Modelling metal speciation in the Scheldt Estuary: combining a flexible-resolution transport model with empirical functions.
Predicting metal concentrations in surface waters is an important step in the understanding and ultimately the assessment of the ecological risk associated with metal contamination. In terms of risk an essential piece of information is the accurate knowledge of the partitioning of the metals between the dissolved and particulate phases, as the former species are generally regarded as the most bioavailable and thus harmful form. As a first step towards the understanding and prediction of metal speciation in the Scheldt Estuary (Belgium, the Netherlands), we carried out a detailed analysis of a historical dataset covering the period 1982-2011. This study reports on the results for two selected metals: Cu and Cd. Data analysis revealed that both the total metal concentration and the metal partitioning coefficient (Kd) could be predicted using relatively simple empirical functions of environmental variables such as salinity and suspended particulate matter concentration (SPM). The validity of these functions has been assessed by their application to salinity and SPM fields simulated by the hydro-environmental model SLIM. The high-resolution total and dissolved metal concentrations reconstructed using this approach, compared surprisingly well with an independent set of validation measurements. These first results from the combined mechanistic-empirical model approach suggest that it may be an interesting tool for risk assessment studies, e.g. to help identify conditions associated with elevated (dissolved) metal concentrations.
Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels, Belgium.
Marc
M
Elskens
Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (IMMC), 4 Avenue G. Lemaître, bte L4.05.02, BE-1348 Louvain-la-Neuve, Belgium; Université catholique de Louvain, Georges Lemaître Centre for Earth and Climate Research (TECLIM), Place Louis Pasteur 2, bte L4.03.08, BE-1348 Louvain-la-Neuve, Belgium.
Olivier
O
Gourgue
Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels, Belgium.
Willy
W
Baeyens
Université Libre de Bruxelles, Biogéochimie et Modélisation du Système Terre (BGéoSys) -Océanographie Chimique et Géochimie des Eaux, Campus de la Plaine -CP 208, Boulevard du Triomphe, BE-1050 Brussels, Belgium.
Lei
L
Chou
Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (IMMC), 4 Avenue G. Lemaître, bte L4.05.02, BE-1348 Louvain-la-Neuve, Belgium; Université catholique de Louvain, Earth and Life Institute (ELI), Georges Lemaître Centre for Earth and Climate Research (TECLIM), Place Louis Pasteur 2, bte L4.03.08, BE-1348 Louvain-la-Neuve, Belgium.
Eric
E
Deleersnijder
Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels, Belgium.
Martine
M
Leermakers
Vrije Universiteit Brussel, Analytical, Pleinlaan 2, BE-1050 Brussels, Belgium; Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (IMMC), 4 Avenue G. Lemaître, bte L4.05.02, BE-1348 Louvain-la-Neuve, Belgium; Université catholique de Louvain, Georges Lemaître Centre for Earth and Climate Research (TECLIM), Place Louis Pasteur 2, bte L4.03.08, BE-1348 Louvain-la-Neuve, Belgium.
Anouk
A
de Brauwere
D001530:Belgium; D004784:Environmental Monitoring; D063366:Estuaries; D008670:Metals / Q000032:analysis*; D008956:Models, Chemical; D009426:Netherlands; D054712:Salinity; D012623:Seawater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
D008670:Metals; D014874:Water Pollutants, Chemical
Data analysis; Estuary; Metal speciation; Modelling; SLIM; Scheldt