Aims: The aim of this study is Cr (VI) removal by titanium dioxide (TiO2) photocatalytic reduction and the effect of phenol and humic acid (HA) on its removal efficiency are investigated. Materials and Methods: The experiments were performed on both simulated synthetic wastewater and real wastewater. Various parameters such as pH, contact time, Cr (VI) and TiO ₂ concentrations, and a constant concentration of phenol and HA were considered to perform the experiments. Results: The removal value of Cr (VI) alone is 81% and in combination with HA and phenol is 89.7% and 96.2%, respectively. Cr (VI) removal efficiency was enhanced by decreasing pH and contact time. With increasing TiO ₂ dosage, the removal of Cr (VI) increased, up to 0.5 g/L and then decreased at 1 g/L. Cr (VI) removal efficiency decreases with the increase of Cr (VI) initial concentration. Removal efficiency, in 10 mg/L initial concentration of phenol and HA, was enhanced as contact time increased. Equilibrium data and adsorption process kinetics obey Langmuir isotherm model and pseudo second-order kinetic model, respectively. Conclusions: Heavy metal ions and organic pollutants are often present in real wastewater. This research suggests that the photocatalytic reaction TiO ₂ could be applied to more effectively treat wastewaters containing both Cr (VI) and organic compounds.

Aims: This work evaluated the surface and groundwater quality of Mohanpur area, Rajshahi district, Bangladesh. Multivariate statistical techniques were also applied to determine the possible sources of water contamination. Materials and Methods: Water samples were collected from randomly selected ten different sampling sites for analyzing the chemical parameters including pH, electrical conductivity, total dissolved solids, total hardness, total alkalinity, Cl⁻ , NO3⁻ and some heavy metals such as Mn, Pb, Cd, and As concentrations. Concentrations of heavy metals were determined using atomic absorption spectrometer (AAS). Results: Based on hydrochemical characteristics, surface and groundwater in the study area were, in general, fresh, hard, and alkaline in nature. All chemical parameters were within the WHO water quality guidelines. Whereas, among four analyzed heavy metals Pb, and Cd concentrations exceeded the WHO recommended values. Pearson correlation matrix showed a number of statistically significant associations (P < 0.01 and P < 0.05) among the examined water quality parameters. Moreover, principal component (PC) analysis (PCA) and cluster analysis (CA) were used to analyze the water quality dataset. PCA analysis identified two PCs as responsible for the data structure explaining 72.53% of the total variance in water quality. PCA indicated that the water quality variations were mainly of anthropogenic origin through agricultural and municipal discharges. Results of CA revealed three significant groups of similarity among the 10 sampling sites. Conclusions: It could be deduced from the present results that water contamination was occurred to some extent throughout the area, and is likely to be continued in the near future. Improvement of local sanitation system along with frequent training and awareness programs can help in developing water quality in the studied area.

Aims: The aims of this study were to monitor the concentration of benzene, toluene, ethyl benzene and xylenes (BTEX) in the ambient air of the city of Shahreza gas stations and to identify the spreading distance of the pollutants from the fueling stations. Materials and Methods: Sampling was carried out from the air of 10 existing fuel stations, (2 compressed natural gas and 8 gasoline and diesel stations) and points of 50, 150 and 250 m away from the stations during cold and warm seasons in 2013. Air samples were taken via active sampling process using activated carbon tubes, extracted by carbon disulfide and analyzed by a gas chromatograph coupled to a flame ionization detector. Results: The averages of all achieved BTEX concentrations were under/around the permitted guideline levels for occupational exposure. According to the ambient air guidelines, the benzene level was much higher than the suggested levels in all the stations. However, the average concentrations of toluene, ethyl benzene, and xylene were not exceeded from the standards. The seasonal variation had no influence on the concentrations of BTEX. There was no significant difference between the pollutants concentrations at points 50, 150 and 250 m away from the stations. Conclusions: Fuel stations could be the main sources of volatile organic compounds emission in the city of Shahreza. The number and volume of refueling in the gas stations influence the emission rates. Therefore, it is suggested to take preventive actions such as repairing of pumps and tanks leak and installing vapor return systems at the time of fuel transferring.

Aims: The objectives of this study were to determine the perchlorate concentrations in surface soils and assess feasibility of anaerobic bioremediation in full-scale for perchlorate-contaminated soils in a war zone. Materials and Methods: Fifteen samples of surface soil were collected using a composite sampling method in the study area. The soil samples, after extraction and preparation, were analyzed by ion chromatography. Anaerobic composting technique (soil excavation, mixing with manure, transfer into treatment cell and cover with a 6-mil high-density polyethylene liner) considered to cleanup perchlorate-contaminated soil in a war zone. Results: The concentration of perchlorate in the soil surface samples ranged from 3 to 107.9 mg/kg, which is more than State advisory levels for residential and protection of domestic groundwater use pathway. This study indicates that technologies, skills, experience, raw materials (manure), lands, and machinery needed for implementation of full-scale composting, are available in the study area. Conclusions: Based on the results, anaerobic composting technique could be considered as a feasible, viable and cost-effective alternative for perchlorate bioremediation in the study area. According to the available of techniques and skills, successful experiences of anaerobic composting in other countries, and potential of study area, The application of anaerobic composting is technically feasible and can be use for perchlorate contaminated soil cleanup in a zone war.

Aims: This study aimed to assess the microbial contamination status of drinking water supply among buses at the main bus terminal in Isfahan. Materials and Methods: About 184 drinking water samples were taken randomly from buses arriving at the Sofeh terminal in Isfahan in 2011. For data analysis of one-sample, Kolmogorov-Smirnov test (α = 0.05).and Mann-Whitney U-test with a significant difference (α = 0.05) was used for the effect of setting insulated water tank in cities bus to reduce microbial contamination. Results: Results showed that 15% of all samples were contaminated with total coliforms and 2.5% of samples contaminated with fecal coliforms. The most contaminated samples were related to buses arriving from Shiraz and Booshehr, (fecal MPN~4). About 16.66% of all samples collected from buses without insulated water tanks were contaminated with total coliforms and fecal coliforms. Conclusion: Results indicated that the drinking water available on investigated public transportation was not safe for public health. However, the highest levels of microbial contamination were observed in samples taken from buses without insulated water tanks. In conclusion, a constant and systematic monitoring system is recommended to prevent contamination of drinking water available on buses.

Aims: The present study aimed to evaluate the assessment methods of human errors and compare the results of these techniques in order to introduce the precise method of human error assessment, and recognize the factors affecting the occurrence of these errors. Materials and Methods: This case study was done at three workstation control room of a cement industry in 2014. After determining the responsibilities and critical jobs by hierarchical task analysis, cognitive reliability and error analysis method (CREAM) and human error assessment and reduction technique (HEART) were used in order to analyze the human errors. Results: The results showed that in the CREAM method, the highest probability of error occurrence is related to monitoring and control (operator) with a probability of 0.207, and that of in the HEART method, is related to control signs (operator) with a probability of 0.416. The number of errors detected by CREAM and HEART method were 85 and 80, respectively. Time and cost of applying the CREAM methods were 235 h and 1175($), while those in the HEART techniques were 215 h and 1075($). Conclusion: We concluded that the highest probability of calculated errors relates to "monitoring and control (operator)," "controlling warning signs (operators)," and "cooperation in solving the problem (supervisor)" for both techniques. By considering the time and cost factors, HEART has superiority, while CREAM is better due to its extensive evaluation and the number of detected errors.

Aims: In this study, management of industrial waste in industries located between Tehran and Karaj in 2009-2010 was examined. Materials and Methods: This is a cross-sectional study which was done by site survey (Iranian environmental protection organization) questionnaire usage and results analysis. This questionnaire was consisted of 45 questions about industrial waste, quantity, quality, and management. A total number of industries with over 50 employees was 283, and Stratified sampling method was used. Sample of size 50 was selected from 283cases. Results: The major hazardous waste-generating industries include chemical and plastic. Private sectors disposed 45% of generated waste. Majority of wastes were buried (62%), and only 17% of industrial waste was recycled. Conclusion: For hazardous waste reduction in this zone and health and economic attractions, the opportunity for reuse and recovery for these wastes must maximize in short-term and burial of industrial waste must be minimized. Industries such as chemical-plastic and electronics which have higher hazardous waste, in long-term, must be replaced with other industries such as wood cellulose and paper that have lower hazardous waste production rate.

Aims: The aim of this study was to investigate the geographical pattern of stomach cancer and its probable link to heavy metal concentration high-risk area of Kurdistan, Iran. Materials and Methods: This descriptive-analytical study analyzed the deaths due to cancer over a period of 2006-2010. The data were collected from health deputy of Kurdistan province. Spatial distribution map of cancer was prepared using geographic information system software. Finally, the distribution map of heavy metals that could be related to stomach cancer was provided. Results: The spatial distribution maps of stomach cancer mortality shows that the highest mortality rate for the stomach cancer was identified in Divandareh, Bijar and Saghez cites. These cities have shown high concentration of heavy metals. Overlaying the map of stomach cancer via distribution of heavy metals in mineral deposits shows that lead, arsenic and antimony concentration in the city were higher density and can lead to stomach cancer. Conclusions: This study showed that the death rate related to cancer in men and rural area was higher than women and urban area. In addition, the statistical analysis showed a high correlation between gastric cancer and living in the area with mineral deposit of lead, arsenic and antimony.

Aims: The aim of this study was the performance evaluation of ultrafiltration (UF) membrane process as an advanced treatment to secondary effluent quality improvement in Isfahan - Morchekhort Industrial Estate wastewater treatment plant. Materials and Methods: Membrane system used in this study included a flat sheet UF module of polysulfone with 0.1 μm pore size. The coagulation, flocculation and sedimentation (Coag, Floc, Sed) and rapid sand filtration in conjunction with granular activated carbon (GAC) filtration was used as pretreatment of secondary effluent. All test methods was obtained of standard method for the examination of water and wastewater. Results: The membrane system could decrease turbidity, chemical oxygen demand (COD), total suspended solids (TSS), total hardness (TH), total coliform (TC), fecal coliform (FC), total nitrogen (TN) and Cl⁻ , 24.5, 19, 48, 10.5, 94.5, 85.1, 15.4 and 1.01%, respectively. Conclusion: UF was able to improve chemical parameters of secondary effluent and meet national environmental standards. However, achievement to optimum operation of this system requires adequate pretreatments such as adding filter aid, sand filtration and GAC. The most part of suspended particles expressed by turbidity was removed within UF membrane, whereas only a little of organic substance expressed by COD or color and salt expressed by conductivity could be removed.