Biodegradation of the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) occurs under anaerobic conditions, yielding a number of products, including: hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine, hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine, hexahydro-1,3,5-trinitroso-1,3,5-triazine, hydrazine, 1,1-dimethyl-hydrazine, 1,2-dimethylhydrazine, formaldehyde, and methanol. A scheme for the biodegradation of RDX is proposed which proceeds via successive reduction of the nitro groups to a point where destabilization and fragmentation of the ring occurs. The noncyclic degradation products arise via subsequent reduction and rearrangement reactions of the fragments. The scheme suggests the presence of several additional compounds, not yet identified. Several of the products are mutagenic or carcinogenic or both. Anaerobic treatment of RDX wastewaters, which also contain high nitrate levels, would permit the denitrification to occur, with concurrent degradation of RDX ultimately to a mixture of hydrazines and methanol. The feasibility of using an aerobic mode in the further degradation of these products is discussed.

The biotransformations of 14C-labeled 2,4,6-trinitrotoluene by thermophilic microorganisms in a compost system were determined. The reduction products identified in solvent extracts were similar to those identified in mesophilic systems. A significant percentage of the 14C-labeled products were bound to humus fractions.

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The fate of "4C-labeled 2,4,6-trinitrotoluene (TNT) in an activated-sludge system was investigated. No [14C]TNT could be detected in the contents of an aerated reactor after 3 to 5 days of incubation. No significant 14C02 was formed, and the radioactivity was about equally divided between the floc and the supernatant. The radioactive carbon present in the microflora was mainly associated with the lipid and protein components, but the characteristic constituents of these compounds (e.g., fatty acids and amino acids) were not radioactive. The

10) Commission of the European Economic Communities (EEC), "Proposal for a Council Directive Concerning the Limit Values for Discharges of Cadmium into the Aquatic Environment and Quality Objectives for Cadmium in the Aquatic Environment"; 12th February 1981; EUR COM (81) 56; February 12, 1981.(11) Wilson, D. C.; Waring, S. "The Safe Landfilling of Hazardous Wastes"; 3rd International Congress on Industrial