|
|
|
| Registros recuperados: 50 | |
|
|
| Dekov, V.m.; Vanlierde, E.; Billstrom, K.; Garbe-schoenberg, C. -d.; Weiss, D. J.; Gatto Rotondo, G.; Van Meel, K.; Kuzmann, E.; Fortin, D.; Darchuk, L.; Van Grieken, R.. |
| Two groundwater-fed river systems (Nete and Demer, Belgium) carry red suspended material that settles on the river bed forming red sediments. The local aquifer that feeds these river systems is a glauconite-rich sand, which provides most of the dissolved Fe to the rivers. The solid component of these systems, i.e., the red suspended material and sediments, has a simple mineralogy (predominantly ferrihydrite), but shows a complex geochemistry pointing out the different processes contributing to the river chemistry: (1) the red sediments have higher transition metal (excluding Cu) and detrital element (e.g., Si, Al, K, Rb, etc.) concentrations than the red suspended matter because of their longer residence time in the river and higher contribution of the... |
| Tipo: Text |
Palavras-chave: Ferrihydrite; Fe-Zn-Sr-Nd-Pb-isotopes; Rivers; Sediments; Suspended matter. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00203/31404/29789.pdf |
| |
|
|
| Rojas, C.; Otten, P.; Van Grieken, R.; Laane, R.W.P.M.. |
| A mathematical approach based on the Monin-Obukhov similarity theory is used to predict the wind speed, friction velocity and drag coefficient, which are then introduced in the well-known deposition model of Slinn and Slinn (1980), to calculate the dry deposition of heavy metals into the North Sea. This model is perfectly suitable for aircraft sampling considering the fact that usually due to safety reasons, flights at the reference height used in deposition models (10m), are not possible. To check this approach, deposition velocities were calculated based on the airborne concentrations of Cu, Cd, Zn and Pb obtained by sampling with the aid of an aircraft over the Dutch continental shelf of the North Sea. Results are in agreement with those found in the... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1991 |
URL: http://www.vliz.be/imisdocs/publications/262330.pdf |
| |
|
| |
|
| |
|
|
| Rojas, C.M.; Injuk, J.; Van Grieken, R.; Laane, R.W.P.M.. |
| During the period from September 1988 to October 1989, 23 sampling flights were carried out over the Southern Bight of the North Sea. In the campaign, both bulk and size-segregated airborne particulate matter samples were collected. Dry deposition velocities for Cd, Cu, Pb and Zn have been estimated using a modified version of the two-layer of Slinn and Slinn and the particle size distribution obtained from size-fractionated samples. Results pointed out that the main difference between our results and those reported in the literature lies in the aerosol size distribution. Dry deposition rates calculated using these deposition velocities as a function of wind sector showed that continental air masses, particularly those associated with the wind sector west... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2745 |
| |
|
|
| Bruynseels, F.; Storms, H.; Van Grieken, R.; Van der Auwera, L.. |
| On aerosol and rain water samples, collected in the Southern Bight of the North Sea, single particle analyses were performed using both laser microprobe mass analysis and electron-probe X-ray microanalysis in combination with an automated image analysis system.In the aerosols collected from an air mass that had traveled from the Atlantic Ocean along the coast of North France, pure seasalt constituted the most abundant particle type, while aluminosilicates (mostly spherical fly-ash particles) amounted to about 20% and mixed seasalt/aluminosilicates, carbonaceous particles, CaSO<sub>4</sub> and spherical iron oxides contributed each 5-10%. In air masses that had a longer residence time over the continent, spherical iron oxides, carbonaceous... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols; Rain. |
| Ano: 1988 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3125 |
| |
|
|
| Van Alsenoy, V.; Bernard, P.; Van Grieken, R.. |
| The elemental composition of sediment and suspended matter samples from the Belgian coastal and offshore regions of the Southern Bight of the North Sea and from the Scheldt estuary has been determined using X-ray fluorescence and atomic absorption spectrometry.Special attention was given to the heavy metals of the black and grey lists. The bulk sediment and the clay/silt fraction were analyzed. The average heavy metal contents in the fraction <63 µm were comparable to the levels in the suspended matter. Different normalization techniques led to the identification of two different populations of sediments. Most of the sediments were enriched in Cd, Cr, Hg, Pb and Zn but no enrichment was found for Cu and Ni. Comparing these data with older data indicates... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Heavy metals; Pollution; Sediments; Suspended particulate matter. |
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2789 |
| |
|
|
| Treiger, B.; Injuk, J.; Bondarenko, I.; Van Espen, P.; Van Grieken, R.; Breitenbach, L.; Wätjen, U.. |
| A multivariate statistical evaluation technique, non-linear mapping, is proposed to extract information from a multielement microbeam proton-induced X-ray emission data set. Individual aerosol particles, collected in the North Sea troposphere, were classified according to their composition. Several groups of particles were identified and suggestions were made for their sources. |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1994 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2683 |
| |
|
|
| De Bock, L.A.; Van Malderen, H.; Van Grieken, R.. |
| Single-particle analysis on North Sea and rainwater samples was performed by electron-probe X-ray microanalysis (EPXMA). The analysis was mainly focused on the determination of the inorganic composition of giant particles with diameters above 1 µm. Multivariate techniques were used for the reduction of the data set and for source apportion. Based on the relative abundances found by hierarchical cluster analyses according to the Ward error sum method, three to eight different aerosol types were distinguished. Crossing the North Sea, the changes in air mass composition appeared as a decrease in the abundance for the aluminosilicate particles and relative increase for NaCl and seawater crystallization products. Principal factor analysis revealed four... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1994 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2570 |
| |
|
|
| Scholkovitz, E.R.; Van Grieken, R.; Eisma, D.. |
| A study of the major-element (Si, Al, Fe, K, Mg, Ca, Ti, Mn and P) composition of suspended matter in the surface waters of the Zaire River and Estuary revealed that this material was enriched in Al, Fe and P and depleted in Si, Ca, K and Mg relative to recent pelagic sediments and to suspended matter carried by the Amazon River. These enrichments and depletions are characteristic of soils in regions of intense chemical weathering as is the situation in western equatorial Africa. Suspended samples from waters near the bottom of the estuary have compositions which indicate that this material has undergone much less chemical weathering. These particles were of greater size and most likely contained a larger proportion of quartz, micas, feldspars and oxides... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Suspended inorganic matter Africa; Zaire R.. |
| Ano: 1978 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3619 |
| |
|
| |
|
|
| Otten, P.; Injuk, J.; Van Grieken, R.. |
| Vertical profiles of SO<sub>2</sub> and O<sub>3</sub> concentrations were measured continuously within the lower atmosphere during 18 flights over the Southern Bight of the North Sea. The average SO<sub>2</sub> concentration below the temperature inversion layer ranged from 1.9 to 19.5 ppb. The highest levels were observed when the air masses came from the southeast-east and under variable wind sector conditions: 15.2 and 12.0 ppb, respectively. The highest SO<sub>2</sub> concentrations were found at altitudes between 100 and 200 m. The overall average O<sub>3</sub> concentration was 46 ppb, with values of 30-40 ppb at sea level to 60-70 ppb at altitudes above 100 m. Low O<sub>3</sub>... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1994 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2648 |
| |
|
|
| Otten, P.; Injuk, J.; Rojas, C.; Van Grieken, R.. |
| The North Sea is being under loaded in many ways, both by organic and anorganic pollutants. Transport over rivers is the most evident way. Direct emission along the coastline and dumping of toxic materials by vessels are another two causes of pollution. Exploitation of oil and gas platforms also lead to operational emission of certain noxious substances. “Last but not least” a part of the pollutants also reach the North Sea through the atmosphere.This article specifically concerns the latter facet of North Sea Pollution. Both gaseous and particular material is being emitted in the atmosphere through incineration and other polluting processes. After physical dispersion and chemical transformation, these pollutants can end up in the sea through deposit... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1992 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2850 |
| |
|
|
| Brügmann, L.; Bernard, P.C.; Van Grieken, R.. |
| In 1984, on a transect covering the whole Baltic Sea and parts of the adjacent North Sea, 160 water samples were taken and analysed for their concentrations of particulate and dissolved metals. In addition, the suspended materials were investigated for their elemental bulk composition.The particulate fractions represented from about 5% (Cd, Cu and Ni) to 50% (Fe and Pb) of the total (particulate plus dissolved) concentrations. For some elements (Ba, Cd, Cu, Pb and Zn), the particulate matter from the surface microlayer was enriched with respect to those suspended materials taken from 0.2 m depth. This could reflect the atmospheric input of metal-rich aerosols. In anoxic deep waters, maximum contents of Zn (6400 µg g <sup>-1</sup>), Cu (1330 µg... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1992 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2695 |
| |
|
|
| Van Malderen, H.; Rojas, C.; Van Grieken, R.. |
| In order to investigate the importance of giant airborne particles, air sampling was carried out using an aircraft which flew at different altitudes over the Southern Bight of the North Sea. A set of 25 samples was collected with a steel rod on top of the airplane. Some 12,500 individual particles were analyzed using electron probe X-ray microanalysis. Principal factor analysis allowed identification of four sources of giant aerosol particles: aluminosilicates, combustion processes, industrial processes, and marine sources. Hierarchical and nonhierarchical cluster analysis enabled us to classify the analyzed particles. A clear distinction was found between flights for which the associated air masses were marine or continental. The experimentally found size... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1992 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2887 |
| |
|
|
| Struyf, H.; Van Grieken, R.. |
| An overview of the wet deposition of micropollutants (trace metals -Cd, Cr, Cu, Pb, Hg, Zn- and organic compounds -PAHs, PCBs, pesticides) to the North Sea and adjacent areas is presented. The results of (in)direct measurements of the wet flux are compared to modeling results. Attention is given to specific problems like revolatilization, sea-spray, contamination, gas-to-particle ratios in wet deposition of Hg and the organic substances. Also, the importance of wet deposition is weighted to that of dry deposition and non-atmospheric input routes to the North Sea. It is concluded that -especially for organic micropollutants- current knowledge is insufficient to yield an accurate and detailed image of the impact and importance of wet deposition to the North... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2785 |
| |
|
|
| Rojas, C.M.; Van Grieken, R.; Laane, R.W.P.M.. |
| Dry deposition velocities have been calculated using three different approaches. Turbulent wind profile theory has been used to predict the drag coefficient, wind speed and friction velocity at 10m height when the wind speed is measured at a higher altitude. The resulting parameters were introduced in a two-layer deposition model. The second approach was the well-known model of Slinn and Slinn (1980, Atmospheric Environment 14, 1013-1016), whereas the third corresponded to the model published by Williams (1982, Atmospheric Environment 16, 1933-1938). Results point to clear differences. However, in a field experiment carried out at the Southern Bight of the North Sea, all three approaches show relatively comparable results. The role played by the size... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2748 |
| |
|
|
| Maenhaut, W.; Raemdonck, H.; Selen, A.; Van Grieken, R.; Winchester, J.W.. |
| By using a polyester sailboat as sampling platform, a series of duplicate aerosol samples was collected by cascade impactors on a trip from Panama to Tahiti in 1979. Elemental analysis mainly by particle-produced X-ray emission (PIXE) indicated, in the samples collected between Panama and the Galapagos Islands, the presence of a substantial crustal component (0.4 µg/m³), fine Cu (0.4 ng/m³ and Zn (0.6 ng/m³), and excess fine S and K (100 and 2.4 ng/m³, respectively in addition to the major sea salt elements. The crustal component and fine Cu and Zn are suggested to result from natural continental sources (i.e., eolian dust transport from the American continents and perhaps geothermal emissions). Samples collected west of the Galapagos Islands in the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aerosols IS; Equatorial Pacific. |
| Ano: 1983 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3398 |
| |
|
|
| Rojas, C.M.; Van Grieken, R.; Maenhaut, W.. |
| During the period from September 1988 to October 1989, 23 flights were carried out over the Dutch Continental Shelf of the North Sea and a total of 108 aerosol filter samples were collected. The samples were analyzed for Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br and Pb using both particle-induced X-ray emission (PIXE) and energy-dispersive X-ray fluorescence (EDXRF). The results from PIXE exhibited better precision and lower detection limits than those from EDXRF. Therefore the further discussion and interpretation was based on the PIXE data only. It was observed that Si, S, V, Mn, Ni, Cu and Pb were enriched with respect to the earth's crust. It was seen that winds from the sector Southeast-South contributed most significantly to... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=8422 |
| |
|
|
| Injuk, J.; Van Malderen, H.; Van Grieken, R.; Swietlicki, E.; Knox, J.M.; Schofield, R.. |
| X-ray emission techniques for bulk and individual particle analysis (EDXRF, EPXMA, micro-PIXE) were combined and applied in atmospheric research on the North Sea area as part of a field-study on air-sea exchange processes of particulate matter. The atmospheric loading for a number of elements was determined by EDXRF, yielding bulk concentrations for Mg, Al, Si, S, Cl, K, Ca, Cr, Mn, FE, Ni,Cu, Zn, BR and Sr. From these EDXRF data, deposition rates were derived and, based on a classical multivariate statistical approach, different aerosol sources were identified. Complementary to this work, EPXMA combined with automated image analysis was applied to individual size-segregated aerosol particles to determine their inorganic composition, physical size and... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1993 |
URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2711 |
| |
| Registros recuperados: 50 | |
|
|
|
