The Lebanese economic crisis, financial crisis, and USD shortage were conducive to an increased drug addiction especially for students who feel that their future in Lebanon is not safe, as well as the psychological fragility of the Lebanese people, and the more permissive sociocultural context. Our study aimed to assess the addiction levels and profiles of university students in Lebanon, and thus to evaluate the rapid rising in dependence regarding smoking, alcohol, and illegal drug use during this crisis. This cross-sectional study was carried out between February and September 2020. A total of 467 participants (315 females, 152 males; Mage = 23.48 ± 6.03) were recruited through convenience sampling through several universities in Lebanon’s governorates. Participants received the online link to the survey. Students were divided into three clusters as follows: cluster 1, which corresponds to students with moderate addictions; cluster 2, which corresponds to students with high addictions; and cluster 3, which corresponds to students with low addictions. When comparing cluster 1 to cluster 3, the results of the multinomial regression showed that older age (aOR=1.08) and having a high monthly income compared to no income (aOR=2.78) were significantly associated with higher odds of being in cluster 1 compared to cluster 3. When comparing cluster 2 to cluster 3, the results of the multinomial regression showed that female gender (aOR=0.19) was significantly associated with lower odds of being in cluster 2 compared to cluster 3, whereas having a dead (aOR=16.38) or divorced parent (aOR=6.54) and having a low (aOR=3.93) or intermediate income compared to zero income (aOR=4.71) were significantly associated with higher odds of being in cluster 2 compared to cluster 3. The results of our study revealed a considerable prevalence of addiction to alcohol, illicit drugs, and specially to smoking, among Lebanese university students. These findings emphasize the need to implement firm policies and rules in an attempt to minimize the tendency of the young population to engage in such addictions.

Large-scale smelting activities release large amounts of potentially toxic elements (PTEs) in fine particles. These particles floating in the air eventually settle on leaves, roads, and even indoors. In smelting areas, indoor environments are generally considered relatively safe. However, these areas are not taken seriously and need to be assessed. This paper systematically studied pollution characteristics, main sources and health risks of ten potentially toxic elements, PTEs (Mn, Ni, Cu, Zn, Hg, Cd, As, Cr, Pb, and Tl), of dust samples from different indoor environments in smelting areas using various methods. Therefore, this study analyzed dust samples from 35 indoor environments. The enrichment factors showed that the indoor dust samples were extremely enriched by Cd and Cu and significantly enriched by Hg, Pb, As, and Zn. The result of the spatial distribution showed that the high-value PTEs were mainly distributed near the Cu smeltery. Three sources were quantitatively assigned for these PTEs, and they were industrial smelting and traffic activities (44.40%), coal-fired activities (18.11%), and natural existence (37.49%). Based on the calculation of health risk, the value of THI for children was 7.57, indicating a significant non-carcinogenic risk. For carcinogenic risk, the values of TCR for children and adults were 2.91×10⁻² and 2.97×10⁻³, respectively, which were much higher than the acceptable risk value 1×10⁻⁴. Combining health risk assessment with source discrimination, we found that the industrial discharges and traffic activities were the most main source of non-cancer and cancer risks. Therefore, smelting activities should be more strictly monitored, and traffic emission management should be strengthened.

This research aims to investigate the effect of copper doping on the photocatalysis performance of TiO₂ nanoparticles for disposal wastewater from organic pollutants. X-ray diffraction analysis manifests the crystallization of a rutile phase for pure and copper-doped TiO₂ except for 2% resulting in a rutile-to-anatase phase transformation. The crystallite size is found less affected by Cu doping, i.e., ~30 nm. BET analysis indicates a decrease in the specific surface area as the doping loading increases. Scanning electron microscopy observations reveal spherical particles at the nanometer range for pure TiO₂ and then larger agglomerates of ultrafine particles with Cu doping. FTIR analysis notifies the existence of hydroxyl groups, which will promote the photocatalysis process. The photodegradation of azucryl red (AR) has been investigated under different conditions; i.e., Cu-loading, initial concentration of AR, and pH. The kinetics of the photodegradation process is further found to comply with the Lagergren kinetic law, regardless the experimental conditions. Nevertheless, the photodegradation process is not only controlled by the intra-particle diffusion mechanism, but also by mass transfer through a liquid film boundary. The maximum degradation of AR, i.e., 86%, has been achieved at pH = 5.0 during 60 min of contact time for the 2% Cu doping, with effective regeneration. The Freundlich model exhibits a better fitting for AR dye photodegradation equilibrium data, compared to Langmuir, Temkin, and Dubinin-Radushkevich.

A wide variety of methods have been applied in indoor air to reduce the microbial load and reduce the transmission rate of acute respiratory diseases to personnel in healthcare sittings. In recent months, with the occurrence of COVID-19 pandemic, the role of portable ventilation systems in reducing the load of virus in indoor air has received much attention. The present study delineates a comprehensive up-to-date overview of the available photocatalysis technologies that have been applied for inactivating and removing airborne viruses. The detection methods for identifying viral particles in air and the main mechanisms involving in virus inactivation during photocatalysis are described and discussed. The photocatalytic processes could effectively decrease the load of viruses in indoor air. However, a constant viral model may not be generalizable to other airborne viruses. In photocatalytic processes, temperature and humidity play a distinct role in the inactivation of viruses through changing photocatalytic rate. The main mechanisms for inactivation of airborne viruses in the photocatalytic processes included chemical oxidation by the reactive oxygen species (ROS), the toxicity of metal ions released from metal-containing photocatalysts, and morphological damage of viruses.

The article presents the possibility of recovering nickel from waste produced as a result of wastewater neutralization during the electrochemical surface treatment of metals. Leaching the sludge with concentrated hydrochloric acid enabled the metals contained in the sludge from precipitate to the solution with the efficiency of 74.4% (Se) to 100% (Zn). The content of elements was determined using the ICP-OES method. The next step was the precipitation of metals from the obtained solution using various reagents. The precipitating reagents used were 0.5 M sodium hydroxide solution, 0.5 M sodium sulphide solution and 1% dimethylglyoxime solution. Selective precipitation made it possible to obtain nickel concentrates with the content of nickel ranging from 15.3 to 98.2% for the first two methods, whereas in the case of the third method based on a dimethylglyoxime solution, the obtained nickel concentrate purity was 94.3%. The process of leaching nickel-dimethylglyoxime complex (Ni-DMG) with sulphuric acid and crystallization enabled obtaining 99.4% purity nickel sulphate, which can be reused in the nickel plating of selected metals. The research shows that waste generated in the process of neutralization of wastewater from electroplating plants is a potentially important source of recycled nickel concentrates.

Polyvinylidene fluoride (PVDF) blended with varying concentrations of titanium nanotubes (TNT) was electrospun to result in a nanocomposite filter media. Sandwich structures were obtained by depositing the electrospun fibers between polypropylene (PP) nonwoven sheets. The synthesized tubular TNT was confirmed for its morphology through a transmission electron microscope (TEM). The prepared filter media was analyzed through a scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The effectiveness of the filter media was evaluated through the zone of inhibition and antibacterial activity against E. coli and S. aureus. The Box-Behnken design is experimented with three-level variables, namely areal density of substrate (GSM), electrospinning time (hours), and concentration of TNT (wt%) for investigating the bacterial filtration efficiency through an Andersen sampler. Among other statistical tests (STATs), PVDF + 15 wt% TNT has a bacterial filtration efficiency of 99.88% providing greater potentials upon application for clean air management. It can be noted that the future application of this formulation could be efficient filtration of other microbes and could be used in facemasks to industrial-scale air filters. Graphical abstract

This work describes a special case of pollution potential assessment applied to an abandoned sulfide tailings impoundment located in the Riotinto mining district (Huelva), near the Tinto River. Three overlapping levels of discharged tailings were recognized in the impoundment, from deeper to upper: pale yellow to white, red, and brownish-yellow. Mineralogical, physical, and chemical characteristics of tailings, water leachates, water, and sulfate efflorescent salts were analyzed. The total toxic element content and the leachate concentration were respectively used to calculate two indices that support potential toxicity assessment: the Index of Contamination (IC) and the Hazard Average Ratio (HAQ). According to the IC values, all tailings samples showed a high potential for contaminating soils and sediments, especially the intermediate tailings with up to As (8.6 g kg⁻¹), Pb (14.8 g kg⁻¹), and Cu (1 g kg⁻¹). Deeper tailings leachate was extremely saline and acidic, with a very high concentration of sulfates and toxic elements, exceeding the values: 2600, 980, 30, and 17 mg L⁻¹ for SO₄, Fe, Al, and Cu, respectively. For this reason, these deeper tailings were linked to the saline and acid seepage, and also to the sulfate acid efflorescences formed at the dike toe. In conclusion, the studied abandoned tailings impoundment is related with a high likelihood of polluting the environment, represented by very high IC and HAQ values. However, when the Tinto River is considered the receiving water body, the severity of the potential contamination must be judged as very low.

Urban planners require an understanding of the composition as well as the spatial distribution of household solid waste (HSW) components to design policies for various wards of a city. This paper aims to study the composition as well as the spatial dependency of the HSW components generated by the wards forming Annaba city in Algeria. The results of the HSW composition have revealed the high content of the organic matters which represents 50%, the textiles with 13.6%, and the plastics with 10% of the total quantity; the rest of the composition was 5.9% of paper and paperboard, 3% of metals, and 1% of glass. Furthermore, the result of the global and the local Moran indexes calculated and mapped through the ArcGIS 10.7 software shows that there is an evident spatial dependency for almost all the HSW components. Thus, 18% of the total quantity is produced by clustered wards, which propose the segregation of individual waste components at the source as an efficient way to support the reuse, recovery, and recycling. The greenhouse gas (GHG) emissions have revealed that 60% of the emissions are the methane produced from the landfill, and 30% is due to the open burning in the air of waste.

The Air Quality Health Index (AQHI) is an aggregate indicator of air pollution used to communicate to Canadians the health impact of short-term exposure to current air pollutant levels. Understanding the stochastic behaviour of the AQHI can aid public health officials in predicting air pollution levels, determining the likelihood and duration of air quality advisories, and planning for increased strain on the health care system during periods of higher air pollution. Previous research has applied discrete-time Markov chains to investigate stochastic behaviour of air pollution indices but only in a handful of regions and none with the same climatic characteristics as Canadian regions. In this study, we investigated the stochastic behaviour of AQHI risk categories in Ontario (34 air monitoring stations) for 5 years from 2015 to 2019. We employed discrete-time Markov chains using three of the AQHI risk categories (Low Risk, Moderate Risk, High Risk) as states to determine (1) the transition probabilities between these states, (2) the long-run proportion of time spent in each state, and (3) the mean persistence time of each state. These results were then used to assess spatial trends in the stochastic behaviour of AQHI risk categories and the likelihood and duration of air quality advisories. Overall, the air quality (as characterised by the AQHI) in Ontario tends to decrease as population density increases. Urban areas spent a greater proportion of time in higher risk categories, and tended to remain in the higher risk categories for longer before transitioning.

Laundry wastewater has a high amount of dirt from the washed items and chemical additives used in washing process. Aiming the primary treatment of this type of wastewater, three different natural coagulants (Tanfloc POP, Tanfloc SL, and Tanfloc SG) were evaluated in the removal of color and turbidity by the coagulation/flocculation/sedimentation process (C/F/S). The results showed that the time between 5 and 10 min was sufficient for the sedimentation of the flakes, with a time of 10 min being adopted for further studies. The statistical analysis and the cost of acquiring the coagulant were decisive in the selection of the best natural coagulant. The maximum values of color (88.7%) and turbidity (92.8%) removal efficiency occurred at a concentration of 120 mg L⁻¹ (concentration determined by the Fischer LSD test) and the lowest cost (0.75$) obtained for the Tanfloc POP coagulant. The volume of sludge generated was higher in the treated effluent sample compared to the control sample, which proves the removal of total solids present in the effluent. The Tanfloc POP coagulant showed a high performance in removing color and turbidity from industrial laundry wastewater; it has been as a promising coagulant in the primary treatment of wastewater in this service sector.