化合物详情

Using a structure estimation method based on molecular connectivity indices(1), the Koc of VX can be estimated to be 187(SRC). According to a classification scheme(2), this estimated Koc value suggests that VX is expected to have moderate mobility in soil. The pKa of VX is 9.12(3) indicating that this compound will partially exist in the cation form in the environment and cations generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(4). Low concentrations of VX are tightly bound to dry Dugway soil(5). VX deposited on sand undergoes rapid adsorption followed by slow evaporation(6); adsorption to the sand can remain, but simulated rainfall can desorb the VX resulting in vapor-phase release(6). No VX sorption was observed with kaolinite,...

An estimated BCF of 11 was calculated in fish for VX(SRC), using a log Kow of 2.09(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

Because chemical agents are dispersed in the form of droplets, it is important to consider the factors affecting the persistence of these droplets. Persistence will be a function of drop size, temperature, and air velocity(1). A linear equation has been developed relating the log of the time for 90% of a droplet to evaporate and the log of the volatility(1). The estimated volatilization time for 1-mm VX drops on a hard surface with a 2 m/sec wind is (time (temperature)): 44.6 days (10 °C), 193.0 days (0 °C), 936 days (-10 °C), 5150 days (-20 °C), 89 yr (-30 °C), 666 yr (-40 °C)(1). Extrapolated vapor pressure data were used below -20 °C. For other drop sizes, the volatilization time is found by multiplying the above volatilization times by the drop diameter in millimeters. For other win...

The measured rate constant for VX (40 to 200 ppm) in filtered seawater as a function of temperature between 15 and 45 °C followed the expression log k = 24.286 - 7954/T where T is in deg K(1) leading to a half-life of 7.3 days at 25 °C and 2.1 yr if extrapolated to 4 °C. The rate in seawater is not appreciably different from that in freshwater(2). The half-lives at 25 °C in seawater at pH 8.6 and 7.9 was 4.8 days and 13.8 days, respectively(1). Extrapolating data for pKa and second order basic hydrolysis rate to 4 °C, one calculates a half-life of 1.85 yr at pH 8.4 and 10 yr at pH 7.7(1). Another investigator estimated a half-life of 230 days in seawater at 5 °C(2). High results (72 times higher) were obtained from a sample of unfiltered seawater. Both adsorption of VX onto particulate...

VX's production may result in its release to the environment through various waste streams(SRC); its use as a nerve gas and chemical warfare agent(1) will result in its direct release to the environment(SRC).

Occupational exposure to VX may occur through inhalation and dermal contact with this compound at workplaces where VX is produced or used(SRC). The general population will not be exposed to VX unless it is used as a weapon; exposure to VX, if used as a weapon, will be via inhalation of ambient air and dermal contact(SRC). VX is thought to be very effective against respiratory organs when dispersed in the form of an aerosol(1). VX is the least volatile of the G-type nerve agents and most efficiently absorbed through the skin(2).

VX's production may result in its release to the environment through various waste streams; its use as a nerve gas and chemical warfare agent will result in its direct release to the environment. If released to air, a vapor pressure of 8.78X10-4 mm Hg at 25 °C indicates VX will exist solely as a vapor in the atmosphere. Below 7 °C (45 °F), VX's vapor pressure is less than 1X10-4 mm Hg, where it can exist in both the vapor and particulate phases. Vapor-phase VX will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 2.5 hours. Particulate-phase VX will be removed from the atmosphere by wet and dry deposition. VX does not absorb UV radiation above 290 nm and, therefore, is not expected to be...

Other Poison - Organophosphate

L(Ct)50 39-70 mg.min/cu m (inh, est.)

It has been suggested that in nerve agent poisoning butyrlycholinesterase acts as a "sink" for nerve agents. If that is the case it would be expected that those with low or absent butyrylcholinesterase activity would be more susceptible to nerve agents.