Nerve agents dissemination

Field protection The principles applied to the nerve agents apply equally as well to the incapacitating agents. It is possible that such agents will be disseminated by smoke-producing munitions or aerosols, using the respiratory tract as a route of entry. The use of protective mask, therefore, is essential. The skin is usually a much less effective route. 

The only reported incidents of nerve agent poisoning, where biomedical samples have been obtained, are those resulting from terrorist dissemination of sarin in Matsumoto (1994) and the Tokyo subway (1995), plus an assassination using VX, also in Japan (60). In contrast to the CW incidents involving sulfur mustard, many of the biomedical samples associated with these terrorist attacks were collected within hours of the event. 

GD is likely to undergo hydrolysis in most soils. As noted above, the rate of hydrolysis will be dependent upon temperature and pH. According to Morrill et al. (1985), evaporation is the primary mechanism for the loss of the GA and GB nerve agents from soil. Although the G agents are liquids under ordinary environmental conditions, their relatively high volatility and vapor pressure permits them to be disseminated in vapor form. Because of this volatility, GD is not expected to persist in soils. 

Those disseminating less easily, such as smallpox, tularemia, nerve agents, i.e. 

This refers to the ability of a nerve agent to survive dissemination and transport to the site of deployment. 

The persistent chemical agents which could be used in a foodborne attack, aimed at poisoning human consumers, include the nerve agent VX, any of the mycotoxins—aflatoxin, T-2 toxin, nivalenol (see Appendix A for discussion of their toxicology)—and compounds such as ricin produced from the castor bean plant. Chapter 5 should be consulted for a full discussion on natural toxins. These chemicals, combined with the biotoxins listed above, could potentially be used in the food supply. This would not be an easy task since many of these agents are toxic to animals and thus might kill the host, preventing dissemination into the food distribution system. 

Nerve agent residues remaining in the natural environment are likely to undergo substantial hydrolysis in the period immediately following dissemination. In investigation of allegations of use it is therefore important to analyse for trace levels of hydrolysis products. The important hydrolysis products of sarin, soman and GF are the isopropyl, pinacolyl and cyclohexyl methylphosphonic acids, which are slowly hydrolysed further to methylphosphonic acid. VX is predominantly hydrolysed to ethyl methylphosphonic acid... 

Log P data (octanokwater partition coefficients and a reflection of lipid solubility) of nerve agents were used to both predict absorption through the skin and determine the distribution of OP compoimds in tissues. Then, the data were correlated with toxicity as measured by the onset of fasciculation in guinea pigs. An excellent correlation (r=0.95) was established between the measured log P value and the rate of onset of local fascicu-lations, reflecting absorption in the skin, penetration to blood, and dissemination to muscle tissue throughout the animal (Czerwinski et al., 2006). 

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