Submitted to: Environmental Science and Pollution Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/11/2011
Publication Date: 1/28/2011
Citation: Chen, D., Banwart, W. 2011. Concentration-dependent RDX uptake and remediation. Environmental Science and Pollution Research. 18:908-917. Interpretive Summary: The toxic RDX was heavily manufactured during the war time as well as in commercial applications such as coal mining. Discharged waste water containing RDX contaminate lagoons during manufacture, packaging, and decommissioning of outdated munitions. This is considered an environmental hazard for soil and water supplies including contaminated areas that are leased for crop production or grazing. Potential contamination of the food chain is an increased concern regarding human health and environment. This study demonstrated that all four examined crop plants of maize, soybean, sorghum, and wheat are able to uptake and accumulate RDX in plant tissues, with the highest capacities by wheat. Results of this study provide information to aid assessment of potential food chain invasion by RDX contaminated soils as well as potential phytoremediation practice.
Technical Abstract: The potential hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) contamination of the food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species including maize, sorghum, wheat, and soybean were capable of RDX uptake with more in aerial parts than roots. The accumulation of RDX in the plant tissue is concentration-dependent up to 21 mg RDX/L solution or 100 mg RDX/kg soil but not proportionally at higher RDX levels from 220 to 903 mg/kg soil. While wheat plant tissue harbored the highest RDX concentration of 2,800 µg per gram dry biomass, maize was able to remove a maximum of 3,267 µg RDX from soil per pot by five 4-week plants at 100 mg/kg of soil. Although RDX is toxic to plants, maize, sorghum, and wheat showed acceptable growth response in the presence of the chemical, whereas soybeans were more sensitive to RDX. Results of this study facilitate assessment of the potential invasion of the food chain by RDX contaminated soils and its phytoremediation by common agricultural crops.