GEOC 59 |
| Barbara Sulzberger, Department of Limnology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Ueberlandstrasse 133, P.O. Box 611, CH-8600 Duebendorf, Switzerland and Diane Buerge-Weirich, Swiss Federal Research Station for Agroecology and Agriculture, Reckenholzstrasse 191, CH-8046 Zuerich, Switzerland. |
| Cu(I) is an important species regarding the bioavailability and hence toxicity of copper. We have investigated the effects of simulated sunlight, salinity, and Cu(II) complexation capacity on Cu(I) steady-state concentrations ([Cu(I)]ss) in water samples from the River Scheldt estuary and the North Sea. [Cu(I)]ss, measured with a new solid-phase-extraction method, were highest in irradiated water samples collected in the North Sea and near the River Scheldt mouth, and lowest in irradiated water samples of intermediate salinity. Comparison with dark controls and electrochemical experiments allow the following interpretation of these results: At high salinity, Cu(I) was formed through light-induced reduction of Cu(II) and stabilization of Cu(I) by chloride whereas at low salinity, Cu(I) was produced mainly through thermal reduction of Cu(II) by sulfide containing compounds. At intermediate salinity, Cu(II) stabilizing ligands seemed to be present thus enhancing the oxidation of Cu(I) and/or lowering the efficiency of photolysis of Cu(II) complexes. |
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Chemistry of Metals in Terrestrial and Aquatic Systems
8:00 AM-11:30 AM, Tuesday, March 30, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |