The Beirut port explosion in 2020 released a huge amount of chemicals including ammonium nitrate, however, the long-term effects of the explosion on air quality and public health remain unclear. In ...this study, particulate matter (PM_(10)) samples were collected in Beirut, Lebanon 1 month and 3 months after the explosion. The average concentrations of main anions measured in 2020 (one and three months after the explosion) were compared with those in 2009-2015 by calculating the percentage of difference, and the average concentrations of cations and anions in September (one month after the explosion) and November (three months after the explosion) 2020 were also compared to identify any abnormal values, indicating insignificant effects on the post-explosion PM in terms of component concentrations. That is, PM and gases directly induced by the explosion might be subject to rapid atmospheric transport and deposition. Hence, the results imply that investigations of the chemical contaminations in soil and water are urgently needed. Long-term monitoring is necessary to avoid subsequent air pollution caused by possible particle resuspension. The continuous demolition and reconstruction after the explosion are possibly the main long-term effect of the Beirut port explosion, causing an elevated concentration of PM_(2.5) at ground level 400% higher than the recommended concentrations (15 μg m^(-3) for 24-hour mean). Protective measures must be taken to reduce the exposure risks by controlling the PM release from demolition and construction, traffic, and diesel generators. The cancer risk in Beirut based on PAHs measurements in 2021 was also estimated and discussed.
Four sesquiterpene lactones were isolated from
Achillea falcata, through bioassay-guided fractionation, based on their differential ability to affect HaCaT cell growth. Identified ...seco-tanapartholides: 3-β-methoxy-iso-seco-tanapartholide (
1), tanaphillin (
2), iso-seco-tanapartholide (
3), and 8-hydroxy-3-methoxy-iso-seco-tanaparatholide (
4) were found to differentially decrease keratinocyte cell viability. In addition, the stereoselectivity, lipophilicity, and number and position of hydroxyl groups present in these compounds were correlated with their biological activities for HaCaT cell growth inhibition. Statistical analyses confirmed an enhanced potency of the β-OH iso-seco-tanapartholide over the α:β-OH diastereoisomeric mixture. The highest potency, however, was mainly the function of the enhanced lipophilicity of the molecule.
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50 values of four seco-tanapartholides differing in chemical properties and number and position of substituents showed that 3-β-methoxy-iso-seco-tanapartholide most potently inhibits keratinocyte cell proliferation due to its enhanced lipophilicity.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Ambient air pollution is a major risk to the human health and to the environment. The data presented quantifies the (PM10) contribution of the Zouk Mikael power plant to the ambient air pollution in ...Lebanon for the year 2014. The data is the outcome of a computer simulation using The Air Pollution Model (TAPM), taking into account the emission source data, the spatio-temporal meteorological conditions, the terrain height, and the land cover characteristics. The data set presents the annual, seasonal and monthly averages of the spatial distribution of the ground-level particulate (PM10) concentrations in the ambient air. The data set also includes spatial distribution of the maximum concentrations, which revealed two zones of elevated concentrations. Monthly averages and maximum concentrations in these two zones are also reported. Analysis of the data can provide information on the health risk the residents in the affected areas are subjected to. The data can also provide insight on the impact of the meteorological conditions (temperature and velocity) and the topography on pollutant dispersion in regions bounded by the sea and by a mountain range.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lower carbonyl concentrations were measured for the first time in two different sampling sites (American University of Beirut (AUB) and Abdel-Aziz (AA)) in Beirut, Lebanon. Formaldehyde (C1) and ...acetaldehyde (C2) were the most abundant carbonyls with respective maximum concentrations of 12.2 and 5.2
ppbv at AUB and 8.6 and 5.1
ppbv at AA. Diurnal variations of carbonyls exhibited similar behaviors, suggesting related formation and decomposition routes. Morning levels of carbonyls were either equal or higher than the ones in the afternoon at the coastal site (AUB) due to atmospheric dilution. However, morning levels were mostly lower than noon levels at a three-busy street intersection (AA) due to the enhancement of photochemical activities. Vehicle emissions constituted the dominant source of carbonyls measured as confirmed by the good correlation between C1, C2 and propanal (C3) and the C1/CO and C2/CO ratios in the mornings. Seasonal variation showed the predominance of summertime photolysis and photo-oxidation reactions of aldehydes. Based on the measured formaldehyde levels, ozone and nitrous acid concentrations, morning and afternoon OH radical fluxes are computed and consequently their contribution to photochemical smog processes are assessed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Particle size distribution at major on-road, roadside, and university-ground sites in Lebanon were studied in summer 2011. In a predominant old traffic fleet, it is shown that calculated PM2.5 mass ...emission factors (EFs) conform to those of heavy duty vehicles. When compared to roads in California, higher PM2.5 mass but similar particle number EFs are obtained for the average fleet of the on-road sites. This confirms the observed particle size distribution pattern, rich in particles in the accumulation range mainly between 0.425 and 0.675 µm with a prevalent peak at 0.475 µm. Corresponding total particle counts (TC) measured on the roadside are as high as 14,050 particles/cm
3
and are up to 67% higher than particle counts measured at the university-ground site. In a hot, dry and humid summer weather with consistent temperature oscillations, particle dispersion is shown to be a function of meteorological factors, mainly the effect of the boundary-layer thickness, with particle counts measured during the morning being around 40% higher than particle counts measured during the afternoon.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
Propylene glycol (PG) and vegetable glycerin (VG) are common ingredients used in the preparation of various products, and notably in e-cigarette liquids. In this work, we investigated the generation ...of light gases from the pyrolysis of PG, VG and their mixtures. ReaxFF-MD was used to study the elementary reactions involved in the pyrolysis of PG/VG mixtures of 50/50 and 30/70 percent by volume. Main reactions included dehydration, dehydrogenation and C-C bond cleavage. In addition, we focused on the elementary reactions that form the light gases: C2 hydrocarbons, CO, CO2, and H2. Kinetic rates of PG and VG decomposition, and the Arrhenius parameters, were calculated, with errors as low as 1% with respect to pure PG and VG kinetic rate constants. Furthermore, experimental results were obtained by conducting pyrolysis experiments on PG, VG and their mixtures, in a continuous flow tube reactor at reaction temperatures ranging between 550°C and 850°C. The main gas products were predominantly CO, CH4, C2H4, in addition to C2H6, C2H2, H2, and CO2. Gas product concentrations increased with temperature except for ethane, which underwent further decomposition, as expected from the elementary reactions. Liquid mixtures proved to produce more products due to reactions taking place between the different pyrolysis products obtained from PG and VG, as shown by ReaxFF-MD simulations.
•Pyrolysis of PG/VG mixtures were studied using MD simulations and experiments.•Elementary reactions in ReaxFF-MD gave methane, C2 hydrocarbons, CO, CO2 and H2•CO, CH4, and C2H4 were the most significant products during experiments.•C2H6, C2H2, H2, and CO2 were detected but at low concentrations.•Kinetic rates of PG/VG mixtures decompositions were comparable to pure liquids.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The antitumor activity of extracts of Centaurea ainetensis (C. ainetensis), a plant endemic to Lebanon, was investigated in human colon carcinoma cells. At concentrations that were non-cytotoxic to ...normal human intestinal epithelial cells, the crude extract inhibited the proliferation of a host of colon-derived cancer cells. The crude extract effect was then investigated in HCT-116 (p53+/+) cells, most sensitive to treatment and was found to cause apoptosis, increase the Bax/Bcl-2 ratio, p53 and p21 protein levels and reduce cyclin B1 proteins. In vivo, the crude extract injected intraperitoneally before the subcutaneous injection of the carcinogen 1,2-dimethylhydrazine, drastically reduced the number of tumors and decreased the mean size of aberrant crypt foci. Further bioassay-guided fractionation of the crude extract resulted in the identification of the bioactive molecule Salograviolide A, a Sesquiterpene Lactone, to which the growth inhibition in colon cancer was linked. Salograviolide A, at non-cytotoxic concentrations to normal human intestinal cells, reduced the growth of colon cancer cell lines. Salograviolide A induced growth inhibition and resulted in an increased preG1 phase and presumably apoptosis induction which was further confirmed by TUNEL. These data support the testing of the C. ainetensis extract and its bioactive molecule, Salograviolide A, in colon cancer treatment.
A sesquiterpene lactone 1-β,10-Epoxy-6-hydroxy-1,10H-inunolide (K100) was isolated through “bioassay-guided fractionation” from Cota palaestina subsp. syriaca, an Eastern Mediterranean endemic plant. ...K100 inhibited endotoxin- (ET-) induced proinflammatory markers: IL-6, MMP-9, and NO in normal mouse mammary SCp2 Cells. Molecular docking in silico suggested that K100, having highly analogous structure as parthenolide (PTL), an anticancer compound, could bind PTL target proteins at similar positions and with comparable binding affinities. Both compounds, K100 and PTL, inhibited the proliferation and prolonged the S-phase of the cell cycle of breast adenocarcinoma MDA-MB-231 cells grown in 2D cultures. Noncytotoxic concentrations of K100 and PTL decreased the proliferation rate of MDA-MB-231 and shifted their morphology from stellate to spherical colonies in 3D cultures. This was accompanied with a significant increase in the amount of small colonies and a decrease in the amount of large colonies. Moreover, K100 and PTL decreased cellular motility and invasiveness of MDA-MB-231 cells. In summary, these results suggest that K100 exhibits PTL-analogous anti-inflammatory, cytostatic, and antimetastatic effects.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK, VSZLJ
Reports on the levels and sources of PAHs in the Middle Eastern region are very scarce and mostly outdated. This study reports for the first time the ambient levels of PAHs during summer and winter ...at three coastal locations in Lebanon. Comparison between PAH levels in the three locations is established and the contribution of major emission sources to PAHs is evaluated.
Gas and particle phase PAHs were collected using a high-volume sampler fitted with a quartz filter and a polyurethane foam (PUF) holder at three coastal sites (American University of Beirut, Dora, and Zouk Mikael). The collected PAHs were then extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). The dispersion of pollutants in the emissions from a local power plant was evaluated using The Air Pollution Model (TAPM), coupled with field measurements to quantify the BaP level in two nearby locations and one background location. One-way ANOVA tests and coefficients of divergence (COD) between paired sites were used for data analysis.
High heterogeneity was detected in the temporal and spatial variations of the PAH profiles and concentrations at the three coastal urban sites. Higher PAH levels were measured in winter than in summer at AUB and Dora, but not at Zouk Mikael. Major sources of pollution were identified as traffic, diesel engines, road dust, and oil fuel. Diesel engines are used as local sources of electricity during rotating blackout and oil fuel are used to run the inadequately maintained local power plant. The BaP levels measured near the power plant were approximately 10 times higher than those at the background site.
The annual average BaP concentrations of 2.07 ng m−3 and 2.9 ng m−3 at Zouk Mikael and Dora, respectively, exceeded the European Union (EU) air quality standard of 1 ng m−3. Owing to the lax governmental regulations, the BaP levels in Lebanon are higher by 60%–99% than those in most cities around the world.
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•PAH levels at 3 coastal urban sites demonstrated statistically significant intratemporal and inter-spatial differences.•All three sites did not follow similar seasonal trend variations.•BaP concentrations of 2.07 and 2.9 ng m−3 in Zouk Mikael and Dora, respectively, exceeded the EU air quality standard.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Many of the best-selling anticancer drugs are plant-derived. We tested for the anticancer properties of extracts isolated from Centaurea ainetensis, a plant species endemic to Lebanon and which is ...often used in folk medicine. We performed bioassay-guided fractionation of Centaurea ainetensis extracts using a panel of normal and neoplastic murine cells to identify a component that is associated with antitumor activities. Among several compounds that were fractionated, the sesquiterpene lactone, Salograviolide A, was identified and found to exert the most significant growth inhibitory effects on neoplastic cells. At concentrations that were non-cytotoxic to primary keratinocytes, Centaurea ainetensis crude extract and Salograviolide A preferentially inhibited the proliferation of papilloma and squamous cell carcinoma (SCC) cell lines without significantly affecting the growth of normal cells. Flow cytometric analysis of DNA content indicated that the inhibition of cell proliferation by Centaurea ainetensis crude extract and Salograviolide A was due to G0/G1 cell cycle arrest and increased pre-G0/G1, respectively. The increase in pre-G0/G1, and presumably apoptosis induction, in Salograviolide A-treated keratinocytes was confirmed by DNA Hoechst staining. Western blot analysis and electrophoretic mobility shift assay showed that both the crude extract and the isolated molecule differentially modulated key cell cycle and apoptotic regulators as well as NF-kappaB signaling. Salograviolide A-induced growth inhibition in neoplastic cells was mediated by the accumulation of reactive oxygen species (ROS) highlighting a potent oxidant role of this molecule. These studies suggest the potential therapeutic effects of Centaurea ainetensis, and its component, Salograviolide A, against epidermal squamous cell carcinogenesis.
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