Chemical and physical speciation of mercury in Offatts Bayou: A seasonally anoxic bayou in Galveston Bay

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dc.acquisition-srcen_US
dc.call-noen_US
dc.contract-noen_US
dc.contributor.authorHan, Seungheeen_US
dc.contributor.authorLehman, Ronald Den_US
dc.contributor.authorChoe, Key-Youngen_US
dc.contributor.authorGill, Gary Aen_US
dc.contributor.otherLimnology and Oceanographyen_US
dc.date.accessioned2010-02-15T16:46:17Z
dc.date.available2010-02-15T16:46:17Z
dc.date.issued2007en_US
dc.degreeen_US
dc.descriptionpgs. 1380-1392en_US
dc.description-otheren_US
dc.description.abstractA chemical equilibrium model was used to predict the solution speciation of dissolved mercury (Hg) in the stratified water column of Offatts Bayou, a subestuary in Galveston Bay, Texas, which undergoes seasonal anoxia in bottom waters. Chemical equilibrium modeling was conducted using conditional stability constants and concentrations of Hg-complexing organic ligands experimentally determined by competitive ligand equilibration methods. Dissolved Hg complexation was dominated by interactions with sulfide and dissolved organic matter (DOM) (HOHgHS super(0), HOHgHS(DOM), HgSHS super(-), and HgS sub(2) super(2-) at all depths. Sulfide and glutathione competed for methylmercury (MeHg) complexation in oxic layers; in anoxic waters, sulfide complexation dominated MeHg speciation. The particle-water distribution coefficient (K sub(d)) of Hg decreased in the anoxic layer of the water column, where the dissolved sulfide concentration increased, providing evidence that sulfide complexation influences the solubility of Hg. The solubility of MeHg was elevated in the anoxic as compared to the oxic layers, and this distributional feature was coincident with a change in the solution speciation of dissolved MeHg from glutathione/sulfide complexation in the oxic layers to a predominantly sulfide complexation in the anoxic layers. Maximum enrichment of Hg, MeHg, and iron (Fe) in suspended particulate matter was observed in the lower layer of the pycnocline, most likely resulting from formation of insoluble Fe oxide, which scavenged dissolved Hg-sulfide and MeHg-sulfide species. The concomitant decrease in dissolved inorganic Hg, Fe, and sulfide in the anoxic layers is suggested to result from scavenging of inorganic Hg by FeS, which is in accordance with the Hg speciation model. Overall, Hg cycling in the water column of Offatts Bayou was associated with sulfide and DOM complexation, Fe dissolution/precipitation, water column production of MeHg, and/or efflux of MeHg from anoxic sediment.en_US
dc.description.urihttp://gbic.tamug.edu/request.htmen_US
dc.geo-codeGalveston Bayen_US
dc.geo-codeOffatts Bayouen_US
dc.history1-16-09 kswen_US
dc.identifier.urihttp://hdl.handle.net/1969.3/18549
dc.latitudeen_US
dc.locationNot available in house - Please contact GBIC for assistanceen_US
dc.longitudeen_US
dc.notesen_US
dc.placeen_US
dc.publisheren_US
dc.relation.ispartofseries10070.00en_US
dc.relation.urien_US
dc.scaleen_US
dc.seriesen_US
dc.subjectanoxiaen_US
dc.subjectbayousen_US
dc.subjectbottom wateren_US
dc.subjectcadmiumen_US
dc.subjectchemical equilibriumen_US
dc.subjectdissolved organic matteren_US
dc.subjectironen_US
dc.subjectligandsen_US
dc.subjectmercuryen_US
dc.subjectprecipitationen_US
dc.subjectpycnoclineen_US
dc.subjectseasonal variationsen_US
dc.subjectsediment pollutionen_US
dc.subjectsolubilityen_US
dc.subjectspeciationen_US
dc.subjectsulfidesen_US
dc.subjectsulfur dioxideen_US
dc.subjectsuspended particulate matteren_US
dc.subjectwater columnen_US
dc.titleChemical and physical speciation of mercury in Offatts Bayou: A seasonally anoxic bayou in Galveston Bayen_US
dc.typeArticleen_US
dc.universityen_US
dc.vol-issue52(4)en_US

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