Strategies to Protect the Health of Deployed U.S. Forces Detecting, Characterizing, and Documenting Exposures (2000) / Chapter Skim
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5 Detecting and Monitoring Harmful Agents
5 Detecting and Monitoring Harmful Agents
Pages 86-109
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From page 86... ...
Are current technologies for sampling and detecting harmful agents capable of answering questions on both short-term threats and the long-term health of deployed forces?
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From page 87... ...
During a deployment, real-time detection of harmful agents will be required to ensure that mission objectives are met and for continued monitoring. The information can be archived and used to determine low levels of chemical concentrations for dose reconstruction and long-term health risk assessments.
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From page 88... ...
88 STRATEGIES TO PROTECT THE HEALTH OF DEPLOYED U.S. FORCES TABLE 5-1 Information Needs and Timing for Measuring Short-Term Threats and Long-Term Health Risks Information Needed Before Deployment During Deployment After Deployment Short-term threat Long-term health risk Intelligence and planning Enemy CB capabilities Means of delivery Agents available Enemy troop CB protection Enemy CB doctrine Prior CB use by enemy Endemic CB threats in the region Large stores of toxic chemicals Threshold concentration/time factors for any CB agents likely to cause short-term casualties Baseline data on exposures prior to deployment Susceptibility of troops to CB agents Threshold concentration/time factors for any CB agents likely to cause long-term health risks Real-time Retrospective measurements assessments Contaminated areas Performancedegrading concentrations CB agent concentrations Location of enemy CB means of delivery Industrial sites with large stores of CB agents and TICs Use of protective clothing Data that can be used to support health studies Data on chemical concentrations and locations of these concentrations Troop location and time histories Use of protective clothing Data on postdeployment exposures Possible low-level exposure during deployment
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From page 89... ...
Many remote or point measurement devices that use infrared beams combine sampling and detection and use software analysis to carry out the separation step. In some measurement methods, a single device does Sampling ~ >< I' Detection Separation FIGURE 5-1 The three steps for measuring chemical concentrations in an environmental medium (air, water, soil, or food)
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From page 90... ...
Passive sampling requires a minimum of equipment and a minimum of operator intervention. For example, airborne chemicals can be sampled actively using a pump to pull contaminants through a collection device.
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From page 91... ...
For personal sampling, a small device is typically mounted on clothing that covers the chest. Measures of concentrations in the breathing zone are generally considerably higher when measured by personal sampling than when measured by area sampling, especially if the individual is engaged in activities that release or resuspend chemicals from soil in the area or from accumulated contamination on clothing.
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From page 92... ...
For example, active samplers linked to a gas chromatography/mass spectrometry system use small pumps to draw air through a collection medium, such as a filter or a vapor trap. Some detection devices require only a small amount of agent, others require much larger amounts.
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From page 93... ...
spectroscopy and tunable infrared laser absorption spectroscopy, mass spectrometry, ion mobility spectrometry (IMS) , enzyme methods, and phosphorous chemiluminescence detection (PCD)
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From page 94... ...
FTIR relies on spectral pattern recognition software to translate individual species concentrations out of complex multicomponent spectra. Thus, an important issue for detecting and monitoring TICs is that the equipment and software be properly calibrated for detecting specific chemical agents.
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From page 95... ...
Currently, aerosol mass spectrometry is used to characterize atmospheric aerosols. However, many emerging technologies have the potential for assessing the size distribution and chemical composition of atmospheric aerosols.
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From page 96... ...
The goal of aerosol mass spectrometry is to provide on-line, real-time chemical analysis of individual aerosol particles, which are characterized in terms of bulk composition, surface composition, organic chemical species, and inorganic chemical species. An on-line system minimizes sampling artifacts caused by condensation, evaporation, and/or chemical transformation.
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From page 97... ...
Chemiluminescence can take place in either the solution or vapor phase and thus can be used for detecting chemicals in water. Determining the presence of chemical agents in food and water is most often performed with the assistance of a gas chromatograph/mass spectrometer following an extraction step.
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From page 98... ...
, DoD's estimated safe concentration, and the AEL. Summary Evaluation of Chemical Detection Technologies DoD's stated strategy for chemical detection is to use a suite of complementary technologies to ensure enough warning time for contamination avoidance (JCS, 1996~.
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From page 99... ...
This appendix includes a review of each system's local and stand-off sampling capability, personal sampling capability, use or calibration with biomarkers, and use of surrogate samples. Measuring Biological Organisms Numerous methodologies are currently available for detecting biological material collected from environmental samples.
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From page 100... ...
Abiotic constituents in the environment may also interfere with the detection of microbial contaminants. Type of Information Needed Qualitative data indicate the presence or absence of biological contaminants at a predetermined threshold.
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From page 101... ...
The lowest possible detection limit will minimize dilution effects of the dispersion of the microbial contaminant in the environment and in sample collection. Although zero presence of an agent may be desirable, acceptable sensitivity levels are determined by the dose of the microbial contaminant that causes adverse effects in the exposed population.
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From page 102... ...
, limitations of this technique include lack of specificity and low sensitivity. Staining with fluorescent-labeled antibodies can result in the detection of target organisms, but the lower detection limits are generally greater than 104 cells/ml of liquid collection medium (ideal detection strategies would detect one cell in a sample)
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From page 103... ...
The presence and concentrations of background biotic and abiotic material may require that samples be pretreated to minimize interference in the sample matrix. Combining PCR with immunological techniques has resulted in a rapid and efficient solution-phase hybridization of labeled targets and biotinylated capture probes.1 Results have been reported in two hours with a detection limit of 10 targets, which is relatively good for biological agents.
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From page 104... ...
Immunomagnetic separation with fluorescent antibody-labeled beads and flow cytometry is also being used (Seo et al., 1998~. Fielded Equipment for Biological Agents Current biological detection equipment is not as mature as chemical detection systems in terms of reliability, sensitivity, selectivity, speed, and portability.
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From page 105... ...
The detection of biological warfare agents on the battlefield in real time with a very low rate of false alarms is a crucial requirement. However, with the possible exception of upconverting phosphordiode laser technology, no technology currently under development is expected to meet these needs in the next five years.
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From page 106... ...
Multipurpose Integrated Chemical Alarm MICAD is an emerging integrated nuclear, biological, and chemical detection, warning, and reporting system. It automates the gathering of NBC contamination data from fielded detectors and sensors and automatically gives alarms and transmits reports up the chain of command.
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From page 107... ...
Incorporating nonvolatile memory in the data management system will be another important goal of these systems. MONITORING, SIMULATION, AND DECISION MAKING The information obtained from detecting and monitoring devices will be very valuable both for anticipating and avoiding potential exposures and for determining the distribution of exposures in postdeployment health studies.
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From page 108... ...
Many field tests are restricted to Dugway Proving Ground or White Sands Missile Range, the only places properly equipped for full-scale field tests. Independent scientific reviews at each stage of the development and testing process appear to have not been done, which could limit the quality and reliability of the final product.
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From page 109... ...
Recommendation. The Department of Defense should establish criteria for detecting and monitoring low-level exposures to chemical and biological warfare agents and toxic industrial chemicals.
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