New grasses eat up all RDX from ground, keep air healthy

A group of US engineers has developed two types of transgenic grass species that can eliminate toxic compounds widely used in explosives which contaminate the air around military bases and battlegrounds.

Explosives and munitions leave behind toxic compounds that have contaminated millions of acres of US military bases -- with an estimated cleanup bill ranging between $16 billion and $165 billion, according to a paper published in Plant Biotechnology Journal.

The University of Washington (UW) and the University of York researchers introduced two genes from bacteria that learned to eat RDX and break it down into harmless components in two perennial grass species: switchgrass (Panicum virgatum) and creeping bentgrass (Agrostis stolonifera).

The best-performing grass strains removed all the RDX from a simulated soil in which they were grown within less than two weeks and they retained none of the toxic chemical in their leaves or stems.

"This is a sustainable and affordable way to remove and destroy pollutant on these training ranges," said Stuart Strand, senior author and UW Professor of civil and environmental engineering.

"The grasses could be planted on the training ranges, grow on their own and require little to no maintenance. When a toxic particle from the munitions lands in a target area, their roots would take up the RDX and degrade it before it can reach groundwater," Strand added.

But when the grasses die, the toxic chemical is re-introduced into the landscape.

Co-authors Professor of biotechnology Neil Bruce and research scientist Liz Rylott, at the University of York, inserted bacterial genes into plant species commonly used in laboratory settings that eventually enabled the new plant strains to remove RDX contamination successfully.

"Considering the worldwide scale of explosives contamination, plants are the only low cost, sustainable solution to cleaning up these polluted sites," Bruce noted.

The research team also found another unexpected side benefit -- because the genetically modified grasses use RDX as a nitrogen source, they actually grow faster than wild grass species.

--IANS

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