigations consisted of testing three redox potentials and four p H I levels in an 18:1 (2,600 m(3) water:150 g soil) suspension spiked with 10 mg/L RDX. Results indicated that RDX was unstable under highly reducing conditions (-150 mV) and relatively stable over the short term(15 days) und er oxidizing and moderately reducing conditions at all pH values. RDX in ar eas of intense reduction would not persist. However, RDX deposited or movin g into areas under moderately reducing or oxidizing conditions would be hig hly mobile and persistent.