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

This work is a study of elemental composition of particulate matter (PM-10, with aerodynamic diameter lower or equalizes to 10 µm, collected in Meknes city in Morocco.The compaigns of measure carried out on a traffic site from March 2007 to April 2008. The chemical concentration 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 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 of fine and coarse fractions. It should be noted that Pb and Ni concentrations exceeded the air quality standars. the calculation of the Enrichment Factor (EF) revealed that Cr and Pb were attributer mainly to anthropogenic sources. The use of the isotopic extraction of lead confirms the anthropic origin of Pb

Caractérisation des particules en suspension totale (PST) dans la ville de Meknès au Maroc, cas des anions et des alcalins

The characterization of the Total Suspended Particules (TSP) was carried out in the town of Meknes in Morocco. Sampling campaigns were carried out once a month from June to November 2006 in sites closest to road traffic and industrial sector. Atmospheric particulate matter was collected by High Volume Sampler (HVS) and the chemical characterization, in particular, anions (Cl-, NO3- and SO42-) and the alkaline ones (Ca, K, Mg and Na) of the TSP were respectively determined by the Ionic Chromatography (IC) and the Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), whereas the physical characterization is carried out by the X-Rays Diffraction (XRD). Results show terrigenous importance of the contributions and re-suspended soil particles with an abundance of Ca and SO42-. The application of the Principal Component Analysis (PCA) presents correlations between on the one hand Ca, Mg and K and on the other hand between NO3-, SO42- and Na.La caractérisation des particules atmosphériques en suspension (PST) a  été réalisée dans la ville de Meknès au Maroc. Les prélèvements ont été effectués une fois par mois entre juin et novembre 2006 dans des sites caractérisés par leur proximité aux principaux axes routiers et des secteurs industriels. La collecte de la matière particulaire a été réalisée par l’échantillonneur à Grand Volume (HVS) et la caractérisation chimique, notamment, les anions (Cl-, NO3- et SO42-) et les alcalins (Ca, K, Mg et Na) des PST ont été respectivement déterminée par la Chromatographie Ionique (CI) et la Spectrométrie d’Emission Atomique avec Plasma Couplée par Induction (ICP-AES), alors que la caractérisation physique est réalisée par la Diffraction des Rayons X (DRX). Les résultats obtenus montrent l’importance des apports terrigène et la remise en suspension du sol avec une abondance du Ca et du SO42-. L’application de l’Analyse en Composantes Principales présente des corrélations entre d’une part le Ca, le Mg et le K et d’autre part entre le NO3-, le SO42- et le Na

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

Catalog of total excitation-emission and total synchronous fluorescence maps with synchronous fluorescence spectra of homologated fluorescent pesticides in large use in Morocco: development of a spectrometric low cost and direct analysis as an alert method in case of massive contamination of soils and waters by fluorescent pesticides

The purpose of this research is to develop a direct spectrometric approach to monitor soils and waters, at a lower cost than the widely used chromatographic techniques; a spectrometric approach that is effective, reliable, fast, easy to implement, and without any use of organic solvents whose utilization is subject to law limitation. It could be suitable at least as an alert method in case of massive contamination. Here, we present for the first time a catalog of excitation– emission and total synchronous fluorescence maps that may be considered as fingerprints of a series of homologated pesticides, in large use in Morocco, aiming at a direct detection of their remains in agricultural soils and neighboring waters. After a large survey among farmers, agricultural workers and product distributors in two important agricultural regions of Morocco (Doukkala-Abda and Sebou basin), 48 commercial pesticides, which are fluorescent, were chosen. A multi-component spectral database of these targeted commercial pesticides was elaborated. For each pesticide, dissolved in water at the lowest concentration giving a no-noise fluorescence spectrum, the total excitation-emission matrix (TEEM), the total synchronous fluorescence matrix (TSFM) in addition to synchronous fluorescence spectra (SFS) at those offsets giving the highest fluorescence intensity were recorded. To test this preliminary multi-component database, two real soil samples, collected at a wheat field and at a vine field in the region of Doukkala, were analyzed. Remains of the commercial Pirimor (Carbamate) and Atlantis (Sulfonylurea) were identified by comparison of the recorded TEEM, TSFM, and SFS to those of the preliminary catalog at one hand, and on the basis of the results of a field pre-survey. The developed approach seems satisfactory, and the fluorimetric fingerprint database is under extension to a higher number of fluorescent pesticides in common use among the Moroccan agricultural regions