Environmental Studies

Description of Subtheme:

Environmental Protection Act (1986) defined “Environment as the sum total of water, air and land, their interrelationships between themselves and with human beings, other living beings, and property”. One of the most important disciplines included in environmental studies is the environmental science which is the scientific study of environmental system (air, water, soil, and Land) including any changes and damages that result from human interaction with the environment. Human activities are polluting natural resources worldwide. Lebanon, like other countries in the region, is suffering from a major pollution crisis that affects both its aquatic and land resources. Understanding the scientific basis of our environmental science is vital to find solutions to these problems to protect the environment and then preserve our nature.

Research topics are centered around the following topics:

• Environmental and anthropogenic effects on radiocarbon distribution in Lebanon.
• Occurrence and levels of pesticides in Lebanon's water.
• Decolorization of synthetic dyes by bacteria.
• Biocontrol of plant pathogens.
• Environmental factors that affect the microbial degradation of phenol.
• Design of new azo compounds to detect and capture carbon dioxide from air.
• Treatment of pharmaceuticals from water using macrocycles
• Environmental protection exploring natural resources
• Environmental Microbiology and Bioremediation
• Design, synthesis, and physic-chemical characterization of macrocyclic ligands that have biological and environmental applications.
• Encapsulation of azophenolic compounds in a drug carrier macrocycle to be used as a food preservative.

Prominent Research:

• Detection of ciprofloxacin residues in milk by sensitive and rapid methods is of great interest due to its use in the treatment of dairy livestock health. Current analytical approaches to antibiotic detection are laboratory-based methods, and they are time-consuming and require trained personnel. We were able to detect the presence of ciprofloxacin in a diluted milk sample without any pretreatment using an assay based on the fluorescence polarization principle. The developed assay allows for the detection of ciprofloxacin at a concentration of 1ppb, which represents an amount lower than the maximum residual limit (MRL) of ciprofloxacin in milk, as defined by the European Union regulation (100 ppb).
• Among the seven bacterial strains isolated from marine samples, Staphylococcus epidermidis represented a promising isolate for biocement production. It was identified biochemically and genotypically. Technically, the biocement produced successfully packed the clay particles tightly and decreased their porosity considerably, leading to increased clay water retention capacity (WRC) compared to the control. Moreover, the compressive pressure resistance of the prepared biocement blocks containing Staphylococcus epidermidis suspension increased regularly along 28 days of solidification.
• Water Hyacinth Biochar (WHB) was produced by pyrolysis at 900°C. The results indicate that WHB has oxygen reduction reaction (ORR) catalytic activity. The ORR catalytic activity of WHB is attributed to its physical and chemical surface properties. The maximum power density produced from an air cathode single chamber microbial fuel cell (ACSC-MFC) with WHB as the ORR catalyst versus the Pt/C catalyst were 24.7 and 12.3 mWm−2, respectively. This study demonstrated that water hyacinth biochar can be used as an inexpensive catalyst for ORR in microbial fuel cells.
• Safe, accessible and good quality water are essential characteristics to reduce various waterborne diseases. Since domestic water is the most consumed water by Lebanese people, cleaning domestic water tanks is important to prevent their exposure to pathogenic microorganisms. Generally, all stages of the value chain of the Lebanese water sector are still imperfect. Thus, the domestic water should be regularly tested, especially in the impoverished landmarks where water quality is the worst. The aim of this study was to evaluate the physicochemical parameters and microbiological quality of the water in the storage tanks of homes in Sidon, Lebanon. The total coliform, fecal coliform, and Escherichia coli contaminate was 54%, 20%, and 16% in each of the samples, respectively. Other bacteria isolated from household water included intestinal Enterococcus faecalis (68%), Staphylococcus aureus (68%), and Pseudomonas aeruginosa (22%). The bacterial isolates showed a prevalence of resistance and intermediate resistance against the tested antibiotic agents. Multi-resistant Staphylococcus aureus (MRSA) was detected in 21% of the collected S. aureus, using cefoxitin agent and mecA gene detection. The prevalence of virulence genes was also observed in both P. aeruginosa and S. aureus. Our data show that Sidon domestic water is not suitable for drinking or home applications.
• A newly synthesized upper rim azocalix[4]arene, namely 5,11,17,23-tetra[(4-ethylacetoxyphenyl) (azo)]calix[4]arene, CA-AZ has been fully characterized and its chromogenic and selective properties for anions are reported. Among the univalent anions, the receptor is selective for the fluoride anion, and its mode of interaction in solution is discussed. The kinetics of the complexation process were found to be very fast as reflected in the immediate colour change observed with a naked eye resulting from the receptor–anion interaction. An emphasis is made about the relevance in selecting a solvent in which the formulation of the process is representative of the events taking place in the solution. The composition of the fluoride complex investigated using UV/vis spectrophotometry, conductance measurements, and titration calorimetry was 1:1, and the thermodynamics of the complexation of anions and CA-AZ in DMSO were determined. The fluoride complex salt was isolated, and a detailed investigation was carried out to assess its ability to remove CO2 from the air. Recycling of the complex was easily achieved.
• The optimal conditions for the extraction of aspirin from water by the modified silicate material were determined as a function of the mass of the extracting agent and the pH of the aqueous solution. The optimum mass was found to be 0.08–0.10 g with 99.9% removal of aspirin. The maximum extraction of aspirin by the material was observed at pH 4. The kinetics, removal capacity, and recycling capacity of the material were investigated. The results indicate that (i) the process is fast, (ii) the removal capacity for the drug is greater than that of previously reported materials, and (iii)the modified silicate can be easily recycled. These data, along with the low cost involved in the production of the material, led to the conclusion that the modified silicate has the required potential for industrial use. Molecular simulation calculations suggest that one unit of aspirin interacts with one unit of the modified silicate L1 through hydrogen bond formation between the amine functional group of the silicate and the oxygen donor atoms of aspirin.