Researchers at the U.S. Army Engineer Research and Development Center validated sample extraction and analysis techniques to cost-effectively detect both legacy and new insensitive munitions constituents at training ranges and manufacturing sites.
By Dana E. Fahey
Figure 1. Preparing to spike soil with legacy and insensitive munitions mixture. Photo Credit: Dr. Anthony Bednar, ERDC
For decades, DoD has addressed munitions constituents in the environment under DoD’s remediation program, called the Military Munitions Response Program, which addresses sites such as former training areas. The military is developing and evaluating new insensitive munitions constituents (IMCs) (e.g., 2,4-dinitroanisole (DNAN) and nitrotriazolone (NTO)) as replacements for legacy munitions constituents, like trinitrotoluene (TNT) and RDX. The methods for detecting new munitions constituents must evolve in tandem with the replacement technologies.
Historically, USEPA Method 8330B is “the most widely used analytical approach” for identifying legacy munitions constituents in water, soil, and sediment; however, this method does not account for IMCs.
In the early 2000s, toxicologists and soil scientists at U.S. Army Engineer Research and Development Center (ERDC) began developing new methods to analyze new munitions constituents, such as NTO and nitroguanidine. They studied each compounds’ biogeochemistry and toxicology as well as developed individual analytical methods. Instead of continuing to approach these classes of munitions separately, Dr. Anthony Bednar, an analytical chemist at ERDC, and his team saw the benefit in the development of an integrated method to “detect new IMCs simultaneously with the legacy compounds, because [the IMCs] are likely to be introduced and found on training ranges where [they] already had used legacy constituents and compounds.”
Under a project funded by the Strategic Environmental Research and Development Program (SERDP), Dr. Bednar and his team developed a holistic method for legacy and insensitive munitions that assesses 24 compounds simultaneously. This effort served as the foundation for their subsequent Environmental Security Technology Certification Program (ESTCP) project. The main goal of the ESTCP project was to validate these novel methods for IM detection through a multi-laboratory comparison study.
The team generated bulk samples of analytes within chosen environmental matrices at ERDC and sent them out to participating laboratories. Each laboratory was first trained in the new method and then processed the samples using the ERDC-developed method. The results showed the method to be successful at detecting IMs, and variations in analyte recoveries could be attributed to specific laboratory equipment operations.
“As long as you know something about the general area of research, you can implement this method,” Dr. Bednar shared about the laboratories participating in their round robin study. The contract laboratories had explosive analysis experience, and the research laboratories had experience with high-performance liquid chromatography (HPLC). Having one of these was necessary for baseline knowledge on the processes. Dr. Bednar added that the method behaves similarly to USEPA Method 8330B.
Figure 2. Setting up solid phase extraction (SPE) manifold. Photo Credit: Dr. Anthony Bednar, ERDC
USEPA Method 8330B is a simple, yet robust, method, that functions effectively on the 17 constituents for which it was developed, because the compounds are all chemically similar. The ERDC method addresses 24 analytes, which includes the 17 in USEPA Method 8330B, in addition to a few other analytes that are of interest to the DoD. As the researchers at ERDC sought to add in new analytes with different chemistries, they had to develop a complex, new approach to continue to obtain sound results with good chromatographic separation. While the ERDC-developed method performs like USEPA Method 8330B, it has more inherent variability in results because of its complexity.
By addressing 24 different analytes simultaneously, the ERDC-developed method could result in enormous cost and time savings, speeding up the remediation cycle. “This method provides the benefit of being able to monitor everything with one technique,” said Dr. Bednar. “If you didn’t have this method, you would still have to use [USEPA Method] 8330B to identify all of the legacy compounds, then you would have to use whatever method was developed for [each individual IMC, driving up costs significantly].”
The method developed by ERDC cannot only detect the new IMCs, but also some of the degradation products of the compounds. This enables researchers to understand the different biogeochemistry and environmental behavior of the new compounds.
ERDC continues to perform ongoing research to expand the scope of their method, informed by toxicologic assessment of munitions constituents. As new IMs are developed or deemed important, the ERDC-developed method can be updated to integrate these novel IMCs. To make this method more widely accessible to site managers, ERDC has also provided the U.S. EPA their documents for review. From the support garnered already, ERDC is hopeful that their method can be included as an addendum to USEPA Method 8330B.
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About SERDP & ESTCP
The Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) harness the latest science and technology to improve the Department of Defense’s environmental performance, reduce costs, and enhance and sustain mission capabilities. The programs respond to energy and environmental technology requirements across the military services. SERDP and ESTCP are independent DoD programs managed jointly to coordinate the full spectrum of research and development efforts, from the laboratory to field demonstration and validation. For more information, visit https://serdp-estcp.mil. Follow us on Twitter, Facebook, and LinkedIn.
