Rhizosphere Bacterial Degradation of RDX, Understanding and Enhancement
ER-1504
Objective
Soluble toxic compounds used in explosives are widely recognized as a significant barrier to attaining sustainable military training ranges. Movement of toxic munitions compounds, such as hexahydro-1,3,5-trinitro-1,3,5-triazine (Royal Demolition Explosive [RDX]), in groundwater and surface waters outside the boundaries of training ranges has the potential to threaten local water supplies and ecosystems. A sustainable solution to this problem must be inexpensive and self-maintaining. Microbial communities are known to use RDX as a source of nitrogen, but their natural activities in many soil and groundwater environments are not sufficient to remove the toxic compounds to levels required by regulation. Because rhizosphere microbial communities have enhanced populations and activity compared to surrounding soils and since specific microbial populations are associated with particular plant communities, manipulation of the plant community offers a way to enhance microbial degradation of RDX with a minimum of expense and maintenance.
This project will focus on understanding the relationship between rhizosphere bacteria and their host plants in environments exposed to munitions compounds. The objectives are to (1) identify RDX-degrading bacteria in plant rhizospheres, (2) discover the factors that control their population levels, and (3) develop probes that can be used in the field to detect them.
Technical Approach
Researchers will characterize bacteria in the rhizosphere by their relative access to carbon in plant root exudates and nitrogen in RDX, thus organizing the rhizosphere microbial community by its trophic structure and ability to degrade RDX. Using this hierarchy, they will evaluate the position of RDX-degrading microorganisms in the rhizosphere trophic structure and the details of their dependence on plant exudates. Molecular probes will be used to survey training range plant microbial communities for RDX-degraders. Methods for selecting plants (and thereby microbial communities) that optimize RDX degradation in soils exposed to surface runoff from training ranges then can be developed. To this end, the project includes a team of scientists and engineers with demonstrated skills in RDX degradation and innovative techniques in microbial ecology.
Benefits
In support of the cost-effective and sustainable prevention of RDX contamination from training ranges, this project will provide novel information about the structures and energetic relationships of microbial communities in plant rhizospheres, the identity and distributions of RDX degraders in the rhizosphere, the organic components of root exudates that support RDX degraders, and how genetic variability in training range plants may be used to select for RDX degraders in the rhizosphere. (Anticipated Project Completion - 2010)
Points of Contact
Principal Investigator
Professor Stuart Strand
University of Washington
Phone: 206-543-5350
Fax: 206-543-3254
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.