Natural Environment Monitoring 2008, No 9, 29-36
CHEMICAL FRACTIONATION METHODS USED IN ENVIRONMENTAL STUDIES
Ryszard Świetlik, Marzena Trojanowska
Trace metals in environmental solid samples may exist in different chemical forms or ways of binding. It is now widely recognized that the toxicity and the mobility of metals depend strongly on their specific chemical forms and physical phases. In environmental studies the determination of different species gives more information on trace metal mobility, as well as on their availability or toxicity in comparison with the total element content. Sequential extraction techniques are commonly used to chemical fractionation the solid-phase forms of metals in environmental samples. Many sequential extraction procedures have been developed for different solid samples (sediments, soils, sludge) and, despite numerous criticism, they remain very useful in environmental studies. The choice of procedure must be related to a definite objective, taking into account the nature of the sample.
This article reviews the methods used to chemical fractionation of metals in different environmental solid samples. Quantification of main phases associations of trace elements in soils and sediments helps in understanding geochemical processes in order to evaluate the remobilization potential and the risk induced.