Teneurs de métaux traces dans des sols à maraîchers dans la ville d’Abidjan (Côte d’Ivoire)

L’objectif principal de cette étude est l’évaluation de l’état de contamination en métaux traces de sols cultivés dans la ville d’Abidjan. Pour ce faire, des sols ont été prélevés dans des fosses pédologiques sur les sites maraîchers de Marcory et Cocody et sur la ferme expérimentale de l’Université d’Abobo-Adjamé. L’analyse des échantillons a révélé que sur les 3 sites, la quasi-totalité des horizons sont sableux, acides, riches en Mn et Fe. Les teneurs en Cd à Marcory et à Cocody, la teneur en Cu à Marcory, les teneurs en Pb à Cocody et sur la parcelle expérimentale, les teneurs en Zn sur les 3 sites, et les teneurs en Ni à Marcory et à Cocody, sont supérieures aux teneurs limites recommandées. L’acidité et la forte macroporosité des sols ont favorisé lamigration verticale des métaux traces.Mots clés: métaux traces, sols à maraîchers, Abidjan, migratio

Validation interne des méthodes d’analyse par SAA et application sur les éléments (Cr, Pb, Fe, Zn Mn et Cu)

In this work, we are interested on evaluation of Atomic Absorption Spectrometer, AAS (Thermo Fischer Scientific iCE 3500). Cr, Pb, Fe, Zn, Mn and Cu are used in order to apply some kind of validation test: calibration function, limits of detection and quantification, repeatability and reproducibility as well as the accuracy of measurements. This was carried out by the two atomization systems of AAS (flame and furnace graphite), by considering the field of desired concentrations and by basing on standards and/or materials of certified references.Dans ce travail, nous nous sommes intéressés à une évaluation du Spectromètre d’absorption Atomique (SAA) de type Thermo Fischer Scientific iCE 3500 en considérant les éléments suivants : Cr, Pb, Fe, Zn, Mn et Cu et en appliquant ces différentes étapes de validation, à savoir,  la fonction d’étalonnage, les limites de détection et de quantification, la répétabilité et la reproductibilité ainsi que la justesse des mesures. Ceci a été effectué par les deux systèmes d’analyse par le SAA (flamme et four), en considérant le domaine de concentrations souhaitées et en se basant sur des étalons et/ou des matériaux de références certifiées

Introduction à la pollution atmosphérique dans la ville de Meknès : dioxyde de soufre, ozone et matière particulaire en suspension

In this work, we were interested in a preliminary evaluation of air quality in the town of Meknes, in particular, the measurement of sulphur dioxide (SO2), ozone (O3) and the particulate matter in suspension (PM-10) whose particles have a diameter lower than 10 µm, with separation of the fractions according to the size: fine fractions (diameter lower or equalizes with 2.5 µg/m3) and coarse fractions (diameter between 2.5 µg/m3 and 10 µg/m3). The samples were collected one day in (July, October and November 2005) in several sites (urban, suburban, proximity,…). The mesures of the gaseous pollutants (SO2 and O3) were realized on the site every 15 min. by automatic analyzers (AF21M and O341M). Whereas, PM-10 were collected respectively by Dichotomous and the Gent samplers. The chemical and mineral composition of the PM-10 was determined by various techniques of physicochemical analyses: Atomic Absorption Spectrometer (SAA), X-ray Fluorescence in Total Reflection (TXRF), Scanning Electron Microscope coupled with Energy Dispersion Spectrometer (SEM-EDS) and X-Rays Diffraction (XRD).Dans ce travail, nous nous sommes intéressés à une évaluation préliminaire de la qualité de l’air dans la ville de Meknès, en particulier la mesure du dioxyde de soufre (SO2), de l’ozone (O3) et de la matière particulaire en suspension (PM-10) dont les particules ont un diamètre inférieur à 10 µm avec séparation des fractions en fonction de la taille : fractions fines (diamètre inférieur ou égale à 2,5 µg/m3) et fractions grossières (diamètre entre 2,5 µg/m3 et 10 µg/m3). Pour cela, nous avons mené trois campagnes de prélèvements journalières en (juillet, octobre et novembre 2005) dans plusieurs sites (urbain, suburbain, proximité, fond). Les mesures des polluants gazeux (SO2 et O3) ont été effectuées sur terrain, tout les quart d’heures  par des analyseurs automatiques (AF21M et O341M). Alors que pour les PM-10, le prélèvement a été réalisé respectivement par le Dichotomous et le Gent. La composition chimique et minérale des PM-10 a été déterminée par différentes techniques d’analyses physico-chimiques : Spectromètre d’Absorption Atomique (SAA), Fluorescence X en Réflexion Totale (FXRT), Microscope Electronique à Balayage couplé au Spectromètre à Dispersion d’Energie (MEB-SDE) et Diffraction des Rayons X (DRX)

Chemical characterization and origin of suspended atmospheric particles in Meknes city in Morocco

International audienceThis work is a study of elemental composition of particulate matter (PM-10, with aerodynamic diameter lower or equalizes to 10 mu m, collected in Meknes city in Morocco. The campaigns of measure carried out on a traffic site from March 2007 to April 2008. The chemical concentrations of 9 elements (Ca, Cr, Cu, Fe, K, Mn, Ni, Pb and Zn) were determined by Total reflection X-Ray Fluorescence (TXRF), Al was determined by the Atomic Absorption Spectrometry (AAS), whereas the Pb isotopic compositions were determined by Thermo Ionisation Mass Spectrometry (TIMS). The obtained results show quite significant seasonal variation of the chemical composition for fine and coarse fractions. It should be noted that Pb and Ni concentrations exceeded the air quality standards. The calculation of the Enrichment Factor (EE) revealed that Cr and Pb were attributed mainly to anthropogenic sources. The use of the isotopic extraction of lead confirms the anthropic origin of Pb

Heavy metals analysis of water, soils and sediments along the Oued Boufekrane river (central Morocco) using WD-XRF and ICP-AES

Oued Boufekrane is a river that takes its source about thirty kilometers southern the city of Meknes central Morocco) The water of this river is used for the irrigation of agricultural soils and it also covers the needs of water for part of rural population. When passing through Meknes city, it is loaded by waste waters of urban and industrial origin and particularly from artisanal tanneries and potteries. The purpose of this study is to measure the heavy metal concentrations in soil, sediment and water samples along the Oued Boufekrane river by means of WD-XRF and ICP-AES. The heavy metals content measured revealed to be below the critical levels defined as risk levels except for Cu in water and sediment which content, in some sites, is close to these risk levels; for Cr in sediments, which content increase from up- to downstream of Meknes city and for Pb in soils, which concentrations revealed to be high in the vicinity of road axes

TXRF characterization and source identification by positive matrix factorization of airborne particulate matter sampled in Kenitra City (Morocco)

15th European X-Ray Spectrometry Conference (EXRS), Vienna, AUSTRIA, JUN 18-22, 2012International audienceSamples of fine and coarse fraction of airborne particulate matter were collected on weekly basis during the period from February 2007 to February 2008 in Kenitra City, Morocco. The samples were collected using a Gent stacked filter sampler in two fractions (<2.5 mu m, fine and 2.5-10 mu m, coarse). The samples were analyzed for their elemental composition by total reflection X-ray fluorescence. The data set was then analyzed by the factor analysis method, positive matrix factorization to identify the possible sources of particulate matter and their contribution to the ambient particulate matter concentrations in Kenitra City. Four factors from positive matrix factorization solutions were found for elemental composition of fine and coarse particulate matter at the Kenitra site. In the case of fine particles, metal smelting sources contribute about 52% of the fine mass. The road dust contributes to about 22% and the rest 26% comprises emissions from motor vehicles and soil dust. In the case of coarse particles, soil dust contributes about 43% and the two stroke engines about 42% of the coarse mass, whereas road dust and motor vehicles apportioned to be about 10 and 4%, respectively. Copyright (c) 2013 John Wiley & Sons, Ltd

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

WD-XRFand ICP-AES analysis methods and their application to sediments of two moroccan rivers (Boufekrane and Oum er Rbia)

International audienceThis paper examines Wavelengths Dispersive X-Ray Fluorescence (WD-XRF) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) as complementary techniques to analyse major and trace elements. A set of Geostandard samples were analyzed and statistical methods were applied to the results. In the second part of this paper, the concentrations of Al, Cr, Fe, Ni, Cu Zn and Pb in sediments of two Moroccan rivers, Oum Er Rbia and Boufekrane, were determined. This study shows that the metal distribution in Oum Rbia sediments is homogeneous throughout the studied area. Whereas in Boufekrane sediments, enrichment was observed downstream (for Al, Cr, Fe, Ni) and inside the city of Meknes (for Cu, Zn and Pb). The Oum Er Rbia river sediments show significantly higher concentrations of Al, Fe, Cr, Ni, Cu and Zn. These higher concentrations can be attributed to the geological features of this river. The Boufekrane river sediments show higher Pb concentrations probably due to the pottery industry activities in the watershed

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