A mathematical model along with physical models were used to determine the fate of complex chemical mixtures released to the multimedia environment. Transport and transformation of phosphorus compounds generated during munition testing were studied by employing the Environmental Protection Agency's (EPA) TOX-SCREEN model. The species modeled were phosphine and a representative linear condensed polyphosphate (LCP). The model predicted that a significant fraction of phosphine was volatilized. The fate of LCP is mainly governed by the sorption capacity of soils. The data gaps identified during the preliminary modeling phase included estimates of polyphosphate sorption capacity onto soil.

Laboratory experiments indicated that the adsorption of total phosphorus onto sand was well represented by Freundlich isotherms. Batch and column studies indicated that sand enhances the oxidation of burn products to orthophosphate in the aqueous environment. The leachate generated from the combustion residue was highly toxic to Daphnia magna. Passage of the leachate through a sand/gravel column removed the toxic compounds and/or transformed them to less toxic products.

A combination of mathematical and physical modeling and toxicity monitoring proved highly effective in evaluating and mitigating potential environmental impacts of phosphorus obscurant smokes.