Simulated rainfall-driven dissolution of TNT, Tritonal, Comp B and Octol particles

Military training activities often leave unexploded high explosives (HE) as particles on soil surfaces. These particles may dissolve during rainfall events, leading to contamination of water systems. Prior research has shown that rainfall can mobilize HE particles, but the specific dissolution mechanisms remain unclear. No prior work had resolved how particle composition and rainfall rate influence dissolution rates. This gap motivated the need to simulate dissolution under controlled conditions. Existing models lack validation for real-world scenarios involving mixed HE particles. Understanding solubility differences between explosive compounds is essential for predicting environmental impact. The role of particle size in dissolution kinetics has not been fully explored. This study aimed to bridge these knowledge gaps through experimental simulation.

The study aimed to simulate how rainfall might dissolve high explosive particles left on soil surfaces after military training. The researchers wanted to test dissolution rates of four specific HE compounds: TNT, Tritonal, Comp B, and Octol. They also sought to verify a predictive model for dissolution based on particle size, composition, and rainfall rate. The study focused on understanding how solubility differences affect dissolution dynamics. The researchers wanted to determine whether particle composition controls dissolution behavior. They also aimed to assess whether a drop-impingement model could accurately predict real-world dissolution. The study addressed a need for better environmental risk assessment tools. The findings could inform strategies for managing contaminated sites.

The researchers used a simulated rainfall setup to study dissolution of HE particles. They dripped water onto individual particles of TNT, Tritonal, Comp B, and Octol. Particle masses ranged from 1.1 to 17 mg to represent different sizes. Drip rates corresponded to rainfall rates of 6 and 12 mm/h. The setup allowed tracking of dissolved mass over time. The study compared dissolution behavior across different HE compounds. The researchers used a drop-impingement model to predict dissolution rates. They validated model predictions against observed dissolved-mass time series.

TNT solubility dominated dissolution rates for TNT and Tritonal particles. In Comp B, RDX’s lower solubility controlled the dissolution of both RDX and TNT. For Octol, HMX’s low solubility slowed but did not control TNT dissolution. Dissolution times varied with particle size and composition. Predicted dissolution rates matched observed data for TNT, Tritonal, and Comp B. The model showed less agreement with Octol dissolution data. Particle size influenced dissolution rates, with larger particles dissolving more slowly. The study confirmed that solubility differences strongly affect dissolution behavior.

The study found that solubility differences among explosive compounds strongly affect dissolution rates. The drop-impingement model accurately predicted dissolution for TNT, Tritonal, and Comp B. The model’s predictions for Octol showed less agreement with observed data. Particle size influences dissolution time, with larger particles dissolving more slowly. The study supports the use of predictive models for environmental risk assessment. The findings suggest that particle composition controls dissolution behavior in mixed HE particles. The study provides a basis for modeling outdoor dissolution under rainfall conditions. The results may help improve strategies for managing contaminated sites.