Phytoremediation of Composition-B Derived TNT and RDX in Herbaceous Plant-vegetated and Bare Lysimeters
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS
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This report describes a study in which phytoremediation of composition-B comp-B derived TNT and RDX was quantified in 0.5-m S. nutans Indian grass-vegetated organic matter and nutrient-poor soil over a 92-day period. The vegetation was allowed to establish in 0.5-m-high soil cores prior to amendment with ground comp-B mixed with the same soil, and effects and fate of comp-B derived TNT and RDX were followed in plants, soil, and leachate under greenhouse conditions. Remediation in vegetated soils exceeded that in bare soils for TNT up to a comp-B level of 218 mg kg-1, and for RDX up to a comp-B level of 73 mg kg-1. Thus, phytoremediation can be used as an effective remediation technology in a given range of explosives contamination. The greatest annual remediation potential was 58.5 g TNT m-2 and 42.4 g RDX m-2 in vegetated soils, and 54.5 g TNT m-2 and 51.0 g RDX m-2 in unvegetated soils. Remediation was attributed to a large degree to processes other than plant uptake, including bioremediation plant-assisted or not, complexation with plant material and soil components leading to non-extractability, and photolysis limited to the upper soil layer. Results of a comparison between 15N-based and chemical-RDX-based mass balances, with 15N derived from uniformly labeled 15N-RDX, indicated greater incorporation of 15N than of RDX in soil and plants of vegetated units than in soil of non-vegetated units.
- Ammunition and Explosives
- Test Facilities, Equipment and Methods