ENVR 34 |
| Jeffrey J. Tsang, Tim F. Rozan, Heileen Hsu-Kim, Katherine M. Mullaugh, and George W. Luther III. |
| Pseudopolarography was used to detect Cd complexes in samples collected at several locations along the Potomac River in spring and summer, 2004. As many as two Cd complexes were detected at each site. These unknown complexes were characterized by their half-wave reduction potential (E1/2). The E1/2 values indicated certain Cd complexes were common at different sites within a season but different complexes were observed in spring and summer. A Cd chelate scale generated from model ligands was used to estimate the thermodynamic stability constants (KTHERM) of the unknown Cd complexes, which ranged from log KTHERM = 21.5 to 32.0. A fraction of the total dissolved Cd was not recovered by pseudopolarography. This was partly attributed to Cd-sulfide species, owing to the presence of acid volatile sulfide. These may be multinuclear Cd-sulfide clusters and/or nanoparticles with KTHERM values that exceed the detection window of Cd pseudopolarography (log KTHERM > 34.4). |
|
Environmental Occurrence, Fate and Transport of Chemicals and Nanomaterials
8:30 AM-12:05 PM, Monday, 27 March 2006 Georgia World Congress Center -- B217, Oral
Division of Environmental Chemistry |