Iranian Journal of

Background and Objective: Extreme use of antibiotics and discharging to the environment lead to serious consequences. Mesoporous silica such as MCM-41 material is widely used to absorb contaminants from the aqueous solution. The aim of this study was to evaluate mesoporous synthesis of MCM-41 and its efficacy for removal of the antibiotic cephalexin from aqueous solution.
Materials and Methods: Physical characteristics and absorbent structure synthesized by techniques BET, FTIR and XRD were analyzed. The effect of variables such as pH values (3, 7, 11), the dose of MCM-41 (200, 500, 800 mg/L), initial concentration of cephalexin (50, 75, 100 mg/L), contact time (30, 60, 90 min), and process temperature (20, 30, 40 ⁰C) on absorption of cephalexin were studied. In order to achieve the optimal experimental conditions, response surface methodology (RSM) model was used.
Results: The results showed that pH (p=0.0001), adsorbent dose (p=0.0001), initial concentration of cephalexin (p=0.0001), contact time (p=0.01), pH² (p=0.0002) and pH (p=0.04) and initial concentration had a significant impact on the response variable. The optimum removal condition based on analysis of variance and the model was at the reaction time 90 min, pH 3, initial concentration 50 mg/L and adsorption dose 600 mg/L. Under these conditions, the removal efficiency of 81.1% was achieved.
Conclusion: The results showed that adsorption process with the mesoporous MCM-41 had a high efficiency on the removal of cephalexin from the aqueous environments.
 

Background and Objective: Rainfall and groundwater level are important parameters of DRASTIC index, thus their time-series were examined using time series analysis for Mahidasht plain vulnerability in Kermanshah Province.
Materials and Methods: DRASTIC model is a quantitative model that seven parameters for transfer of pollution are considered including depth of water table, net recharge, aquifer, soil, topography, unsaturated environment and hydraulic conductivity. The data was prepared in seven-layer information in Arc GIS10 software. After integration, weighting and ranking, DRASTIC index for the region was estimated between 34 and 120. Precipitation is an uncertainty factor in water projects. Precipitation is the origin of other uncertainties such as surface runoff, recharge, and water balance.  Underground water level and recharge are main factors in the DRASTIC model that are considered as component hydrological variables and time series, thus, they were analyzed and forecasted using stochastic methods on the horizon in 2032.
Results: Finally, selection of the data predicted in 2032 and the creation of dual new depth to the water table and recharge, as well as the weighting and ranking of the repeated placement in the DRASTIC model, another vulnerabilities map is prepared in which the index DRASTIC was 34 to 110 units.
Conclusion: Results showed that due to further decrease of water table and reduced rainfall, DRASTIC index will be less in the next 18 years (2014-2032).
 

Background and Objective: In the field of environmental risk assessment, Cyanide is one of the most important pollutants of water, soil and air that has an important impact on the ecosystem and environment of the contaminated area. Therefore, the present study aimed to prove the biological effectiveness of Vetiveria zizanioides in phytoremediation of soils contaminated with cyanide.
Materials and Methods: This research study was conducted on a gold mine wastewater. The dried effluent samples amended with soil with various cyanide concentrations. Seven treatments with different concentrations of cyanide were obtained (mean cyanide content in G soil, 14.77 mg/kg, F soil, 10.13 mg/kg, E soil, mg/kg 8.09, D soil, mg/kg 7.53, C soil, 3.32 mg/kg, B soil, 2.52 mg/kg and A soil without cyanide (as control). After two months, the amount of cyanide in the soil, roots and leaves of the plant, as well as the total protein and proline content, and the number and length of the leaves of the plant were measured and then statistically evaluated by SPSS15 Tukey and t Paired Samples T Tests.
Results: The results of this study showed that the increase of cyanide had a significant effect on the amount of proline (proline in the plant increased), total protein (in the plant increased), number of leaves (decrease in number) and the length (length reduction) of the leaves of the vetiver. The amount of cyanide in the leaves and roots of the plant was increased. Cyanide content was decreased in the different treatments. Cyanide content was decreased in G 50.93%, F 38.20%, E 27.19%, D 38.37%, C 17.77% and B 16.66%.
Conclusion: The results indicated that increase of the amount of cyanide in soil resulted in observational changes in the morphological and biochemical characteristics of the plant. However, Vetiveria zizanioides exhibited very high resistance to soil cyanide and the planting of vetiver in highly contaminated soils can lead to a reduction of cyanide up to 50 percent. Vetiveria zizanioides had higher resistance to cyanide and showed better phytoremediation than the other plants.
 

Background and Objective: Lead is a dangerous heavy metal for human health. This research was conducted to study the potential of a new Iranian corn (Maxima CV.) and white clover in monoculture and mixed culture for phytoremediation of Pb in a Pb polluted soil.
Materials and Methods: The experimental treatments consisted of corn and white clover in a mixed culture (with 10 and 20 plant density) and either corn or white clover in a monoculture system (with 10 and 20 plant density) in a Pb polluted soil (800 mg Pb (kg soil)^‌-1) at 60 and 90 days of  experiment. Plant and soil Pb concentration were measured using atomic absorption spectroscopy.
Results: Root and shoot Pb concentration of corn and white clover were significantly increased in a mixed culture system relative to mono culture system. In addition, the increase of white clover density from 10 to 20 in a mixed culture system caused a significant increased Pb concentration in root and shoot of corn and white clover. The highest Pb translocation factor (TF) and shoot Pb concentration were observed in white clover in a mixed culture of corn and white clover (with 20 plants density).
Conclusion: The results of this study showed that the Pb concentration of corns shoot in a mixed culture system with corn and white clover (20 densities) was three times higher than that of the monoculture system.
 

Background and Objective: Chromium is present in two oxidation forms of Cr(III) and Cr(VI). Cr(III) is less toxic than Cr(VI). The aim of this article was to optimize an artificial neural network structure in modeling the photocatalytic reduction of Cr(VI) by TiO₂-P25 nanoparticles.
Materials and Methods: In this work, an artificial neural network (ANN) for the modeling photocatalytic reduction Cr(VI) by TiO₂-P25 nanoparticles were used and its structure was optimized. The operating parameters were initial concentration of chromium, amount of photocatalyst, ultraviolet light irradiation time and pH. All the experiments were conducted in a batch photoreactor. The Cr(VI) concentration was measured with a UV/Vis spectrophotometer. ANN calculations were performed using Matlab 7 software and the ANN toolbox.
Results: The results show that the optimization of the ANN structure and the use of an appropriate algorithm and transfer function could significantly improve performance. The proposed neural network in modeling the photoactivity of TiO₂-P25 nanoparticles in reducing Cr(VI) was acceptable, based on a good correlation coefficient (0.9886) and a small mean square error (0.00018). All the input variables affected the reduction of Cr(VI), however the effect of pH with an impact factor of 34.15 % was more significant than the others. The results indicated that pH = 2 was the best pH for photocatalytic reduction of Cr(VI). Increasing photocatalyst dosage and irradiation time in the investigated range increased Cr(VI) photocatalytic reduction.
Conclusion: Optimized structure of the ANN includes a three-layer feed-forward back propagation network with 4:10:1 topology and the most appropriate algorithm is a scaled conjugate gradient backpropagation algorithm.
 

Background and Objective: Water pollution due to heavy metals is a critical and increasing problem worldwide. In this study, removal of cadmium and lead heavy metals using a graphene oxide (GO) adsorbent was examined.
Materials and Methods: GO nanosheets were synthesized through Hummer’s method, and its characterizations were examined using FTIR, XRD, and SEM. The effect of independent variables pH, contact time and initial concentration of the solution on removal efficiency of Cd²⁺and Pb²⁺ using response surface methodology was evaluated according to Box-Behnken experimental design. Applying quadratic model, adsorption rate of Cd²⁺ and Pb²⁺ achieved 99%. ANOVA was applied for statistical analysis of responses.
Results: According to SEM images, the average size of graphene oxide sheets was 1 to 3 µm. After optimization through RSM, the adsorption capacity for Pb²⁺ and Cd²⁺ was 136 mg/g and 68 mg/g, respectively. Examination of the isotherms suggested that Cd²⁺ and Pb²⁺ adsorption follows Langmuir and Freundlich isotherm, respectively.
Conclusion: the results show that the graphene oxide performed well in removing both Cd²⁺ and Pb²⁺ ions from aqueous solutions. The most influential parameters on the above-mentioned heavy metals adsorption were pH of the solution and the initial concentration.
 

Background and Objective: Nowadays, the increasing use of antibiotics to control diseases and mismanagement and inappropriate disposal of medicinal wastes cause environmental problems and threatens human health. The present study was conducted to determine removal of antibiotic Metronidazole as one of the most used drugs during the process of composting.
Materials and Methods: In this experimental study, a mixture of livestock manure, fruit, straw and sludge were used for the preparation of compost. Duration of the process was 40 days. Metronidazole was added to the compost reactors at three concentrations of 20, 50 and 100 mg/kg. Totally, 42 Samples were taken weekly. HPLC was used to analyze the samples. The experiment was repeated twice. SPSS22 software was used to analyze the results.
Results: The rate of Metronidazole removal after day 21 and end of the thermophilic phase was 99.9, 96.73 and 93.48 % in the reactors contained 20, 50 and 100 mg/kg, respectively. Increasing concentrations in the reactors caused the removal rate to decrease, while increasing removal time caused to increase the removal rate. At the end of the process, the removal rate for all three reactors was 99.99 %. The physico-chemical properties of the final compost were within the national standard.
Conclusion: The use of an aerobic composting process to degrade antibiotic Metronidazole is an economical, effective and, environmentally friendly method. At the end of the process, 99.99 % of Metronidazole was degraded.
 

Background and Objective: Noise pollution causes many physiological, psychological, economic and social effects on human life. This issue is more important in the environment of industrial workplaces. This research aimed to adopt the functions of GIS for evaluating and spatial analysis of noises in industrial environments.
Materials and Methods: At the initial step, the spatial data for industrial halls were collected and stored as map layers into GIS database. Then, the noise pollution data sampled. The data, including the locations and values of sound pressure levels, were used for the relevant spatial analyses.
Results: The analyses included: the estimation of sound pressure levels in different areas of halls and at the given distance from machines, determination of noisy areas, development of sound noise risk map, interpolation of sound pressure level data, prioritization of the sound sources (i.e., machines) for a given point, prediction of sound pressure levels by moving machines, and optimal site selection and distribution of machines. The mean of noise pressure level was 95 dB for knitting hall,  93 dB for spinning hall 1 and 88 dB for spinning hall 2.
Conclusion: GIS plays a key role in the assessment of noise pollution in industrial workplaces. It is an appropriate tool to store, analyze, manage, and present all types of sound pressure spatial data. Specifically, the use of such system provides spatial intelligence and could help monitor, detect, control, and solve real word sound noise pollution issues.
 

Background and Objective: Radon is a radioactive, odorless gas. Radon gas with the emission of alpha radiation and sticking to aerosols in the air can cause lung cancer. This study evaluated the concentration of radon in residential houses and public places in Firuzkuh city and compared the values with the recommended international guidelines.
Materials and Methods: Radon gas concentration was measured by passive measurements using CR-39 detectors. The detectors were placed in houses and schools of the city for three months. After this time, the detectors were located and placed in a 6.25% normal solution at 85 °C for 4 hours in a laboratory. After preparation, using an automatic scan and appropriate statistical method, the concentration of radon gas was determined.
Results: The results indicated that the average concentrations of radon gas in homes and public places were 137.74 and 110.17 Bq/m³, respectively. Comparing the results with the WHO guideline showed that 76.3% of the homes and 66.7% of the sites had a concentration above the guideline (100 Bq/m³).
Conclusion: The results of this study can be used to prepare the National Radon gas map in the country.
 

Background and Objective: Chahnimeh water reservoirs in Sistan and Baluchestan Province are the most important sources for drinking water and irrigation purposes. Many factors such as precipitation, the geography of the watershed, atmosphere, geology and Human activities affect on the chemical, physical, and biological compositions of Chahnimeh water reservoirs. Therefore, the main goal of the present study was to monitor and assess water quality in four Chahnimeh reservoirs during two sampling periods.
Materials and Methods: 84 water samples were taken based on the standard methods (in September 2017 and April 2018) for measurement of the most important physicochemical parameters including major anions, total coliform, BOD, EC, TDS, pH and nitrate. Water quality index (WQI) was used to evaluate the overall water quality status in the Chahnimeh reservoirs.
Results:  The results of hydro-geochemical analysis indicated that the water type changed from sodic bicarbonate and sulfur dioxide to radicle chloride during sampling periods. The Gibbs chart showed that weathering of rocks mainly controlled the chemistry of the main water ions. The results of statistical analyses revealed that there was a high correlation between parameters such as chlorophyll, nitrate, sulfate and chlorine with water quality index. Water quality zoning results based on the WQI index indicated a decrease in the water quality of the wells by 3, 2, 1, and 4, respectively.
Conclusion: In this study, the use of WQI was helpful for fast data interpretation for drinking water purposes in the area. Based on the WQI classification, majority of the samples are falling under good to poor water category.
 

Background and Objective: Traditional cheese has desirable organoleptic characteristics for Iranian consumers. Escherichia coli, Staphylococcus aureus and Salmonella are some of the most important microbial agents in food poisoning and gastrointestinal infections, which can contaminate this product and endanger the health of consumers. The aim of this study was to survey the contamination rate and determination of antibiotic resistance of Staphylococcus aureus, Escherichia coli and Salmonella strains isolated from traditional cheeses distributed in Mahabad, Iran.
Materials and Methods: In a cross-sectional study, 100 samples of traditional cheese from the production and distribution centers in Mahabad city were randomly selected in 2016 to determine the bacterial contamination in accordance to national standard guidelines for the presence of Staphylococcus aureus, E.coli and Salmonella spp. Anti-biograms test was conducted using a standard disc diffusion method through the measurement of the inhibitory zone diameter on the Muller Hinton agar.
Results: Among the 100 samples, 54, 45 and 0 samples were positive for Escherichia coli, Staphylococcus aureus and Salmonella, respectively. All E.coli (100%) were found to be resistant to Amoxicillin, while Staphylococcus aureus isolates (100%) were resistant to Amoxicillin-Clavulanic acid and Amoxicillin. However, 66.6% isolates of E.coli were susceptible to Ceftriaxone and 97.7% isolates of Staphylococcus aureus were susceptible to Trimethoprim – Sulfamethoxazole.
Conclusion: The microbial quality of traditional cheeses distributed in Mahabad city was not evaluated as appropriate and the values did not meet the national standards. Thus, further monitoring and control are needed.
 

Background and Objective: Environmental pollution emitted from industrial areas while enter the food chain can cause serious adverse health effects. Therefore, this study was conducted to use Ziziphus spina-christi and Prosopis cineraria leaves as bio-indicators of environmental pollution emitted from the complex of Steel Company.
Materials and Methods: In this descriptive study, a total of 90 surface soil samples and also 90 leave samples were collected. After acid digestion of samples, the heavy metal contents were measured using atomic absorption spectrophotometer. Also, the Bioconcentration Factor (BCF) of metals were computed. All statistical analyses were performed using SPSS statistical package.
Results: The highest content of the metals (mg/kg) with an average of 2180.3 ± 202.3 and 2237.9 ± 315.1 for Fe, 76.6 ± 9.6 and 114.3 ± 4.5 for Pb and 69.2 ± 16.8 and 107.2 ± 6.8 for Cd were found to be in Z. spina-christi and P. cineraria unwashed leaves respectively. Also, the BCF of all studied metals were higher than 1.
Conclusion: Based on the values of BCF, it can be concluded that Z. spina-christi and P. cineraria can be considered as a suitable species for phytoextraction of heavy metals in the most polluted regions including industrial and urban areas.
 

Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater.
Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H₂O₂ concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal.
Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H₂O₂, voltage of 20, pH of 3, and contact time of 30 min).
Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process.
 

Background and Objective: Groundwater resources are the most valuable resources of each country. Development of agricultural activities in Ardabil plain and over-use of fertilizers and pesticides, improper disposal of municipal sewage and industrial areas are responsible for groundwater pollution. Clean-up of groundwater resources is very difficult and expensive. One of suitable method in preventing groundwater contamination is determination of the vulnerable zones of an aquifer to manage water resources and sustainable development. 
Materials and Methods: In this study for determining of vulnerability of aquifer Ardebil, information of 52 observational wells, 43 pumping tests, average of annual precipitation of 8 stations, 45 logs of exploration wells, land use map, topographic map and geological map have been gathered. Then, data layers of groundwater depth (D), Recharge (R), Aquifer media (A), Soil media (S), topography (T), impact of vadose zone (I) and hydraulic conductivity of aquifer (C) were prepared and overlaid based on DRASTIC method in ArcGIS software.
Results: Zoning map of DRASTIC method showed that DRASTIC index varied between 63 to 195 units. Areas with high vulnerability potential were characteristic with shallow depth groundwater, coarse-texture soil, thin soil and gentle topographic slope. Accuracy of the zoning map was evaluated by nitrate concentration map which showed the increase of DRASTIC index with nitrate concentration.
Conclusion: Northwestern and central parts of the Ardabil plain showed high vulnerability. The results of this study could help to reduce the environmental impact of contaminants on groundwater resources of the study area in future.
 

Background and Objective: Increased use of pesticides and chemical fertilizers in agriculture in order to increase the productivity of fertile lands has led to pollution of water resources with a variety of pollutants, including herbicides. In this study, a new polymer magnetic nanoadsorbent named PV/S-g-3D-GO/N was synthesized and used to remove 2,4-D and MCPA herbicides from aquatic environment.
Materials and Methods: To investigate the synthesized nanoadsorbent structure FTIR, FESEM, TEM, XRD, VSM and TGA techniques were used and the effect of parameters affecting the optimal removal of herbicides by the adsorbent, including pH, temperature, contact time, adsorption dose and initial herbicide concentration was investigated. The kinetic, isotherm and thermodynamic studies of adsorption were also investigated.
Results: The results showed that in the optimal adsorption conditions including pH 3 for both herbicides, contact time of 180 min for 2.4-D herbicide and 300 min for MCPA herbicide, absorption dose 5 g/L and temperature 50°C for both herbicides, the maximum absorption capacity (q_max) was 5.62 mg/g for 2.4-D and 4.94 mg/g for MCPA. The synthesized nanoparticles that were used to remove 2,4-D and MCPA herbicides from real samples were totally successful (100% removal efficiency). For both herbicides studied, the isothermal data followed the Longmuir model (2,4-D: R² = 0.995; MCPA: R² = 0.998), and the kinetics of the adsorption process was a pseudo-second-order model (2,4-D: R² = 0.991; MCPA: R² = 0.999).
Conclusion: The results of the present study indicate that the synthesized nano-adsorbent can be used to remove phenoxic herbicides from agricultural runoff as well as water sources contaminated with the studied herbicides.

Background and Objective: Conversion of houses into residential towers in worn-out urban textures increases population. Schools of the vicinity would face with multiplicity and limited space for students, leading to noise pollution. The purpose of this study was to evaluate the noise levels during morning and afternoon shifts among two primary schools in Zanjan.
Materials and Methods: Measurements had been done using sound level meter, KIMO DB100. The equivalent noise level (L_eq) measured during school year (2018-2019) in 10 stations. The measurements were done in three seasons (autumn, winter and spring) and in each season for two weeks. The data of the two schools were used for drawing charts and zoning by ArcGIS using IDW method. In addition, questionnaires were distributed among the teachers and school’ neighbors. The data were analyzed by SPSS software.
Results: The results showed that all the stations were tackled with noise pollution. The highest levels were related to school’s shift change and break times. The morning shift schools experienced higher levels of noise in comparison to the afternoon ones (1.87 and 2.1 dB, respectively for boys and girls). L_eq values for boys’ school was 2 dB higher than that of the girls’. The noise level in the schools were 72 dB, which is 17 dB higher than the standard level 55 dB.
Conclusion: The residents living close to the schools were exposed to noise pollution for almost 10 hours a day. This could be regarded as harmful. The zoning maps showed that southwest side of the yard, adjacent to the neighboring residential buildings, had the highest levels of noise. This study demonstrated the site selection for the schools were not properly done.  Having a control strategy is needed.

Background and Objective: The purpose of this cross-sectional study is to evaluate the microbial contamination of food-handlers' hands and food contact surfaces in food preparation and distribution centers.
Materials and Methods: This study was performed in 2019 in Fardis city of Alborz province. In this study, 100 samples of food contact surfaces and 48 samples of staff hands were collected from three traditional bakery units, pastry centers and snack shops and the microbial load was determined using a luminometer device. The samples were then analyzed for the presence of coliforms, Escherichia coli and Staphylococcus aureus bacteria.
Results: Among the samples studied, 62 samples (62%) of contact surfaces and 27 samples (56.25%) of food-handlers' hands had microbial load more than 30 RLU.  According to the results, the main cause of microbial contamination of equipments were 44.40% of Coliform bacteria and 11.10% of Staphylococcus aureus on the equipment of confectionery centers,  10% of Escherichia coli, 20% of coliforms and 20% of Staphylococcus aureus were detected on food tools and 2.30% of Escherichia coli, 14% of coliforms and 14% of Staphylococcus aureus –on the tools of traditional bakeries.Moreover coliform bacteria was noticed onconfectionary-handlers' hands and all three types of bacteria were also found on the hands of bakers.
Conclusion: The results showed that the cleanliness of food contact surfaces and the personnel hands hygiene was in poor condition which may pose serious threat to public health. Therefore, adequate personal hygiene practices, food safety and inspections should be implemented to protect the health of society.