Biotransformation pathways dictating the fate in soil of insensitive munition compounds, 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazole-5-one (NTO)

2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazole-5-one (NTO) are insensitive munition compounds (IMCs) that are replacing conventional explosive formulation components. Due to their emerging nature, little is known about the environmental fate in natural systems, such as soils. While both DNAN and NTO readily undergo biological nitrogroup reduction to amino-bearing products such as 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN) for DNAN, and 3-amino-1,2,4-triazole-5-one (ATO) for NTO, the type of biodegradation end-products and their environmental fate differ. In the case of DNAN, there has been no evidence of mineralization in soils by indigenous bacteria, and the dominant long-term products expected are azo-dimers formed during nitroreduction. However, incorporation of amino products as well as continuous polymerization could remove bioavailable products from DNAN pollution. On the other hand, in the case of NTO, subsequent aerobic biodegradation of ATO lead to the mineralization to CO₂ and inorganic N species in specific soils. Ongoing efforts to develop clone libraries to identify the microorganisms involved in the mineralization of NTO. These findings, taken globally, could help devise bioremediation strategies that lead to environmentally benign products.