Metal mobilization in soils

Metal Mobilization in Soils Direct Influence of Individual DOM Components... 

Indirect Effects of Humic Substances on Metal Mobilization in Soils... 

Laboratory studies provide some insight into the possible role of DOM onstituents in metal mobilization in soils. These studies suggest that LMW organic ligands, specifically bidentate ligands, are more likely to promote min-rral dissolution than are humic substances. LMW organic acids have been identified in soil waters and in leachates of forest litter at concentrations sufficient to effect oxide dissolution. 

Metal mobility in soils is governed by interfacial processes, such as dissolution. The role of DOM in such processes will be determined by the nature t organic matter-surface associations. The surface complexation model pro-odes a conceptual framework for estimating the contributions of specific DOM components, particularly LMW organic ligands, to the mobilization f metals in soils. With this framework, the effects of humic substances on mineral dissolution can be interpreted to provide some insight into hu--mate-surface interactions. 

Wenzel, W. W., and Blum, W. E. H. (1994). Assessment of metal mobility in soil methodological problems. In Metal Speciation and Contamination of Soil, ed. Allen, H. E., and Huang, C. P., Lewis Pubhshers, Boca Raton, FL, Chap. 9. 

Metals applied to land are relatively immobile, particularly if the soil has a high pH and high organic content. Many complex physical-chemical processes affect metal mobility in soil. Lead and mercury, which form strong complexes, move very slowly. Zinc, cadmium, and copper move a little faster. Metal profiles in highly contaminated soil penetrate little below the 4-8 inch region even after 60 years. ... 

Testing Metal Mobility in Soils by Elution Tests... 

Himer AV (1994) Testing metal mobility in soils by elution tests (this volume)... 

Lahd Geagea, M., Kyser, K., and Chipley, D. (2012) Characterization of metal mobilization in soils and vegetation over a VMS ore deposit using Zn and Cu isotopic systems. J. Geochem. Explor., in press. 

---