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Zebracki M.,Center National Of Recherches Sur Les Sites Et Sols Pollues Cnrssp | Zebracki M.,Institute for Radiological Protection and Nuclear Safety | Alary C.,Center National Of Recherches Sur Les Sites Et Sols Pollues Cnrssp | Lefevre I.,CEA Saclay Nuclear Research Center | And 4 more authors.
Journal of Soils and Sediments | Year: 2016

Purpose: Contamination of river sediment reaches problematic levels in industrialised regions. This study investigates the relevance of using beryllium-7 (7Be), a short-lived environmental radionuclide (53 days half-life), for quantifying the deposition and resuspension of sediment and associated metallic contaminants in a heavily polluted channelized river of Northern France (The Lower Scarpe River). Materials and methods: Activities in 7Be were measured in bed and suspended sediments collected each month over a hydrological year. Suspended sediments were analysed for metal contents (Pb, Zn, Cd, Cu). The determination of short-term sediment dynamics is based on the variation of total 7Be inventory between two successive samplings. Total inventory of 7Be consists of two components, i.e., the residual inventory and the new inventory. Results and discussion: Inventories of 7Be in sediment varied from 1 to 135 mBq cm−2. Observed spatial and temporal variations reflected the dynamic behaviour of sediment in the studied channel section. The succession of sediment deposition and resuspension periods was demonstrated during the study, with maximum deposition and erosion rates of 0.3 ± 0.2 and −0.46 ± 0.05 g cm−2 month−1, respectively. A sediment resuspension rate of 0.06 g cm−2 month−1 supplied to the water column a flux of 12, 13, 23 and 145 μg cm−2 month−1 of Cd, Cu, Pb and Zn, respectively. During this 15-month study, 28 to 50 % of Pb that was deposited in the riverbed sediment was resuspended, thereby contributing to the (short term) degradation of water quality. Conclusions: The present work provides a useful tool for examining the role of sediment as a sink or source of contamination for the water column. It produces knowledge of how sediment processes affect the fate and the transport of contaminants and the implications for future downstream fluxes. © 2015, Springer-Verlag Berlin Heidelberg. Source


Fourneau C.,University of Mons | Delvosalle C.,University of Mons | Breulet H.,Institute Scientifique Of Service Public Issep | Brohez S.,University of Mons
Chemical Engineering Transactions | Year: 2013

The ISO 5660-1 Cone Calorimeter is commonly used for the measurement of main fire properties of products and materials, such as the heat release rate, the effective heat of combustion, the mass loss rate or the time to ignition. The standard Cone Calorimeter has been designed with an 'open configuration', allowing to test specimens through use of freely driven room air for combustion. For testing specimens in oxygen depleted atmospheres (air vitiation effect) or in fuel rich combustion (ventilation effect) a modified apparatus working under controlled atmosphere can be used. A Cone Calorimeter fitted with a controlled atmosphere device has been further modified to improve the air tightness of the combustion chamber, and reduce the biasing post-combustion phenomena. This experimental setup gives promising results regarding the characterization of fire properties of materials under highly under-ventilated conditions, among them the production of toxic and unburned species. © 2013, AIDIC Servizi S.r.l. Source


Fourneau C.,University of Mons | Delvosalle C.,University of Mons | Breulet H.,Institute Scientifique Of Service Public Issep | Brohez S.,University of Mons
Fire and Materials | Year: 2016

The cone calorimeter, originally designed with an 'open configuration', may be used in combination with a closed-combustion chamber in order to test specimens in oxygen-depleted atmospheres (air vitiation effect) or in fuel-rich combustion (ventilation effect). However, highly under-ventilated conditions are not achievable, as a consequence of an overconsumption of oxygen due to the incomplete confinement of the flame and imperfections in the air tightness of the combustion volume. In this work, these issues were solved by lowering the combustion zone, in order to fit a 600 mm chimney on the top of the controlled-atmosphere chamber, and further improving the sealing of the whole setup. n-Heptane was used as a reference fuel, and its combustion properties were determined in under-ventilated conditions. The yields of main combustion species correlated well with the global equivalence ratio, for values of Φ up to three. The use of a Fourier-transform infrared spectrometer allowed further refinement of the total unburned-fraction composition. The relative concentration of species like methane, ethylene, or acetylene was shown to be relatively constant over the range of under-ventilated conditions. © Copyright 2015 John Wiley & Sons, Ltd. Source


Merbitz H.,RWTH Aachen | Detalle F.,Institute Scientifique Of Service Public Issep | Ketzler G.,RWTH Aachen | Schneider C.,RWTH Aachen | Lenartz F.,Institute Scientifique Of Service Public Issep
International Journal of Environment and Pollution | Year: 2012

In the framework of the Interreg-IV 'PM-Lab' project a local-scale exercise was set up to evaluate air pollution in terms of particulate matter (PM) within the centre of Liège, Belgium (pop. 190,000). Sixteen sites distributed on a boulevard and its side streets were selected to determine the spatio-temporal variation of PM concentration in this traffic-dominated area. In addition to the in situ measurements numerical simulations were performed by means of AUSTAL2000. The performance of this Lagrangian dispersion model was checked through some basic qualitative and quantitative comparisons. As the model was able to detect highest PM concentrations both in space and time, test scenarios of emission reductions were also run in order to examine the impact of different traffic related measures. © 2012 Inderscience Enterprises Ltd. Source


Izquierdo M.,CSIC - Institute of Environmental Assessment And Water Research | Izquierdo M.,University of Limerick | Querol X.,CSIC - Institute of Environmental Assessment And Water Research | Phillipart C.,Institute Scientifique Of Service Public Issep | And 2 more authors.
Journal of Hazardous Materials | Year: 2010

This study deals with the synthesis of geopolymers from co-fired fly ash and blast furnace slags. Geopolymer bodies were simultaneously synthesized in open and closed curing conditions in order to elucidate the role of this parameter on their resultant properties. Open curing conditions produce solid bodies characterized by high porosity, low compressive strength and exacerbated leaching of certain oxyanionic metalloids. By contrast, protected curing promotes the binder development, giving rise to higher strength and less porous systems. This imposes physical restrictions to leaching which decreases and/or retards releases of oxyanionic metalloids in comparison to open curing conditions. Fly ash-slag-based geopolymers may immobilize a number of trace pollutants such as Be, Bi, Cd, Co, Cr, Cu, Nb, Ni, Pb, REE, Sn, Th, U, Y and Zr, regardless of the curing conditions. Due to geopolymers displaying weak assimilation capacity for oxyanionic species, their successful regarding oxyanionic retention is strongly dependent on porosity and therefore on curing conditions applied. © 2009 Elsevier B.V. All rights reserved. Source

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