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Purpose Municipal sewage sludge generated from three operational wastewater treatment plants, located in the Bekaa valley of Lebanon, was assessed for its potential use as agricultural soil amendment. Methods Sludge samples were taken from three treatment plants located in the villages of Iaat, Ablah and Joub Jannine during the summer season of 2018, from June to September, on a monthly basis. The evaluation was based on characterizing the physicochemical parameters such as the metal content, the pathogenic microorganisms (Salmonella, E.Coli, Staphylococcus aureus, Helminth eggs, Ascaris, Acinetobacter) and the phytotoxicity-stability indicators of the sludge samples. Results The obtained results were compared to the Lebanese guidelines for sludge reuse in agriculture. For the physicochemical analysis, all the samples showed a possibility to be used in agriculture due to the high content of minerals and organic matter. Considering the metal content of sludge, Iaat and Ablah sludge were classified as Class A according to the Lebanese guidelines; however, sludge from Joub Janine was classified as B due to its high content of zinc that exceeded the limit of 700 ppm. Helminth eggs and Salmonella were absent in the sludge samples. Pathogenic organisms, mainly E. coli, were detected in Iaat dry sludge, Staphylococcus aureus was present in Joub Jannine sludge and Acinetobacter in Ablah station (> 100 CFU/100 g). Conclusion It is recommended to submit the sludge which did not meet the required criteria, for further treatments, particularly the composting process to reduce the metal content and pathogenic microorganisms for a safer reuse in agriculture.

The use of polluted water to irrigate is an increasing problem in the developing world. Lebanon is a case in point, with heavily polluted irrigation waters, particularly in the Litani River Basin. This study evaluated the potential health risks of irrigating vegetables (radishes, parsley, onions, and lettuce) using three water sources (groundwater, river water, and treated wastewater) and three irrigation methods (drip, sprinkler, and surface) over two growing seasons in 2019 and 2020. Water, crop, and soil samples were analyzed for physicochemical parameters, pathogens, and metals (Cu, Cd, Ni, Cr, and Zn). In addition, the bioaccumulation factor, estimated dietary intakes, health risk index, and target hazard quotients were calculated to assess the health risk associated with metal contamination. The study showed that, for water with less than 2 log E. coli CFU/100 mL, no pathogens (Escherichia coli, salmonella, parasite eggs) were detected in irrigated vegetables, irrespective of the irrigation method. With over 2 log E. coli CFU/100 mL in the water, 8.33% of the sprinkler-and surface-irrigated vegetables, and 2.78% of the drip-irrigated root crops (radishes and onions), showed some degree of parasitic contamination. E. coli appeared only on root crops when irrigated with water having over 3 log CFU/100 mL. The concentrations of most metals were significantly lower than the safe limits of the FAO/WHO of the Food Standards Programme Codex, except for zinc and chromium. The trends in the bioaccumulation factor and the estimated dietary intakes of metals were in the order of Cu < Cd < Ni < Cr < Zn. The target hazard quotient values for all metals were lower than 1.0. Under trial conditions, the adoption of drip irrigation with water with less than 3 log E. coli CFU/100 mL proved to be safe, even for vegetables consumed raw, except for root crops such as onions and radishes that should not be irrigated with water having over 2 log E. coli CFU/100 mL. Treated wastewater had no adverse effect on vegetable quality compared to vegetables irrigated with other water sources. These results support efforts to update the Lebanese standards for water reuse in agriculture; standards proposed in 2011 by the FAO, and currently being reviewed by the Lebanese Institution of Standards. This research will inform a sustainable water management policy aimed at protecting the Litani River watershed by monitoring water quality.

Biomonitoring airborne pollution has been a widespread practice. Its advantages make it an alternative to costly technological techniques. In this context, a rare species "Urginea maritima" was tested to measure the changes surrounding Bentael natural reserve in Lebanon, triggered by the inauguration of a new road on its south side, and revealed alarming results through two years study (2015-2016). Three environmental indicators were evaluated: Air Pollution Tolerance Index, Total Antioxidant Capacity and leaf Relative Water Content. These factors showed the escalated evolution of the air pollution during the studied months. In addition, six parameters, separated between pollution markers and scavengers, were studied: hydrogen peroxide, pheophytin, proline, ascorbic acid, carotenoids and total phenolic compounds showed a gradual and sharp increase. The passive biomonitoring with plants confirmed to be a reliable method to evaluate airborne pollution effects which will expose new extent to establish a routine monitoring program in Lebanon.

The Turkey oak is a frequent tree species in the Mediterranean climate zones of southern Europe and Asia Minor. It has been used in the human diet, for medicinal purposes, firewood and charcoal production. Like all oaks, Turkey oak is suffering from dieback and decline owing to the combination of several detrimental factors, such as insects, diseases and unfavorable environment, leading to their deterioration and sometimes resulting in their early death.