The heavy metal in-taken by plants from contaminated soils is usually assessed by extraction with 0.1N HCl. This study characterized the chemical form of lead in the solid residue of 0.1N HCl-extracted Pb-contaminated kaolin. The results indicate that most lead in the 0.1N HCl-extracted residue of the Pb(NO 3) 2-contaminated kaolin dried at 105 ?C is mainly in form of PbCl 2. For other lead-containing kaolin sample heated at 900 ?C, the XAS analysis also shows that majority of the lead compound was converted into PbCl 2 precipitate that remained in the solid residue during the 0.1N HCl extraction. Because PbCl 2 is only slightly soluble in dilute acids or water, it is suggested that using 0.1N HCl liquid as an extracting reagent to represent the heavy metal uptake by plants might actually underestimate the uptake. ? 2005 Elsevier B.V. All rights reserved.
Relation:
Journal of Electron Spectroscopy and Related Phenomena 144-147 , pp. 299-301
