Optimization of a Sequential Extraction Scheme for the Characterization of Heavy Metal Mobility in Iron Oxide Rich Sediments

Abstract

Several parameters governing the extraction of metals from iron oxide rich sediments, using sequential extraction schemes were optimized. The mode of shaking, soil/extractant ratio and concentrations of MgCl₂ and NH₂OH·HCl, for samples collected in the Odiel Marshes Natural Park (SW Spain), were considered. The concentration of NH₂OH·HCl deserved particular attention due to the nature of the studied sediments. A 0.4 M concentration of this extractant was needed to avoid readsorption of Cu and As in the samples. In addition, readsorption processes were studied using a candidate to reference material with a high organic matter content that was previously analyzed in an interlaboratory study.

Key Words:

• Sequential extraction
• metals
• marshes
• readsorption