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UPTAKE AND TRANSFORMATION OF EXPLOSIVES BY EASTERN COTTONWOOD (POPULUS DELTOIDES)
Citation:
Sealock, G. A. AND N L. Wolfe. UPTAKE AND TRANSFORMATION OF EXPLOSIVES BY EASTERN COTTONWOOD (POPULUS DELTOIDES). Presented at Sixth International Symposium on Environmental Biotechnology and Fourth International Symposium on Cleaner Bioprocesses and Sustainable Development, Vera Cruz, Mexico, June 9-12, 2002.
Impact/Purpose:
Elucidate and model the underlying processes (physical, chemical, enzymatic, biological, and geochemical) that describe the species-specific transformation and transport of organic contaminants and nutrients in environmental and biological systems. Develop and integrate chemical behavior parameterization models (e.g., SPARC), chemical-process models, and ecosystem-characterization models into reactive-transport models.
Description:
The explosives 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine (HMX) have been extensively used by the United States military to manufacture munitions. Since World War II, both the commissioning and disposal of weapons at ammunition plants have led to soil, ground, and surface water contamination by these and other recalcitrant pollutants. It has been reported that certain plants have the ability to absorb and transform some explosives from contaminated water. Limited work has been conducted on testing this ability in field-contaminated soils. In this study, Eastern Cottonwood (Populus deltoides) was grown both hydroponically and in explosives-contaminated soil which was obtained from the Naval Surface Warfare Center Crane, Indiana (NSWCC). Cottonwood cuttings were cultivated in 2L Erlenmeyer flasks containing a hydroponic nutrient solution spiked with TNT and RDX. The nutrient solution was sampled daily to determine the rate of uptake by following EPA Method 8330. The results showed TNT was removed at a rate ten-fold faster than RDX. When the munitions reached undetectable concentrations in the growth medium, the plants were harvested. Cuttings were also grown in columns containing munitions contaminated soil and harvested weekly for up to eight weeks. Due to high soil concentrations all seedlings displayed signs of growth inhibition. In both studies, TNT, 2-amino-4,6-dinitrotoluene (2-ADNT), 4-amino-2,6-dinitrotoluene (4-ADNT), and RDX were identified in leaf, root, and stem tissues.