Le bassin versant du Narh Ibrahim est classé parmi les sites du patrimoine mondial. Les rejets sauvages solides et liquides ont un impact important sur le développement d’une contamination bactériologique tout au long de la rivière. Dans cette étude, des paramètres physico-chimiques et bactériologiques ont été suivis sur neuf sites de prélèvement qui couvrent la rivière Nahr Ibrahim de son amont jusqu’à son estuaire. L’ensemble des paramètres est étudié pendant des périodes de l’année caractérisées par un temps sec ou un temps de crue. Au cours de ces périodes, ces paramètres ont révélé une influence importante du type d’occupation des sols et des phénomènes de lessivage sur la composition bactériologique de la rivière. L’origine et le degré de la contamination bactérienne instantanée ont été également identifiés. Une approche statistique multivariée a montré que l’effet de la localisation du site masque l’effet date sur un même site et pendant la même période. Les sites en aval de la rivière sont caractérisés par une pollution en nitrate et une contamination bactériologique alors que les sites en amont sont marqués par une contamination bactériologique seulement.

The chemical composition of Lebanese Hypericum scabrum essential oil (EO) was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GG-MS). Its antimicrobial activity was evaluated by determining its minimal inhibitory concentrations (MICs) against a Gram-negative and a Gram-positive bacterium, one yeast, and five dermatophytes. H. scabrum EO was most active on filamentous fungi (MIC values of 32–64 µg/mL). Synergy within the oil was investigated by testing each of the following major components on Trichophyton rubrum: α-pinene, limonene, myrcene, β-pinene and nonane, as well as a reconstructed EO. The antifungal activity of the natural oil could not be reached, meaning that its activity might be due, in part, to minor constituent(s). The interactions between H. scabrum EO and commercially available antifungals were assessed by the checkerboard test. A synergistic effect was revealed in the combination of the EO with amphotericin B.

Origanum ehrenbergii Boiss., an endemic plant to Lebanon, is widely acknowledged in Lebanese traditional medicine. The aim of the present study was to evaluate the influence of the drying method, region, and time of harvest on yield and chemical composition of O. ehrenbergii essential oils (EOs). Plants were harvested monthly throughout 2013 and 2014, from two different regions, Aabadiye and Qartaba, then dried using two drying methods: lyophilization and shade-drying at 4 °C. EO was extracted by hydrodistillation and analyzed by GC/MS. GC-MS data, combined with independent component analysis (ICA) and common component and specific weight analysis (CCSWA), showed that drying techniques, region of harvest, and soil composition have no effect on the chemical composition of O. ehrenbergii EOs. Of the factors analyzed, only harvesting time affected the EO composition of this species. High and stable amounts of carvacrol, associated with reliable antimicrobial activities, were detected in material harvested between March and October. EOs obtained from plants harvested in Aabadiye in January and February showed high amounts of thymoquinone, related to anti-inflammatory and cytotoxic effects. The use of ICA and CCSWA was proven to be efficient, and allowed the development of a discriminant model for the classification of O. ehrenbergii chemotype and the determination of the best harvesting time.

To valorize olive stones, this study focuses on the composition of their dilute-acid hydrolysate DAH and aims to highlight the effect of the overliming process to achieve an effective treatment that maximizes sugar concentrations while minimizing the number of toxic materials. The study examined the impact of pH (10 and 12), temperature (25 and 60 °C), and detoxification time (15, 30, and 60 min) on the viability and vitality of M. pulcherrima and S. cerevisiae, using an experimental design of 2²3¹. Detoxification was significantly influenced by pH and temperature, with xylose and furans probably following the same kinetic degradation. Viability improved to 52% for M. pulcherrima and 67% for S. cerevisiae in detoxified hydrolysate due to reduced toxic compounds. Optimal conditions were found to be a pH of 10 at 25 °C for 30 min, achieving 71% and 62% degradation of hydroxymethylfurfural and furfural, respectively, with a minimum polyphenol concentration of 580 mg·L⁻¹. M. pulcherima exhibited greater vitality than S. cerevisiae because of the medium’s high xylose content and low glucose concentration. Conversely, pH 12 not only promoted sugar (xylose) loss but also generated new toxic compounds that negatively affected yeast development. To improve fermentation, further attention needs to be paid to these conditions.

Monitoring surface water quality offers a clear understanding of its parameters over time and space. The Ibrahim River, one of the main rivers in Lebanon, was monitored over one hydrological year, from March 2021 to April 2022. Samples were collected from seven stations in the watershed, once every two weeks. A total of 504 samples were then analyzed for pH, conductivity, turbidity, total dissolved solids, dissolved oxygen, biochemical oxygen demand, dissolved nitrate, dissolved potassium, dissolved chloride, total alkalinity, fecal coliforms, and total coliforms. Principal Component Analysis (PCA) was able to highlight two principal components (PCs), representing spatial and temporal variations, identifying areas of pollution and the influence of flow on water quality. The adapted Water Quality Index (WQI) confirmed the PCA trend with an overall average for the entire watershed of 83.70 ± 4.97, indicating a “good” water quality.