Transfer and accumulation of lead, zinc, cadmium and copper in plants growing in abandoned mining-district area

The analysis of the Jebel Hallouf-Sidi Bouaouane mining-district soil has shown that the surface horizons are strongly contaminated by heavy metals, especially during floods or in lee-side areas. The contents of metallic-trace elements (MTE), in the soil and two cultivated plant species, have been determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). The results show that the concentration of metals in the soil are up to 39 g. kg-1, 6.3 g. kg-1, 56 mg. kg-1 and 131 mg. kg-1, for lead (Pb), zinc (Zn), cadmium (Cd) and copper (Cu), respectively. The chemical analysis of plants: broad beans [Vicia faba (L.)] and barley [Hordeum vulgare (L.)], sampled inside the mining district, show that the roots and the upper part (leaves and stem) are enriched for Pb (up to 508 and 220 mg.kg-1, respectively), Cd (up to 8 and 5 mg.kg-1, respectively), and Zn (up to 491 and 468 mg.kg-1, respectively) when compared with similar species collected far from the contaminated site (up to 9.6 and 0.8 mg.kg-1 for Pb, up to 0.04 and 0.04 mg.kg-1 for Cd, up to 44 and 15 mg.kg-1 for Zn, respectively). Statistically, the concentration of MTE in the soils and plants of the mining area is significantly different from the concentrations of the same elements in the soils and plants of the control ones (p < 0.01). This is expressed by a strong Enrichment Coefficient (EC), which is given by the ratio between the concentration of the metal in the contaminated plant and the concentration of the same element in the similar control one. The results (up to 405, 342 and 32, respectively), indicate that the contamination has reached the first link of the food chain. However, the calculation of the translocation factor (TF), deduced from the ratio between the concentration of the metal in the outer part of the plant and the concentration of the same element in the roots, shows that, the broad beans accumulates metals in the roots (TF < 1); whereas for barley, metals are fairly distributed between the roots and the outer part (TF ≈ 1). These results suggest that the cultivated areas inside the mining district constitute a serious source of contamination of the food chain. Therefore, actions have to be taken in order to remedy this problem.Key words: MTE, contamination, transfer, soil, plant

L’évolution de l’application de la loi Littoral par le juge administratif

Moutte J.-F. L’évolution de l’application de la loi Littoral par le juge administratif. In: Revue Juridique de l'Environnement, numéro spécial, 2012. Les 25 ans de la Loi Littoral. pp. 173-184

Initiation à la gestion des entreprises

Ce guide aborde les bases de la gestion des entreprises. Du management stratégique à la gestion des ressources humaines, en passant par la comptabilité, la finance, le marketing ou encore la gestion de la production, chacun y trouvera l'essentiel de ce qu'il faut savoir

Identification and optimization of the constitutive model for die-formed expanded graphite for sealing applications

International audienceThe die-formed expanded graphite is used in industry for sealing applications subjected to extreme pressure and temperature. Its chemical inertness, excellent elastic recovery and adaptability to damaged flanges serves the sealing function. However, in some cases, the high load required for tightening leads to significant mechanical effects related to flanges bending or radial thrust. To address this effect and support the implementation of graphite seals investigations are performed to identify a constitutive model for that specific material and describe the interaction of these seals with their environment [1]. Instrumented axial die-compaction tests are performed to characterize the load-compression curve as well as the radial pressure from the sample [2], [3]. A methodology is then developed for the identification of the coefficients related to the constitutive model, assuming a Drucker-Prager Cap model, and especially the hardening behaviour, which drives the seals compression and unloading curves. The work is based on a parametric optimization and a numerical simulation close to the test device itself. The identified model is finally used for graphite seals simulation, to address mechanical interactions with their environment and comparison with tests performed with dedicated instrumented seals validate its relevance

Heavy metals assessment in Oum Er Rbia bassin using WD-XRF and ICP-AES

International audienceThe analysis of water, suspended particulate matter (SPM) and sediment collected from Oum er Rbia Moroccan basin for the content of six elements has been performed utilizing ICP-AES and WD-XRF methods. Sediment have been analyzed by WD-XRF; Water and MPS by ICP-AES. The detection limits are sufficient for most of the elements to be determined. Results were assessed for the accuracy by the analysis of a multi-elemental standards. The results for most of the elements obtained were accurate to about 2-15%. The objective of the analysis were to determine the geochemical areas on this bassin, to explain the mechanisms of sediment transport and nevertheless, to assess the pollution of the bassin by heavy metals generated by human activities. This work interests only the last aspect. It has done one 30 samples of water and SPM, and about 80 sediments. Samples were collected along the river, between its source in meddle Atlas and the Atlantic ocean at Azemour city. The results obtained on the basin were normalized to the international norms

Étude comparative des techniques d'analyse par fluorescence X à dispersion d'énergie (ED-XRF) et à dispersion de longueur d'onde (WD-XRF), et par spectrométrie d'émission atomique à source plasma couplée par induction (ICP-AES)

Dans ce travail, nous présentons une étude comparative des techniques d'analyse par fluorescence X à dispersion d'énergie (ED-XRF) et à dispersion de longueur d'onde (WD-XRF), et par spectrométrie d'émission atomique à source plasma couplée par induction (ICP-AES). Les résultats de la calibration des spectromètres à dispersion d'énergie, à excitation par sources radioactives ($^{55}$Fe, $^{109}$Cd et $^{241}$Am) et à excitation secondaire (cible secondaire Mo et Cu) du Centre National pour l'Energie, les Sciences et les Techniques Nucléaires (CNESTEN, Rabat, Maroc) sur des échantillons étalons de références de l'Agence International de l'Energie Atomique (AIEA) et du Community Bureau of Référence (BCR) ont été comparés aux résultats d'analyse des mêmes échantillons étalons par la spectrométrie X à dispersion de longueur d'onde (WD-XRF) et par spectrométrie d'émission atomique à source plasma couplé par induction (ICP-AES) au département GENERIC du centre SPIN à l'Ecole des Mines de Saint-Etienne (France). Les trois techniques d'analyse utilisées donnent des résultats comparables pour le dosage des éléments majeurs, alors que pour les traces on note des déviations importantes à cause des effets de matrice qui sont difficiles à corriger dans le cas de la fluorescence X