Project Details:

Determination of Trace Elements Bound to Soil and Sediment Fractions

Objectives of monitoring are to assess pollution effects on man and his environment, to identify possible sources and establish relationships between pollutant concentrations and health effects or environmental changes. Thus, it is necessary to investigate and understand the mechanisms of transport of trace elements and their complexes to understand their chemical cycles in nature. Concerning natural systems, the mobility, transport and partitioning of trace elements are dependent on the chemical form of the elements. The process is controlled by the physico-chemical and biological characteristics of that system. Major variations of these characteristics are found in time and space due to the dissipation and flux of energy and materials involved in the biogeochemical processes which determine the speciation of the elements.

A draft has been preapred that presents an overview of methods for chemical speciation analysis of elements in samples of sediments and soils. Sequential leaching procedure is thoroughly discussed and examples are shown of different applications. It can be stated that despite some drawbacks, the sequential extraction method can provide a valuable tool to distinguish among trace element fractions of different solubility related to mineralogical phases. The understanding of the speciation of trace elements in solid samples is still rather unsatisfactory because the appropriate techniques are only operationally defined. The essential importance of proper sampling protocols is highlighted, since the sampling error can not be estimated and corrected by standards. The standard protocols for sediment and soil give a good basis for most of the solid samples and the results can be compared among different laboratories.

Project completed - IUPAC Technical Report published in PureAppl. Chem. 76(2), 415-442, 2004