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Abstract:In this study, heavy metals pollutions in waters, soils and vegetables were investigated from farms, near oil refi nery in south of Tehran city, Iran (Shahre Ray). The most important heavy metals in Iranian oil are vanadium, cobalt, nickel, arsenic and mercury (V, Co, Ni, As, Hg). In this region, the concentration of heavy metals in soils, well waters and leafy edible vegetables were evaluated in ten different points of farms. Geographic information systems (GIS) were used to estimate the levels of heavy metals concentration at unmeasured locations. After sample preparation, concentrations of heavy metals in vegetables, soils and waters were determined by atomic absorption spectrometry (AAS). Five different leafy edible vegetables from farms, i.e., Persian leek, dill, parsley, spinach and radish were sampled in spring, summer and autumn 2012. In vegetables and well water samples, the concentrations of V, Ni and Co were above the permissible limit of heavy metals as compared to WHO guidelines and the concentrations of these metals in agricultural soils were found to be lower in accordance to soil references. The industrial waste waters had high concentration of heavy metals in this area. In consequence, the results of this study indicate that industrial waste water can cause pollution in well waters and edible vegetables. So, this region is not suitable for cultivation and growing vegetables.Unauthenticated Download Date | 5/13/18 2:45 AM

Objectives: The present study aimed to assess the risk of cancer due to benzene in the ambient air of gas stations and traffic zones in the north of Tehran. The cancer risk was estimated using the population distribution data for benzene levels and the unit risk for benzene proposed by the United States Environmental Protection Agency (US EPA). Material and Methods: Sixteen sampling locations were monitored, once every week, during 5 April 2010 to 25 March 2011. Results:The results showed that the mean annual benzene concentration was 14.51±3.17 parts per billion (ppb) for traffic zones and 29.01±1.32 ppb for outside gas stations. The risk calculated was 1026×10 -6 for gas station 27 and 955×10 -6 for gas station 139. Conclusions: According to our results, the annual benzene level in Tehran ambient air is 2 to 20 times higher than the respective value specified in International Standard (1.56 ppb). Moreover, the results showed a notable increase of cancer risks, ranging from 10% to 56%, for the vicinity population close to the gas stations in comparison to the vicinity population in the traffic zones.

Human exposure to high levels of benzene in the air leads to toxic effects in human body and so, it is necessary to determine by high sensitivity and precision methodology. A simple and efficient method based on the triphenyl(3-sulfopropyl) phosphonium p-toluenesulfonate as TSIL was coated on multi-walled carbon nanotubes ([TPhPP][SUTO]-MWCNTs) and used for benzene vapor removal from air. By procedure, the tube and headspace sorbent based on solid-phase extraction coupled to gas chromatography-flame ionization detector (ST/HS-SPE-GC-FID) was used in dynamic and static systems, respectively. All effected factors including the flow rate, the mass sorbent, benzene concentration, the contact time and the temperature were optimized in dynamic and static systems. Chamber was designed for benzene generation in pure air, and then, mixture of gas moved to passive thermal desorption tubes (ST) or head space (HS) in the glass chromatography vials as dynamic and static methods, respectively. The benzene was eliminated from air with 10 mg of ([TPhPP][SUTO]-MWCNTs); C 28 H 29 O 6 PS 2 -MWCNTs, 1:1] at 25 °C, desorbed from the sorbent at 95 °C and measured by GC-FID. The removal efficiency and the absorption capacity of [TPhPP][SUTO]-MWCNTs for benzene were obtained to be 98.8% and 169.6 mg g −1 at flow rate of 300 ml min −1 . The chemical adsorption of benzene from air was related to π-π, electrostatic, hydrophobic interactions between aromatic chains of TSILs with the benzene molecules, and it caused the increase the removal efficiently of benzene vapor from air more than 95%. The results were validated by GC-MS and spiking of real samples which was determined by GC-FID.