SOLIDIFICATION/STABILIZATION OF ADAMSITE AND LEWISITE IN CEMENT AND THE STABILITY OF ARYLARSENICALS IN SOIL

摘要

Cement can be used for the solidification/stabilization of inorganic arsenic species; however, leaching studies of Adamsite incorporation into cement reveal that the interaction with the cement is not very strong and that the agent is easily removed. The leachate contains the oxidation product phenarsazinic acid. Solid state NMR studies on Adams-ite/cement mixtures confirm that the basic structure of the molecule is preserved without cleavage of the As-C or As-N bonds, and suggest that an oxidized species is formed on incorporation. Leaching studies of Lewisite incorporated into cement show that loadings of up to 15% are retained reasonably well although the arsenic species present in the leachate was not determined. Solid state NMR spectra of Lewisite/cement mixtures reveal that most of the agent has hydrolyzed even at a 25% loading. The measurement of ~(75)As NMR spectra in these and related material is expected to yield more information about loading and binding. Bacteria and fungi present in soil collected from a site contaminated with arseni-cals do not seem to have the general ability to catalyze the cleavage of As-aryl bonds.