Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2006
Publication Date: 11/29/2006
Citation: Craig, A.M., Duringer, J.M., Smith, D.J., Delorme, M.M., Chaney, R.L. 2006. Absorption, Distribution, Metabolism, and Elimination of [14C]-2,4,6-Trinitrotoluene in Sheep After a 30-Day Exposure to Dietary Unlabeled 2,4,6-Trinitrotoluene. Meeting Abstract. p. E109. Interpretive Summary: .
Technical Abstract: Much work has been done to find cost effective ways to remediate the highly toxic and persistent explosive compound trinitrotoluene (TNT) from contaminated soils and groundwater. Over 700,000 cubic yards of soil and 10 billion gallons of ground water require treatment at tremendous costs to the Department of Defense. TNT is the primary contaminant at these sites, along with dinitrotoluene (DNT) and other nitro substituted explosives (i.e., RDX and HMX). The relatively high cost of ex situ remediation techniques has led to the search for in situ methods of degrading or transforming TNT. Efforts have more recently focused on developing methods to treat TNT biologically. The highly electrophilic nature of TNT lends itself to transformations by reductive pathways. Phytoremediation of TNT has been proposed because several plant species have been shown to absorb and transform trinitrotoluene. Biotransformation of TNT by microbes occurs most commonly under anaerobic conditions through the sequential reduction of the nitro groups to amine groups to form aminodinitrotoluenes, diaminonitrotoluenes, triaminotoluene, and azoxy dimers along with other unknown products. In particular, ruminant animals possess a highly reductive anaerobic environment in their rumen, making them excellent candidates for reduction of TNT. Taking this information together, we have proposed a new method for bioremediation of TNT, namely that plants on contaminated sites bring TNT into their blades after which sheep graze these plants and remediate TNT in the rumen. Questions have been asked about the toxicity of TNT to sheep. Here we report on a study conducted to measure the absorption, disposition, metabolism, and excretion of 2,4,6-trinitro[14C]toluene in sheep after a 30 day dietary exposure to unlabeled 2,4,6-trinitrotoluene. Urine, feces, kidney, liver, muscle, fat and rumen fluid were collected and analyzed for [14C] TNT and its metabolites. Previous studies have shown the conversion of TNT into dinitro followed by diamino into unknown polar metabolites in the rumen. It is expected that these polar products will be found in the tissues and bodily fluids examined.