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Title: Mercury speciation driven by seasonal changes in a contaminated estuarine environment

In this study, seasonal changes of mercury (Hg) species in the highly variable estuary of Soča/Isonzo River (northern Adriatic Sea) were investigated. Samplings were performed on a seasonal basis (September 2009, May, August and October 2010) and Hg species (total Hg, methylmercury (MeHg), dissolved gaseous Hg (DGM)) in waters, sediments and pore waters were determined. In addition, a range of ancillary parameters were measured (salinity, nutrients, organic carbon (OC), nitrogen species). Hg values were interpreted using these parameters and hydrological conditions (river flow, wave height) around the time of sampling. There were no significant changes in Hg load from river to the gulf, compared to previous studies. The load was temporarily higher in May 2010 due to higher river flow. Wave height, through changing hydrostatic pressure, was most likely to cause resuspension of already deposited Hg from the bottom (August 2010). The estuary is a net source of DGM to the atmosphere as suggested by DGM profiles, with salinity, redox potential and organic matter as the most probable controls over its production. MeHg is produced in situ in sediment or in water column, rather than transported by river, as indicated by its correlation with OC of the marine origin. Calculatedmore » fluxes for THg and MeHg showed sediment as a source for both the water column. In pore waters, OC in part affects partitioning of both THg and MeHg; however other factors (e.g. sulphide and/or oxyhydroxides precipitation and dissolution) are also probably important. -- Highlights: ► Water, sediment and pore water mercury species in front of Soča River estuary were measured. ► Seasonally variable hydrological conditions were shown to influence water column Hg speciation. ► Fluxes for total Hg and MeHg from sediment to water were calculated. ► Sediment is a source of total Hg and MeHg to the water column. ► Correlation of MeHg with organic carbon of marine origin suggests in situ formation.« less
Authors:
 [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1]
  1. Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)
  2. Marine Biology Station, Fornače 41, 6330 Piran (Slovenia)
  3. Faculty of Civil and Geodetic Engineering, Jamova 2, 1000 Ljubljana (Slovenia)
  4. Faculty of Engineering, Kyushu University, Fukuoka 812-8581 (Japan)
  5. Faculty of Engineering, Nagasaki University, Bunkyo-machi 1-14, Nagasaki 852-8521 (Japan)
Publication Date:
OSTI Identifier:
22246948
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Research; Journal Volume: 125; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ADRIATIC SEA; CARBON; CORRELATIONS; ESTUARIES; MERCURY; METHYLMERCURY; NUTRIENTS; ORGANIC MATTER; PARTICLE RESUSPENSION; REDOX POTENTIAL; RIVERS; SALINITY; SAMPLING; SEDIMENTS; SULFIDES; WATER