Data/hora: 05/06/2024 06:39:14

Provedor de dados: | 5
País: | France
Título: | Mercury speciation and exchanges at the air-water interface of a tropical artificial reservoir, French Guiana
Autores: | Muresan Paslaru, Bogdan; Cossa, Daniel; Richard, S; Burban, B.
Data: | 2007-10
Ano: | 2007
Palavras-chave: | Fluxes; Speciation; Mercury; Artificial reservoir; Atmosphere.
Resumo: | The distribution and speciation of mercury (Hg) in air, rain, and surface waters from the artificial tropical lake of Petit-Saut in French Guiana were investigated during the 2003/04 period. In the air, total gaseous mercury (TGM) at the dam station averaged 12 +/- 2 pmol m(-3) of which &gt; 98% was gaseous elemental mercury (GEM). GEM distribution depicted a day-night cycling with high concentrations (up to 15 pmol m(-3)) at dawn and low concentrations (down to 5 pmol m(-3)) at nightfall. Reactive gaseous mercury (RGM) represented &lt; 1% of the GEM with a mean concentration of 4 3 fmol m(-3). Diel RGM variations were negatively related to GEM. In the rain, the sum of all Hg species in the unfiltered (HgTUNF) averaged 16 +/- 112 pmol L-1. Temporal distribution of HgTUNF exhibited a pattern of high concentrations during the late dry seasons (up to 57.5 pmol L-1) and low concentrations (down to 2.7 pmol L-1) in the course of the wet seasons. Unfiltered reactive (HgRUNF), dissolved gaseous (DGM) and monomethyl (MMHgUNF.) Hg constituted 20, 5 and 5% of HgTUNF, respectively. All measured Hg species were positively related and displayed negative relationships with the pH of the rain. In the reservoir surface waters, dissolved total mercury (HgTD) averaged 3.4 +/- 1.2 pmol L-1 of which 10% consisted of DGM. DGM showed a trend of high concentrations during the dry seasons (480 +/- 270 finol L-1 and lower (230 +/- 130 finol L-1) in the course of the wet seasons. Diel variations included diurnal photo-induced DGM production (of about 60 firiol L-1 h(-1)) coupled to minute to hour oxidation/ reduction cycles (of &gt; 100 firiol L-1 amplitude). Finally, calculated atmospheric Hg inputs to the Petit-Saut reservoir represented 14 mot yr(-1) whereas DGM evasion reached 23 mol yr(-1). Apportionment among forms of Hg deposition indicated that up to 75% of the total Hg invasive flux follows the rainfall pathway. (C) 2007 Elsevier B.V. All rights reserved.
Tipo: | Text
Idioma: | Inglês

Identificador:

http://archimer.ifremer.fr/doc/2007/publication-3329.pdf

DOI:10.1016/j.scitotenv.2007.06.013

Editor: | Elsevier
Relação: | http://archimer.ifremer.fr/doc/00000/3329/
Formato: | application/pdf
Fonte: | Science of The Total Environment (0048-9697) (Elsevier), 2007-10 , Vol. 385 , N. 1-3 , P. 132-145
Fonte: | 2007 Elsevier B.V. All rights reserved