2006 Annual Report 4d.Progress report. This report serves to document research conducted under a reimbursable agreement between ARS and Oregon State University. Additional details of research can be found in the report for the parent project 1265-12000-037-00D, Risk Assessment and Remediation of Soil and Amendment Trace Elements. Oregon State University and cooperators had found that rumen fluid could biodegrade TNT, while even flooded soils cause little biodegradation of TNT and cause metabolites to be covalently linked to soil organic matter. The rumen is more reducing than soils and this or the specific microbes in the rumen fluid are able to metabolize TNT while other systems have much slower rates of biodegradation. This ability of rumen microbes suggests that a phytoextraction-bioremediation technology could be developed for remediation of soil TNT. Significant uptake of TNT was also found in some grasses such that a model of sheep grazing grass pastures growing on TNT contaminated soils would achieve needed remediation and degradation of TNT over time. Tests being conducted in FY-2006 include a whole body test of the metabolism and balance of 14C-TNT fed to sheep in a controlled study, and plant uptake tests from TNT amended soils by representative grasses of commercial importance in Oregon. These experiments are still in progress so no details are available for this annual report.