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Antwerpen, Belgium

De Saedeleer V.,Free University of Brussels | Cappuyns V.,Free University of Brussels | Cappuyns V.,Catholic University of Leuven | De Cooman W.,Vlaamse Milieumaatschappij | Swennen R.,Catholic University of Leuven
Geologica Belgica | Year: 2010

In the present study, the relationship between heavy metals (As, Cd, Cr, Cu, Hg, Pb, Ni, Sn and Zn) and major elements and the location and/geological substrate of 105 river sediments in Flanders was investigated. Factor Analysis was used to divide the dataset into four components: a first component including clay, organic matter, Na, Ca, K and Mg, a relationship between Fe, As and Cd, an anthropogenic factor (including Cu, Hg, Pb, Sn and Zn) and finally the pH and insoluble residue. Regression equations were constructed, using major elements such as Fe and Ca as independent variables, besides more classical explaining variables such as clay content (< 2μm fraction), organic matter content and pH. Most heavy metal concentrations could be predicted very well by the independent variables, except Zn, Se and Sn. The results from this study, performed on a dataset of 105 riverbed sediments, indicate that, besides organic matter and clay content, other variables such as the total Fe and Ca content can be relevant parameters to predict heavy metal concentrations in sediments. The more general applicability of the obtained regression equations should be verified, and the inclusion of Fe and Ca in regression equations that are applied for the standardization of total metal concentrations in soils and sediments, should be considered. Source

Boets P.,Ghent University | Brosens D.,Research Institute for Nature and Forest INBO | Lock K.,Ghent University | Adriaens T.,Research Institute for Nature and Forest INBO | And 3 more authors.
Aquatic Invasions | Year: 2016

Biological invasions of aquatic macroinvertebrates are gaining interest because of their potential for significant ecological and socio-economic impacts (positive and negative). In the present study, an inventory was made of the alien macroinvertebrates occurring in Flanders (northern Belgium) based on extensive existing collections of biological samples and supplemented with our additional sampling programs. Fresh and brackish waters as well as the Belgian coastal harbours, situated at the interface of the marine environment, were investigated. Over 2,500 samples containing alien macroinvertebrates were identified to species level, which allowed us to accurately map their distribution in Flanders. Alien macroinvertebrates are widespread and abundant in many watercourses in Flanders. Four new macroinvertebrate species for Flanders were discovered: Procambarus clarkii (Girard, 1852), Echinogammarus trichiatus (Martynov, 1932), Synurella ambulans (F. Müller, 1846) and Laonome calida Capa, 2007. Fifty-two alien macroinvertebrates were encountered in fresh and slightly brackish surface waters, and 21 alien species were reported for the Belgian part of the North Sea and its adjacent estuaries. Most alien macroinvertebrates collected were crustaceans and molluscs. Alien species found in fresh and brackish water mainly originate from the Ponto-Caspian area and North America; fewer species originated from Asia and South- and East-Europe. The major pathways were probably shipping and dispersal through canals. Based on observations in neighbouring countries, several additional species are expected to arrive in the near future. Follow-up work is needed to assess the ecological and economic impacts of existing alien macroinvertebrates, and a monitoring program is needed to detect new incoming species. © 2016 The Author(s). Source

Brown R.J.C.,National Physical Laboratory United Kingdom | Jarvis K.E.,Center for Environmental Policy | Disch B.A.,Center for Environmental Policy | Goddard S.L.,National Physical Laboratory United Kingdom | And 2 more authors.
Accreditation and Quality Assurance | Year: 2010

A comparison study of the measurement of metals in ambient particulate matter collected on air filters, using energy-dispersive X-ray fluorescence (ED-XRF), laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) and wet chemical digestion followed by ICP-MS analysis according to the European 'reference method' EN14902, is presented. Whilst it is shown that the methods have a low systematic bias with respect to each other, overall they do show a high random variability, and when considered individually using regression methods, some analytes have shown bias with respect to the EN14902 method. The low systematic bias observed is not unexpected since both the ED-XRF and LA-ICP-MS methods have been calibrated using results from the EN14902 technique. The uncertainty of each analysis has been estimated and compared with the data quality objectives for uncertainty specified in the relevant European air quality legislation. This has tentatively shown that approximately 75% of the analyses using ED-XRF and LA-ICP-MS meet the requirements of the legislation. However, improvements in repeatability and calibration methods for both ED-XRF and LA-ICP-MS would be needed before these methods were truly applicable for routine use in air quality measurements of this type. © 2010 Springer-Verlag. Source

Lefebvre W.,Flemish Institute for Technological Research | Cosemans G.,Flemish Institute for Technological Research | Van De Vel K.,Flemish Institute for Technological Research | Janssen S.,Flemish Institute for Technological Research | And 5 more authors.
International Journal of Environment and Pollution | Year: 2012

When simulating concentration fields in the direct vicinity of plants emitting heavy metals by using the bi-Gaussian model IFDM and the reported emissions, the simulated concentrations were much lower than the measured ones. Detailed analysis of these results showed that this was due to building downwash. We show that it is possible for a bi-Gaussian model to simulate correct concentration levels by inserting extra virtual sources. It is shown that inverse modelling can be used to produce detailed and validated concentration maps of the surroundings of the industrial site and that building downwash has an important effect on local concentrations. Copyright © 2012 Inderscience Enterprises Ltd. Source

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