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LINKING SOLID PHASE SPECIATION OF PB SEQUESTERED TO BIRNESSITE TO ORAL PB BIOACCESSIBLITY: IMPLICATIONS FOR SOIL REMEDIATION
Citation:
BEAK, D. G., N. T. BASTA, K. G. SCHECKEL, AND S. J. TRAINA. LINKING SOLID PHASE SPECIATION OF PB SEQUESTERED TO BIRNESSITE TO ORAL PB BIOACCESSIBLITY: IMPLICATIONS FOR SOIL REMEDIATION. ENVIRONMENTAL SCIENCE AND TECHNOLOGY. American Chemical Society, Washington, DC, 42(3):779-785, (2008).
Impact/Purpose:
Journal article
Description:
Lead (Pb) sorption onto oxide surfaces in soils may strongly influence the risk posed from incidental ingestion of lead-contaminated soils. In this study, Pb was sorbed to a model soil mineral, birnessite, and was placed in a simulated gastrointestinal tract (in vitro) to simulate the possible effects of ingestion of a soil contaminated with Pb. The changes in Pb speciation were determined using Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Spectroscopy (XANES). Birnessite has a very high affinity for Pb with a sorption maximum of 0.59 mol Pb kg-1 (approximately 12% Pb sorbed by mass) in which there was no detectable bioaccessible Pb (< 0.002%). Surface speciation of the birnessite Pb was determined to be a binuclear bidentate (external) complex and a triple corner sharing complex in the birnessite interlayer. Lead sorbed to Mn oxide in contaminated media will have a very low (≈ 0) Pb bioaccessibility and present little risk associated with incidental ingestion of soil. These results suggest that birnessite, and other Mn oxides would be powerful remediation tools for Pb-contaminated media because of their high affinity for Pb.
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URL.PDF (PDF, NA pp, 24 KB, about PDF)Linking Solid Phase Speciation of PB, etc.
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