COMMISSION ON MICROCHEMICAL TECHNIQUES AND TRACE ANALYSIS
(V.2)
Number: 523/2/89
Title: Determination of Trace Elements Bound to Soil and Sediment
Fractions
Coordinator(s): J.
Hlavay
Completion Date: 2004 - project completed
Description:
In environmental sciences the development of monitoring systems
is of main importance. Increasingly strict environmental regulations
require the development of new methods for analysis and ask for simple
and meaningful tools to obtain information on metal fractions of different
mobility and bioavailability in the solid phases. 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.
Progress:
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 Pure
Appl. Chem.
76(2), 415-442, 2004
Last Update: 3 April 2004