Stability constant data now available will be used to determine the concentrations of metal complexes and chelates formed in solution by react ions of organic pollutants with a wide variety of metal ions as a function of pH. Specially designed computer programs will be employed to determine speciation in complex systems containing many metal ions and a large number of organic ligands for which reliable stability constant data have been measured. The information obtained by this procedure will be extended to hundreds of known organic environmental pollutants with coordinating functional groups, for which stability data are not available, by comparing their structures with those of similar ligands for which reliable stability constants have been published. These correlations will be carried out by developing new empirical equations relating each functional group to stability increments for the metal ions of interest. In this manner calculations will be carried out on speciation involving hundreds of thousands of metal complexes that may be formed from the 20-30 metal ions naturally present, or artifically introduced, in the environment. It is planned to estimate rates of change of speciation and composition of environmental pollutants by determining the dynamics of solid-solution exchange and of metal-catalyzed oxidation and hydrolysis of known metal complexes, and applying these data to multicomponent mixtures found in the environment. The toxicities of a metal-containing multicomponent environmental mixture depend on mobilities, solubilities, and availabilities of metal ions, organic pollutants and their metal complexes, and on the toxicities of the individual species actually present in the mixture. The resulrs of the speciation determinations described above will be employed with known toxicities of the metal complex components to estimate toxicites of mixtures of metal ions and complexes in the environment. When toxicity data necessary for such estimates are not available the speciation determinations will be employed to designate key metal complexes for which toxicity data are needed, and for which detoxification methods should be developed.