Mercury speciation in Galveston Bay, Texas
- 出版日期：2004.
- 页数：1 v. :
- 第一责任说明：Seunghee Han.
- 分类号：a225 ; a272 ; a484
- ISBN：0496898213(ebk.) :
MARC全文
02h0029743 20121025101151.0 cr un||||||||| 120627s2004 xx ||||f|||d||||||||eng | 3157432 0496898213(ebk.) : CNY371.35 NGL NGL NGL a225 ; a272 ; a484 Han, Seunghee. Mercury speciation in Galveston Bay, Texas [electronic resource] : the importance of complexation by natural organic ligands / Seunghee Han. 2004. 1 v. : digital, PDF file. Adviser: Gill, Gary A. Thesis (Ph.D.)--Texas A&M University, 2004. The major goal of this research is the development of a competitive ligand equilibration-solvent solvent extraction CLE-SSE) method to determine organically complexed mercury species in estuarine water. The method was applied to estuarine surface waters of Galveston Bay and the water column of Offatts Bayou. Thermodynamic equilibrium modeling estimated organically complexed mercury species in estuarine water using the conditional stability constants of mercury-organic complexes and the concentrations of organic ligands determined by CLE-SSE. Two competing ligands, chloride and thiosalicylic acid TSA), were used for CLE-SSE. Chloride ion competition determined conditional stability constants for 1:1 mercury-ligand complexes ranging from &sim；1023 to &sim；10 24 with concentrations of organic ligands at low nM levels. TSA competition determined stronger mercury-binding ligands by manipulating the TSA concentration such that a higher binding strength was achieved than that for the mercury-chloride complex. TSA competition determined conditional stability constants for 1:1 mercury-ligand complexes ranging from &sim；1027 to &sim；10 29, with ligand concentrations ranging from 10 to 100 pM. Mercury-organic binding strengths in these ranges are consistent with bidentate mercury complexation by low molecular weight organic thiols. A linear relationship was observed between log stability constants for the mercury-ligand complex and log ligand concentrations, supporting the hypothesis that there is a continuum of mercury binding site strengths associated with dissolved organic matter. In Galveston Bay, organically complexed mercury accounted for ＞95% of the total dissolved mercury in surface water. Organic complexation of mercury coupled with mercury dissolution from particulate phases controls the filter-passing mercury distribution in surface waters of Galveston Bay. The estuarine distributional features of mercury-complexing organic ligands were similar to those of glutathione, supporting mercury complexation by a thiol binding group. In Offatts Bayou, a seasonally anoxic bayou on Galveston Bay, thermodynamic equilibrium modeling suggests that the speciation of dissolved mercury in anoxic systems is dominated by sulfide complexation rather than organic complexation. Mercury ; Estuary ; Trace elements in water Environmental aspects Texas ; Galveston Bay. ; Texas ; Galveston Bay. ; Texas ; Galveston Bay. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=uWLE7pfU1Rw%3d NGL Bs1615 rCNY371.35 ; h1 bs1204