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| Guedron, Stephane; Grimaldi, Michel; Grimaldi, Catherine; Cossa, Daniel; Tisserand, Delphine; Charlet, Laurent. |
| Total mercury (HgT) and monomethylmercury (MMHg) were investigated in a tropical head watershed (1 km(2)) of French Guiana. The watershed includes a pristine area on the hill slopes and a former gold mined flat in the bottomland. Concentrations of dissolved and particulate HgT and MMHg were measured in rain, throughfall, soil water and at three points along the stream. Samples were taken in-between and during 14 storm events at the beginning and middle of the 2005 and 2006 rainy seasons. Dissolved and particulate HgT concentrations in the stream slightly increased downstream, while dissolved and particulate MMHg concentrations were low at the pristine sub-watershed outlet (median = 0.006 ng L-1 and 1.84 ng g(-1), respectively) and sharply increased at the... |
| Tipo: Text |
Palavras-chave: Mercury; Methylmercury; Tropical watershed; Gold placers; Stream water; Oxisols; Hydromorphic soils. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00035/14628/12134.pdf |
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| Guedron, Stephane; Cossa, Daniel; Grimaldi, Michel; Charlet, Laurent. |
| Sites of monomethylmercury (MMHg) production in Amazonian regions have been identified in hydraulic reservoirs, lake sediments and wetlands, but tailings ponds have not yet received sufficient attention for this purpose. This work evidenced high MMHg production within the water column and the interstitial water of two tailings ponds of French Guiana Au mines located; (i) in a small scale exploitation (Combat) where Hg was used for Au amalgamation, and (ii) in an industrial on-going Au mine (Yaoni) processing without Hg. The (MMHg)(D) maximum (2.5 ng L-1) occurred in the oxic water column above the sediment-water interface (SWI) of the most recent tailings pond (Combat), where the substrate was fresh, the redox transition was sharp and the pool of total Hg... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00030/14117/12133.pdf |
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| Cossa, Daniel; De Madron, Xavier Durrieu; Schafer, Jorg; Guedron, Stephane; Marusczak, Nicolas; Castelle, Sabine; Naudin, Jean-jacques. |
| Ocean margins are focal regions in terms of mercury (Hg) exchanges between the continent and the open sea. The aim of this paper is to describe the distribution and partition of Hg between the gaseous, dissolved and particulate phases in the waters of the Northwestern Mediterranean (NWM) margin, in order to assess the Hg sources and exchanges within the continuum between the continental shelf (Gulf of Lions) and the open sea (Northern Gyre). Mean (± standard deviation) of total Hg species (HgT) concentrations in unfiltered water samples were 1.52 ± 1.00 pmol L-1 (n=36) in the inner shelf, 1.09 ± 0.15 pmol L-1 (n=30) along the slope, and 1.10 ± 0.13 pmol L-1 (n=99) in the Northern Gyre. The dissolved phase (<0.45µm) average concentrations were 0.80 ±... |
| Tipo: Text |
Palavras-chave: Mercury; Ocean margin; Coastal area; Mediterranean. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00384/49563/50055.pdf |
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| Cossa, Daniel; De Madron, Xavier Durrieu; Schafer, Jorg; Lanceleur, Laurent; Guedron, Stephane; Buscail, Roselyne; Thomas, Bastien; Castelle, Sabine; Naudin, Jean-jacques. |
| Despite the ecologic and economical importance of coastal areas, the neurotoxic bioaccumulable monomethylmercury (MMHg) fluxes within the ocean margins and exchanges with the open sea remain unassessed. The aim of this paper is to address the questions of the abundance, distribution, production and exchanges of methylated mercury species (MeHgT), including MMHg and dimethylmercury (DMHg), in the waters, atmosphere and sediments of the Northwestern Mediterranean margin including the Rhône River delta, the continental shelf and its slope (Gulf of Lions) and the adjacent open sea (North Gyre). Concentrations of MeHgT ranged from <0.02 to 0.48 pmol L−1 with highest values associated with the oxygen-deficient zone of the open sea. The methylated mercury to... |
| Tipo: Text |
Palavras-chave: Mercury; Methylmercury; Ocean margin; Coastal area; Mediterranean. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00363/47399/47477.pdf |
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