Phyto-Ruminal-Bioremediation and Land Contaminated with Ordinance

With an extensive background as a former Oregon State University toxicology professor, Dr. A. Morrie Craig researched extensively on livestock and agriculture. In one study, A. Morrie Craig Ph.D. and his colleagues demonstrated the repeated ability of perennial ryegrass and fescue to extract munitions from the soil.

This ability is classified by the US Department of Agriculture as Phyto-ruminal-bioremediation and encompasses the varying biochemical processes that enable detoxification of explosives, including newer shock-insensitive explosive compounds.

With military explosives traditionally centered on TNT (2,4,6-trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), next-generation compounds currently undergoing testing include NTO (nitro-1,2,4-triazole-5-one) and DNAN (2,4-dinitroanisole). Accumulation of such materials in soil and groundwater is a major concern, with military land spanning at least 10 million hectares contaminated in the United States alone.

Patterns of terrestrial contamination tend to be heterogeneous, with vast areas of relatively little contamination interspersed with hotspots of high explosive content. In addition, sites may contain lead, antimony, and other inorganic pollutants at levels that are phytotoxic. Because of unexploded ordnance, ground access to sites may be restricted, making accessibility a major issue.

With clean-up methods such as incineration, landfill, and oxidation best suited to highly polluted, localized areas, plant-based phytoremediation is ideal for larger-scale sites, as well as those with acceptable timeframes of three years or more.