Comparison of Sequential Extraction and Bioaccessibility Analyses of Lead Using Urban Soils and Reference Materials

Howard, Jeffrey L.; Dubay, Brian R.; McElmurry, Shawn P.; Clemence, Josiah; Daniels, W Lee

Comparison of Sequential Extraction and Bioaccessibility Analyses of Lead Using Urban Soils and Reference Materials

2013

Howard, Jeffrey L. | Dubay, Brian R. | McElmurry, Shawn P. | Clemence, Josiah | Daniels, W Lee

A study was undertaken using urban soils in Detroit, MI and reference materials (cerussite, anglesite, pyromorphite, apatite, goethite, calcite, pyrolusite, and peat) to determine which geochemical forms of Pb measured by sequential extraction analysis are bioaccessible. The results suggest that the water soluble (Pb-fulvic acid complexes), exchangeable, and part of the carbonateoccluded fractions are bioaccessible. The Fe oxideoccluded, Mn oxide-occluded, and higher molecular weight component of the organically bound fraction are not bioaccessible. Sequential extraction predicts the presence of detectable levels of bioaccessible Pb in the rhizosphere when the summed total is ≥90 mg kg-1 and labile Pb is ≥30 mg kg-1. Cerussite (paint-Pb) and anglesite (auto-Pb), recovered mainly in the carbonateoccluded fraction, may cause an overestimation of calcite-Pb. Pyromorphite and apatite Pb (bone) may cause an overestimation of Fe oxide-occluded Pb. © Springer Science+Business Media Dordrecht 2013.

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