Dissolution, sorption, and phytoremediation of IMX-101 explosive formulation constituents: 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine

The insensitive munition, IMX-101 approved for use in the USA, contains 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ) and is designed to be less sensitive to shock and sympathetic detonation. Given the estimated future use of IMX-101, an understanding of IMX-101 constituent attenuation mechanisms on testing and training ranges is needed. Studies were conducted to determine (1) the rates of IMX-101 fragment dissolution during simulated rainfall, (2) DNAN and NTO soil sorption coefficients, (3) ability of grasses to germinate in and phytoremediate IMX-101 contaminated soil, and (4) effect of the addition of IMX-101 degrading enrichment cultures on phytoremediation. The IMX-101 particles were found to dissolve slowly under simulated rainfall conditions with NQ and NTO dissolving first, leaving DNAN crystals. DNAN and NTO sorption to soils fit Freundlich isotherms and limited desorption was observed. DNAN and NQ were shown to be taken up into the roots and shoots of a mixture of big bluestem grass (Andropogon gerardii), Nash Indiangrass (Sorghastrum nutans), and switchgrass (Panicum virgatum) during phytoremediation of soils contaminated with up to 50 mg kg−1 IMX-101. Complete degradation of IMX-101 to below detection limits occurred over 225 days. The addition of an IMX-101 degrading enrichment culture to the treatments significantly increased the root and shoot mass.