Mohamad Amine Fakih

Associate professor
Life & Earth Sciences department - Section V - Nabatiyeh
Speciality: Biology
Specific Speciality: Biogeochemistry

Teaching 6 Taught Courses
(2014-2015) Biol 113 - Genetics, human anatomiy and plant reproduction

BS Earth and life sciences

(2014-2015) Biol 114 - Organization of the plant living world and environment

BS Earth and life sciences

(2014-2015) Biol 114 - Organization of the plant living world and environment

BS Earth and life sciences

(2014-2015) Biol 213 - Kingdom of Higher Plants (Vegetative structures)

BS Earth and life sciences

(2014-2015) Biol 216 - Kingdom of higher plants (reproductive structures)

BS Earth and life sciences

(2014-2015) Biol 320 - Vegetal Physiology

BS Earth and life sciences

Publications 10 publications
Chaden Haydar, Nada Nehme, Sadek Awad, Bachar Koubayssi, Mohamad Fakih, Ali Yaacoub, Joumana Toufaily, Frédéric Villieras, Tayssir Hamieh Physiochemical and Microbial Assessment of Water Quality in the Upper Litani River Basin 2014

Water resources in Lebanon are witnessing serious challenges and reached depletion. One of the major challenges is the quality deterioration, which is accompanied with uncontrolled resources management, and thus the increasing demand. There are several consumption aspects, mainly the domestic, industrial and irrigation. Yet, exploitation of water resources in Lebanon implies both the surface and groundwater. However, surface water resources are most used due to the ease of exploitation processes, and more certainly water from rivers. Typically, the Litani River is the largest one in Lebanon. The river has been lately subjected to several aspects of deterioration in its quality. This includes the major physiochemical characteristics. This study aims to assess the seasonal variations in water quality in the Upper Litani River Basin, including the Qaraaoun Lake. Samples were collected from particular sites along the river, and at several dates during the years of 2010 and 2011. The carried analysis implies the physical (pH, T°, TDS, Ec), chemicals (Na+, Ca2+, Mg2+, Cl?, SO42?, NH3+, NO3?, PO42?, K+, BOD5 and COD, Heavy metals (Fe, Ni, Zn, Cu, Cr, Al, Ba, Pb, Mn) and microbiological parameters. This resulted numeric data are being compared with WHO guidelines. In addition, PCA was applied to evaluate the data accuracy. We can conclude that the variables used are very efficient and the dry season shows the worst water quality with nitrate, metal and microbial enrichments.

Mélanie Davranche, Aline Dia, Mohamad Fakih, Bernd Nowack, Gérard Gruau, Georges Ona-nguema, Patrice Petitjean, Sébastien Martin, Rebecca Hochreutener Organic matter control on the reactivity of Fe(III)-oxyhydroxides and associated As in wetland soils: A kinetic modeling study 2013

Iron (Fe) reactivity and arsenic (As) reactivity in wetland soils were studied by applying a generalized dissolution rate law to data recovered from reductive dissolution experiments using As-bearing-Fe(III)-oxyhydroxides (ferrihydrite and lepidocrocite). Although As does not correspond to a separate mineral, the kinetic law can be successfully used to investigate the dynamics of As. This was possible as As was coprecipitated in all the tested Fe(III)-oxyhydroxides. The generalized rate law was also applied to available published and here produced datasets of reduction experiments of Fe(III)-oxyhydroxides (with reducing agent: ascorbate, Shewanella putrefaciens, purified soil Fe(III)-reducing bacteria and no purified autochthonous wetland soil bacteria). A comparison of the calculated kinetic parameters and modeling demonstrates that Fe reactivity is strongly increased in the wetland soil as compared to simple bacterial reduction experiments. Dissolved organic matter appears to be a key factor in the control of the Fe(III)-oxyhydroxide dissolution rate. More specifically, organic matter by strongly binding Fe(II) prevents Fe(II) readsorption and subsequent Fe secondary mineral formation, both of which are known to strongly decrease Fe(III)-oxyhydroxide dissolution rates. Arsenic solubilization is driven by Fe dissolution with the extent of the reduction pathway and therefore indirectly by the occurrence of dissolved organic matter. In this type of organic environment, where the formation of Fe secondary minerals is reduced or inhibited, As is not taken up and is thereby strongly solubilized. Therefore, wetlands appear to be favorable areas for the active transfer of As from the soil to both surface- and ground-waters.

Amale Mcheik, Mohamad Fakih, Noureddine Bousserrhine, Joumana Toufaily, Evelyne Garnier-Zarli and Taysir Hamieh Biomobilization of Heavy Metals from the Sediments Affect the Bacterial Population of Al-Ghadir River (Lebanon) 2013

Although there is no doubt about the importance of the bacterial activity on the solubilisation and the distribution of heavy metals in aquatic sediments, hydromorphic soils and ground waters; little is known about the involvement of bacterial dissolution in periodically anaerobic environments like that found in dredged sediments and little is known about the processes and the environmental factors controlling this process.The aim of this paper was to study the effect of the autochthonous bacterial activity on the biodegradation of organic matter and the mobilization of heavy metals in the sediments of Al-Ghadir river (Mount Lebanon). Sediments were incubated under standard anaerobic conditions and enriched with glucose to stimulate and accelerate microbial metabolism. The evolution of carbon metabolism (Organic matter evolved, carbon consumed and organic acids produced) and metals released in batch reactors were followed over time. Under the adopted conditions, analysis of the chemical parameters indicated that the incubated sediments showed a significant release of organic carbon corresponding to bacterial development. Mineral analysis showed an important solubilisation of Fe2+ and Mn2+ indicating the presence of Fe- and Mn-reducing bacteria in sediments. Pb, Cd and Cr solubilisation profiles were observed and appeared concomitant to the solubilisation profiles of Fe and Mn indicating that the redox cycle has been well installed and that Pb, Cd and Cr were associated to Fe and Mn oxides. The production of Cu appeared in parallel to the mineralization of the organic matter in the sediment indicating that Cu was associated to this fraction. Zn appeared associated to the sulphide fraction than to the Fe and Mn oxides fraction. Microbiological and genetic analysis showed a decrease and the disappearance of some bacterial strains due to the shift in the culture conditions and the toxicity of the released heavy metals but at the same time the development and the growth of many other populations which showed to be tolerant to the same conditions

Amale Mcheik, Mohamad Fakih, Zakia Olama, Hanafi Holail Bioremediation of Four Food Industrial Effluents 2013

Some effluents ((Whey Effluent (WhE); Orange Effluent (OE); Carrot Effluent (CE) and Chocolate Effluent (ChE)) were bioremediated using some allochthonous microorganisms (Lactobacillus delbrueckii subsp. bulgaricus, Saccharomyces cerevisiae Y-1347 and Dekkera bruxellensis). The highest biodegradable efficiency of the Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD) and Total Organic Nitrogen (TON) of the effluents under investigation was noticed when using the allochthonous microorganisms together with the autochthonous one. Saccharomyces cerevisiae Y-1347 proved to be the best utilizer of Whey (WhE) organic and nitrogenous compounds with the reduction of BOD, COD and TON by 12.36, 20.09 and 68.42%, respectively. Dekkera bruxellensis proved to be the organism of choice on using Orange Effluent (OE) where BOD, COD and TON were reduced by 18, 20 and 53.39%, respectively. Lactobacillus delbrueckii subsp. bulgaricus proved to be the best utilizer of the Carrot Effluent (CE) constituents by reducing BOD, COD and TON by 24.27, 19.33 and 63.63%, respectively. Dekkera bruxellensis proved to be the best utilizer of the Chocolate Effluent (ChE) constituents by improving its quality and reducing BOD, COD and TON by 18.36 and 15.86 and 73.07%, respectively. A successful trial was made to use the treated effluents in the irrigation of Lens culinaris and Phaseolus vulgaris seeds for germination.

Nada Nehme, Chaden Haydar, Bachar Koubaissy, Mohamad Fakih, Sadek Awad, Joumana Toufaily, Frédéric Villieras and Tayssir Hamieh Evaluation of the Physicochemical Characteristics of Water in the Lower Litani Basin 2013

The physicochemical characteristics of water in the Lower Litani River Basin (LLRB) were evaluated. It concerns with analyzing six representatives sites which are investigated over three seasons of the year 2011. The principal component analysis (PCA) method was used to interpret the elemental concentrations in the river water. Many variables were evaluated, especially the components or metals Fe, NO2-, CaCO3, Cu. Three groups were identified and differentiated by PCA according to the seasons. The first group is rich in Fe and NO2, and low in NH4 and EC (in the mid rainy season). The second group formed in dry season and the third group with low concentration of K+, PO43- and Cl- (in mid rainy). However, no critical pollution has been reported in this part of the river; except the high concentration of Fe and NO2 - in all investigated sites due to the reject of wastewater and touristic activities.

Christopher J. Daughney, Mohamad Fakih and Xavier Châtellier Progressive sorption and oxidation/hydrolysis of Fe(II) affects cadmium immobilization by bacteria-iron oxide composites 2011

Iron-bacteria composite suspensions were prepared by exposure of Anoxybacillus flavithermus cells to increasing concentrations of Fe2+ cations under different degrees of oxidation. Cd2+ immobilization was investigated during and after the synthesis of the iron-bacteria composites via scanning electron microscopy and isotherm sorption experiments conducted at varied ratios of total iron to bacteria (expressed by the variable ρ, mg Fe per g dry bacteria). At ρ less than about 20, precipitation of Fe(III) oxide was hindered, and for ρ up to about 50 Cd immobilization was decreased relative to iron-free control experiments, even for conditions where Fe(III) oxide was forming. For ρ above 50 to the maximum investigated value of 124, the Cd immobilization capacity of the iron-bacteria composite suspensions was partly recovered. Surface complexation models developed to describe the data indicate that 1) Fe2+ and Cd2+ cations compete with comparable affinities for the reactive sites on the bacterial cell walls, and 2) sorption of the progressively oxidizing iron can reduce the total concentration of bacterial surface sites available for metal adsorption by more than 40%, inferred to be due to masking or blocking of the binding sites by Fe(II) or Fe(III) monomers or oligomers or precipitated Fe(III) oxides. This study demonstrates that the immobilization of metal cations in bacteria-bearing settings cannot be examined independently of redox processes such as the oxidation, hydrolysis and precipitation of iron.

Hiba Noureddine, Mohamad Fakih, Yolla Makhour, Dana Zeineddine and Noureddine Bousserrhine Co and Mn decrease chemical and biological reduction rate of iron oxyhydroxides 2011

Very few studies related to the solubilization of Fe (III) oxides substituted by Mn and Co, whereas such oxides are frequent in natural environment. In this present work, goethites substituted for various Mn and Co rates were synthesized and subjected to the reducing action, first, by chemical treatment, with a the dithionite-citratebicarbonate (CBD) reagent, and secondly, by biological treatment with Clostridium butyricum a fermentative Fe (III). The comparison of two processes showed that the dissolution rates of iron decreased with substitution. The study of the bacterial fermentative balance shows that substitution, its rate and its nature, does not influence the bacterial fermentative balance (total activity and number of electron produced were unchanged). However, it decreases the percentage of electrons engaged in the reduction process. This result demonstrates the control of the bacterial reduction of iron oxides by the cristallo-chemical characteristics of the latter.

Mohamad Fakih, Mélanie Davranche, Aline Dia, Bernd Nowack, Guillaume Morin, Patrice Petitjean, Xavier Châtellier and Gérard Gruau Environmental impact of As(V)–Fe oxyhydroxide reductive dissolution: An experimental insight 2009

Polymer slides covered by synthetic As-spiked ferrihydrite (As-Fh) or As-spiked lepidocrocite (As-Lp) were inserted into an organic-rich wetland soil in non conventional columns system under anaerobic conditions. Slides were recovered after different periods of time to evaluate (i) the impact of (bio)reduction on both Fe-oxide dissolution and secondary mineral precipitation and, (ii) the subsequent effects on As mobility. The calculated Fe dissolution rates for As-Fh and As-Lp were 2.02 · 10− 9 and 1.92 · 10− 9 mol Fe m− 2 s− 1, respectively, and were higher than what has been commonly reported in laboratory studies. Important bacterial colonization and occurrence of biofilm suggest the presence of biologically mediated processes. The newly formed minerals were mostly composed of Fe-sulphides. Fe(II) complexation by organic molecules in solution likely prevented formation of secondary Fe(II, III)-rich minerals. The relative proportion of As(III) increased with time on the As-Fh slides, and was combined with a decrease of the Fe/As ratio, suggesting a partial adsorption of As(III) onto minerals. By contrast, for lepidocrocite, the Fe/As ratio increased, suggesting that As(III) was less readsorbed due the lower available site number and the deletion of As adsorption sites on the reduced lepidocrocite surface. Reduction and subsequent As sequestration appeared to result from a coupled biotic–abiotic reaction pathway in which Fe or As reducing-bacteria allowed the reduction of As(V) to As(III).

Mohamad Fakih , Xavier Châtellier *, Mélanie Davranche and Aline Dia Bacillus subtilis bacteria hinder the oxidation and hydrolysis of Fe2+ ions 2008

Bacteria are known to associate closely with secondary iron oxides in natural environments, but it is still unclear whether they catalyze their precipitation. Here, Fe2+ ions were progressively added to various concentrations of Bacillus subtilis bacteria in permanently oxic conditions while maintaining the pH at 6.5 by adding a NaOH solution at a monitored rate. The iron/bacteria precipitates were characterized by wet chemistry, SEM, and XRD. Abiotic syntheses produced nanolepidocrocite, and their kinetics displayed a strong autocatalytic effect. Biotic syntheses led to the formation of tiny and poorly crystallized particles at intermediate bacterial concentrations and to a complete inhibition of particle formation at high bacterial concentrations. The occurrence of the autocatalytic effect was delayed and its intensity was reduced. Both the oxidation and the hydrolysis of Fe2+ ions were hindered.

Mohamad Fakih, Mélanie Davranche, Aline Dia, Bernd Nowack, Patrice Petitjean, Xavier Châtellier and Gérard Gruau A new tool for in-situ monitoring of Fe-mobilization in soils’. Applied Geochemistry 2008

The aim of this study was to design and test a new tool for (i) the quantitative in situ monitoring of Fe(III) reduction in soils and (ii) the tracking of the potential mineralogical changes of Fe-oxides. The tool consists of small (2 × 2 × 0.2 cm) striated polymer plates coated with synthetic pure ferrihydrite or As-doped ferrihydrite (Fh–As). These slides were then inserted within two different horizons (organo-mineral and albic) located in a wetland soil with alternating redox conditions. Dissolution was quantified by X-ray fluorescence (XRF) analyses of total metal contents before and after insertion into the soil. The crystallographic evolution of Fe-oxides was characterized by scanning electron microscope equipped with an energy-dispersive spectrometer (SEM–EDS). Over the months, the ferrihydrite progressively disappeared, at rates comparable to those previously measured in laboratory studies, i.e. in the 1–10 × 10−12 mol Fe m−2 s−1 range. SEM observations indicate that the supports were highly colonized by bacteria and biofilms in the organo-mineral horizon, suggesting a biological-mediated process, while the albic horizon appeared to be characterized by a mostly chemical-mediated process. In the albic horizon, Fe-sulphide and other micro-precipitates were formed after 7 months of incubation in balance with a quasi dissolution of initial Fe-oxides.

Supervision 1 Supervised Student
Évaluation de la biodisponibilité des métaux dans l’eau de surface et les sédiments de la rivière Al-Ghadir (Mont-Liban)

Amale Mcheik

Le cycle biogéochimique des métaux traces a été fortement accéléré par les activités anthropiques qui ont entraîné une contamination des eaux et des sédiments des rivières. A la suite de leurs émissions, la majorité des métaux traces se trouvent sous forme particulaire qui se transportent par ruissellement et se retrouvent en milieu fluvial où elles sédimentent et dont une partie est susceptible d'être solubilisée vers la colonne d'eau suite aux modifications des conditions physico-chimiques du milieu et sous l'action des microorganismes autochtones et pouvant après interagir avec la chaîne alimentaire et présenter un danger potentiel de toxicité pour l'homme et pour les autres organismes vivants. Dans cette étude, nous avons choisit de travailler sur le site de la rivière Al-Ghadir qui présente un cas exceptionnel et original des pollutions où la hauteur de sédiments, comprenant plusieurs types de polluants, est plus qu'un mètre. L'objectif de cette thèse était de comprendre et d'évaluer le rôle du compartiment microbien dans les sédiments de la rivière Al-Ghadir, qui est la source la plus polluante de la méditerranéen, sur la mobilité des métaux et leurs effets sur les eaux souterraines. Cette étude était réalisée en deux séries d'expériences (Batch et colonne du sol) semblables aux situations se trouvant dans la rivière. Une caractérisation physico-chimique et chimique des sites d'étude a été effectuée comme première étape afin ensuite de débuter l'approche expérimentale qui a permis d'isoler les processus physico-chimiques de ceux qui sont imputables à l'activité microbiologique. Dans les expériences menées en réacteurs fermés (batchs), nous avons montré que les activités microbiennes sont corrélées aux fortes dissolutions des métaux, en particulier du Fe, Mn, Pb, Cu et Zn. Le fer semble apparaître comme l'élément le plus solubilisé et sa solubilisation était corrélée à celle d'autres métaux traces laissant supposer que ces métaux sont associés aux oxydes de fer. Cette hypothèse a été confirmée par les extractions séquentielles indiquant la présence de bactéries ferri-réductrices qui, lors de la fermentation du glucose et la production d'acides organiques, ont réduit les oxydes de fer. Ces derniers ont entraîné la dissolution des métaux traces et une modification des populations bactériennes qui ont été détectés par l'étude microbiologique et génétique après cinq jours d'incubation. L'effet des bactéries sur la mobilisation des métaux a été ensuite étudié selon des expériences portant sur l'étude hydrodynamique du transfert des métaux en colonnes de sédiments et dans des conditions proches à celles du terrain. Nous avons montré que (i): les métaux étudiés ne sont pas lixiviés dans les mêmes ordres et en règle générale montrent l'ordre suivant (en μg/l): Fe>Mn>Cd>Zn>Cu>Pb≥Cr ; (ii) les métaux vont se reprécipiter sur les phases néoformées après que le système regagne l'équilibre. Les études du profil de distribution des métaux dans les colonnes ont mis en évidence que les métaux ont été lixiviés des sédiments durant l'incubation de façon homogène. Cette répartition dépend de la hauteur du sédiment: la ré-distribution est maximale à la surface des sédiments (0-10 cm), alors qu'à une profondeur située entre 10 et 25 cm elle est nulle. Ce phénomène est expliqué par le fait que les métaux après avoir été solubilisés et passés en solution, ils seraient réadsorbés sur les phases électrochimiques négatives, néoformées et colloïdales ce qui explique la diminution de la concentration des métaux dans le lixiviat obtenu en laboratoire et permet de penser que ce mécanisme de piégeage des métaux dans la colonne limite la migration de ces derniers vers les eaux souterraines, tant que la capacité d'adsorption des colloïdes présents n'est pas atteinte et que le système soit en équilibre


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