CAS RN: 50782-69-9

Disposal Methods

Principles and methods for destruction of chemical weapons: ... "Destruction of chemical weapons" means a process by which chemicals are converted in an essentially irreversible way to a form unsuitable for production of chemical weapons, and which in an irreversible manner renders munitions and other devices unusable as such. ... Each /nation/ shall determine how it shall destroy chemical weapons, except that the following processes may not be used: dumping in any body of water, land burial or open-pit burning. It shall destroy chemical weapons only at specifically designated and appropriately designed and equipped facilities. ... Each /nation/ shall ensure that its chemical weapons destruction facilities are constructed and operated in a manner to ensure the destruction of the chemical weapons; and that the destruction process can be verified under the provisions of this Convention. /Chemical warfare agents/
The US Army is pilot testing the neutralization of VX nerve agent stockpiled at Newport, Indiana using caustic hydrolysis in a Sequencing Batch Reactor (SBR). The resulting hydrolysate was tested at the bench-scale for treatment with activated sludge biodegradation in two distinct studies, one in the SBR and another, in the PACT process. The feed to both biological systems was pretreated to enhance the biodegradability of the hydrolysis products. Both biodegradation studies demonstrated that the hydrolysate could easily meet the Chemical Weapons Convention treaty and US environmental regulations following pretreatment.
The Newport Chemical Agent Disposal Facility (NECDF) was designed and constructed to safely neutralize more than 1,000 tons of liquid nerve agent VX currently stockpiled at the Newport Chemical Depot in Indiana. The NECDF uses a chemical neutralization process called caustic hydrolysis to eliminate the lethal toxicity of the nerve agent. ... In a carefully controlled, monitored environment, NECDF operators neutralize the VX by adding the agent to a solution of water and sodium hydroxide. The mixture is heated to accelerate the chemical reaction that breaks down the VX. The resulting byproduct of the neutralization process is a caustic wastewater also called caustic hydrolysate. After the reaction is complete, excess sodium hydroxide is maintained in the caustic hydrolysate to create a "reactive matrix." The excess sodium hydroxide ensures that agent cannot be present or form over time. Before the hydrolysate is removed from the NECDF, lab analysis must confirm the following stringent criteria are met: (1) Hydrolysate is non-detect for VX, with a Method Detection Limit (MDL) of less than or equal to 20 parts per billion (ppb); and (2) Hydrolysate contains less than 1 part per million (ppm) of EA2192, a byproduct of the neutralization process.
A Preliminary Assessment of Health Impacts (PAHI) study was conducted to look at potential human and environmental health impacts due to the air and water emissions generated from the proposed Newport Chemical Agent Disposal Facility (NECDF) in Newport, Indiana. As an alternative to incineration, the NECDF will use a neutralization-based treatment process followed by supercritical water oxidation to destroy the VX nerve agent stored in ton containers at the Newport Chemical Depot. There is no regulatory guidance on conducting an assessment of health impacts for this type of facility. Therefore, The U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) designed a Preliminary Assessment of Health Impacts study based on bench-scale data and best engineering estimates that conservatively evaluate possible health effects from the projected air and water emissions. The air portion of the Preliminary Assessment of Health Impacts focused primarily on estimating carcinogenic risks and noncarcinogenic hazards from direct and indirect exposures to the subsistence farmer, subsistence fisher, adult resident, and child resident. The water portion of the Preliminary Assessment of Health Impacts evaluated potential human and environmental impacts using two different procedures individual compound analysis and whole effluent toxicity analysis. The individual compounds analysis compared constituent concentrations in the water emission to Indiana State Water Quality Standards and U.S. Environmental Protection Agency Ambient Water Quality Criteria to evaluate the potential health impacts to human, terrestrial, and aquatic life. The whole effluent toxicity tests were conducted on mammalian (mouse, rat, and rabbit) and aquatic (water flea, algae, and minnows) species to test for potential additive, synergistic, and antagonistic effects. The results of the air and water portion of the study showed that the operation of NECDF would be safe to exposed human and environmental receptors. A Final Assessment of Health Impacts (FAHI) will also be conducted by USACHPPM, after NECDF is constructed and before full-scale operations, to validate the results of the Preliminary Assessment of Health Impacts.
Cyclodextrins catalyzed the inactivation of sarin and soman but did not inactivate tabun and VX. Furthermore, sarin and soman showed greater affinity for beta-cyclodextrin than for alpha- or gamma-cyclodextrins.
SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.
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