The sulphur-mercury(II) system in natural waters

Dyrssen, David; Wedborg, Margareta

doi:10.1007/bf00342295

Cited by 255 publications

(180 citation statements)

References 17 publications

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“…This is consistent with bulk samples of hydrothermal crusts from the site having elevated Hg contents (5.8 -17.3 ppm; Table 2) relative to typical rock concentrations (10 -300 ppb [McDonough and Sun, 1995]), particularly for material of low sulfide concentration. Supersaturation of Hg in the fluid phase could also be the result of the prominence of MMHg, however, which is more soluble than Hg 2+ in the presence of sulfide [Dyrssen and Wedborg, 1991]. In order to further constrain the conditions under which Hg accumulates in these rocks, samples were examined using transmitted and reflected light microscopy to determine mineralogy and paragenetic relationships.…”

Section: Resultsmentioning

confidence: 99%

Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge

Lamborg¹,

Damm²,

Fitzgerald³

et al. 2006

Geophysical Research Letters

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Submarine hydrothermal systems are hypothesized to be a potentially important source of monomethylmercury (MMHg) to the ocean, yet the amount of MMHg in vent fluids is unknown. Here, we report total Hg and MMHg concentrations in hydrothermal vent fluids sampled from the Sea Cliff site on the Gorda Ridge. MMHg is the dominant Hg species, and levels of total Hg are enhanced slightly compared to seawater. Hg is enriched in deposits surrounding the site, suggesting near‐field deposition from fluid plumes, with rapid MMHg demethylation and scavenging of Hg(II) complexes. Assuming the flux of MMHg from Sea Cliff is representative of global submarine hydrothermal inputs, we estimate a flux of 0.1–0.4 Mmoles y−1, which may be attenuated by scavenging near the vents. However, deep waters are not typically known to be elevated in Hg, and thus we suggest that hydrothermal systems are not significant sources of MMHg to commercial fisheries.

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Section: Resultsmentioning

confidence: 99%

Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge

Lamborg¹,

Damm²,

Fitzgerald³

et al. 2006

Geophysical Research Letters

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“…Interestingly, Mason et al (1984) have shown that the nephrocytes of Littorina littorea specimens collected from clean and polluted sites contain very high intravacuolar concentrations of sulfur. The well-known affinity of mercury for sulfur compounds (Dyrssen & Wedborg 1991) could easily explain the striking capacity of nephrocytes to bioconcentrate this metal. Nevertheless, further studies are still needed to clearly identify the chemical nature of the vacuole content and to establish whether the internalized mercury is present as a non-toxic form.…”

Section: Discussionmentioning

confidence: 99%

Bioaccumulation of inorganic and methylated mercury by the gills of the shore crab Carcinus maenas: transepithelial fluxes and histochemical localization

Laporte¹,

Truchot

Mesmer-Dudons³

et al. 2002

Mar. Ecol. Prog. Ser.

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In order to better understand the role of the gills in the accumulation of contaminants, branchial uptake and bioaccumulation of inorganic (HgCl 2 ) and monomethylmercury (CH 3 HgCl) were quantified in the shore crab Carcinus maenas, using living animals and an in vitro perfused gill preparation exposed to 50 µg l -1 of either chemical forms in the external medium. In addition, localization of accumulated mercury was studied using the histochemical autometallographic technique by both light and electron microscopy. Gill tissue strongly accumulated either inorganic or methylated mercury at similar levels in vitro and in vivo. For both chemical forms of the metal, only about 1% of the total mercury input was recovered in the effluent fluid from in vitro perfused gills and could thus be considered available to distribute inside the animal via the circulatory system. Inorganic Hg was histochemically found to be accumulated at 2 markedly different locations in the gills: at the cuticular surface in direct contact with the contaminated medium and at high local levels in the central vacuole of gill nephrocytes. Although also present at these 2 locations, methylmercury was distributed more diffusely and more evenly in all cells. These results suggest that the high affinity of gill tissue for both forms of mercury may confer on this organ the role of an external barrier strongly limiting the invasion of the metal toward other compartments of the body.

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“…Sediment−water fluxes of dissolved MMHg (< 0.2 µm), presumably as CH 3 HgSH 0 (Dyrssen and Wedborg, 1991), were calculated from the concentration gradient between pore waters of surface sediments and water sampled below the seasonal thermocline (30 m) at each location, which ranged between 0.17 pM and 0.44 pM. MMHg was measured in filtered pore water of surface sediment in three cores from each station.…”

Section: Estimated Sediment−water Fluxes Of Mmhgmentioning

confidence: 99%

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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The sulphur-mercury(II) system in natural waters

Cited by 255 publications

References 17 publications

Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge

Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge

Bioaccumulation of inorganic and methylated mercury by the gills of the shore crab Carcinus maenas: transepithelial fluxes and histochemical localization

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

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