Aquatic Sciences Meeting, Albuquerque 2001

SS02 Photochemical Reactions In Surface Waters: A Major Issue in the 21st Century? (Environmental Connections)

Date: Thursday, February 15, 2001, Time: 4:45:00 PM

Location: San Miguel

Whitehead, R, F, Dept. of Chem. and Center for Marine Science, Univ. of North Carolina at Wilmington, Wilmington, USA, whiteheadrf@uncwil.edu

Shank, G, C, Dept. of Marine Science, Univ. of North Carolina at Chapel Hill, Chapel Hill, USA, shankc@uncwil.edu

Skrabal, S, A, Dept. of Chem. and Center for Marine Science, UNC Wilmington, Wilmington, USA, skrabals@uncwil.edu

Kieber, R, J, Dept. of Chem. and Center for Marine Science, UNC Wilmington, Wilmington, USA, kieberr@uncwil.edu

Cooper, W, J, Dept. of Chem. and Center for Marine Science, UNC Wilmington, Wilmington, USA,

PHOTOCHEMICAL INTERACTIONS WITH COPPER-COMPLEXING DOM IN THE CAPE FEAR ESTUARY, NC

Competitive ligand equilibration cathodic stripping voltammetry analysis of highly colored Cape Fear Estuary waters (southeastern North Carolina) shows that strong copper ligands (log K’ > 12) typically exceed total Cu concentrations by a factor of two or more, suggesting that most of the Cu in the estuary is tightly complexed by DOM. We are investigating the role of photochemical reactions as a possible sink for these strong Cu ligands and the influence of Cu-organic complexes on the photochemical behavior of the milieu. Results indicate the copper complexing ability of DOM is reduced following exposure to natural and simulated sunlight. The loss of copper complexing ability is accompanied by photobleaching of CDOM absorbance and fluorescence even when there is no measurable loss of DOC. In samples with added Cu, initial CDOM absorbance was not affected, but photobleaching was greatly reduced. These results indicate that Cu-organic complexes may be potential sinks for the photoproduced reactive intermediates involved in photobleaching of CDOM.

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Aquatic Sciences Meeting, Albuquerque 2001

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