Explosive research has implications for landmine clearing and fracking

Blowing up landmines and other undetonated explosives may be safer and more environmentally friendly than physically removing them from contaminated land, according to new research by the University of Dundee and partner institutions.

Explosives can be a common soil contaminant at a range of sites, including military training facilities, manufacturing plants and post and current conflict zones. If these areas are to be brought back into productive use then they need to be cleared of the explosive and any toxic residue of explosives in the soil.

The Dundee research, carried out in conjunction with an interdisciplinary team of scientists from the James Hutton Institute in Aberdeen and the ChemCentre and Curtin University, both in Australia, saw the team stage a series of controlled explosions to explore how different soils behave and what happens to the explosive residue as a result.

Their results suggest that residues are more quickly and effectively bio-remediated when explosives are detonated rather than when they are chemically or physically removed, a process that incurs both expense and risk.

“Our research investigates what happens to explosives present in soils following an actual detonation and compares this to the fate of explosives spiked into undetonated soils,” said Professor Niamh Nic Daeid, Director of Dundee’s Leverhulme Research Centre for Forensic Science.

“The effects of detonations on the physical properties of the soils were also examined. When explosions occur, soil is fractured and dispersed in such a way that allows removal of TNT by soil-borne bacteria, resulting in an increased effectiveness in the removal of toxins that may cause adverse environmental effects. 

“The detonations caused an increase in soil porosity, which directly related to an increased rate of TNT loss within the detonated soils as the surface area available for bio-degradation to occur increased. This new discovery potentially exposes novel remediation methods for explosive contaminated soils where actual detonation of the soil significantly promotes subsequent TNT degradation.”

Ultimately, the results from the work, published in the journal PLOS One, suggest that pores present within some soil types may act as ‘sinks’ for soil contaminants such as TNT, reducing its availability for subsequent microbial degradation of the contaminant. By physically detonating the soil, these pores increase in size and availability allowing for an increased bio-degradation and consequent reduction of the TNT to occur. The findings may also have possible implications for the fracking industry.

“Because our work examines the effects of detonation of sub surface soil it might also have implications for other high-energy soil disruption, such as fracking, which should be pursued and explored,” added Professor Nic Daeid.

The paper can be read at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0189177.