Porewater Distribution and Benthic Flux Measurements of Mercury and Methylmercury in the Gulf of Trieste (Northern Adriatic Sea)

Covelli, Stefano; Faganeli, Jadran; Horvat, Milena; Brambati, A.

doi:10.1006/ecss.1999.0466

Cited by 179 publications

(95 citation statements)

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“…As noted, the mean sediment−water fluxes of MMHg (pmol m −2 d −1 , ± 1 SE; n = 3) are 6.6 ± 0.6 at 71north, 12 ± 1.0 at 71central, and 8.2 ± 1.7 at 71south. These fluxes are 10−10 2 less than those estimated or measured for sediments in near-shore embayments, including LIS (basin-wide mean, 47 pmol m −2 d −1 ; , Lavaca Bay (mean, 210 Gill et al, 1999), and a site in the Gulf of Trieste, northern Adriatic Sea (2300 Covelli et al, 1999). Direct atmospheric deposition is the presumed primary source of Hg(II) to sediments at our sampling locations on the continental shelf, whereas sediment Hg loadings in LIS, Lavaca Bay, and the Gulf of Trieste are enhanced by fluvial sources of Hg, both from atmospheric deposition and anthropogenic activities in the watershed (Covelli et al, 1999;Gill et al, 1999;.…”

Section: Sediment−water Flux Of Mmhgmentioning

confidence: 79%

Methylmercury cycling in sediments on the continental shelf of southern New England

Hammerschmidt

Fitzgerald

2006

Geochimica et Cosmochimica Acta

169

127

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Exposure of humans to monomethylmercury (MMHg) occurs primarily through consumption of marine fish, yet there is limited understanding concerning the bioaccumulation and biogeochemistry of MMHg in the biologically productive coastal ocean. We examined the cycling of MMHg in sediments at three locations on the continental shelf of southern New Moreover, the efflux of dissolved MMHg to overlying water (i.e., net production at steady state) is correlated with the gross potential rate of MMHg production in surface sediments. These results suggest that the production and efflux of MMHg from coastal marine sediments is limited by Hg(II), loadings of which presumably are principally from atmospheric deposition to this region of the continental shelf. The estimated diffusive flux of MMHg from the shelf sediments averages 9 pmol m −2 d −1 . This flux is comparable to that required to sustain the current rate of MMHg accumulation by marine fish, and may be enhanced by the efflux of MMHg from nearshore deposits contaminated more substantially with anthropogenic Hg. Hence, production and subsequent mobilization of MMHg from sediments in the coastal zone may be a major source of MMHg to the ocean and marine biota, including fishes consumed by humans.

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Section: Sediment−water Flux Of Mmhgmentioning

confidence: 79%

Methylmercury cycling in sediments on the continental shelf of southern New England

Hammerschmidt

Fitzgerald

2006

Geochimica et Cosmochimica Acta

169

127

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“…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: 99%

“…First, intact sediment cores were collected from several sites in the Delta, and steady-state diffusional flux was estimated by vertical distributions in pore water. This approach is based on Fick's first law and has often been used in studies of Hg and MMHg (Gobeil and Cossa 1993;Gagnon et al 1997;Covelli et al 1999;Gill et al 1999). The second approach employed benthic flux chambers; in situ flux was directly determined on the basis of the concentration gradient over time.…”

mentioning

confidence: 99%

“…This method provides information on the effect of advective processes on benthic transport and the temporal scales for which sampling is conducted. Because of analytical difficulties, very few studies have tested the latter approach for Hg and MMHg (Covelli et al 1999;Gill et al 1999). The information obtained from this study will be used in future efforts to model the mass balance and biogeochemistry of Hg and MMHg in the Bay-Delta ecosystem.…”

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confidence: 99%

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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

110

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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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“…The same sediment samples were used to determine total organic carbon (TOC), total organic nitrogen (TON), total phosphorus (TP) and biogenic silica (Bio-Si). Sediment porosity was calculated by measuring the weight loss of sediment dried overnight at 105 °C to constant weight [7]. The sediment content of Chla and pheo-pigments were determined according to the method of Lorenzen [8] as described by Parsons [9].…”

Section: B Sampling Sitementioning

confidence: 99%

Diffusive Fluxes across Sediment–Water Interface in the Seto Inland Sea, Japan

Srithongouthai¹,

Tada²

2015

International Advanced Research Journal in Science, Engineering

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Spatial investigations of pore water nutrient concentrations and their theoretical fluxes were carried out in six different sediment types within a coastal environment (Shido Bay, the Seto Inland Sea, Japan fluxes increased with the C:N ratio of sedimentary organic matter. Differently, the highest Si(OH) 4 fluxes were related with the relative high pheo-pigments and biogenic silica (Bio-Si) contents in the surface sediment, which are affected by fecal matter from the oyster culture. As a result, organic matter availability was found to be an important factor in regulating spatial variability of NH 4 + and PO 4 3− fluxes, whereas significant contents of sedimentary pheo-pigments and Bio-Si characterise the sites where Si(OH) 4 is available.

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Porewater Distribution and Benthic Flux Measurements of Mercury and Methylmercury in the Gulf of Trieste (Northern Adriatic Sea)

Cited by 179 publications

References 0 publications

Methylmercury cycling in sediments on the continental shelf of southern New England

Methylmercury cycling in sediments on the continental shelf of southern New England

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

Diffusive Fluxes across Sediment–Water Interface in the Seto Inland Sea, Japan

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