New grasses neutralize toxic pollution from bombs, explosives, and munitions

On military live fire training ranges, troops practice firing artillery shells, drop bombs on old tanks or derelict buildings and test the capacity of new weapons. 

But those explosives and munitions leave behind toxic compounds that have contaminated millions of acres of U.S. military bases—with an estimated cleanup bill ranging between $16 billion and $165 billion.

University of Washington and University of York researchers describe new transgenic grass species that can neutralize and eradicate RDX—a toxic compound that has been widely used in explosives since World War II.

UW engineers 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 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.

It is the first reported demonstration of genetically transforming grasses to supercharge their ability to remove contamination from the environment. Grasses are hearty, fast-growing, low-maintenance plants that offer practical advantages over other species in real-world cleanup situations.

"This is a sustainable and affordable way to remove and destroy pollutants on these training ranges," said senior author and UW professor of civil and environmental engineering Stuart Strand, whose lab focuses on taking genes from microorganisms and animals that are able to degrade toxic compounds and engineering them into useful plants.