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ASSESSMENT OF A SEQUENTIAL EXTRACTION PROCEDURE FOR PERTURBED LEAD CONTAMINATED SAMPLES WITH AND WITHOUT PHOSPHORUS AMENDMENTS
Citation:
Scheckel*, K G., C A. Impellitteri**, AND J A. Ryan*. ASSESSMENT OF A SEQUENTIAL EXTRACTION PROCEDURE FOR PERTURBED LEAD CONTAMINATED SAMPLES WITH AND WITHOUT PHOSPHORUS AMENDMENTS. Presented at ACS National Meeting, New Orleans, LA, 3/23-27/2003.
Description:
Sequential extraction procedures (SEP) attempt to determine the solid-phase association of elements in natural matrices. However, a major obstacle confronting SEP is species alteration of extracted metals before separation of solids from solution. The objectives of this study were to investigate the potential formation of pyromorphite during the sequential extraction steps of Pb-spiked samples with and without phosphate amendments, and examine the differences in the operationally defined distribution of Pb in samples with and without the presence of phosphate. The systems that were examined in the absence of phosphate behaved adequately according to operational definitions. The results changed when the samples were amended with phosphate. Pb redistribution occurred due to pyromorphite formation during the SEP as confirmed by X-ray diffraction and X-ray absorption spectroscopies. These results indicate that sequential extraction methods may not be suitable for Pb speciation in perturbed environmental systems.