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In urban cities, the environmental services are the responsibility of the public sector, where piped water supply is the norm for urban household. Likewise, in Beirut City (capital of Lebanon) official water authorities are the main supplier of domestic water through a network of piping system that leaks in many areas. Beirut City and its suburbs are overpopulated since it is the residence of 1/3 of the Lebanese citizens. Thus, Beirut suffers deficiency in meeting its water demand. Water rationing, as a remedial action, is firmly established since four decades by the Lebanese Water Authorities. Consumers resorted then to private wells to supplement their domestic water needs. Consequently, household water quality is influenced by external factors relating to well water characteristics and internal factors depending on the types of the pipes of the distribution network and cross connections to sewer pipes. These factors could result in chemical and microbial contamination of drinking water. The objective of this study is to investigate domestic water quality variation in Beirut City emerging form the aforementioned factors. The presented work encircles a typical case study of Beirut City (Ras Beirut). Results showed deterioration pattern in domestic water quality. The predicted metal species and scales within the water pipes of distribution network depended on water pH, hardness, sulfate, chloride, and iron. The corrosion of iron pipes mainly depended on Mg hardness.

BackgroundThe consumption of dietary supplements is widely spread and on the rise. These dietary supplements are generally used without prescriptions, proper counseling or any awareness of their health risk. The current study aimed at analyzing the metals in 33 samples of imported dietary supplements highly consumed by the Lebanese population, using 3 different techniques, to ensure the safety and increase the awareness of the citizen to benefit from these dietary supplements.ResultsSome samples had levels of metals above their maximum allowable levels (Fe: 24%, Zn: 33%, Mn: 27%, Se: 15%, Mo: 12% of samples), but did not pose any health risk because they were below permitted daily exposure limit and recommended daily allowance except for Fe in 6% of the samples. On the other hand, 34% of the samples had Cu levels above allowable limit where 18% of them were above their permitted daily exposure and recommended daily allowance. In contrast, all samples had concentration of Cr, Hg, and Pb below allowable limits and daily exposure. Whereas, 30% of analyzed samples had levels of Cd above allowable levels, and were statistically correlated with Ca, and Zn essential minerals. Similarly 62% of the samples had levels of As above allowable limits and As levels were associated with Fe and Mn essential minerals.ConclusionDietary supplements consumed as essential nutrients for their Ca, Zn, Fe and Mn content should be monitored for toxic metal levels due to their natural geochemical association with these essential metals to provide citizens the safe allowable amounts.

Determination of only total element in sediments does not give an accurate estimate of the likely environmental impacts. Speciation study of metals in sediment provides information on the potential availability of metals (toxic) to biota under various environmental conditions. In water, the toxic metal specie is the free hydrated metal ion. The toxicity of metals depends especially on their chemical forms rather than their total metal content. The present study focuses on Qaraaoun Reservoir, Lebanon. Earlier studies focused only on total metal concentrations in sediment and water. The objective of this study was to determine metal speciation (Fe, Cr, Ni, Zn, Cu, Pb, Cd) in the (operationally defined) sediment chemical fractions and metal speciation in reservoir water. This would reflect on metal bioavailability and toxicity. Water samples and bed sediments were collected from nine sites during the dry season and a sequential chemical fraction scheme was applied to the <75-μm sieve sediment fraction. Metal content in each fraction was determined by the FAAS technique. The data showed that the highest percentages of total metal content in sediment fractions were for: Fe in residual followed by reducible, Cr and Ni in residual and in reducible, Cu in organic followed by exchangeable, Zn in residual and in organic, Pb in organic and carbonate, Cd was mainly in carbonate. Total metal content in water was determined by ICP-MS technique and aqueous metal speciation was predicted using AQUACHEM software interfaced to PHREEQC geochemical computer model. The water speciation data predicted that a high percentage of Pb and Ni were present as carbonate complex species and low percentages as free hydrated ions, highest percentage of Zn as carbonate complex species followed by free hydrated ion, highest percentage of Cd as free hydrated ion followed by carbonate complex species. The sensitivity attempt of free hydrated ion of Ni, Zn, Pb, and Cd in reservoir water revealed dependence of Zn and Cd on pH and alkalinity, while Ni and Pb were only dependent on pH.

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