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Geochemistry of trace metals in estu...

Wen, Liang-Saw.

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Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach./
Author:	Wen, Liang-Saw.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 1996,
Description:	218 p.
Notes:	Source: Dissertations Abstracts International, Volume: 58-05, Section: B.
Contained By:	Dissertations Abstracts International58-05B.
Subject:	Oceanography. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9701738
ISBN:	9780591080674

Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach.
Wen, Liang-Saw.

Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach. - Ann Arbor : ProQuest Dissertations & Theses, 1996 - 218 p.

Source: Dissertations Abstracts International, Volume: 58-05, Section: B.

Thesis (Ph.D.)--Texas A&M University, 1996.

This item must not be sold to any third party vendors.

A series of laboratory and field investigations were conducted using ultraclean techniques to study the speciation and estuarine geochemistry of colloidal and particulate trace metals (Ag, Al, Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn), These metals were chosen for this study based on their different chemical properties and their importance as contaminants in Texas estuaries. Colloids were observed to have significantly affected the fate and speciation of these trace metals. Calibrations of the cross-flow ultrafiltration system used for the collection of colloidally sized trace metals and organic matter resulted in considerable improvements (better recovery, lower system blanks) for the collection of colloidal matter and associated trace elements. All metals exhibited significant colloidal fractions (10$\\sim$90%) in Galveston Bay waters. In order to determine major phases for trace metals, the following analytical or statistical tests were performed: (1) sequential extraction of particulate phases, (2) correlations between colloidal fractions of trace metals and those of organic carbon or iron, and (3) comparisons of partition coefficients between colloids or particles and true (ultrafiltered) solution. It is demonstrated that colloids have considerably higher complexation capacities than suspended particles for a number of trace metals, including Ag, Cd, Cu, Ni and Zn. Functional groups other than carbon, such as sulfhydryls, might control surface complexation for some metals such as Ag or Fe. Molecular weight distributions of organic carbon and associated trace metals in Galveston Bay waters and controlled laboratory experiments using radiolabelled colloids showed that two competing processes are of primary importance. Namely, coagulation of colloidal metals resulting in particle formation and production of lower molecular weight species, possibly mediated by photochemical or microbiological reactions. The determination of estuarine distributions of these trace metals also made possible the calculation of their fluxes into and out of the estuary. Filter-passing ($\\leq$0.45$\\mu$m) and colloidal (1kDa$\\sim$0.45$\\mu$m) trace metal export fluxes to the continental shelf were enhanced during the summer of 1995 due to internal sources in Trinity Bay.

ISBN: 9780591080674Subjects--Topical Terms:

535383
Oceanography.
Subjects--Index Terms:

colloid

Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach.
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245 1 0 $a Geochemistry of trace metals in estuarine waters: A multi-phase speciation approach.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 1996
300 $a 218 p.
500 $a Source: Dissertations Abstracts International, Volume: 58-05, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Santschi, Peter H.
502 $a Thesis (Ph.D.)--Texas A&M University, 1996.
506 $a This item must not be sold to any third party vendors.
506 $a This item must not be added to any third party search indexes.
520 $a A series of laboratory and field investigations were conducted using ultraclean techniques to study the speciation and estuarine geochemistry of colloidal and particulate trace metals (Ag, Al, Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn), These metals were chosen for this study based on their different chemical properties and their importance as contaminants in Texas estuaries. Colloids were observed to have significantly affected the fate and speciation of these trace metals. Calibrations of the cross-flow ultrafiltration system used for the collection of colloidally sized trace metals and organic matter resulted in considerable improvements (better recovery, lower system blanks) for the collection of colloidal matter and associated trace elements. All metals exhibited significant colloidal fractions (10$\\sim$90%) in Galveston Bay waters. In order to determine major phases for trace metals, the following analytical or statistical tests were performed: (1) sequential extraction of particulate phases, (2) correlations between colloidal fractions of trace metals and those of organic carbon or iron, and (3) comparisons of partition coefficients between colloids or particles and true (ultrafiltered) solution. It is demonstrated that colloids have considerably higher complexation capacities than suspended particles for a number of trace metals, including Ag, Cd, Cu, Ni and Zn. Functional groups other than carbon, such as sulfhydryls, might control surface complexation for some metals such as Ag or Fe. Molecular weight distributions of organic carbon and associated trace metals in Galveston Bay waters and controlled laboratory experiments using radiolabelled colloids showed that two competing processes are of primary importance. Namely, coagulation of colloidal metals resulting in particle formation and production of lower molecular weight species, possibly mediated by photochemical or microbiological reactions. The determination of estuarine distributions of these trace metals also made possible the calculation of their fluxes into and out of the estuary. Filter-passing ($\\leq$0.45$\\mu$m) and colloidal (1kDa$\\sim$0.45$\\mu$m) trace metal export fluxes to the continental shelf were enhanced during the summer of 1995 due to internal sources in Trinity Bay.
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