Metal speciation in solid wastes — Factors affecting mobility

TLDR: The availability of trace metals for metabolic processes is closely related to their chemical species both in solution and in particulate matter as discussed by the authors, which can be used for assessment of sources by characterization of typical speciation patterns, estimation of biological availability of metal pollutants, differentiation of geochemical environments, and estimation on the potential remobilization of metals under changing environmental condition.

Abstract: The availability of trace metals for metabolic processes is closely related to their chemical species both in solution and in particulate matter. For the differentiation of the solid metal species — e.g., cation exchangeable forms, carbonate phases, reducible fractions, associations with organic substances and sulfides, and the inert “residual” fractions — chemical extraction sequences have been developed, which can be used for (i) assessment of sources by characterization of typical speciation patterns, (ii) estimation of biological availability of metal pollutants, (iii) differentiation of geochemical environments, (iv) evaluation of diagenetic effects, and (v) estimation on the potential remobilization of metals under changing environmental condition. There is a tendency, that elements introduced with solid waste material are less stably bound than those in natural systems. Even at relative small proportions of these materials, therefore, mobilization (and subsequent transfer to biota) of potentially toxic elements by acidity, complexing agents, or redox changes, may be significantly increased.