SREL Reprint #2200

Distribution and chemical speciation of metals and metalloids in biota collected from contaminated environments by spatially resolved XRF, XANES, and EXAFS

D.B. Hunter1, P.M. Bertsch1, K.M. Kemner2, and S.B. Clark1

1Advanced Analytical Center for Environmental Sciences, The University of Georgia, SREL,
Drawer E, Aiken, SC 29802, USA
2U. S. Naval Research Laboratory, Washington D. C, USA

Abstract: Shell fragments from turtles collected in a wetland receiving outfall from coal combustion ash basins were elevated in a number of contaminants, notably Se and As. Micro-XANES analysis of the epithelial layer on the shell and of the bone tissue revealed that the keratin associated Se was present exclusively in seleno-amino acid coordination environments, whereas Se in the bone tissue was a mixture of selenate and proteinaceous Se. Elemental distribution maps of hyperaccumulating plants generated by XRF reveal a heterogeneous distribution of Se and Cr, with Se being concentrated within the nuclei of cells and Cr within discrete aggregates in the cytoplasm. Micro-XANES measurements taken on these same regions demonstrated the total loss of the Cr(VI) diagnostic pre-edge feature, indicating the complete reduction of the Cr(VI) to Cr(III) after uptake by the plants.

SREL Reprint #2200

Hunter, D.B., P.M. Bertsch, K.M. Kemner, and S.B. Clark. 1997. Distribution and chemical speciation of metals and metalloids in biota collected from contaminated environments by spatially resolved XRF, XANES, and EXAFS. Journal de Physique IV France 7:767-771.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).