Activités de l’uranium et du radium dans des échantillons d’eau naturelle au Sahara marocain

Measure of uranium and radium activities in some natural watersamples from Moroccan SaharaThe preliminary results of  238U, 234U, 226Ra, 228Ra and 228Th activities and of 234U/238U,228Ra/226Ra, 228Th/228Ra and 226Ra/238U activity ratios obtained for 8 wells, 5 drillings, 2 springs and 3 tap water samples collected in Laayoune and Es-Smara regions in the Moroccan Sahara are given in this work. The analyzed natural water samples have been  collected from sources situated in a desert region rich in phosphates. Except for the one water drilling sample no used by population, the calculation of  equivalent doses to the maximal activities for each isotope show that all measured activities are inferior to the maximum contaminant levels recommended by the International Commission of Radioprotection and they don't present any risk for population health. The obtained results are comparable to those already found in other regions in Morocco or in the world

Mesure des activités de l'uranium ( 238U, 234U) et du rapport isotopique 234U/238U dans des échantillons d’eau naturelle au Maroc à l'aide de la spectrométrie alpha

Measurement of the activities of uranium (238U, 234U) and of Isotopic ratio 234U 238U in natural water samples in Morocco using spectrometry alphaIn this work, specific activities of     234U and 238U and isotopic activity ratios have been measured for 68 natural water samples collected from 5 principal sources of water in Morocco: Wells (18 samples), springs (17 hot spring water samples and 7 cold spring water samples), rivers (13 samples), lakes (5 samples) and tap water (8 samples). These samples have been collected in Moroccan regions characterized by various geology, different socio-economical activities. The obtained results have allow us to establish general tendencies of measured parameters repartition in sources of the analysed waters. This tendency is clear for hot springs where activities of  uranium are relatively low and 234&U/238&U activities ratios are important. This is due to temperature and oxydoreduction conditions of waters that are favourable in particularly to 234U solubility. The results so-obtained are comparable to those habitually found in natural waters in different regions of world and show that there is no radioactive pollution in these water

Caractérisation physico-chimique des eaux usées d’abattoir en vue de la mise en oeuvre d’un traitement adéquat : cas de Kénitra au Maroc

Notre objectif principal est de caractériser les eaux usées d’abattoir municipal de la ville de Kénitra (Maroc) et de recommander un traitement adéquat permettant leurs réutilisations, réduisant ainsi les nuisances que subit le milieu récepteur (Oued Sebou) et de remédier aussi à la perte de cette source hydrique en matières valorisables. La caractérisation physico-chimique des eaux usées brutes a révélé que ce rejet liquide est très chargé en matière organique en terme de DCO (Moy. = 219,52 mg/L ±51,07), en DBO5 (Moy. = 181,34 mg/L±30,04), en MES (Moy. = 482 mg/L ±222,7) et en matière minérale exprimée en terme de Chlorures (Moy. = 237 mg/L ±109,6), en Conductivité électrique (Moy. = 1360,5 μs/cm ±1120,8) et en Alcalinité exprimée en CaCO3 (Moy. = 201 mg/L ±74,2) avec un pH de 7,5 (±0,8). Les teneurs moyennes en Nitrates et en Orthophosphates respectivement de l'ordre de 1,74 mg/L (±2,7) et 0,08 mg/L (±0,1). Malgré que ces eaux usées présentent une charge organique élevée (rapports DBO5/DCO = 0,83 et MES/DBO5 = 2,66), elles présentent une biodégradabilité satisfaisante. L’examen de rapport DCO/DBO5 = 1,21 souligne bien le caractère biodégradable des eaux usées de l'abattoir municipal de Kénitra auxquelles un traitement biologique paraît tout à fait convenable. Cependant, il faut tenir compte les eaux usées domestiques mélangées avec les effluents de l'abattoir. Il existe une corrélation hautement significative entre la DCO et la DBO5 de nos échantillons d’eaux usées (R2= 0,93 et y = 1,2689x + 23,814). Par ailleurs, la corrélation établie entre l’oxygène dissous et la DBO5 montre un R2= 0,75 (y = 0,0057x + 0,7964).Mots-clés : eaux usées, abattoir, paramètres physico-chimiques, traitement, Kénitra

Integration of instrumental neutron activation analysis and inductively coupled plasma-optical emission spectrometry with mathematical modeling for the elemental analysis of plants.

Metals in fourteen plants were analyzed in parallel by instrumental neutron activation analysis (INAA) and inductively coupled plasma-optical emission spectrometry (ICP-OES) for the possible integration of the analytical techniques. INAA correlates well with ICP-OES for Ca, K, Fe, Mn, Mg, and Zn. Advantages of INAA include its nondestructive nature and ease of sample preparation. ICP-OES requires destructive sample digestion, but provides superior limits of detection. Therefore, ICP-OES is the method of the choice for low elemental concentrations. In general, ICP-OES is a better choice for Cr, Sr, and Cu in plant analysis for accuracy. On the other hand, a simple mathematical model was developed for predicting the concentrations of Cu and Cr that were measured by INAA. The predicted values of the elements showed consistency to their corresponding certified values as well as to the concentrations measured by ICP-OES, specifically for Cu or when the concentrations exceeded 5 mg/kg

Numerical and experimental characterization of the reaction rates in the core of the CNESTEN’s TRIGA Mark II research reactor

Education, training and isotopes production are the most important uses of the Moroccan 2 MW TRIGA Mark II reactor situated at the National Center for Energy Sciences and Nuclear Techniques (CNESTEN, Morocco). To develop new R&D projects in research reactors, the particular and advanced knowledge of neutron and photon flux distribution, within and around the reactor core, is crucial. In order to precisely preparing the experiments in the CNESTEN’s TRIGA reactor, a detailed model was developed using the 3D continuous energy Monte Carlo code TRIPOLI-4 and the continuous energy cross-section data from the JEFF3.1.1 nuclear data library. This new model was used to carry out preliminary neutron and photon calculations to estimate flux levels in the irradiation channels as well as to calculate kinetic parameters of the reactor, core excess reactivity, integral control rods worth and power peaking factors. As a first step of the validation of the model, the obtained results were compared with the experimental ones available in the Final Safety Analysis Report (FSAR) of the TRIGA reactor. A study is being carried out at the end of which the results will be published as an evaluated benchmark. Furthermore, this work aims at experimentally characterize the reaction rates in various irradiation channels inside and outside the reactor core. The measurements are carried out using the neutron activation technique. To set up the experimental design for the activation experiments a series of preliminary calculations were performed using the TRIPOLI-4 model to calculate the expected gamma flux/intensity levels of various materials after irradiations in different positions in the irradiation facilities. Different activation foils with known characteristics are then irradiated and the activity of several isotopes is measured with the Gamma Spectrometry Method. The measured relative reaction rates are then compared with the calculated ones evaluated through the new TRIPOLI-4 reactor model. Fairly good agreement was found, which indicates that the new computational model is accurate enough to reproduce experiments

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