Environmental Impact to the Chemical Signature Emanating from Buried Unexploded Ordnance.

摘要

Detecting the presence of buried unexploded ordnance (UXO) using chemical vapors derived from the main charge explosive has been considered possible with advances in sensitivity and selectivity of emerging chemical sensing technologies. Understanding the environmental impacts to this chemical signature is critical, as environmental factors have a dramatic effect on the source release, transport, phase transfers and degradation in soil systems. This project established several tasks to evaluate the environmental impact to the chemical signature from buried UXO. These tasks included simulation model development and utilization to evaluate the interdependent physico-chemical transport phenomena in near surface soils, fundamental property measurement for those parameters needed in the simulation model that had insufficient or poor quality data, and laboratory-scale experiments that produced data for comparison to simulation model results. This project also sponsored work to produce data on the chemical release characteristics of a small subset of ordnance and UXO, and to determine the chemical residues in the field adjacent to actual UXO. This work has resulted in the development of a simulation model, T2TNT, which incorporates the soil chemodynamic processes most important to near surface soil transport of chemical residues from buried UXO. Measurements were made of the temperature dependent water solubility of TNT and DNT, soil-liquid partition coefficient for DNT, and the soil-vapor partitioning coefficient as a function of soil moisture content for TNT and DNT. Comparison of T2TNT simulation results to laboratory-scale vapor flux experiments simulating a buried source release were excellent. UXO source release tests showed that prior to firing, ordnance contained a sufficient chemical reservoir for release into the soil. However, after firing and recovery (now as an UXO), the ordnance chemical flux was insufficient to overcome biochemical degradation rates.