Overview of trace element speciation

This section is not intended to be a full review on speciation there are many papers and books dealing with the subject e.g. Quevauviller etal. 1995 Quevauviller 1998. In this chapter, the determination of redox species, mainly chromium and organometallic compounds, will be briefly addressed. In principle, the difference between the two types of determination is negligible since the species determination is mostly preceded by an extraction. 

The environmental impact of metallic contaminants in soils is dependent both on the chemical speciation of the metal and the response of the matrix to biological and physicochemical conditions. These factors are responsible for the mobilisation of the metal from the solid into the aqueous phase hence transport within the immediate vicinity, has an impact on the rate of dispersal, dilution, uptake and transfer into living systems. The impact of changing environmental conditions on the contaminant inventory can be to enhance or moderate these phenomena, with subsequent consequences for the broader risk assessment of the contaminants. During the last ten years, extensive research in analytical chemistry was initiated to develop highly specific and sensitive methods for measuring potentially harmful substances in various 

Chemical species (Chemical element). Specific form of an element defined based on its isotopic composition, electronic or oxidation state, and/or complex or molecular structure. 

Speciation analysis (Analytical chemistry). Analytical activities to identify and/or measure the quantities of one or more individual chemical species in a sample. 

Speciation of an element speciation. Distribution of an element amongst defined chemical species in a system. The term fractionation has been defined as follows. 

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