Airborne Vapors

SPMD sample extracts, e.g., certain organochlorine pesticides (OCPs), are known to inhibit cholinesterase activity. Therefore, these results were not unexpected. However, it was surprising that a similar response was not observed with brain cholinesterase activity. It is possible that brain cells can more readily metabolize the chemicals, that the chemicals did not pass the brain blood barrier or that the effects occurred earlier in the exposure period, effectively allowing the activity to recover. Considering the numerous neurotoxic chemicals potentially entering aquatic ecosystems or present as airborne vapor phase chemicals, the neurotoxic mode of action related to exposure to contaminants is of increasing interest. Evidence presented in this work demonstrate that SPMDs concentrate members of this class of toxicants. 

Fatal cases of 2,4-DNP poisoning were reported among workers in the munitions industry in France. Workers were exposed to airborne vapor and dust of 2,4-DNP and had direct dermal contact with the solid material, although duration and levels of exposure were not reported. Deaths were preceded by sudden onset of extreme fatigue, elevation of body temperature to 40°C or more, profuse sweating, thirst, and labored respiration. No characteristic lesions were found at autopsy. 

Kado, N. Y., J. M. Wing, P. A. Kuzmicky, J. E. Woodrow, H. Ning, J. N. Seiber, and D. P. H. Hsieh, Quantitative Integration of the Salmonella Microsuspension Assay with Supercritical Fluid Extraction of Model Airborne Vapor-Phase Mutagens, Mutat. Res., 271, 253-260 (1992). 

Ventilation is the standard method of controlling exposure to airborne vapors of epoxy resins and solvents. Ventilation involves controlling air flow to reduce exposure. Local exhaust ventilation systems capture the vapor at the source and either filter or remove it from the work area. The ventilation system needs to be designed so that vapors, aerosol, and dusts are pulled away from, and not into, the breathing zone of the workers. A constant supply of fresh, noncontaminated air should be available at all times. 

Death. Occupational exposure of humans to 2,4-DNP has resulted in death (Gisclard and Woodward 1946 Perkins 1919). This exposure included airborne vapor, mists, dust, and direct dermal contact with the solid form of 2,4-DNP, indicating that exposure probably occurred via inhalation, dermal, and possibly oral routes. Death from occupational exposure to 2,4-DNP appeared to occur at a greater rate in workers having alcoholism or liver or kidney disease (Perkins 1919). Case studies reported death in humans ingesting 2,4-DNP and its sodium salt (doses expressed here as mg/kg... 

The vapor pressures and volatilities of the various chemical threat agents are particularly relevant to their detection as airborne vapors. The volatility of sarin is comparable to that of water or volatile organic compounds such as limo-nene and cyclohexanone (24,000 to 28,000 mg m-3). In contrast, VX has a low volatility, on the order of long-chain aliphatic waxes (for example, the volatility of docosane [C22H46] is about 17 mg m-3). TICs of concern as threat agents typically have higher vapor pressures than many other chemical threat agents they could be attractive to attackers because they can be dispersed more easily than compounds with low vapor pressure. 

Pyrotechnically generated smokes from grenades or powder clouds may not be acceptable from a safety point of view in certain circumstances for example, where fires may be produced, or in confined spaces with low rates of ventilation where asphyxial effects could develop. In order to reduce such potential hazards, a variety of approaches have been investigated. One of these is the use of highly volatile PCSI materials, which can be projected into enclosed spaces, but no material of sufficiently low toxicity has yet been found which is acceptable. An alternative approach is the use of a PCSI substance dissolved in a volatile solvent, and the mixture projected into the area by means of a pressurized aerosol canister or a frangible missile. This results in the development of an airborne vapor or aerosol of irritant (Ballantyne, 1979). 

Lovelock s discovery that airborne vapors affect simple ionization detectors, establishing a link to ambient air monitoring origins of electron capture detector 25,26... 

Spills which result in a substantial release of toxic liquids or airborne vapors such that the release extends beyond the facility boundaries invoke the requirements of the Community Right-To-Know Act. Notification of the local emergency coordinator by the dispatcher would be the first legal step to get the mechanisms moving. 

A recent study published in the Chinese Journal of Instrumental Analysis, Fenxi Ceshi Xuebao, showed a detection limit of 500 ng of Sulfur Mustard (HD) by using accelerated solvent extraction-gas chromatography (ASE-GC) coupled with a flame photometric detector (EPD) in the sulfur mode, in soil. In this case, the study showed evidence that ASE results in better recoveries and sensitivity than liquid solid extraction (LSE) [50]. In 1996, a paper was published on a method for the analysis of Lewisite through derivatization of the compound before introduction into a gas chromatograph. In order to simplify the derivatization process, a tube packed with absorbent was used for collection of airborne vapors. If a positive response occurs when screening analytes using a GC coupled with an FPD, then the same sample can be analysed using a GC equipped with an AED for confirmation based on the elemental response to arsenic (in the case of Lewisite) and sulfur (in the case of Sulfur Mustard) within the appropriate GC retention time window [54]. 

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