Camila Madeira

Department: 
Chemical and Environmantal Engineering
Abstract: 

Environmental Fate of the New Insensitive Munition Compounds
     Insensitive Munition Compounds (IMC) are used by the army as a replacement to conventional explosive compounds (such as TNT) because they are more stable and, as a consequence, safer to handle. As IMC have become more popular, their increased use has led to the contamination of water and soil. However, the pathways and impacts of these compounds in the environment are still unknown. It is important to develop techniques to degrade IMC in the environment.
     Biodegradation, or transformation using microorganisms, is an efficient technique for removing organic compounds from the environment. In this study, soil bacteria were used to degrade the insensitive munitions compounds NTO (5-nitro-1,2,4-triazol-3-one) and DNAN (2,4-dinitroanisole). In addition, assays were conducted to assess the toxicity of these compounds.
     NTO was chemically transformed to ATO (5-amino-1,2,4-triazol-3-one) by soil bacteria in the absence of oxygen, and ATO was degraded in the presence of oxygen.  DNAN was chemically transformed into various reduced products in the absence of oxygen, which were either mineralized or formed oligomers, ending up in the humus fraction of the soil. NTO and DNAN were not transformed in the absence of microorganisms, suggesting that biological mechanisms are the main responsible for the degradation process. Furthermore, microbial toxicity assays show that DNAN is more toxic than most of its reduced degradation products.
     Biodegradation is an effective method of removal of IMCs from soil. The results obtained in this research suggest that a sequence of anaerobic and aerobic degradation can mineralize or transform NTO and DNAN into environmentally safer compounds, decreasing their risks to the ecosystems and to human life.