Fate and Transport of 2,4,6-Trinitrotoluene in Loams at a Former Explosives Factory

Abstract

Natural attenuation processes affecting 2,4,6-trinitrotoluene (TNT) were determined within loams for two study areas at the former Explosives Factory Maribyrnong, Australia. TNT fate and transport was investigated through spectrophotometric/High Performance Liquid Chromatography (HPLC) analyses of soil and groundwater, adsorption and microcosm testwork. A five tonne crystalline TNT source zone delineated within near surface soils at the base of a TNT process waste lagoon was found to be supplying aqueous TNT loading (7 ppm) to subsurface soils and groundwater. The resultant plume was localized within the loam aquitard due to a combination of natural attenuation processes and hydrogeological constraints, including low hydraulic conductivity and upward hydraulic gradients. Freundlich described sorptive partitioning was the main TNT sink (K F = 29 mL/g), while transformation rates were moderate (1.01 × 10 −4 h −1 ) under the aerobic conditions. Increasing 2-amino-4,6-dinitrotoluene predominance over 4-amino-2,6-dinitrotoluene was discovered with depth (in situ) and time (microcosms). Simplified dissolution rate calculations indicate that without mitigation of the TNT source, contaminant persistence within the vadose zone may approach 2000 years, while ATRANS20 simulations demonstrate that the TNT plume propagates very slowly along the flow path within the aquitard.

Organic Analysis for Urban Geochemical Survey Soil Samples

“…It is used in the analysis of soil that has been contaminated with explosives (e.g. Robertson et al, 2007). A methodology for the clean-up, preconcentrations and HPLC-UV analysis is presented in USEPA Method 8330B (USEPA, 2007f).…”

Stable Isotopes of Nitrate Reflect Natural Attenuation of Propellant Residues on Military Training Ranges

“…In the past decade, contamination of soils, groundwater and surface water by energetic materials (EMs) has been recognized as an important environmental issue. The presence of various EMs in soils and water has been documented at ammunition production facilities, 1 as well as on military training ranges throughout Canada and the United States. 2,3 At military training facilities, firing positions of antitank ranges are among the sites most heavily impacted by the presence of EMs.…”

“…In the past decade, contamination of soils, groundwater and surface water by energetic materials (EMs) has been recognized as an important environmental issue. The presence of various EMs in soils and water has been documented at ammunition production facilities, as well as on military training ranges throughout Canada and the United States. , At military training facilities, firing positions of antitank ranges are among the sites most heavily impacted by the presence of EMs. , In this context, double-base propellants are used, which are composed of nitroglycerin (NG) embedded within a nitrocellulose (NC) matrix. During ammunition firing, incomplete combustion causes significant amounts of propellant residues to be deposited at the soil surface, mainly behind the firing position.…”

“…This approach was adopted because NG concentrations in pore water are often very low, 5,26,27 which would render isotopic analyses difficult, while NO 3 − concentrations are usually sufficient to allow analysis. 5,18 The objectives of this study are therefore to (1) analyze the isotopic ratios of NO 3 − coming from the degradation of NG and NC through controlled processes, (2) determine whether these ratios can help identify the processes involved in natural attenuation of propellant constituents at an antitank firing position, and (3) evaluate whether isotopic ratios can be used to distinguish the sources of NO 3…”