HR: 17:00h
AN: B52F-05    [PDF]
TI: Metal-sulfide species in oxic waters: Complexes, clusters, or colloids?
AU: * Wang, F
EM: wangf@ms.umanitoba.ca
AF: University of Manitoba, Environmental Science Program & Department of Chemistry, Winnipeg, MB R3T 2N2 Canada
AU: Sukola, K
EM: umsukola@cc.umanitoba.ca
AF: University of Manitoba, Environmental Science Program & Department of Chemistry, Winnipeg, MB R3T 2N2 Canada
AU: Tessier, A
EM: andre_tessier@inrs-ete.uquebec.ca
AF: INRS-ETE, C.P.7500, Sainte Foy, QC G1V 4C7 Canada
AB: A weight-of-evidence approach is employed to characterize metal-sulfide species that have recently been suggested to be present in oxic waters. Sulfide in synthetic Cd-, Zn-, Pb-, Cu-sulfide solutions persists in oxic waters for a prolonged period of time (2 to more than 10 weeks) whereas it is oxidized rapidly in Fe-, Mn- and Ni-sulfide solutions. Direct mass spectrometric (MS) analysis and transmission electron microscopic (TEM) analysis revealed that the metal-sulfide species resistant to oxidation in oxic waters are not soluble molecular nanoclusters as suggested previously; instead, they are a mixture of truly dissolved metal-sulfide complexes and dynamic metal-sulfide colloids. The morphology and size of the colloids change significantly with time. Nanomolar to sub-micromolar levels of acid-volatile sulfide (AVS) and chromous-volatile sulfide (CVS) were measured in oxic surface waters of 6 lakes located on the Canadian Shield and nearby areas. Thermodynamic calculations indicated that at the AVS levels measured, the dissolved metal-sulfide species play a minor role in the speciation of Class B metal ions such as Pb, Cd, Cu, Hg.
DE: 0400 Biogeosciences
DE: 1065 Trace elements (3670)
DE: 1845 Limnology
SC: Biogeosciences [B]
MN: 2003 Fall Meeting