Publication Type Journal Article
Title Dissolved gaseous mercury formation and mercury volatilization in intertidal sediments
Authors Rute Cesário Laurier Poissant Martin Pilote Nelson J. O Driscoll Ana M. Mota João Canário
Groups
Journal SCIENCE OF THE TOTAL ENVIRONMENT
Year 2017
Month December
Volume 603
Number
Pages 279-289
Abstract Intertidal sediments of Tagus estuary regularly experiences complex redistribution due to tidal forcing, which affects the cycling of mercury (Hg) between sediments and the water column. This study quantifies total mercury (Hg) and methylmercury (MMHg) concentrations and fluxes in a flooded mudflat as well as the effects on waterlevel fluctuations on the air-surface exchange of mercury. A fast increase in dissolved Hg and MMHg concentrations was observed in overlying water in the first 10 min of inundation and corresponded to a decrease in pore waters, suggesting a rapid export of Hg and MMHg from sediments to the water column. Estimations of daily advective transport exceeded the predicted diffusive fluxes by 5 orders of magnitude. A fast increase in dissolved gaseous mercury (DGM) concentration was also observed in the first 20-30 min of inundation (maximum of 40 pg L-1). Suspended particulate matter (SPM) concentrations were inversely correlatedwith DGM concentrations. Dissolved Hg variation suggested that biotic DGM production in pore waters is a significant factor in addition to the photochemical reduction of Hg. Mercury volatilization (ranged from1.1 to 3.3 ngm(-2) h(-1); average of 2.1 ngm(-2) h(-1)) and DGM production exhibited the same pattern with no significant time-lag suggesting a fast release of the produced DGM. These results indicate that Hg sediment/water exchanges in the physical dominated estuaries can be underestimated when the tidal effect is not considered. (C) 2017 Elsevier B.V. All rights reserved.
DOI http://dx.doi.org/10.1016/j.scitotenv.2017.06.093
ISBN
Publisher ELSEVIER SCIENCE BV
Book Title
ISSN 0048-9697
EISSN 1879-1026
Conference Name
Bibtex ID ISI:000405981500030
Observations
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