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Registros recuperados: 32
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Trace metals in the eastern part of the North Sea: 2. Flows of Cd, Cu, Hg, Pb and Zn through the coastal area OMA
Baeyens, W.F.J.; Gillain, G.; Ronday, F.; Dehairs, F.A..
The residual flow lines of the Belgian coast are more or less parallel to the coast except in the area where the northeasterly flowing watermass coming from the Channel encounters the southwesterly-oriented Scheldt outflow. The result is a residual hydrodynamical front with, at the northern side, a less saline estuarine watermass, and at the southern side a more saline marine watermass. From the steady-state salinity pattern, diffusion coefficients perpendicular to the residual flow were deduced; they ranged from 21 to 108 m².s<sup>-1</sup>.The steady-state profiles of dissolved metals versus salinity indicate a dilution effect in the coastal-estuarine watermass and almost constant concentration in the marine watermass. Offshore fluxes of Cd,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Coastal zone Trace metals ANE; North Sea.
Ano: 1987 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3156
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An automated method for the assessment of mercury adsorption rates on particulate suspended matter OMA
Baeyens, W.F.J.; Decadt, G.; Dehairs, F.A.; Goeyens, L..
A continuous filtration system connected to a mercury auto-analyzer has been constructed for obtaining mercury adsorption rates on particulate suspended matter. The capabilities of this device have been demonstrated by carrying out a series of experiments under controlled physicochemical parameter conditions on samples of the Scheldt estuary. Duplicate measurements showed coefficients of variation ranging from 1 to 6 %. Depending on the physico-chemical conditions, the initial adsorption rate per unit of dissolved mercury concentration varied between 1.2 and 8.1 x 10<sup>-2</sup> mn<sup>-1</sup>.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Adsorption; Mercury; Methodology; Particulates; Suspended matter.
Ano: 1982 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3413
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Particulate trace metals above the Southern Bight of the North Sea: 1. Analytical procedures and average aerosol concentrations OMA
Baeyens, W.F.J.; Dedeurwaerder, H..
Heavy metal concentrations in total particulate suspended matter and size fractionated particulate suspended matter above the Southern Bight of the North Sea have been assessed. Most of the samples were collected from a light vessel; the total sampling period covered about 70 days at sea. Stringent precautions were taken during sampling, storage, handling and analysis of the samples. As a conclusion, we found that on a long-term basis the aerosol concentrations above the North Sea have a fairly homogeneous composition, but short-term variations probably resulting from point emissions were observed. The cascade impactor results indicated that Pb, Cu, Cd and Zu were carried by submicrometer aerosols, Na, Fe, Mn and Al by supermicrometer aerosols. Most of the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aerosols Air pollution Atmospheric particulates Meteorology Seasonal variations Statistical analysis Trace metals Troposphere Winds ANE; North Sea; Southern Bight.
Ano: 1991 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3106
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Tight coupling between enrichment of iron and manganese in North Sea suspended matter and sedimentary redox processes: evidence for seasonal variability OMA
Dehairs, F.A.; Baeyens, W.F.J.; Van Gansbeke, D..
Suspended matter and sediments from the North Sea were analysed for Al, Fe and Mn. A seasonal variation of Mn and Fe over Al ratios is observed. For most of the year suspended matter is enriched in Mn and Fe relative to average soil composition. No enrichment, and even depletion, occurs during a short period of the year (April-May) coinciding with the occurrence of the spring phytoplankton bloom. Surface sediments from the Southern Bight show the inverse image, with Mn and Fe enrichment occurring only in April-May and no enrichment during the rest of the year. These observations suggest a tight coupling between: (1) the change of redox potential in surface sediments, as triggered by the advection of organic matter from the spring bloom; (2) the outflow of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ferromanganese oxides Iron compounds Manganese compounds Redox reactions Seasonal variations Sediment chemistry Suspended load ANE; North Sea.
Ano: 1989 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3010
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Particulate trace metals above the Southern Bight of the North Sea: 2. Origin and behaviour of the trace metals OMA
Baeyens, W.F.J.; Dedeurwaerder, H..
Ninety-six aerosol samples were collected in all seasons and wind conditions in the troposphere of the Southern Bight of the North Sea. About one third of these samples were collected with a six stage cascade impactor sampler. Considering that in each sample metals were analyzed, the data set we had to handle consisted of about 2000 results. In addition, wind directions and wind speeds are also included in this data set. To interpret all these results, we relied upon two methods: (1) enrichment factors were calculated and allowed us to identify some of the metal sources; (2) three factors resulted from a multivariate analysis method: in the first factor we only find Na, representing the marine component; the second factor includes Al (a crustal and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aerosols Air pollution Atmospheric particulates Meteorology Seasonal variations Statistical analysis Trace metals Troposphere Winds ANE; North Sea; Southern Bight.
Ano: 1991 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3109
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Behaviour and speciation of mercury in the Scheldt estuary (water sediments and benthic organisms) OMA
Baeyens, W.F.J.; Meuleman, C.; Muhaya, B.; Leermakers, M..
Surface waters, sediments and the polychaete <i>Nereis diversicolor</i> were sampled in the Scheldt Estuary between 1990 and 1994. In surface waters particulate Hg (Hg<sub>p</sub>) concentrations ranged from 350-1610 ng g-¹. They are essentially controlled by physical mixing of polluted fluvial particulates with relatively unpolluted marine particulates, but unaffected by seasonal changes. Dissolved Hg species, on the other hand, show large seasonal variations essentially controlled by the redox conditions in the estuary, as well as by bacterial and phytoplankton activity. Total dissolved (Hg<sub>TD</sub>) concentrations ranged from 0.5 to 3.0 ng l-¹ with 10 to 90% as reactive Hg. High concentrations of...
Tipo: Info:eu-repo/semantics/article
Ano: 1998 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7047
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Ammonium regeneration in the Scotia-Weddell Confluence area during spring 1988 OMA
Goeyens, L.; Tréguer, P.; Lancelot, C.; Mathot, S.; Becquevort, S.; Morvan, J.; Dehairs, F.A.; Baeyens, W.F.J..
Tipo: Info:eu-repo/semantics/article
Ano: 1991 URL: http://www.vliz.be/imisdocs/publications/279128.pdf
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Estimates of dry and wet deposition and resuspension fluxes of several trace metals in the Southern Bight of the North Sea OMA
Dedeurwaerder, H.L.; Dehairs, F.A.; Decadt, G.; Baeyens, W.F.J..
In this study we have investigated air-sea exchanges in the Belgian coastal area located in the Southern Bight of the North Sea. Since 1980 the tropospheric aerosol contents for the trace elements Cd, Cu, Mn, Pb, Zn and for the reference elements Al , Fe, Na have been monitored on an intermittent basis from a maritime sampling platform (Light-Vessel West-Hinder; position: 51°23.5'N- 2°21.5'E, fig. 1). During 1981 sampling campaigns at sea were paralleled by sampling campaigns on land, in the coastal area (natural reserve De Blankaert, located at 20 Km inland), in order to allow for a better evaluation of the specific source or sink role of the sea. No major source of pollution exists between the maritime and the continental sampling sites. During these...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aeolian deposits Resuspension Trace metals ANE; North Sea; Southern Bight.
Ano: 1984 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3323
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Dynamic patterns of dissolved nitrogen in the Southern Bight of the North Sea OMA
Baeyens, W.F.J.; Mommaerts, J.-P.; Goeyens, L.; Dehairs, F.A.; Dedeurwaerder, H.; Decadt, G..
Spatial and temporal variations of dissolved inorganic nitrogen (DIN) have been assessed in onshore and offshore areas of the Southern Bight on the basis of several years' measurements. They indicate that both the residual flow lines and DIN isoconcentration lines run parallel with the coast except in the vicinity of important freshwater discharge points such as the Scheldt estuary. Evidence was found that the seasonal DIN oscillations are not created through fluctuations in input conditions at the lateral boundaries, despite considerable fluctuations in these inputs which include the English Channel (from 500 tons(t) N day<sup>-1</sup> in June up to approximately 2000 t N day<sup>-1</sup> in February) and also rivers such as the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Dissolved organic nitrogen ANE; North Sea; Southern Bight.
Ano: 1984 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3310
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Comparative study of different wet mineralisation digestion methods for the measurement of total mercury in biological samples OMA
Dehairs, F.A.; Decadt, G.; Baeyens, W.F.J..
Three botanical substrates and one milkpowder were mineralised and digested by the following methods in order to measure their total mercury content: (1) HF/HNO<sub>3</sub>-KMnO<sub>4</sub>; (2) H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>-KMnO<sub>4</sub>; (3) H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>- H<sub>2</sub>O<sub>2</sub>; (4) H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>-UV irradiation/KMnO<sub>4</sub>; (5) H<sub>2</sub>SO<sub>4</sub>/HNO<sub>3</sub>/V<sub>2</sub>O<sub>5</sub>-catalyst...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Digestion; Mercury; Nutrients (mineral).
Ano: 1982 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3380
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Distribution, transport and fate of Bi, Cu, Cd, Hg, Pb, Sb and Zn in the Belgian coastal marine environment. Part V: Interaction kinetics between dissolved inorganic mercury and estuarine suspended matter OMA
Baeyens, W.F.J.; Decadt, G.; Dehairs, F.A.; Goeyens, L.; Dedeurwaerder, H.; Gillain, G..
Tipo: Info:eu-repo/semantics/article
Ano: 1982 URL: http://www.vliz.be/imisdocs/publications/286410.pdf
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Evolution of trace metal concentrations in the Scheldt estuary (1978-1995): a comparison with estuarine and ocean levels OMA
Baeyens, W.F.J..
Dissolved and particulate metal concentrations assessed in the Scheldt estuary in the period 1978-1995, yield a clear indication that the levels of all metals decreased significantly. A comparison with other estuaries classifies the Scheldt as being moderately polluted for all metals in the dissolved phase, but as being fairly high polluted in the particulate phase, especially for Cd. However, even the dissolved metal concentration fractions in the Scheldt are still between 10 to 50 times enriched compared to total metal concentrations in unpolluted seas and oceans.
Tipo: Info:eu-repo/semantics/article
Ano: 1998 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=7067
Registros recuperados: 32
Primeira ... 12 ... Última
 

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