Pore-water silver concentration gradients and benthic fluxes from contaminated sediments of San Francisco Bay, California, U.S.A.

Rivera-Duarte, Ignacio; Flegal, A. Russell

doi:10.1016/s0304-4203(96)00086-2

Cited by 48 publications

(40 citation statements)

References 22 publications

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“…Moreover, in shallow estuarine environments, exchange of a constituent across the sedimentwater interface could be substantial enough to influence the overlying water column concentration (Rivera-Duarte andFlegal 1994, 1997;Gill et al 1999;Warnken et al 2001). To test these hypotheses in the Bay-Delta, a surface-water transect study was conducted in Franks Tract, moving Collectively, these results demonstrate that sediment-water exchange influences the water column concentrations of Hg and MMHg and that this influence is markedly enhanced in the nearshore marsh environment because of both shallow water depth and enhanced MMHg production.…”

Section: Mmhg In Sediments-mentioning

confidence: 99%

“…As an example, in the upper Galveston Bay, Texas, it was suggested that benthic inputs of manganese, nickel, zinc, and nutrients were significant enough to increase water column concentrations (Warnken et al 2000(Warnken et al , 2001, resulting in nonconservative estuarine mixing behaviors previously observed in that region of Galveston Bay (Wen et al 1999). Similarly, recent studies noted that benthic transport of lead and silver could be greater than the fluvial input in South San Francisco Bay (Rivera-Duarte andFlegal 1994, 1997). The importance of benthic transport of Hg has been tested in other coastal (Covelli et al 1999) and estuarine environments (Gill et al 1999), but little is known about the sediment-water exchange of Hg in the BayDelta.…”

mentioning

confidence: 97%

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Sediment‐water exchange of total mercury and monomethyl mercury in the San Francisco Bay‐Delta

Choe

Gill

Lehman

et al. 2004

Limnology & Oceanography

109

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Five field trips were conducted in the San Francisco Bay-Delta between May 2000 and October 2001 to investigate the sediment-water exchange of total mercury (Hg) and monomethyl mercury (MMHg). Solid-phase Hg averaged ϳ1 nmol g Ϫ1 and did not show any variability with depth or time or among sites. In contrast, solid-phase MMHg showed considerable vertical, temporal, and spatial variability (0.4-66 pmol g Ϫ1 ), with the highest values occurring at a peat-rich environment in May 2001, suggesting that MMHg production was largely controlled by temporal factors and habitat type. In pore water, both Hg and MMHg concentrations were generally elevated near the sediment-water interface during warm months. Sediment-water exchange flux of MMHg, determined with benthic chamber deployments, ranged from Ϫ92 to 850 pmol m Ϫ2 d Ϫ1 , with higher values occurring in May. In most cases, diffusional fluxes of Hg and MMHg, estimated with the use of interfacial concentration gradients, constituted only a minor portion of the measured fluxes, suggesting the importance of advective processes on sediment-water exchange. Surface-water transect and time series studies conducted in Franks Tract support the commonly held belief that wetland and marsh regions are major sources for MMHg within the Delta. The integrated sediment-water fluxes of Hg and MMHg in the study area were estimated to be 130 and 6 mmol d Ϫ1 , respectively, and the benthic input was as important a source of Hg and MMHg as the riverine input within the Delta during low-flow months.

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Section: Mmhg In Sediments-mentioning

confidence: 99%

mentioning

confidence: 97%

Sediment‐water exchange of total mercury and monomethyl mercury in the San Francisco Bay‐Delta

Choe

Gill

Lehman

et al. 2004

Limnology & Oceanography

109

View full text Add to dashboard Cite

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“…Coastal pore water profiles suggest that Ag is released at the sedimentwater interface during the oxidation of organic matter (Rivera-Duarte and Flegal, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Pore water Ag profiles from Long Island Sound and speciation calculations suggest that metal-polysulfide and bisulfide complexes control pore water Ag concentrations under anoxic conditions (Lyons and Fitzgerald, 1983), and elevated pore water Ag concentrations from San Francisco Bay, which has anoxic pore waters, are presumably due to the formation of soluble Ag-sulfide complexes (Rivera-Duarte and Flegal, 1997). Under more oxidizing conditions, pore water Ag concentrations that are greater than bottom water concentrations suggest Ag release from Mn and/or Fe (oxyhydr)oxides or oxidation of Fe monosulfides (Lyons and Fitzgerald, 1983;Kalnejais, 2005).…”

Section: Introductionmentioning

confidence: 99%

Geochemical cycling of silver in marine sediments along an offshore transect

et al. 2008

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Although there have been many surface water and water column silver (Ag) analyses in the ocean, the absence of high resolution pore water and solid phase Ag profiles has hampered our understanding of its oceanic geochemical cycling. This manuscript presents pore water and solid phase profiles of Ag along an offshore transect water profiles represent non-steady state conditions. Clearly, the early diagenesis of Ag is a highly dynamic process and more research is required to fully understand Ag cycling in sediments in continental margin locations.

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“…Several analytical techniques have been reported for the determination of dissolved silver in natural waters, including graphite furnace atomic absorption spectroscopy (GFAAS) after solvent extraction [2,[5][6][7][8][9], and inductively coupled plasma mass spectrometry (ICP-MS) after solvent or solid extraction [3,10,11]. Although voltammetric techniques have been reported for dissolved silver measurements in natural waters (including seawater) [12], they have been scarcely applied to environmental studies [13] because of the challenges posed by the low concentrations of silver in these waters.…”

Section: Introductionmentioning

confidence: 99%

Automation of a flow injection system for the determination of dissolved silver at picomolar concentrations in seawater with inductively coupled plasma mass spectrometry

Barriada¹,

Truscott²,

Achterberg³

2003

Journal of Automated Methods & Management in Chemistry

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An automated flow injection system for the determination of dissolved silver at ultratrace concentrations in seawater, and controlled under LabVIEW TM , is described. The flow injection system allows online processing of seawater samples before their analysis using a magnetic sector inductively coupled plasma mass spectrometry (MS-ICP-MS) instrument. Samples were analysed with a minimum amount of manipulation, thereby reducing the risk of contamination. In addition, the flow injection approach with incorporation of an anion exchange minicolumn allowed ready removal of analytical interferences caused by the saline matrix. The software allowed full control of all flow injection components (valves and pumps) and removed manual time control and, therefore, operator errors. The optimized system was capable of five sample injections per h, including preconcentration and wash steps. The limit of detection was 0.5 pM for a 240-s sample load time, which allowed the determination of dissolved silver in open ocean waters, where picomolar concentration levels are typically encountered.

show abstract

Pore-water silver concentration gradients and benthic fluxes from contaminated sediments of San Francisco Bay, California, U.S.A.

Cited by 48 publications

References 22 publications

Sediment‐water exchange of total mercury and monomethyl mercury in the San Francisco Bay‐Delta

Sediment‐water exchange of total mercury and monomethyl mercury in the San Francisco Bay‐Delta

Geochemical cycling of silver in marine sediments along an offshore transect

Automation of a flow injection system for the determination of dissolved silver at picomolar concentrations in seawater with inductively coupled plasma mass spectrometry

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