EXPLOSIVES-CONTAMINATED DEBRIS

A recent U.S. Army study (performed by Battelle) identified, described, and evaluated technologies to facilitate remediation of oversize ex-plosives-contaminated debris. During composting of explosives-contaminated soil at military installations, such debris interferes with the operation of the flail-type windrow equipment used to turn and aerate the composting soil. The study examined size reduction and return of the crushed debris to the compost pile and removal of the contaminants from the debris followed by disposal of the cleaned debris. If the debris is to be returned to the compost pile, the particle size must be less than V2-inch diameter. For removal, the explosives contaminants level must be reduced to below 30 mg/kg. 

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The identification, quantification, and characterization of the contaminants present at a site form the logical and necessary basis to study the applicability of a treatment technology. Characteristics influencing selection of remedial options for explosives-contaminated debris include ... 

Quantity of Debris Requiring Remediation The quantity of explosives-contaminated debris is in the range of 2,000 to 25,000 tons. The debris is assumed to be 20% of the total weight of the soil being composted. 

The technology evaluation for treatment of explosives-contaminated debris assumes that the concentration of energetic material in the soil with debris is below the AEC reactivity threshold and does not exhibit RCRA ignitability or reactivity characteristics. 

Although high-temperature thermal treatment has proven effective, the cost for process implementation historically has been high. As a result, this study focused on evaluation of low-temperature treatment technologies for the explosives-contaminate debris. 

Three types of commercially available crushing/grinding equipment potentially are applicable to reducing the size of the explosives-contaminated debris ... 

BatteUe personnel contacted manufacturers and vendors of these types of crushers to determine the applicability of the equipment types to the specific requirements for the explosives-contaminated debris. Toothed-roll crushers would be unable to achieve the required size reduction. This type of equipment was not recommended by the manufacturers and/or vendors. 

Researchers at Roy F. Weston performed treatability studies of washing explosives-contaminated debris with water and surfactants. Due to the low water solubility of the explosives, washing with water alone did not remove the contaminants to the 30 mg/kg level. However, washing with a surfactant was able to decrease concentrations to below the 30 mg/kg level. 

Evaluation of Processes for Remediating Explosives-Contaminated Debris,... 

Incineration processes can be used to treat the following waste streams explosives-contaminated soil and debris, explosives with other organics or metals, initiating explosives, bulk explosives, unexploded ordnance, bulky radioactive waste, and pyrophoric waste. In addition, incineration can be applied to sites with a mixture of media, such as concrete, sand, clay, water, and sludge, provided the media can be fed to the incinerator and heated for a sufficient period of time. 

Much contaminated debris is incompatible with flail-type windrow aeration equipment used for composting due to its large size. Physical size reduction is an effective option for preparing the debris for compatibility with the windrow equipment. Crushing is a standard method to reduce the particle size of rock materials. The size-reduced debris would be returned to the composting system to reduce the explosives concentrations to the remedial action objective levels. The crushing process will use mechanical size reduction equipment to crush the large debris. 

Hammermills are capable of reducing 3 inch diameter rock to less than Vi-inch diameter in a single step. Hammermill designs typically include an outlet screen that controls die size of particles leaving the crusher. Hammermills are available in standard sizes to meet the relatively low through-put required and are shipped within reasonable delivery times from a variety of vendors. The hammermill was selected as the preferred type of rock crusher for explosives-contaminated rock debris. 

Safety risk, also called acute risk, relates to immediate fatalities or injuries due to accidental events, such as fire, explosion, falling debris, or a concentrated toxic gas cloud. It should be noted that some accidental undesirable events might also lead to health risks due to environmental contamination during that single event and long-term exposure of the... 

Denmark 1.5 days after the explosion. Air samples collected at Roskilde, Denmark on April 27-28, contained a mean air concentration of 241Am of 5.2 pBq/m3 (0.14 fCi/m3). In May 1986, the mean concentration was 11 pBq/m3 (0.30 fCi/m3) (Aarkrog 1988). Whereas debris from nuclear weapons testing is injected into the stratosphere, debris from Chernobyl was injected into the troposphere. As the mean residence time in the troposphere is 20-40 days, it would appear that the fallout would have decreased to very low levels by the end of 1986. However, from the levels of other radioactive elements, this was not the case. Sequential extraction studies were performed on aerosols collected in Lithuania after dust storms in September 1992 carried radioactive aerosols to the region from contaminated areas of the Ukraine and Belarus. The fraction distribution of241 Am in the aerosol samples was approximately (fraction, percent) organically-bound, 18% oxide-bound, 10% acid-soluble, 36% and residual, 32% (Lujaniene et al. 1999). Very little americium was found in the more readily extractable exchangeable and water soluble and specifically adsorbed fractions. 

Some explosives are not volatile enough to be analyzed via GC the relatively high temperatures required can cause decomposition of some explosives (e.g., nitrate esters, nitramines) excessive contamination often present in hand swabs from postexplosion debris can interfere with optimum performance of some detectors... 

One can view samples from an explosion scene as belonging to one of two work streams (i) clean and (ii) dirty. Separation between these work streams needs to be established at the earliest possible moment in the process with appropriate laboratory facilities to handle each. The clean work stream contains items which are to be examined for invisible chemical traces of explosives. Such items need protection from any external contamination to a degree commensurate with the sensitivity of the chemical analysis techniques to be employed. The dirty work stream contains items that do not require trace analysis precautions, e.g., scene debris for physical searching. Nonetheless, such items still need to be handled in a way which protects their evidential integrity. Some items can start in the clean stream and then be transferred to the dirty stream, e.g., damaged motor vehicles may first be examined for explosive traces, and then transferred out of the trace examination area to be searched for physical evidence. 

Explosions in buildings and urban situations frequendy damage sewers and drainage systems, spreading their contents over the scene. Consequendy, there is a risk of debris being contaminated by dangerous infectious agents. 

Reception arrangements need to provide for checking the safety of items being submitted, separation of items to prevent cross-contamination, initial identification of submitted material, and the preparation of aU the requisite documentation. After items have been received and documented they wiU need to be transferred to an appropriate storage area, whether this be for trace analysis, biohazard, explosive, flammable, toxic, or bulk debris. It is advisable to have pre-planned quarantine storage for anything whose characteristics or provenance cannot be guaranteed. 

In Seveso, Italy, an explosion occurred during the production of 2,4,5-T and a cloud of toxic material including 2,3,7,8-TCDD was released (Cerlisi et al. 1989 MMWR 1988 Mocarelli et al. 1991). Debris from the cloud covered an area of approximately 700 acres (2.8 km2). The total amount of 2,3,7,8-TCDD released during the accident was estimated to be 1.3 kg. Soil samples from this industrial accident were measured in three areas Zone A, the most contaminated zone where residents were evacuated Zone B, the moderately contaminated area where residents were advised not to eat locally raised produce and Zone R, where 2,3,7,8-TCDD contamination in soil was lowest of the three areas. Mean soil concentrations in these 3 areas were 230 g/m2 (maximum 5,477 g/m2) in Zone A, 3 g/m2 (maximum 43.9 g/m2) in Zone B, and 0.9 g/m2 (maximum 9.7 g/m2) in Zone R (MMWR 1988). 

Tetryl may be released to the air, water, and soil when old stores of the explosive ate destroyed by exploding or burning. However, tetryl has not been measured in air during any of these activities. Tetryl that was manufactured or stored at military installations, like Army ammunition plants, may still be present in the soil and water at or around these sites. Tetryl is not likely to evaporate into air from water or soil surfaces. However, tetryl may be present in air associated with dust from these sites. Tetryl appears to break-down rapidly in some soils. Picric acid, is one of the break down products of tetryl in soil. Tetryl probably does not easily travel from soil to groundwater. Erosion of soil from contaminated sites may release tetryl to nearby surface water. Once it is in the water, tetryl may dissolve or associate with small particles of suspended solids, sediments, or organic debris. Some of these particles will settle to the bottom. Tetryl breaks down rapidly in sunlit rivers and lakes but much more slowly in groundwater. It is not known whether tetryl will build up in fish, plants, or land animals. See Chapters 4 and 5 for more information on tetryl in the environment. 

Contaminated Media Soil, surface, and groundwater have been contaminated with explosive compounds and their decomposition products. Metal fragments are also widely spread in open bum/open detonation areas and on bombing/firing ranges. In many cases, the area that has been contaminated with explosive and metal debris is very extensive. Time and cost for restoration are considerable. Prior to reuse of the area and to protect resources from contamination, areas where these contaminants exist must be remediated. Advanced technologies are needed to identify areas of contamination in a more cost effective and accelerated manner and to remediate soils in situ without excavation and the resulting environmental destruction. 

A problem is also associated with abandoned open bum/open detonation areas at which neutralization and demilitarization were carried out in the past without stringent environmental controls. The debris remaining in these areas can pose both explosive and toxic chemical threats. A need exists for the adaptation of present methods of soil cleaning (which are typically applied to the removal of hydrocarbon or heavy-metal contamination from soil) and development of new approaches to address the problem of removing specific explosive and toxic compounds from soils. Such approaches could be applied both to the remediation of abandoned open burn/open detonation sites and to that of other areas (including... 

Emergency Response Upon discovery of a product or waste leak or spill, appropriate regulatory agencies are notified and immediate actions are taken to repair the source of the release and abate any immediate threat to safety, health, or the environment (e.g., fire, explosion, etc.). Such emergency response measures may include site access control, containment diking, product removal, vapour suppression, protection of water resources, and/or contaminated soil and debris removal. The emergency response is complete once the release has been terminated and any associated acute hazards (i.e., immediate threats to safety, health, etc.) have been identified and controlled. 

One of the primary safety risks in industrial environments is electrical arc flash. Arc flash is an explosive blast of flame, debris, sounds and force, reaching up to 35,000°F in less than one second. Easily ignited, the causes of arc flash are diverse and often uncontrollable, including accidental contact with an energized part, contamination from dust or wiring errors, each creating a spark that creates a dangerous burst of flames. 

It should be emphasized that the routine use of GC-MS for post-explosion analysis is not without problems. Highly contaminated extracts from the debris often decrease the efficiency of the GC-MS analysis. This is especially true for some nitrate esters and nitramines, where a significant decrease in sensitivity has been observed. 

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