COLUMBIA, Mo. – Two native Missouri grasses show promise in breaking down military explosives that contaminate soil and water at sites across the country, say University of Missouri and Lincoln University researchers.

Switch grass and eastern gamma grass have high potential for breaking down TNT and RDX, two of the military’s most important high explosives, said Chung-Ho Lin, research assistant professor at the MU Center for Agroforestry.

The U.S. Army has identified more than 538 sites contaminated by explosives, including 20 EPA-designated Superfund sites, said John Yang, Lincoln University associate professor of environmental chemistry.

Their high potential for degrading TNT and RDX indicates that these grasses could play a role at military facilities in reducing contamination of soil and water, a technique called phytoremediation, Lin said.

Switch grass and gamma grass nourish microorganisms in the soil that do the actual work of breaking down the explosives.

Earlier research showed these grasses degraded farm herbicides such as atrazine. Later, researchers found these same grasses stimulated microbes to degrade munitions such as TNT and RDX, said Bob Lerch, USDA soil scientist and MU adjunct assistant professor.

Lerch said that TNT and RDX share some chemical characteristics with certain herbicide families. “They are not that structurally different from herbicides,” he said.

In growth chamber studies, the two native grasses proved more effective than tall fescue, orchard grass, perennial rye grass and others.

Phytoremediation is one of the most cost-effective and environmentally safe strategies to clean up sites contaminated by many organic pollutants, including explosives.

Funding for this collaborative research was provided by grants from the U.S. Department of Defense and Lincoln University’s Center of Excellence for Environmental Science.

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