Presented May 28, 2015 - Webinar Slides
Representative Sampling and Analysis for Energetic Residues in Soil by Dr. Thomas Jenkins
In the 1970s and 1980s, the Army found that many of their ammunition plants and depots were contaminated with residues of high explosives from the synthesis of energetic compounds, and the load assemble of packing of military munitions. Analytical methods were developed to enable characterization of source zones, and potentially contaminated ground water. The results indicated that certain energetic chemicals, particularly RDX, were leaching into underlying groundwater at many of these installations.
Characterization of energetic residues at military training ranges is an even more difficult problem. Due to a substantial investment in research by SERDP/ESTCP and the Canadian Department of National Defense, the types of residues present at various types of ranges are now understood. Experiments have revealed the extreme heterogeneity in the distribution of residues at these ranges complicating the characterization of source zones. Due to SERDP sponsorship, sampling methods have been developed to allow the collection of representative soil samples in these environments, and laboratory methods have been modified to allow accurate and precise results for these samples. The physical size of these ranges makes the task daunting, but it also makes the consequences of ignoring the problem in the present, a huge potential expense to the DoD in the future.
Bioremediation of Co-Mingled Perchlorate and Explosives in Groundwater at an Active Military Range by Dr. Paul Hatzinger
Military propellants and explosives, including perchlorate, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are commonly found co-mingled in soils and groundwater at military ranges. These contaminants are mobile and persistent in groundwater, sometimes leading to offsite migration. This project was undertaken to investigate the feasibility of using a passive biobarrier to remediate these compounds while minimizing impacts to routine range activities. Based on laboratory microcosm and column testing, a field-scale biobarrier consisting of a buffered emulsified oil was installed using a series of temporary injection wells. A zone of increased pH and decreased dissolved oxygen and oxidation-reduction potential was quickly established in the aquifer. Perchlorate, RDX, and HMX were observed to decrease markedly (>95%) downgradient of the biobarrier during the first several months after barrier installation. Nitroso- breakdown products of RDX were observed and then declined with time. Studies were conducted to evaluate both the dominant bacteria degrading RDX in the aquifer and the extent to which RDX degradation can be quantified in situ using C and N stable isotope analysis. The project has resulted in no impacts to ongoing range activities. The field trial suggests that an emulsified oil biobarrier can be a viable approach to remove perchlorate and explosives from shallow groundwater at this and other range sites.
Dr. Thomas Jenkins is a private consultant after retiring from the U.S. Army ERDC-CRREL after a career spanning over 37 years. His research was directed at developing analytical methods for determining the concentrations of explosives related chemicals in the environment, and the development of sampling strategies that minimize the contribution of spatial heterogeneity in the uncertainty associated with site characterization. He also conducted research targeting the detection of buried landmines using chemical detection. His achievements include the development of standardized laboratory methods for the determination of nitroaromatic, nitramine, and organo-nitrate explosives in soil and water (USEPA SW846 Method 8330 and 8330B, ASTM, and the Association of Official Analytical Chemists), and onsite methods for RDX and TNT (USEPA SW846 Methods 8510 and 8515). He along with Marianne Walsh and Alan Hewitt helped pioneer the use of multi-increment sampling strategies that minimizes the uncertainty due to spatial heterogeneity in the distribution of energetic compounds at explosives-contaminated sites. Dr. Jenkins has published over 60 journal articles and over 100 government reports and has presented his research at numerous professional symposia.
Dr. Paul Hatzinger is the Director of the Biotechnology Development and Applications Group of CB&I Federal Services. He holds PhD from Cornell University, and has more than 20 years of experience in biodegradation, bioremediation, microbial ecology, stable isotope analysis, and groundwater microbiology. Dr. Hatzinger’s research group has been instrumental in the development and field application of new remedial approaches for several contaminants of concern to the Department of Defense, including perchlorate, methyl tertiary butyl ether (MTBE), nitramine and nitroaromatic explosives (RDX, HMX, TNT), N-nitrosodimethylamine (NDMA), and 1,2-dibromoethane (EDB). In addition to his research, Dr. Hatzinger does extensive consulting on the sources, fate, and remediation of organic and inorganic pollutants.