Yehya Elsayed

A health risk assessment of Arabian incense (Bakhour) smoke in the United Arab Emirates

Burning Arabian incense (Bakhour) is a common practice in the Middle East and Arabian Gulf. Although the incense generates large amounts of chemicals and air pollutants, little is known with regard to the nature of these chemicals and their potential health risks. The aim of this study is to provide a comprehensive characterization of the chemical constituents emitted in Bakhour smoke, and subsequently to examine the associated health implications of these components. Thermo-gravimetric analysis was used to investigate the presence and the thermal profile of volatile organic compounds in three different samples of Bakhour smoke. Thermal desorption-gas chromatography-mass spectrometry was then applied to isolate all the volatile and semi-volatile compounds present in the Bakhour smoke samples. Using a spectral library and an extensive literature search, all organic compounds detected were analyzed for potential health risks. A total of 859 compounds were emitted from burning the different Bakhour samples. The novel finding of this research shows that 42 detected compounds are suspected/known carcinogens, 20 are known to have toxic effects, and at least 200 compounds are known irritants to the eyes, skin, respiratory and digestive tracts, as reported in human and/or animal studies. Our study suggests that inhaled Bakhour smoke contains a substantial number of adverse compounds, which are known to be detrimental to human health. Moreover, the evidence presented shows that incense burning is a significant source of environmental pollution; with the potential of significant health concerns particularly with long term exposure. As the majority of the compounds detected have no reported clinical data, there is an urgent need for significant research in this field.

Effect of increased basicity of activated carbon surface on valeric acid adsorption from aqueous solution activated carbon

Two types of activated carbons of different origins were used to study the adsorption of valeric acid from aqueous solution. Nitrogen-containing basic groups were introduced into the surface by impregnating the initial samples with urea followed by heat treatment at 1223 K. Characterization of the surface was done using the following techniques: Boehm titration, potentiometric titration, thermal analysis and sorption of nitrogen. Valeric acid adsorption isotherms were measured at 333 K and fitted to the Freundlich equation. A direct correlation of the capacity coefficients with both the total number of groups and the volume of micropores smaller than 10 A was found. The amount of valeric acid adsorbed on activated carbons, calculated from the isotherms, showed similar trend. The results obtained from DTG analysis showed that the strongly adsorbed amount of valeric acid per unit surface area increases with an increase in the density of basic groups. On the other hand, the amount adsorbed decreases with an increase in the density of acidic groups on the surface. This is related to attractive/repulsive interactions of adsorbate with surface species.

Chemical analysis and potential health risks of hookah charcoal.

Hookah (waterpipe) smoking is a very common practice that has spread globally. There is growing evidence on the hazardous consequences of smoking hookah, with studies indicating that its harmful effects are comparable to cigarette smoking if not worse. Charcoal is commonly used as a heating source for hookah smoke. Although charcoal briquettes are thought to be one of the major contributors to toxicity, their composition and impact on the smoke generated remains largely unidentified. This study aims to analyze the elemental composition of five different raw synthetic and natural charcoals by using Carbon-Hydrogen-Nitrogen (CHN) analysis, inductively coupled plasma (ICP), and scanning electron microscopy coupled with energy dispersive X-Ray spectrometry (SEM-EDS). Elemental analysis showed that the raw charcoals contain heavy metals such as zinc, iron, cadmium, vanadium, aluminum, lead, chromium, manganese and cobalt at concentrations similar, if not higher than, cigarettes. In addition, thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) was used to analyze the chemical composition of the smoke produced from burning the charcoal samples. The smoke emitted from charcoal was found to be the source of numerous compounds which could be hazardous to health. A total of seven carcinogens, 39 central nervous system depressants and 31 respiratory irritants were identified.

Chemical characterization and safety assessment of dokha: An emerging alternative tobacco product

Dokha is known to be one of the most rapidly spreading alternative tobacco products (ATPs) in the Middle East and North Africa (MENA) region. It is smoked using a pipe known as Midwakh. There is no scientific research published on the chemical composition of dokha and only very little was done to investigate its impact on human health. Three different types of dokha were included in this study. The trace metals content in the dokha samples were analyzed using inductively-coupled plasma-optical emission spectroscopy and energy-dispersive X-ray spectroscopy-scanning electron microscope. Dokha smoke was generated using a device that simulates human smoking/puffing. The smoke samples were collected on Tenax and activated carbon adsorbent tubes followed by chemical analysis using thermal desorption-gas chromatography-mass spectrometry. The results showed the presence of toxic metals in dokha samples such as cobalt, cadmium, chromium, and lead in amounts classified as harmful to human health. In addition, the presence of several potentially harmful and even toxic organic compounds in dokha smoke was identified based on the available clinical data. These included 22 irritants, 3 known carcinogens, and 5 central nervous system (CNS) depressants in addition to several other compounds with miscellaneous effects. The findings of this work demonstrate evidence for the presence of potentially harmful and toxic metals and compounds in dokha tobacco as well as dokha smoke. More research is required to further investigate the clinical impact of dokha on human health.

Chemical and biological assessment of sediments and water of Khalid Khor, Sharjah, United Arab Emirates.

Water and sediments were collected on March 2013 and April 2014 from Khalid Khor creek area in United Arab Emirates to assess their quality parameters. The pH and alkalinity of the water samples were measured and their values were similar to those of shallow saltwater ecosystems. In addition, elemental analyses and organic compounds were done using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) and Gas Chromatography-Mass Spectroscopy (GC-MS), respectively. The concentration of heavy and trace metals in the water samples were within the acceptable limits except for lead which showed high values, while the concentrations of metals in the sediment samples were relatively high and ranged from 6517 to 13,768mg/kg. GC-MS analysis showed the presence of polyaromatic heterocyclic (PAHs) compounds in sediments near the shipping area and in amounts classified as highly carcinogenic; however, no polychlorinated biphenyls (PCB) were identified. Moreover, fecal bacterial contamination in water was detected in concentrations that range between 300 and 10,140 organisms/100mL.

Development of Semi-Static Steam Process for the Production of Sludge-Based Adsorbents

In this study, a specially developed unique process was used to prepare sludge-based activated adsorbents (SBAs) from municipal sewage sludge collected from a wastewater treatment plant in Sharjah. A reaction chamber is designed to allow the carbonization and activation of sewage sludge in a saturated steam environment generated inside the chamber (semi-static). The semi-static steam process is carried out in the absence of any external gas flow into the reaction chamber. The activated sample is subjected to acid treatment. Other SBA samples are also prepared at the same temperatures using a conventional method in the presence of external flow of nitrogen gas. The surface chemistry for the SBA samples is characterized using Boehm titrations, pH measurement, ash content and scanning electron microscope integrated with energy-dispersive spectroscopy (EDAX). The semi-static steam method results in the formation of an SBA sample with acidic surface and higher carbon content as compared with the samples prepared by the conventional method. The metal contents of the SBAs are significantly different and depend on the methods of preparation. Nitrogen sorption isotherms are measured and used for the analysis of structure and porosity. The BET surface area for the SBA sample produced in the proposed method is calculated to be 838 m2/g. The SBA samples are then compared for adsorption efficiency of lead ions from aqueous solution, which is observed to be dependent on the microporosity and surface basicity.