Comparison of sequential and kinetic extractions for As speciation in contaminated soils.

Comparison of sequential and kinetic extractions for As speciation in contaminated soils. We compared the results obtained by sequential extraction combined with physical fractionation to those obtained by kinetics for As speciation in slightly polluted soils through irrigation. The soil samples were sieved through a 50-mum mesh. Particulate organic matter was manually sorted and joined to the less than 50-mum fractions. This last fraction was sequentially extracted with phosphates, NaOH and hydroxylamine + acetic acid at 90degreesC. Kinetic extractions by EDTA were also performed on whole samples. Results show that As originating from irrigation was rather mobile. The different compartments defined by the sequential extraction were in agreement with those defines by kinetics. (C) 2004 Academie des sciences. Publie par Elsevier SAS. Tons droits reserves.