Monday, November 13, 2006

Uptake and Biotransformation of 2,4,6-Trinitrotoluene (TNT) by Wheat (Triticum aestivum).

Kabindra Man Shakya, Padmini Das, Konstantinos Makris, Rupali Datta, Dibyendu Sarkar, and Devanand Pachanoor. University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249

The compound TNT (2,4,6-trinitrotoluene) is the predominant conventional explosive used by military forces. During its manufacture and use, large quantities of TNT was released into the environment leading to soil, sediment, and water contamination.  TNT is the most toxic among nitroaromatic explosives, as confirmed by mutatox and green algal bioassays. It is a potential mutagen and a human carcinogen, and has a toxic effect on liver, blood, eyes, and skin. Phytoremediation can help reduce TNT levels significantly from contaminated soil and water. Wheat plants were tested for their potential to uptake and transform TNT in a hydroponic experiment. The main objectives of this study were i) to observe the uptake of TNT by wheat plants, ii) to observe the effect of urea (chaotropic agent) in facilitating the uptake of TNT, and ii) to elucidate the transformation products of TNT in root and shoot extracts of wheat plants. Four week old wheat seedlings were grown in Hoagland nutrient media with 0, 5, 10, 20, and 40 ppm TNT, and 0%, 0.01%, and 0.1% urea. The experiment was conducted for two weeks. The results from HPLC analysis showed decrease of TNT in solution, confirming the uptake of TNT by wheat. However, wheat plants grown in higher concentrations (10 and 20 ppm) of TNT showed some signs of stress. Thus, wheat plant may have the potential to remove TNT at lower concentrations.