Owing to environmentally-destructive impact of aromatic hydrocarbons, such as benzene, benzene ethyl, toluene, and xylenes or BTEXs, these materials are classified as hazardous pollutants in the air. This study studies cancer and non-cancer risk in District 12 of Tehran Municipality, through these components for two groups of employees or storekeepers and gas station customers. By measuring pollutant concentrations along with doing related calculations, the areas and gas stations of the study area with the highest risk have been found. Results show that Station 7, located in Zone 4, is one of the most dangerous spots in terms of cancer and non-cancer risk to employees or storekeepers in the area. Additionally, there is no risk of non-cancerous disease for the customers, using these stations, during their lifetime. Finally, the study proposes some solutions for making appropriate decisions, concerning the sustainable management plan.

In Nigeria irrigated agriculture is an important tool for economic growth, food security, and poverty reduction during dry periods of rain-fed agriculture. The concentration and composition of dissolved constituents in water determines its quality for irrigation use. Water quality studies strongly suggest that agriculture is a leading source of water quality problems, due to pesticides and other agro-inputs, widely used by farmers to improve agricultural productivity. Poor quality irrigation water would therefore obviously affect soil quality and crop productivity. This study was carried out in 2015 to assess the presence of metals and physical properties of water, used for irrigation in Kwara state, Nigeria. Samples were randomly collected from thirty irrigation sources in three senatorial zones of Kwara State. The samples were analyzed for the presence of metals and water quality parameters, using standard procedures. Results showed that the highest concentration of Sulphate (7.0mg/L), Nitrate (8.9mg/L), Sodium (31.6mg/L), Calcium (3.1mg/L), and Magnesium (0.7) ions were within acceptable limits. The Sodium Adsorption Ratio, an indicator for water suitability in agricultural irrigation as well as a standard diagnostic parameter for the sodicity hazard of a soil, was significantly the highest (22.7) in Kwara North. Results of the study point to the need for an effective irrigation water quality assessment to curb nonpoint source pollution that could be caused by improper use of chemicals and pesticides by farmers.

The current study assesses the effect of fibrous clay minerals’ amendments and arbuscular mycorrhiza incubation on heavy metal uptake and translocation in Eucalyptus grandis and Ailanthus altissima plants. For doing so, Eucalyptus and ailanthus trees have been grown in a soil sample, contaminated with heavy metal iron ore mining and collected from southern Iran. The area under study is arid, with the majority of trees being ailanthus and eucalyptus. Amounts of Cd, Pb, Zn, Cu, and Mn have initially been at toxic levels which declined after cultivation. Fibrous clay minerals have been added to soils as a natural adsorbent to adsorb heavy metals like Pb, Cd, Zn, and Mn. Accumulation of the elements in the roots and shoots has been in the following order: Cu>Zn>Mn>Cd>Pb>Fe. The organ metal concentrations have not statistically translocated from roots to shoots of plants, except for Zn and Cu whose concentrations have been significantly higher in roots. Eucalyptus is well capable of extracting elements from contaminated soils, compared to ailanthus, particularly in case of Cu and Cd. The percentage of mycorrhizal colonization proves to be more in pots with ailanthus plants grown in contaminated soil, suggesting enhanced effect of high metal concentrations on plant infection by G. mosseae. AMF assists soil remediation by enhancing the growth and retention of toxic elements by ailanthus, while no substantial change has been observed between inoculated and non-inoculated eucalyptus plants by AFM, regarding translocation of elements to plants. The possibility of increasing metal accumulation in roots is interesting for phytoremediation purposes, since most high-producing biomass plants, such as eucalyptus, retain heavy metals in roots.

The present study analyzes air quality for Carbon monoxide (CO), in Esfahan with the measurements taken in three different locations to prepare average data in the city. The average concentrations have been measured every 24 hours, every month and every season with the results showing that the highest concentration of CO occurs generally in the morning and at the beginning of night, while the least concentration has been found in the afternoon and early morning. Monthly concentrations of CO show the highest values in August and the lowest values in February. The seasonal concentrations show the least amounts in spring, while the highest amounts belong to summer. Relations between the air pollutant and some meteorological parameters have been calculated statistically, using the daily average data. The data include Temperature (min, max), precipitation, Wind Direction (max), Wind Speed (max), and Evaporation, considered independent variables. The relations between the pollutant concentration and meteorological parameters have been expressed by multiple linear regression equations for both annual and seasonal conditions, using SPSS software. Analysis of variance shows that both regressions of ‘enter’ and ‘stepwise’ methods are highly significant, indicating a significant relation between the CO and different variables, especially for temperature and wind speed in annual condition. RMSE test shows that among different prediction models, stepwise model is the best option.

This research aims to study the effect of Mycorrizal fungus and Plant-Growth-Promoting Bacteria (PGPB) on Cadmium (Cd) uptake by one-year-old Eucalyptus Camaldulensis seedlings. The treatments have involved three levels of heavy metal (0, 30, and 60 mg/kg) for Cd, and three bacterial levels (no bacteria (B0), Bacillus (Ba105), and Pseudomonas (Ps36, Ps448)), inoculated with mycorrhizal fungus Glomus mosseae (M1) and non-inoculated with fungus (M0). Results show that absorption of these elements in plant increased as Cd concentration in soil became more. Inoculation by Ps448 bacteria had an incremental effect on Cd uptake by 90%, compared to the non-inoculated (control) samples. Moreover, inoculation of the plants with mycorrhizal fungus increased Cd uptake by 24%, compared to the control. Also, it has been observed that plant resistance to metal stress and plant growth under such conditions ascended in treatments wherein inoculation happened with mycorrhizal fungus and bacteria. The highest Cd heavy metal uptake has been observed in Eucalyptus (shoots and roots), treatment (C2B2M1) with 648.19 micrograms per one seedling in pot. According to the obtained results, Eucalyptus with biological factors (fungi and bacteria) has the ability to clean and purify the contaminated soil with Cd heavy metal.

Benzyl Alcohol Dehydrogenase (BADH) is an important enzyme for hydrocarbon degradation, which can oxidize benzyl alcohols to aldehydes, while being capable of catalyzing a reversible reaction by reducing benzaldehyde. BADH is a member of medium chain alcohol dehydrogenases, in which zinc and NAD are essential for enzyme activity. This paper describes the expression, purification, and characterization of recombinant benzyl alcohol dehydrogenase, encoded by xylB gene from Rhodococcus ruber UKMP-5M. The gene has been amplified and cloned into E. coli, and the recombinant plasmid pGEMT-xylB has been digested by NdeI and HindIII to construct plasmid pET28b-xylC and then ligated into E. coli BL21 (DE3), itself induced by 0.3 mM isopropyl β-D-thiogalactoside (IPTG) at 25°C. The expressed BADH has been 38 kDa, and is purified by affinity chromatography, in which the specific activity was 30 U/mg after 17 folds purification, leading to a NAD-dependent enzyme that uses benzyl alcohol as a substrate for enzyme characterization. The final metabolite is benzaldehyde, identified by gas chromatography mass spectrometry (GC-MS). The BADH activity has been 0.7 U/mL and the optimum pH and temperature, 9.5 and 30ºC, respectively. Also the Michaelis constant (Km) and maximum velocity (Vmax) have accounted to 705 µM and 1.3 U/mL, respectively. Benzyl alcohol dehydrogenase from R. ruber UKMP-5M can be used for hydrocarbon biodegradation in contaminated sites.

The quick growth of vehicles is due to fast urbanization in mega cities during last decades. This phenomenon has serious impacts on air quality, as emission from mobile vehicles is the major source of air pollution. As a result, any attempt to reduce the emitted air pollutants is needed. This study aims at improving the fuel quality in transporting system with particular emphasis on taxis in Tehran in 2014. As a clean fuel, Euro IV is being used to reduce the emission of pollution, toxic substances, and greenhouse gases. A bottom-up approach to evaluate vehicular emission, using IVE (International Vehicle Emission) model in Tehran, has been presented, which employs the local vehicle technology and its distributions, vehicle soak distributions, power based driving factors, and meteorological parameters to evaluate the emission, itself.  Results show that the most abundant air pollutant (CO) has been reduced by 87.6% due to the clean fuel consumption (Euro IV). Also, the emission rates of the predominant toxic pollutant (Benzene) decreased by 98.7%. As a clean fuel, Euro IV managed to increase the emitted amount of CO2 and NH3. It can be concluded that upgrading transportation system with updated fuel quality is an essential step to improve air quality in Tehran.

Increasing consumption of chicken products in Iran makes it very important to analyze their residual heavy metal contents; therefore, the present study has been conducted to determine Pb, Cd, Cr, and Cu in commercial hen eggs, marketed in the city of Hamedan in 2016. In this descriptive study, a sum of 27 samples of hen eggs has been collected from the Hamedan City's market. After preparation and processing the samples in the laboratory, the concentration of metals has been determined in mixed albumen and yolk, using inductively coupled plasma-optical emission spectrometry. Also, all statistical analyses have been conducted, using the SPSS statistical package (version 20) with the results showing that the mean concentrations (mg/kg) of Pb, Cd, Cr, and Cu in the samples have been 0.29±0.16, 0.18±0.04, 0.31±0.03, and 2.81±1.56, respectively. Also, the mean contents of Cd and Cr have surpassed the maximum permissible levels (MPL), established by WHO/FAO. The computed health risk index values show that there is no potential risk for adults and children through egg consumption at the current rate in the study area.According to the results, considering the mean contents of Cd and Cr observed in egg samples have been higher than the MPL; therefore, it is recommended to pay serious attention to pollutants discharge in the environment and monitor chemical residue, especially heavy metals, in the foodstuff.

The present study investigates the transesterification of corn oil with methanol over two oxides of MgO and ZnO at 65 ͦC and 1 atm. These two catalysts have been prepared via a conventional co-precipitation process. As for MgO, the corresponding mixed metal nitrate solution has been mixed and heated at the presence of urea. ZnO has also been synthesized by co-precipitation of metal acetate at the presence of oxalic acid and ethanol. The catalysts then have been characterized by means of X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM). XRD results indicate high purity for both catalysts. Also, catalytic activity has been evaluated in methanol reflux temperature through corn oil transesterification, with the impacts of reaction variables, like catalyst amount, methanol/oil molar ratio, and reaction time on biodiesel yield, investigated by means of HNMR spectrum. Under appropriate transesterification conditions at 65 °C (catalyst amount= 5%, methanol/ oil ratio= 20, and reaction time= 10 hr), an ME content of 62.61% can be achieved, using MgO catalyst. Similarly, the experiments have been repeated to achieve the best yield, using ZnO catalyst, with the highest rate, equal to 53.1%, obtained in 9% of catalyst and methanol/oil ratio of 30 over 10 hr. Furthermore, reusability of ZnO and MgO has been evaluated in transesterification reaction.

The current study assesses critical condition of oil dispassion, considering the unsaturated soil condition dispersity behavior for oil dispersion. The numerical model is used as a finite element method to model the oil spill pollution with two different saturated and unsaturated soil conditions chosen and their pollution dispersion results compared. Extracted results from numerical model show that considering the form of unsaturated soil, by changing the matric suction its soil conductivity ratio will differ. Regarding the current study analysis, it has been observed that the pattern of oil dispersion in case of unsaturated soil can be changed, in comparison to saturated soil condition. The vertical penetration of oil pollution in both cases of saturated and unsaturated soil condition will be more than horizontal dispersion pollution speed.  As for oil pollution control in soil domain, the condition of unsaturated soil may be controllable, compared to the saturated one. Extracted results show that oil dispersion velocity, considering saturated soil, is more than 10 times greater than unsaturated one.