Authors: Ana de SantiagoMartín Inmaculada ValverdeAsenjo Jose R Quintana Antonio Vázquez Antonio L Lafuente Concepción GonzálezHuecas
Publish Date: 2013/04/16
Volume: 20, Issue: 9, Pages: 6392-6405
Abstract
A set of periurban calcareous agricultural Mediterranean soils was spiked with a mixture of Cd Cu Pb and Zn at two levels within the limit values proposed by current European legislation incubated for up to 12 months and subjected to various onestep extraction procedures to estimate mobile neutral salts and potentially mobile metal fractions complexing and acidic extraction methods The results obtained were used to study metal extractability patterns according to the soil characteristics The analytical data were coupled with mineralogical investigations and speciation modelling using the Visual Minteq model The formation of soluble metalcomplexes in the complexing extracts predicted by the Visual Minteq calculations led to the highest extraction efficiency with complexing extractants Metal extractability patterns were related to both content and composition of carbonate organic matter Fe oxide and clay fractions Potentially mobile metal fractions were mainly affected by the finest soil fractions recalcitrant organic matter active lime and clay minerals In the case of Pb scarce correlations between extractable Pb and soil constituents were obtained which was attributed to high Pb retention due to the formation of 4PbCO3·3PbO corroborated by Xray diffraction In summary the high metal proportion extracted with complexing agents highlighted the high but finite capacity to store potentially mobilizable metals and the possible vulnerability of these soils against environmental impact from metal accumulationThis work was supported by the Universidad Complutense de Madrid and the Madrid Autonomous Region through Grant GR58/08 Research Team 950605 and Network CARESOIL Ref P2009/AMB1648 We especially wish to thank Miguel Juanco Ortenbach Centro Superior de Investigaciones Científicas CSIC and Julián Velázquez Cano Universidad Complutense de Madrid UCM for their helpful advice on mineralogical analysis Ms Pru BrookeTurner for the revision of the English version of the manuscript and the comments and suggestions of the editor and the anonymous referees
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