Nerve agent degradation products toxicity

Other scenarios that need to be considered include contamination of food and public places and, in such situations, levels to which it is necessary to decontaminate to ensure public safety. A further consideration of importance is the toxicity of nerve agent degradation products (see review by Munro et al., 1999) and, particularly in the case of terrorist use, manufacturing contaminants. 

All of the parent nerve agents are highly toxic to aquatic organisms (Munro et al, 1999). Acute ecotoxicity information was found only for the degradation product, MPA. The 48- to 96-h LC50 values of several thousand mg/1 for daphnids and fish indicates that MPA has low environmental toxicity. 

Once chemical agents are fully dispersed, they do not tend to persist in the environment because of their high chemical reactivity, particularly with water (hydrolysis). However, in extremely dry desert climates, they can persist for considerable periods of time (U.S. Army, 1988). The major environmental degradation products of nerve and mustard agents have recently been assessed and their persistence and toxicity evaluated. A potential hydrolysis product of VX (S-(2-diisopropylaminoethyl) methylphosphonothioic acid [EA-2192]) is a degradation product expected to display a high level of mammalian toxicity. Some mustard partial hydrolysis products are also toxic (Munro et al., 1999). 

In addition to hydrolysis, nerve agents may be transformed in soil by microbial degradation via 0-dealkylation and C-dealkylation with resulting toxic products (Morrill et al. 1985). GA can also be biodegraded via nitrile hydrolysis, resulting in a nontoxic compound N-dealkylation results in a compound that is... 

Technical experts generally agree that sea-dumped CW should be left undisturbed, because any attempt to move them could result in an explosion or other rupture of the munitions, thereby spilling the contents into the environment. Organophosphorus nerve agents hydrolyze readily in sea water into essentially benign degradation products of low toxicity. The primary environmental and human health threats are posed... 

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