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Chromium speciation in Changjiang River and its estuarine region
748
C. Chemical Oceanography
usually lower in the bayou, indicating retention by the marsh/aquatic system. Coastal Ecol. Inst., Louisiana State Univ., Baton Rouge, LA 708037507, USA.
C80. Physical chemistry in seawater 87:4983 Elliott, Scott, Eric Lu and F.S. Rowland, 1987. Carbonyl sulfide hydrolysis as a source of hydrogen sulfide in open ocean seawater. Geophys. Res. Letts, 14(2):131-134.
If pico to nanomolar levels of the hydrogen sulfides are included in standard equilibrium models of seawater complexation chemistry, several trace metals speciate predominantly as sulfide complexes and are supersaturated with respect to their solid sulfides. This supersaturation argues for solubilization of the metals through other unexpected complexes, perhaps involving reduced sulfur ligands associated with dissolved organics, or even intermediates along the hydrogen sulfide oxidation chain. Dept. of Chem., Univ. of Calif., Irvine, CA, USA. 87:4984 Huang, Huarui and Xuezhong Pang, 1986. Chromium speciation in Changjiang River and its estuarine region. Stud. mar. sin., 27:115-123. (In Chinese, English abstract.) Inst. of Oceanol., Acad. Sinica, People's Republic of China. 87:4985 Middelburg, J.J., G.J. de Lange and C.H. van der Weijden, 1987. Manganese solubility control in marine pore waters. Geochim. cosmochim. Acta, 51 (3) :759-763.
A theoretical study of the system CaCO3-HzO provides evidence that solid solution is limited to three mole fraction ranges corresponding to Mncalcite, kutnohorite and calcic-rhodochrosite. All these authigenic phases may control the concentration of manganese in suboxic marine pore waters. As a consequence the solubility of manganese cannot be adequately described by a single thermodynamic equilibrium constant. Dept. of Geochem., Inst. of Earth Sci., Univ. of Utrecht, P.O. Box 80.021, Budapestlaan 4, 3508 TA Utrecht, Netherlands. van den Berg, C.M.G. and M. Determination of interactions dissolved organic material in cathodic stripping voltammetry. ronment, 60:185-195.
87:4986 Nimmo, 1987. of nickel with seawater using Sci. total Envi-
OLR (1987) 34 (9)
Procedures and theory are presented to determine complexing capacities for nickel in seawater using cathodic stripping voltammetry of complexes with dimethylglyoxime (DMG). Values are determined for seawater of several salinities by ligand competition with EDTA. Preliminary measurements on samples from various locations reveal the presence of low concentrations (2-4 nM) of strong complexing ligands with values for the conditional stability constant between 17.3 and 18.7. Dept. of Oceanogr., Univ. of Liverpool, Liverpool L69 3BX, UK.
CI00. Alkalinity, acidity, pH 87:4987 Van den Berg, C.M.G. and Howard Rogers, 1987. Determination of alkaliulties of estuarine waters by a two-point potentiometric titration. Mar. Chem., 20(3):219-226.
Gran plots of titrations of seawater with acid are straight lines after protonation of all weak acids when ion-pairing is taken into account. This property is used to calibrate the pH electrode and to determine the endpoint of what is essentially a two-point alkalinity titration of the sample. First the initial sample pH is measured; then a standard addition of acid is made giving a pH near 3.2 (pHi); a further acid addition is made giving a pH near 2 (pH2). The slope of the electrode response and the total alkalinity are calculated from pH 2 and pHi. The standard deviation of the alkalinity determination of seawater by the proposed technique was _+0.10%. Dept. of Oceanogr., Univ. of Liverpool, Liverpool L69 3BX, UK.
CII0. Radioactivity, radioisotopes 87:4988 Gamo, Toshitaka, Yoshio Horibe and Hiromi Kobayashi, 1987. Comparison of oceanic AI4C d~t~ with those of GEOSECS. Vertical profiles in 1973 (GEOSECS) and in 1980 (at 30°N, 170°E) in the northwestern Pacific Ocean. Radiocarbon, 29(1):53-56.
Values for A~4C reported in this study are comparable to the 1973 GEOSECS data below 700 m, but are significantly higher in the intermediate water layer. Input of bomb ~4C from the atmosphere followed by transport of sinking surface water over the 6.6 yr period is proposed to account for the difference. Ocean Res. Inst., Univ. of Tokyo, Minamidai, Nakano-ku Tokyo, 164, Japan. (gsb)
C. Chemical Oceanography
usually lower in the bayou, indicating retention by the marsh/aquatic system. Coastal Ecol. Inst., Louisiana State Univ., Baton Rouge, LA 708037507, USA.
C80. Physical chemistry in seawater 87:4983 Elliott, Scott, Eric Lu and F.S. Rowland, 1987. Carbonyl sulfide hydrolysis as a source of hydrogen sulfide in open ocean seawater. Geophys. Res. Letts, 14(2):131-134.
If pico to nanomolar levels of the hydrogen sulfides are included in standard equilibrium models of seawater complexation chemistry, several trace metals speciate predominantly as sulfide complexes and are supersaturated with respect to their solid sulfides. This supersaturation argues for solubilization of the metals through other unexpected complexes, perhaps involving reduced sulfur ligands associated with dissolved organics, or even intermediates along the hydrogen sulfide oxidation chain. Dept. of Chem., Univ. of Calif., Irvine, CA, USA. 87:4984 Huang, Huarui and Xuezhong Pang, 1986. Chromium speciation in Changjiang River and its estuarine region. Stud. mar. sin., 27:115-123. (In Chinese, English abstract.) Inst. of Oceanol., Acad. Sinica, People's Republic of China. 87:4985 Middelburg, J.J., G.J. de Lange and C.H. van der Weijden, 1987. Manganese solubility control in marine pore waters. Geochim. cosmochim. Acta, 51 (3) :759-763.
A theoretical study of the system CaCO3-HzO provides evidence that solid solution is limited to three mole fraction ranges corresponding to Mncalcite, kutnohorite and calcic-rhodochrosite. All these authigenic phases may control the concentration of manganese in suboxic marine pore waters. As a consequence the solubility of manganese cannot be adequately described by a single thermodynamic equilibrium constant. Dept. of Geochem., Inst. of Earth Sci., Univ. of Utrecht, P.O. Box 80.021, Budapestlaan 4, 3508 TA Utrecht, Netherlands. van den Berg, C.M.G. and M. Determination of interactions dissolved organic material in cathodic stripping voltammetry. ronment, 60:185-195.
87:4986 Nimmo, 1987. of nickel with seawater using Sci. total Envi-
OLR (1987) 34 (9)
Procedures and theory are presented to determine complexing capacities for nickel in seawater using cathodic stripping voltammetry of complexes with dimethylglyoxime (DMG). Values are determined for seawater of several salinities by ligand competition with EDTA. Preliminary measurements on samples from various locations reveal the presence of low concentrations (2-4 nM) of strong complexing ligands with values for the conditional stability constant between 17.3 and 18.7. Dept. of Oceanogr., Univ. of Liverpool, Liverpool L69 3BX, UK.
CI00. Alkalinity, acidity, pH 87:4987 Van den Berg, C.M.G. and Howard Rogers, 1987. Determination of alkaliulties of estuarine waters by a two-point potentiometric titration. Mar. Chem., 20(3):219-226.
Gran plots of titrations of seawater with acid are straight lines after protonation of all weak acids when ion-pairing is taken into account. This property is used to calibrate the pH electrode and to determine the endpoint of what is essentially a two-point alkalinity titration of the sample. First the initial sample pH is measured; then a standard addition of acid is made giving a pH near 3.2 (pHi); a further acid addition is made giving a pH near 2 (pH2). The slope of the electrode response and the total alkalinity are calculated from pH 2 and pHi. The standard deviation of the alkalinity determination of seawater by the proposed technique was _+0.10%. Dept. of Oceanogr., Univ. of Liverpool, Liverpool L69 3BX, UK.
CII0. Radioactivity, radioisotopes 87:4988 Gamo, Toshitaka, Yoshio Horibe and Hiromi Kobayashi, 1987. Comparison of oceanic AI4C d~t~ with those of GEOSECS. Vertical profiles in 1973 (GEOSECS) and in 1980 (at 30°N, 170°E) in the northwestern Pacific Ocean. Radiocarbon, 29(1):53-56.
Values for A~4C reported in this study are comparable to the 1973 GEOSECS data below 700 m, but are significantly higher in the intermediate water layer. Input of bomb ~4C from the atmosphere followed by transport of sinking surface water over the 6.6 yr period is proposed to account for the difference. Ocean Res. Inst., Univ. of Tokyo, Minamidai, Nakano-ku Tokyo, 164, Japan. (gsb)