High-frequency monitoring of surface water quality at the outlet of the Ibrahim River (Lebanon): A multivariate assessment

Surface water quality monitoring is essential to evaluate the quality of a water resource. The current study assesses the quality of the Ibrahim River, one of the main Lebanese rivers, exposed to considerable human activities. 285 samples were collected at the outlet of the river, between May 2016 and July 2017, covering one hydrological year. Twenty-three physico-chemical parameters (flow, pH, temperature, electrical conductivity, turbidity, total suspended solids, total dissolved solids, dissolved oxygen, dissolved organic carbon, biochemical oxygen demand, chemical oxygen demand, chemical oxygen demand/biochemical oxygen demand, specific ultraviolet absorbance, dissolved cations (Na+, K+, Ca2+, Mg2+), total alkalinity, dissolved anions (Cl−, NO3 −, NO2 −, PO4 3− and SO4 2−)) and five microbiological tests were assessed (total germs, total coliforms, fecal coliforms, Escherichia coli and Enterococcus). A Principal Component Analysis (PCA) was applied for data analysis. The first component showed high levels of anthropogenic characteristics mainly due to organic and bacteriological parameters, differentiating low and high river discharges (explaining around 35% of the total variance). The second component was mainly influenced by mineral variables showing a clear annual discrimination (explaining about 17% of the total variance). Moreover, this study led to variables reduction from twenty-eight to ten. The final shortlisted parameters are Q, pH, EC, NO3 −, total coliforms, fecal coliforms, BOD5, K+, TA and Cl−. A new PCA performed with the reduced matrix validated this selection. The water quality index (WQI) was then calculated in this study, using the shortlisted parameters characterizing the basin, excluding the flow since it cannot be considered as a quality indicator. Thus, the water was evaluated as « medium » to « good » with values ranging from 63.1 (August 2016) to 73.1 (November and December 2016) with an average of 69.0 ± 1.9. The proposed WQI should be further tested for monitoring practices in the Ibrahim River basin or other similar basins of the region

Les métaux lourds dans les engrais phosphatés et les sulfates rejetés par les industries des fertilisants (recherche sur leur transfert et leur mobilité dans les sols libanais)

Afin d'établir l'impact et le risque lié aux fertilisants chimiques depuis leur fabrication jusqu'à leur amendement sur la contamination des sols par les éléments traces métalliques, une étude de leur mobilité et leur transfert s'avère nécessaire. L'objectif de ce travail de thèse était d'évaluer la source de contamination du sol par les éléments traces autour de l'industrie des fertilisants chimiques et suivre l'évolution temporelle de la mobilité et du transfert de ces éléments dans un profil du sol agricole amendé par des engrais phosphatés du type simple superphosphate (SSP) ou du phosphogypse. Pour cela nous avons utilisé des techniques permettant la caractérisation structurale et minéralogique des sols collectés comme la diffraction des rayons X et la microscopie électronique. Puis une caractérisation chimique des sols collectés concernant la concentration totale des éléments traces et des éléments majeurs a été établie. Comme la mobilité n'est pas stable au cours du temps dépendant de plusieurs paramètres physico-chimiques comme le pH, le potentiel redox, la teneur en matière organique, une extraction séquentielle a été adoptée le long de l'étude au cours du temps et dans le profil du sol amendé jusqu'à une profondeur de 55 cm. En outre, l'absorption des éléments traces par les plantes cultivées sur le terrain agricole amendé par les engrais ou le phosphogypse a été analysée au cours du temps afin d'évaluer le risque lié à la chaîne alimentaire et plus particulièrement la chaîne alimentaire humaine induisant des effets négatifs sur la santé. Une comparaison entre l'application du phosphogypse et celle des engrais a été mise en évidence à la finalité de ce travailTo determine the impact and risk of chemical fertilizers, from their manufacture to their amendment, on soil contamination by trace metals, the study of their mobility and transfer would be necessary. The objective of this work was to evaluate the source of soil contamination by trace elements around the industry of chemical fertilizers, and to follow the temporal evolution of mobility and transfer of these elements in the profile of agricultural soil amended by superphosphate (SSP) fertilizers or phosphogypsum. To achieve our objective, we used techniques allowing the determination of structural and mineralogical characterization of collected soil samples, such as X-ray diffraction and electron microscopy. Chemical characterization related to the total concentration of trace and major elements of collected soils was established. As mobility was unstable over time, depending on several physico-chemical parameters such as pH, redox potential, and organic matter content, a sequential extraction was adopted throughout the study over time in the amended soil profile to a depth of 55 cm. In addition, the absorption of trace elements by agricultural crops cultivated over land amended with fertilizer or phosphogypsum was analyzed over time to assess the risk of their transfer to the food chain, especially the human food chain, imposing health hazards. A comparison between the effects of the application of phosphogypsum and phosphate fertilizer was carried out in concluding this workMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

Application of 2D correlation spectroscopy on olive stones acid hydrolysates: Effect of overliming

In order to valorize olive stones we are studying their dilute-acid hydrolysate (DAH) composition, and trying to highlight the effect of the overliming process on DAH composition in order to perform an effective treatment that maximize sugars concentrations (xylose) and minimizes the amount of toxic materials (FF and HMF). An 2(2)3(1) experimental design was established to describe the effects of three controlled factors with distinct levels: pH (10 and 12), temperature (25 and 60 degrees C) and detoxification time (15,30 and 60 min) on the concentration of xylose, FF and HMF. A better understanding of this overliming process was possible by exploring the chromatograms obtained with 2D Correlation Spectroscopy (2DCOS). 2D correlation spectroscopy gave information about the relations that exist between chromatographic peaks and chromatograms. The order in which the constituents vary can be deduced from the sign of peaks in the synchronous and asynchronous matrices, facilitating the interpretation of kinetic studies. (c) 2011 Published by Elsevier B.V

First principles account for large changes in electronic structure and bonding from LaCu to LaCuMg and LaCuMg4

Increasing amounts of magnesium in LaCu intermetallic are shown to bring drastic electronic, chemical and mechanical changes. Based on DFT methodologies this is quantified for the cohesive energies, relative charge transfers, bulk modules, electronic structures and bonding properties for the three compounds LaCu, LaCuMg and LaCuMg4. Particularly the cohesive energies increase with Mg amounts: This is illustrated by the increasing number of pair interactions: While in the binary the bonding is ensured by La–Cu, in the ternaries La–Cu, La–Mg and Cu–Mg interactions contribute to the bonding with the extra electrons brought by Mg occupying bonding states. Along the series, increasing magnesium contents lead to moderate increase of the compressibility

TIC et enseignement de la Chimie : au-delà des discours, quels dispositifs d’enseignement pour quels apprentissages?

In this research we suggest to take advantage of the opportunities offered by the new information and communication technologies (NICT). This new techno-scientific process of investigation will be realized via a laboratory of CAE (Computer assisted experimentations) where the computer is the learning tool that seeks in real time concrete observations. Experimental know- how, and the using of abstract representations to solve problems. To do this, we have introduced innovated courses in Didactics based on ICT/CAE in our Masters programs in the Holy Spirit University of Kaslik (USEK). These courses are intended for initial and continuous training of our student-teachers in mathematics and science and technology. Subsequently, our student-teachers will use CAE with their students in high schools for teaching chemistry to test and validate the functional aspect of the environment CAE proposed. The educational validation of this paradigm will be based on the confrontation between a priori analysis and subsequent findings to measure the gap of understanding that students have acquired

Mass Transfer of Carbaryl from Pure Water to Salt Aqueous Solution: Result Comparison Between Sea and Lab-Made Water

International audienc

Characterization of spatial and temporal patterns in surface water quality: a case study of four major Lebanese rivers

International audienceIn this work, four major Lebanese rivers were investigated, the Damour, Ibrahim, Kadisha, and Orontes, which are located in South, Central, and North Lebanon and Bekaa Valley, respectively. Five sampling sites were considered from upstream to downstream, and 12 sampling campaigns over four seasons were conducted during 2010–2011. Thirty-seven physicochemical parameters and five microbial tests were evaluated. A principal component analysis (PCA) was used for data evaluation. The first PCA, applied to the matrix-containing data that was acquired on all four rivers, showed that each river was distinct in terms of trophic state and pollution sources. The Ibrahim River was more likely to be polluted with industrial and human discharges, while the Kadisha River was severely polluted with anthropogenic human wastes. The Orontes and Damour rivers seemed to have the lowest rates of water pollution, especially the Orontes, which had the best water quality. PCA was also performed on individual data matrices for each river. In all cases, the results showed that the springs of each river have good water quality and are free from severe contamination. The other monitoring sites on each river were likely exposed to human activities and showed important spatial evolution. Through this work, a spatiotemporal fingerprint was obtained for each studied river, defining a “water mass reference” for each one. This model could be used as a monitoring tool for subsequent water quality surveys to highlight any temporal evolution of water quality

Chemical diversity and antimicrobial activity of the essential oils of four Apiaceae species growing wild in Lebanon

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Chemical composition and antimicrobial activity of Satureja, Thymus, and Thymbra species grown in Lebanon

International audienceThe essential oils were extracted by hydrodistillation from Satureja cuneifolia, Satureja thymbra, Coridothymus capitatus, Thymus syriacus, and Thymbra spicata growing wild in Lebanon. Their phytochemical analysis performed by GC/MS showed that the aforementioned species are characterized either by carvacrol (60.9%) or thymol (54.3%) or by a more or less equal amounts of these two phenols. Assessment of their in vitro antimicrobial activity against Candida albicans and six pathogenic bacteria using the broth dilution method revealed that the tested oils have a broad activity spectrum with minimum inhibitory concentration ranging from 0.1 to 0.8 mg/ml. Among the tested species, S. thymbra EO showed the highest antimicrobial potential whereas T. syriacus showed the lowest inhibitory activity. These results give scientific evidence for the use of those species in the Lebanese folk medicine and lend support to implement them as natural alternatives for synthetic antimicrobials

Chemical composition and antimicrobial activity of Origanum libanoticum , Origanum ehrenbergii and Origanum syriacum growing wild in Lebanon

International audienceThe essential oils (EOs) of the aerial parts of Origanum libanoticum and Origanum ehrenbergii, endemic to Lebanon, and Origanum syriacum, endemic to the Levantine, were obtained by distillation with a Clevenger apparatus. GC and GC/MS allowed identification of 96.4%, 93.5%, and 95.2% of their constituents, respectively. Carvacrol was the major component of both O. syriacum EO (79%) and O. ehrenbergii EO (60.8%). This compound was absent in O. libanoticum EO and the major compounds were β-caryophyllene (26.8%), caryophyllene oxide (22.6%), and germacrene D (17.2%). The assessment of their antimicrobial activity against Candida albicans and six pathogenic bacteria revealed that O. libanoticum EO was inactive, while O. syriacum and O. ehrenbergii showed moderate antimicrobial activity with minimal inhibitory concentrations varying from 400 to 1200 μg/ml. These results support the traditional use of these last two species in traditional herbal preparations in Lebanon