%0 Journal Article
%T A Critical Evaluation of Single Extractions from the SMT Program to Determine Trace Element Mobility in Sediments
%A Val¨¦rie Cappuyns
%J Applied and Environmental Soil Science
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/672914
%X Two commonly applied single extractions procedures, namely extractions with ammonium-EDTA and acetic acid, were evaluated based on the analysis of 72 samples from alluvial sediments. For most trace elements (Cu, Zn, Cd, Ni, As, and Pb), a significant linear relationship could be established between their ammonium-EDTA or acetic acid extractable concentrations and their total concentrations, the organic carbon content, pH, and Fe , Al, and/or Ca content in the sediments. The scientific understanding of trace element partitioning in the complex soil-water system with these simple models is rather limited, but they offer the opportunity to use data from single extractions in a more comprehensive way. Despite the fact that these extractions cannot directly be related to the bioavailability of elements, they can provide input data for use in risk assessment models. Additionally, they also offer possibilities to perform a fast screening of the mobilizable pool of elements in soils and/or sediments. 1. Introduction The contamination of soils and sediments is widespread and is a potential threat for the environment in the short and long term. The impact of trace elements in soils and sediments on the environment depends on their speciation, mobility, and bioavailability. Over the past decades, the term ¡°heavy metals¡± has increasingly been used, without any consistency to denote trace element contamination of environmental media. An overview of the use of the term ¡°heavy metals¡± in scientific dictionaries and relevant literature can be found in Duffus [1]. Since ¡°heavy metals¡± is a poor scientific term and many alternatives exit [2], we will use the term ¡°trace elements¡± in the present study to refer to As, Cd, Cu, Cr, Ni, Pb, and Zn. Talking about trace metals would be incorrect because arsenic is actually a metalloid. Before discussing the different methods for determination of ¡°trace element¡± availability in soils and/or sediments and before addressing the pros and cons of single and sequential extraction procedures, the difference between soils and sediments will be clarified, as well as the terminology used throughout this paper. 1.1. Soils versus Sediments Soils and sediments are different matrixes from many viewpoints, especially under the environmental context. ¡°Soil¡± can be defined as a ¡°three-dimensional body with properties that reflect the impact of climate, vegetation, fauna, and topography on soils parent material over a variable time span. Soils are still in a process of change. As a result of ¡°soil formation¡± or ¡°pedogenesis,¡± soil profiles show
%U http://www.hindawi.com/journals/aess/2012/672914/