Aim: In this study, the levels of urinary metabolites of toluene and xylene isomers in pregnant women in Isfahan and Khansar cities and their associations with air quality index (AQI) and demographic factors were investigated. Materials and Methods: Depending on the population, 55 pregnant women from Isfahan and 15 pregnant women from Khansar, a total of 70 people were enrolled in the study and 140 urine samples were collected during their 1^st and 3^rd trimesters of pregnancy (autumn and spring). Urinary metabolites of hippuric acid (HA), ortho-, meta-, and para-methyl HA (o-m-p-MHA) were extracted by dispersive liquid-liquid microextraction method, derivatized and analyzed using gas chromatography/mass spectrometer. The results were statistically correlated with AQI level and demographic factors using appropriate statistical methods. Results: Mean urinary concentrations of HA, o-m-p-MHA in the 1^st trimester of pregnancy were 371.2, 1.14, 2.48, and 1.97 mg/g cr, and those in the 3^rd trimester were 582.1, 3.54, 6.93, and 2.43 mg/g cr, respectively. In the 1^st trimester, the mean urinary level of ortho-MHA was significantly associated with the outdoor exposure time on workdays and fragrances use (P < 0.05). In the 3^rd trimester, the mean concentration of HA was significantly correlated to age and outdoor exposure time on workdays (P < 0.05). Conclusion: The mean urinary concentrations of HA and MHA isomers in the 1^st trimester of pregnancy in Isfahan were more than those in Khansar. Because the level of air pollution in Isfahan was higher than Khansar and that in autumn was higher than spring. In the 3^rd trimester of pregnancy, the mean levels of MHA isomers in Isfahan were more than those in Khansar. Only the amount of p-MHA was significantly associated with AQI in the 1^st trimester of pregnancy. Thus, women who lived in high-traffic urban areas with high AQI were more exposed to toluene and xylene compounds.

Aims: In this study, the concentration of particulate matter (PM)_2.5and PM₁₀particles and volatile organic compounds (VOCs) was measured from July of 2016 to June of 2017 in Gorgan City and the values of the air quality index (AQI) for particles were calculated and investigated. Materials and Methods: The concentrations of PM_2.5, PM₁₀, and VOCs were measured at eight stations in the city, and the relationship between different atmospheric conditions and the concentration of pollutants was assessed by statistical tests of variance analysis. Furthermore, the AQI values for the particles were measured, and based on the values of this index, using ArcGIS 10.3 software (ESRI Compony, USA), the zoning maps were prepared. Results: The average concentrations of PM_2.5, PM₁₀, and VOCs in the eight stations were 30.6 μg/m³, 41.3 μg/m³, and 0.82 ppm, respectively. The average concentration of PM_2.5and VOCs is higher than Environmental Protection Agency and clean air standards. Analysis of variance test was showed that the concentration difference of particles in different stations was not significant (P > 0.05), but for VOCs concentration, there was a statistically significant difference between the station of Seyed Masoud restaurant and Terminal square (P < 0.05). Furthermore, the results were showed that the temperature has an inverse relationship with the concentration of pollutants. AQI values for PM_2.5in the cold months of the year and in the central parts of the city were in the range of 101–150. The maximum AQI for PM₁₀was equivalent to 55, which was in December 2016. Conclusion: The air quality of Gorgan City was not in desirable conditions due to the high concentration of pollutants, especially PM_2.5and VOCs, and should be taken control proceedings.

Aims: This study was carried out to investigate the effect of predators' growth on biological excess sludge reduction of adsorption/bio-oxidation process (A/B process) as a modification of activated sludge system. Materials and Methods: The real municipal wastewater after screening and gritting was pumped into A/B pilot plant which consists of two aeration and sedimentation tanks in series. The hydraulic residence time for A and B stages was set at 1 and 4 h, respectively, at an average flow rate of 32 L/h. During operation, the mixed liquor suspended solids (MLSS) in A and B stages was gradually increased. In this period, the operational parameters including dissolved oxygen, pH, volatile suspended solids (VSS), MLSS, alkalinity, biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), phosphorus, nitrogen, and sludge volume index were monitored. Results: The results showed that with increasing solid retention time (SRT) from 0.6 to 56.8 days in Stage A, the biomass yield (Y) decreased from 1.29 to 0.23 g VSS/g COD. Similar results were observed in Stage B and correspondence to 67% reduction of Y as SRT increased from 1.6 to 123.8 days. During the A/B operation, overall tBOD₅and tCOD removal was 70% ± 20% and 57% ± 24%, respectively. Conclusion: Based on the results, A/B process operation with high SRT led to predator growth enhancement and lower biological excess sludge production.

Aims: Comparing to strong traditional oxidation, the persulfate and sulfate radicals was characterized by relatively low cost and easy application. The present study aimed to investigate the performance of sulfate radical-based advanced oxidation process (SR-AOP) for pretreatment of compost leachate in order to improvement of its biodegradability. Materials and Methods: The sulfate radicals was used for pretreatment of compost leachate in the batch reactor followed by aerobic and anaerobic biological reactors. Results: the results of combination of SR-AOP with biological treatment showed that BOD5/COD ratio was increase. However, the different trend was observed in COD removal by sequencing batch reactor (SBR) and anaerobic sequencing batch reactor (ASBR). Comparing to SR-AOP with ASBR, the SR-AOP with SBR substantially improved final COD removal efficiency up to 70%. Although pretreatment of compost leachate with the SR-AOP clearly improved the BOD5/COD ratio of entering raw leachate into ASBR (from 0.4 to 0.65), but, the COD removal efficiency was ranging between 25% and 27%. Conclusion: Based on the results, it can be concluded that the BOD5/COD ratio cannot be suggested as biodegradability improvement indicator without considerations of changing of substrate nature during pretreatment.

Aims: Plankton abundance and diversity are governed by certain aquatic environmental factors which collectively determine the health of the aquatic ecosystem. This study was aimed at investigating the water quality of lower Ogun River, Abeokuta, in relation to plankton abundance and diversity. Materials and Methods: The dataset consists of physicochemical and plankton data collected for 7 months within the period of December 2011 and June 2012 in four stations. Spatial correlations were determined between physicochemical parameters, plankton abundance, and diversity. Physicochemical parameters that exhibited strong correlation with plankton abundance and diversity were used in the calculation of a water quality index (WQI) for the protection of aquatic life. Results: Results showed highly significant correlations (P ≤ 0.05) between plankton abundance, diversity, and the physicochemical parameters monitored during the study period excluding alkalinity and phosphates. The Canadian Council of Ministers of the Environment WQI showed that the river water quality in all the sampled stations (A, 63; B, 63; C, 56; and D, 64) was marginal in classification. Conclusion: It was concluded that River Ogun is polluted beyond doubt. Hence, corrective measures should be put in place so as to prevent total ecological collapse.

Aims: This study aimed to evaluate some relevant serum biochemical and hematological changes in concentration level involved firefighters in comparison to normal controls. Materials and Methods: This study involved two groups of male firefighters to participate in the study. The first group included 50 firefighters from Dammam while the second group included 50 firefighters from Khobar. An additional control group of 50 male nonfirefighters from both cities was included in the study. Blood samples were collected from all participants and investigated for some relevant biochemical, hematological differences and blood heavy metals between the three studied groups. Results: The results obtained showed that there were statistically significant differences in liver function, serum lipid profile, creatine kinase, lactate dehydrogenase, iron and ferritin, and blood picture in firefighters as compared with normal control group, while there were no statistically significant differences in the levels of blood heavy metals in firefighters as compared to normal controls. These results indicate that fire smoke mainly affects serum biochemical and hematological parameters but does not affect serum heavy metals levels. Conclusion: Such results might point out to the need for more health protective and prophylactic measures to try to avoid such hazardous health effects that might endanger firefighters under their highly drastic working conditions, and firefighters must be under continuous medical follow-up through a standard timetabled medical laboratory investigations to allow for the early detection of any biochemical or hematological changes.

Background and Aims: Severe contamination with organic compounds and very high color is characteristic of yeast industry wastewater. Discharging this wastewater into the environment has adverse effects on the environment. The present study was conducted to determine the efficiency of the electrocoagulation (EC) using aluminum electrodes for the removal of color, turbidity, and chemical oxygen demand (COD) from the baker's yeast industry wastewater. Materials and Methods: In this experimental study, the effect of current densities (60, 80, 100, and 120 A/m²) and reaction times (15, 30, 45, and 60 min) using aluminum electrode was investigated on removal efficiencies of COD, color, and turbidity. The pilot consisted of a reactor with a useful volume of 2.5 l of epoxy glass, a direct current power supply, and aluminum electrodes of 8 cm × 8 cm in diameter. Results: The highest removal efficiencies were obtained to be 83% for COD, 93% for color, and 96% for turbidity at density of 80 A/m² and 45-min contact time (pH = 7). Under these conditions, the power and electrode consumption was 16.89 kWh and 94.3 g/m³, respectively, and the treatment cost of wastewater was estimated to be 1.5 $ per each cubic meter. Conclusion: The results showed that EC process using aluminum electrode is an appropriate and effective method for removing color, turbidity, and COD from baking industry wastewater.

Aim: Anxiety reduces performance at work. Anxiety is significantly prevalent among medical staff in general, and especially operating room staff. The present study was an attempt to investigate the effect of suction-induced white noise on anxiety and hemodynamic parameters of operating room staff during cesarean section. Materials and Methods: The present study was a crossover, single-blind clinical trial on 29 scrub staff during cesarean section. The subjects were assigned once to the control group and once to the intervention group with a 10-day washout period. In the intervention group, the suction machine was left on during surgery for 3 days in a row, but in the control group, the suction machine was switched off in idle times to make sure that noise exposure time would remain below 30 min. Hemodynamic parameters of subjects were measured on the last day immediately after surgery, and the Spielberger State-Trait Anxiety Inventory was used to measure the level of anxiety. SPSS 22 software and linear mixed model were used to analyze the collected data. Results: The control and intervention groups were not significantly different in terms of hemodynamic parameters, anxiety as well as the carryover-crossover effects (P > 0.05). A significant negative correlation was observed between anxiety score and age of the subjects (P < 0.05). Conclusions: Suction-induced white noise has no effect on anxiety and hemodynamic parameters of operating room staff. Adaptation to workplace noises can reduce the adverse effects of noise.