Fate of 2,4,6-trinitrotoluene and its metabolites in natural and model soil systems

The sorption-desorption characteristics of 2,4,6-trinitrotoluene (TNT), 4-a mino-2,6-dinitrotoluene (4-ADNT), and 2,4-diamino-6-nitrotoluene (2,4-DANT) within a natural topsoil, an illite shale, and a sanely aquifer material ( Borden sand) were studied. The sorption capacity constant (K-d(s)) of the t hree nitroaromatic compounds (NACs) increased with the number of amino grou ps (i.e., 2,4-DANT > 4-ADNT > TNT) for topsoil, and there was significant s orption-desorption hysteresis. Traces of 4-N-acelylamino-2-amino-6-nitrotol uene (4-N-AcANT) formed during sorption of 2,4-DANT by nonsterile topsoil ( 22 h), but this did not account for the hysteresis. For longer contact time s (66 h), 4-N-AcANT accounted for 26% of the biotic disappearance of 2,4-DA NT, and traces of 2-N-acetylamino-2-amino-6-nitrotoluene (2-N-AcANT) were d etected. For illite, the K-d(s) increased with the number of nitro groups ( i.e., TNT > 4-ADNT > 2,4-DANT), and there was also sorption-desorption hyst eresis. Most of the 2,4-DANT was neither desorbed nor extractable by aceton itrile from illite or topsoil. Sorption of the NACs by Borden sand was slig ht or nonexistent This study illustrates that soil and NAC type will have a significant effect on the K-d(s) as well as the formation of acetylated me tabolites.