CHARACTERIZATION OF INSOLUBLE FRACTIONS OF TNT TRANSFORMED BY COMPOSTING

Soil contaminated with explosives was supplemented with carbon-14 labelled 2,4,6-trinitrotoluene (C-14-TNT) and was composted in a field static pile composting experiment. After 90 d of composting, the distribution of carbon-14 (C-14) activity in fractions from acetonitrile extraction (''free'' fraction, 1.2% of the initial C-14-activity) and filtration (''insoluble - particle'' fraction, 17.9%), alkaline hydrolysis (''insoluble hydrolyzable'' fraction, 56.8%), and combustion of the residue (''insoluble nonhydrolyzable'' fraction, 4.7%) showed that the bulk of the C-14-activity, and presumably transformed product(s) of the C-14-TNT, accumulated in a nonextractable, but hydrolyzable fraction. Repetitive aqueous leaching of the compost and also ultraviolet light irradiation followed by leaching suggest that the insoluble fraction of transformed TNT should not be released appreciably by the action of acid rain or sunlight.