Fired munition residues constitute a major environmental concern on military ranges and training grounds as the unspent energetic materials (EMs) may be leached into groundwater following precipitation events. Assessment of subsurface mobility and leaching potential of EMs have focused mostly on their dissolution from fired residues and their sorption to soil components. However, the role of nitrocellulose – a common binding material in propellants – in controlling the environmental fate of EMs remains unclear. This study aims to clarify the potential role of nitrocellulose in the release of bound EMs from fired munition residues. Experimental studies were conducted to understand the sorption capacity of military grade nitrocellulose for nitroglycerine (NG) and 2,4-dinitrotoluene (2,4-DNT) which served as two model EMs. Sorption isotherms for the binding of NG and 2,4-DNT to nitrocellulose were determined in a month-long batch sorption experiment to be S = 250C0.916 and S = 1200C0.668, respectively, with S and C in units of mg/kg and mg/L. The organic carbon normalized partition coefficients for nitrocellulose were approximately 10 times higher than the corresponding soil KOC’s for both NG and 2,4-DNT. Nitrocellulose is capable of sorbing NG and 2,4-DNT up to 23 and 5%, respectively, of its mass, overlapping substantially the composition ranges of NG and 2,4-DNT in common propellants. This implies that nitrocellulose may slow down the overall release of EMs from propellant residues through retarded diffusion. The strong binding capacity of nitrocellulose for NG and 2,4-DNT can support and explain observations from previous soil column studies: (i) the overall dissolution rate of propellant-bound EMs declined with time, and (ii) the percolation of EMs was much slower when using fired residues, rather than dissolved EM solution, as source. Implications of for remediation of EM-impacted training ranges and directions for further investigations will be elaborated.

Can nitrocellulose possibly control the release of energetic materials from fired munition residues?

253rd National Meeting (2017)

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