Sources and remediation for mercury contamination in aquatic systems: a literature review

Energetic materials comprise both explosives and propellants. When released to the biosphere, energetics are xenobiotic contaminants which pose toxic hazards to ecosystems, humans, and other biota. Soils worldwide are contaminated by energetic materials from manufacturing operations; military conflict; military training activities at firing and impact ranges; and open burning/open detonation (OB/OD) of obsolete munitions. Energetic materials undergo varying degrees of chemical and biochemical transformation depending on the compounds involved and environmental factors. This paper addresses the occurrence of energetic materials in soils including a discussion of their fates after contact with soil. Emphasis is placed on the explosives 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and the propellant ingredients nitroglycerin (NG), nitroguanidine (NQ), nitrocellulose (NC), 2,4-dinitrotoluene (2,4-DNT), and perchlorate.

https://downloads.hindawi.com/journals/aess/2012/617236.pdf

Distribution and Fate of Military Explosives and Propellants in Soil: A Review

An explosion occurs when a large amount of energy is suddenly released. This energy may come from an over-pressurized steam boiler, from the products of a chemical reaction involving explosive materials, or from a nuclear reaction that is uncontrolled. In order for an explosion to occur, there must be a local accumulation of energy at the site of the explosion, which is suddenly released. This release of energy can be dissipated as blast waves, propulsion of debris, or by the emission of thermal and ionizing radiation. Modern explosives or energetic materials are nitrogen-containing organic compounds with the potential for self-oxidation to small gaseous molecules (N 2 , H 2 O, and CO 2 ). Explosives are classified as primary or secondary based on their susceptibility of initiation. Primary explosives are highly susceptible to initiation and are often used to ignite secondary explosives, such as TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitroperhydro-1,3,5-triazine), HMX (1,3,5,7-tetranitro-1,3,5,7-tetrazocane), and tetryl (N-methyl-N-2,4,6-tetranitro - aniline).

Soils contaminated with explosives: Environmental fate and evaluation of state-of- the-art remediation processes (IUPAC Technical Report)*

Dissolution rates of three high explosive compounds: TNT, RDX, and HMX.

: Waste disposal practices associated with military production of weapons, especially before and during World War II, have resulted in significant contamination of soils and ground water with high explosives such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). Development of remediation and risk management strategies for these contaminated sites as well as development of approaches for sustainable use of active training and weapons testing sites require an understanding of how the energetic compounds interact with the environment Factors affecting fate and transport such as adsorption, microbial degradation, dissolution kinetics, solubility, and photolysis are determinants of ultimate environmental fate and exposure potential. This report summarizes the current understanding of these interactions, identifies significant data deficiencies, and provides updated process descriptors for primary explosives, transformation products, and impurities.

Environmental Fate and Transport Process Descriptors for Explosives

: Subsurface contamination by 2,4,6-trinitrotoluene (TM), 2,3,5-trinitro-1,3,5-triazine (RDX), and oxyhydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMx) is a problem at many military installations associated with munitions manufacturing, loading, assembling, and packing. To support Department of Defense remediation and containment goals, information on the processes affecting the subsurface transport of these explosives is needed. Specifically, information pertaining to sorption and transformation of these explosives is needed in order to facilitate numerical model development. This study provides complementary batch and column information on TNT and RDX sorption and transformation and column information on HMX sorption and transformation. Batch and column testing included soils with a wide range of physical properties, and attention was given to sterilized and unsterilized soils. One soil was common to both batch and column. Reductive transformation was established as an important process for TNT. Measurement of reductive transformation products provided definitive evidence of TNT transformation. Reductive transformation was also suspected for RDX and HMX, although RDX and HMX transformation products were not measured.

Laboratory Studies of Soil Sorption/ Transformation of TNT, RDX, and HMX

: Subsurface contamination with 2,4,6-trinitrotoluene (TNT), 2,3,5-trinitro-1,3,5-triazine (RDX), and oxyhydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is a problem at military installations where these explosives were manufactured or used in loading munitions. Recent laboratory batch and column studies conducted to identify processes affecting subsurface transport of TNT, RDX, and HMX provide new information on the relative significance of transformation and sorption for these explosives and yield estimates of key process descriptors. This report assesses the current state of knowledge regarding subsurface transformation and sorption of TNT, RDX, and HMX, provides estimates for subsurface transport descriptors, and recommends further research. Transformation and sorption are important processes in the subsurface transport of TNT, RDX, and HMX. Measurement of transformation products has provided unequivocal evidence of TNT transformation. Research has also indicated that RDX and HMX are affected by subsurface transformations, but RDX and HMX transformation products have not been measured due to lack of chemical analytical capability. The order to magnitude of transformation is TNT >> RDX approx equal to HMX, and the order of magnitude of sorption in TNT > HMX > RDX. jg p37

https://erdc-library.erdc.dren.mil/jspui/bitstream/11681/4827/1/8531.pdf

Recent developments in formulating model descriptors for subsurface transformation and sorption of TNT, RDX, and HMX

Centrifuge simulation of the consolidation characteristics of capped marine sediment beds

: Exposure assessment and risk management of explosives-contaminated soil, sediment, surface water, and groundwater require knowledge of the fate and effects of explosives and their transformation products in the environment. Most of the information available on fate and transport of explosives is for the subsurface environment. The information available for the subsurface shows that transformation and sorption are two of the most important environmental processes affecting the fate and transport of TNT. For RDX and other explosives, additional processes such as mineralization to CO2 may also be important while processes such as sorption may be less important. Redox potential strongly affects the rate and products resulting from explosives transformation. Sorption can be affected significantly by cation substitution on clay minerals, and competitive sorption can affect the mobility of explosives and their degradation products. Recent findings show that considerable work remains to be conducted, even in the subsurface. At present, we possess a good qualitative understanding of the processes that are operative in soils and aquifer materials and an inferential understanding of the processes that may be occurring in other environments. Translating this qualitative understanding and speculation into quantitative mathematical process descriptors is impeded by the nature of the information available and will require additional process level research.

/pdf/review-of-fate-and-transport-processes-of-explosives-4tzd0tjd5j.pdf

Tommy E. Myers

Papers

Laboratory Studies of Soil Sorption/ Transformation of TNT, RDX, and HMX

Recent developments in formulating model descriptors for subsurface transformation and sorption of TNT, RDX, and HMX

Centrifuge simulation of the consolidation characteristics of capped marine sediment beds

Review of Fate and Transport Processes of Explosives.

Determination of the environmental impact of consolidation induced convective transport through capped sediment.