Explosive detonation causes an increase in soil porosity leading to increased TNT transformation

• Published in: PloS one 2017-12, Vol.12 (12), p.e0189177
• Main Authors: Yu, Holly A, Nic Daeid, Niamh, Dawson, Lorna A, DeTata, David A, Lewis, Simon W
• Format: Article
• Language: English
• Subjects: 2,4,6-Trinitrotoluene; Bacteria; Bacteria - metabolism; Bioavailability; Biodegradation; Biological Availability; Biology and Life Sciences; Bioremediation; Computed tomography; Contaminants; Detonation; Ecology and Environmental Sciences; Electron microscopy; Engineering and Technology; Environmental aspects; Environmental degradation; Environmental effects; Explosive Agents; Explosives; Fractures; Industrial engineering; Industrial plants; Industrial wastes; Laboratories; Manufacturing engineering; Manufacturing industry; Medicine and Health Sciences; Microscopy, Electron, Scanning; Physical properties; Physical Sciences; Planes; Porosity; Remediation; Research and Analysis Methods; Scanning electron microscopy; Sediment pollution; Soil aggregates; Soil analysis; Soil bacteria; Soil contamination; Soil erosion; Soil investigations; Soil loss; Soil Microbiology; Soil microorganisms; Soil physical properties; Soil Pollutants - analysis; Soil pollution; Soil porosity; Soil properties; Soil remediation; Studies; TNT (Trinitrotoluene); Tomography; Transformation; Trinitrotoluene - analysis; Trinitrotoluene - chemistry; Trinitrotoluene - metabolism; X-Ray Microtomography
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0189177

Explosives are a common soil contaminant at a range of sites, including explosives manufacturing plants and areas associated with landmine detonations. As many explosives are toxic and may cause adverse environmental effects, a large body of research has targeted the remediation of explosives residues in soil. Studies in this area have largely involved spiking 'pristine' soils using explosives solutions. Here we investigate the fate of explosives present in soils following an actual detonation process and compare this to the fate of explosives spiked into 'pristine' undetonated soils. We also assess the effects of the detonations on the physical properties of the soils. Our scanning electron microscopy analyses reveal that detonations result in newly-fractured planes within the soil aggregates, and novel micro Computed Tomography analyses of the soils reveal, for the first time, the effect of the detonations on the internal architecture of the soils. We demonstrate that detonations cause an increase in soil porosity, and this correlates to an increased rate of TNT transformation and loss within the detonated soils, compared to spiked pristine soils. We propose that this increased TNT transformation is due to an increased bioavailability of the TNT within the now more porous post-detonation soils, making the TNT more easily accessible by soil-borne bacteria for potential biodegradation. This new discovery potentially exposes novel remediation methods for explosive contaminated soils where actual detonation of the soil significantly promotes subsequent TNT degradation. This work also suggests previously unexplored ramifications associated with high energy soil disruption.