Showing 81 results for Rat
Marzieh Razavi, Mosen Saeedi, Ebrahim Jabaari,
Volume 6, Issue 3 (12-2013)
Abstract
Background & Objectives: In this study, treatability of wastewater from a laundry unit was investigated by applying electrocoagulation method in which two pairs of aluminum and iron electrodes were utilized. Electrocoagulation is a noble treatment method suitable for different kinds of wastewater which has been given a considerable attentions by researchers recently. Applying direct current to two or several suitable metallic electrode in a batch reactor containing effluent would result in flocks of metal hydroxide.
Materials & Methods: We studied the effect of different operational parameters such as pH, electrodes distance, intensity of electrical current, and type of electrodes on the treatment efficiencies.
Results: Aluminum electrodes showed better effects on the treatment efficiencies in nitrate and COD removal. Maximum phosphate removal (99.93%)took place at pH=7 using Al electrodes. Whereas, in the case of iron electrode, maximum nitrate and COD removal efficiencies were about 97.60 and 80% at pH=9 and pH=6 respectively. Operational cost analysis showed that the corresponding costs of Al application as an electrode is different from that of iron electrode application.
Conclusion: Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.
Mohammad Sadegh Sekhavatjou, Roya Zekavati, Mohsen Peymani Froshani,
Volume 6, Issue 3 (12-2013)
Abstract
Objectives: Many of non-respiratory and respiratory disorders are associated with bioaerosols in indoor and outdoor air. The best conditions for bioaerosols life are high humidity and moderate temperatures, which exist usually in indoor spaces such as the prisons, where density of individual is high. Pathogen spreading centers cause the prisoners health at risk of disease outbreaks through airborne and breathing, sneezing, and coughing. Therefore, the aim of this research work was to measure concentration of particulate matters and also to identify and determine bacteria existing in the prisoners breathing air at high-density areas in one of the prisons and their relationship with each other.
Materials & Method: we conducted this research during summer and winter of 2012. We used TSI apparatus for collecting particles (PM2.5 and PM10). Blood agar and EMB agar media were applied to measure bacteria in indoor air (bedchambers and clinical admission wards) of the prison. According to NIOSH 0800 method, High volume pump with 28.3 L/min flow and a Single-stage Anderson Impactor were used for sampling. The time of measuring for each plate was 2.5 min. Finally, the data achieved were analyzed using SPSS after counting and detecting bacterial colonies grown and determining its density (CFU/m³) for two consecutive seasons of summer and winter. The tests analyzed by SPSS were ANOVA, Post hoc, correlation, and Pearson correlation tests.
Results: Amounts of particulate matter in bedchambers were exceeded than 24-hour EPA limits, while it was less than the limits in clinical admission wards. Gram-positive and gram-negative bacteria were found in three bedchambers (50% of the bedchambers) however, gram-positive bacteria were cultivated only in three bedchambers. The maximum bacterial contamination was measured at the main Lobby of the prison and bedchamber II and the minimum value was observed in admitted patient and TB patient wards. Results showed that there is no significant relationship between the particulate matters and the bacterial density during neither summer nor winter, but there is a strong and direct relationship between the prisoners population density, ventilation systems, and bacterial density n indoor air of the studied prison.
Conclusion: Based on the results, the maximum contamination load and exceeded concentration was observed in public sections and bedchambers. This findings were attributed to the daily entry of new prisoners, high population density in prison, presence of ill prisoners, prisoners with hidden respiratory disease showing no symptoms yet, old building, climatic conditions of the region, low efficiency of ventilation systems, and influx of particulates. To filter and purify prison indoor air, it is crucial to take serious action plans such as reducing criminal population density, sanitary and engineering measures
Hossein Banejad, Mahsa Kamali, Kimia Amirmoradi , Ehsan Olyaie,
Volume 6, Issue 3 (12-2013)
Abstract
Background and Objectives: Rivers are the most important resources supplying drinking, agricultural, and industrial water demand. Their quality fluctuates frequently due to crossing from different regions and beds as well as their direct relationship with their peripheral environments. Thus, it is essential to be considered the surveying and predicating changes in the water qualitative parameters in a river. In this study, in order to estimate some of the qualitative parameters (Total dissolved solids, electrical conductivity and sodium absorption rate) for Tehran Jajroud and Kermanshah Gharasu rivers, we used wavelet-artificial neural network (W-ANN) hybrid model during a statistical period of 24 years. Methods: We compared W-ANN model with ANN model in order to evaluate its capability in detecting signals and separating error signals for estimating water quality parameters of the abovementioned rivers. The evaluation of both models was performed by the statistical criteria including correlation coefficient, the Nash-Sutcliffe model efficiency coefficient (NS), the root mean square error (RMSE) and the mean absolute error (MAE). Results: The results showed that the optimized W-ANN with correlation coefficient of 0.9 has high capability to estimate SAR parameter in the stations studied. Moreover, we found that W-ANN had less error and higher accuracy in the case of EC and TDS parameters rather than ANN model. Conclusion: W-ANN proved high efficiency in forecasting of the water quality parameters of rivers, therefore, it can be used for decision making and assurance of monitoring results and optimizing the monitoring costs.
Kamiar Yaghmaeian , Ali Akbar Roudbari, Saeeid Nazemi,
Volume 6, Issue 3 (12-2013)
Abstract
Background & Objectives: The aim of the study was to design and implement integrated solid wastes management pattern in Shahroud industrial area, to evaluate the results, and to determine possible performance problems.
Materials & Methods: This cross - sectional study was carried out for 4 years in Shahroud industrial area and the implementation process included: 1. qualitative and quantitative analysis of all solid wastes generated in the area, 2. determining the current state of solid waste management in the area and identifying programs conducted, 3. designing and implementation of integrated management pattern including design and implementation of training programs, laws, penalties and incentives, and illustrating and implementing programs for all factories, and 4. monitoring the implementation process and determining the results.
Results: Annually, 1,728 tons of solid waste is generated in the area including 1603 tons of industrial waste and 125 tons of municipal wastes. By implementing this pattern, two separated systems of collection and recycling of domestic and industrial waste were launched in this area. Moreover, consistent with the goals, the amount of solid waste generated and disposed in 2011 was 51.5 and 28.6 kg per 100 million Rials production respectively. In addition, 42 and 40% of the industrial waste and paper were recycled.
Conclusion: Results showed that implementation of this pattern, i.e. running source separation, training programs, capacity building, providing technical services, completing chain of industries and strengthening the cooperation between industrial estate management and industrial units could greatly reduce the waste management problems.
Ali Kazemi, Habibollah Younesi, Nader Bahramifar,
Volume 6, Issue 4 (3-2014)
Abstract
Background and Objectives: bisphenol A and nonylphenol are xenoestrogen materials used as a monomer of plastics in widely volume in the production of plastic materials especially mineral water bottles and disposable plastic containers. In this study, we investigated the potential of migration of bisphenol A and nonylphenol from disposable plastic containers into water at different temperatures and also from mineral water into water at different temperatures. Materials and Methods: We conducted bisphenol A and nonylphenol extraction from each sample through liquid-liquid extraction. For identification and quantitative determination of bisphnol A and nonylphenol, we used gas chromatography equipped with mass detector, and for quantitative determination of these two compounds, we used high-performance liquid chromatography equipped with fluorescence detector. Results: We found that increasing temperature increased significantly the rate of migration of these two compounds in the water. Moreover, it was revealed that only the presence of bisphenol A in water of mineral water bottles was detected and the increase in temperature also increases the rate of migration bisphenol A into water. Conclusion: In general, results of this study showed that improper storage of mineral water bottles and also use of disposable plastic containers for hot drinks would result in increasing consumer exposure to these compounds.
Behrooz Karimi, Mohamad Sadeg Rajaie, Mohamad Javad Ghanadzadeh, Masome Mashayekhi,
Volume 6, Issue 4 (3-2014)
Abstract
Backgrounds and Objectives: Nowadays, global concerns about nitrate in groundwater and its adverse impact on health have increased. This study aims to evaluate the efficiency of nitrate reduction from aqueous solution through modified Fenton process using Nano scale zero-valent iron. Material and Methods: This research was an experimental study and performed at laboratory scale. Nitrate reduction was conducted by advanced oxidation process of Fe°/FeІІ/FeШ/H2O2 at pH 2-10, contact time 10-90 min, nitrate concentrations of 50-300 mg/L, and the molar ratio of [H2O2]/[Fe] 0.5-5. The effect of adding H2O2, molar ratio of reagents, contact time, and pH on nitrate removal was examined and optimal conditions for each of these parameters were determined. Spectrophotometer Dr/5000 was used to measure nitrate in the effluent. Results: We found that the optimal parameters in our studywere pH 3, the molar ratio [H2O2]/[Fe°] of 0.5, and the contact time 15 min. By applying these conditions, nitrate removal efficiency at the retention time 15 min, initial nitrate concentration of 100 mg/L, iron concentration of 10 mg/L, and pH 4 for FeШ، FeІІ، Fe°، FeІІ/Fe°/H2O2 and FeШ/Fe°/H2O2 was 10.5, 27.6, 36.5, 62.3, and 74% respectively. Conclusion: According to the experimental results, it was determined that modified Fenton process using zero iron nano-particles can reduce nitrate under optimal conditions and this method can be used for the removal of similar compounds.
Shaho Karami, Gholamreza Nabibidhendi, Hamidreza Jafari, Hassan Hoveidi, Amir Hedayati,
Volume 7, Issue 2 (10-2014)
Abstract
Background & Objectives: Human environment is surrounded bychemicals that could directly or indirectly endanger human health. Some statistics of WHO is indicative of the fact that four million people are employed in the chemical industry throughout the world and one million people die or become disabled annually due to contact with chemicals. Moreover, 1-4 Millions chemical toxicity occur annually. The purpose of this study was to understand the risks involved in chemicals in the workplace, to assess the task risk, and to propose appropriate control measures in order to eliminate or reduce risk in the petrochemical industry. Materials & Methods: In this study, the chemicals were identified in Arak Petrochemical and features that are indicative of hazardous materials were identified and using TOPSIS, The hazard rate were determined. Then the job duties of employees and employee exposure rate with chemicals were calculated and finally, a risk rate for exposure to chemicals in job duties was determined. Results: It was found that chemicals do not have too high risk to employees however, but the high risky chemicals were five chemicals including naphtha, ammonia, acetic acid, chlorine, and methanol for operational staff and two chemicals, i.e. ammonia and chlorine for operation and maintenance staffs . Conclusion: It is better to have an alternative for the materials that their risk rang is high and very high, and their production is suggested to be avoided.
Samira Akhavan, Hamid Zare Abyaneh, Maryam Bayat Varkeshi,
Volume 7, Issue 2 (10-2014)
Abstract
The objective of this study was to collect all the conducted studies on nitrate concentration in water resources of Iran. To achieve this purpose, the published papers in ISC and ISI journals as well as conferences and seminars were evaluated. The results of this survey showed that 116 studies have been carried out in 26 provinces of Iran. But,there was no published paper in Ilam, Alborz, South Khorasan, Kohgiluyeh and Boyer-Ahmad, and Lorestan provinces. According to these studies, the largest number of studies was performed in Hamadan province (14 cases), Khuzestan, and Mazandaran provinces (10 cases) and the least number of studies was conducted in Ardabil, Bushehr, Qazvin, Qom, and Kermanshah provinces. In Hamadan province, more than 1435 water samples were collected from water resources of this province, which is representative of large number of studies in this region. Maximum nitrate concentration (318 mg/L) was reported in Isfahan province and then in Zahedan city (295 mg/L), Sistan and Baluchestan Province. Based on the reported results in these studies, the nitrate pollution in water resources of Iran is at medium level. In most of the studies, high nitrate concentrations are due to lack of sewage collection network, discharge of urban and industrial sewage to water resources, and agricultural activities, which use high amounts of manure and fertilizer.
M. Nemati Varnosfaderany, A. Riyahi Bbakhtiari, Z. Gu, G. Chu,
Volume 7, Issue 3 (5-2014)
Abstract
Background and Objectives: Few investigations on polycyclic aromatic hydrocarbons (PAHs) in surface sediments have reported medium to high petrogenic contamination at the southwest coasts of the Caspian Sea. The aim of this study was to investigate distribution and potential sources of 16 PAH compounds in surface sediments of the southwest coasts of the Caspian Sea (Gillan province). Materials and methods: A total of 45 sediment samples from 15 stations at coasts of the Gillan province (from Astara to Lahijan) were collected from 10, 20, and 50 meters depths. Each sample was analyzed using Gas chromatography – Mass spectrometry. Diagnostic ratios were used for source identification. Results: The main PAH compounds in the study area were phenanthrene (87.6±74.6 ng/g), pyrene (43.1±23.5 ng/g), and naphthalene (34.4±40.4 ng/g) respectively. According to the calculated diagnostic ratios such as LMW/HMW (0.25-7.75), Ant/178 (0.02-0.11), Flu/202 (0.20-0.49), and B(a)Ant/228 (0.09-0.54) the main source of PAHs is petrogenic in this study area. Conclusion: According to PAH diagnostic ratios and similarity of dominant PAH compounds in study area with dominant PAH compounds of Azerbaijan oil field, main probable source of PAH compounds in Gillan province coasts is Azerbaijan oil pollution.
B. Kakavandi, M. Mokhtari, R. Rezaee Kalantari, E. Ahmadi, N. Rastkari, M. Fatehi, A. Azari,
Volume 7, Issue 3 (5-2014)
Abstract
Background and Objectives: Phenol is one of priority pollutants produced through leather, paint, resin, and pharmaceutical industries and it can contaminate groundwater after entering to the environment. Hence, it is necessary to use a suitable method for its removal. The aim of this study was synthesize and efficiency evaluation of magnetic nanocomposite of activated carbon powder-zero valent iron/silver (PAC-Feo/Ag) in the removal of phenol from aqueous solution. Material & Methods: Reduction method was used for converting bivalent iron to zero valent iron and co-precipitation method for depositing of iron on activated carbon. For coating silver on nano zero valent iron, rapid mixing at high temperature was used. The adsorbent was characterized using SEM, TEM, and XRD techniques. Then, the impact of pH, contact time, agitation speed, temperature, adsorbent, and initial phenol concentration were evaluated and optimized by one factor at the time method. Reaction kinetics and isotherms were also determined. Results: It was found that PAC-Feo/Ag has cubic and intertwined structure and has a diameter in the range from 40 to 100 nm. The optimum conditions for phenol removal by PAC-Feo/Ag were as pH=3, 90 min contact time, 200 rpm agitating speed and adsorbent concentration equal to 1 g/l. Isotherm and kinetic equations showed that the experimental data of phenol adsorption onto PAC-Feo/Ag are correlated to the Langmuir (R2>0.969) and pseudo-second order (R2<0.965) models, respectively. Conclusion: Under optimum conditions, modified adsorbent by zero valent iron and silver with maximum efficiency of 97% has quickly and effectively ability in removal of phenol and it can be easily separated from the solution sample by magnet because of its magnetic properties.
E Sadeghi, K Sharafi, A Almasi, M Dayhim, E Azizi, M Ghayebzadeh,
Volume 7, Issue 4 (1-2015)
Abstract
Background and objectives: Nitrate and nitrite threaten the human health. According to recent research works, one of the great sources of exposure to nitrate and nitrite in human diet is vegetables. The aim of this study is to determine the effect of drying and frying processes on nitrate and nitrite levels in abundant vegetables. Materials and methods: In this descriptive – analytical study, 180 vegetable samples were taken randomly from Kermanshah markets. Nitrite and nitrate concentration was determined by Greece- Ilosoay method. Then, freezing and boiling processes were carried out on samples and again, nitrite and nitrate levels were measured. The mean differences were analyzed using ANOVA and SPSS program. Results: the concentrations of nitrate and nitrite were significantly different (p<0.5) in terms of vegetable type, storage process, or consumption. As average, frying and drying process led to increase nitrite and nitrate levels in the vegetables except Garlic chives. Frying process and drying process decreased the nitrite levels by 13 and 52% respectively, while in the case of nitrate, it was 29 and 25% respectively. Conclusion: Reducing nitrite and nitrate levels does not occur in frying and drying processing in vegetables. Therefore, it is essential to study other methods of processing or control of nitrate and nitrite levels in the vegetables. It is crucial to monitor and control the quality of this product and studying other food processing because of the daily intake of vegetables and potential risks of nitrate and nitrite accumulation and its association with some illnesses and gastrointestinal tract cancers. .
T Rajaee, R Rahimi Benmaran, H Jafari,
Volume 7, Issue 4 (1-2015)
Abstract
Background & Objectives: The prediction and quality control of the Karaj River water, as one of the important needed water supply sources of Tehran, possesses great importance. In this study, performance of artificial neural network (ANN), combined wavelet-neural network (WANN), and multi linear regression (MLR) models were evaluated to predict next month nitrate and dissolved oxygen of “Pole Khab” station located in Karaj River. Materials and Methods: A statistical period of 11 years was used for the input of the models. In combined WANN model, the real monthly-observed time series of river discharge (Q) and the quality parameters (nitrate and dissolved oxygen) were analyzed using wavelet analyzer. Then, their completely effective time series were used as ANN input. In addition, the ability of all three models were investigated in order to predict the peak points of time-series that have great importance. The capability of the models was evaluated by coefficient of efficiency (E) and the root mean square error (RMSE). Results: The research findings indicated that the accuracy and the ability of hybrid model of wavelet neural network with the attitude of elimniations of time series noise had beeb better than the other two modes so that hybrid model of Wavelet artificial neural network wase able the improve the rate of RMSE for Nitrate ions in comparison with neural network and multiple linear regression models respectively, amounting to 35.6% and 75.92%, for Dissolved Oxygen ion as much as 40.57% and 60.13%. Conclusion: owing of the high capability wavelet neural network and the elimination of the time series noises in the prediction of quality parameters of river’s water, this model can be convenient and fast way to be proposed for management of water quality resources and assursnce from water quality monitoring results and reduction its costs.
M Jahangiri-Rad, R Nabizadeh, J Nouri, M Yunesian, F Moattar,
Volume 8, Issue 1 (8-2015)
Abstract
Background and Objective: Nitrate is one of the dissolved anions having great health importance in water. Human activities and natural sources are considered as the main roots of nitrate intrusion in to water bodies. The main objective of this paper was to study nitrate removal by packed bed column filled with (PAN)-oxime-nano Fe2O3. Materials and Methods: PAN-oxime-nano Fe2O3 were synthesized and used as an adsorbent in glass column for the removal of nitrate from aqueous solution. Nitrate solution tank was set above the prepared column. The effect of factors, such as flow rate (2, 5, and 7 mL/min) and bed depth (5, 10, and 15 cm) were studied. Results: It was found that the data fit well with Thomas model and breakthrough curve was designed accordingly. The column performed well at lowest flow rate. As the flow rates and time increased, earlier breakthrough was observed. The column breakthrough time (Ce/C0 = 0.05) was reduced from 9 to 4 h, as the flow rates increased from2 to 7 mL/min. Conclusion: fixed-bed using PAN-oxime-nano Fe2O3 exhibited good removal of nitrate. The adsorption studies showed that at longer bed depth, better removal of nitrate would be achieved. Thomas model was suitable for the normal description of breakthrough curve at the experimental condition. The data also were in good agreement with logistic regression.
E Rafeemanesh, L Nezakati Olfati,
Volume 8, Issue 2 (8-2015)
Abstract
Background and Objectives: Food borne diseases are one of the common and persistent problems of health system that staff in food preparation and distribution centers play important role in their incident. This study aimed to evaluate the effects of educational courses on changing hygienic knowledge and practice of managers and staff in food preparation and distribution centers in Mashhad in 2012. Materials and Methods: In this cross-sectional study, knowledge and practice in tree domains of personal, construction and tools hygiene were studied in 513 employees and employers of food preparation and distribution centers in Mashhad. The data was collected through interview, observation, and inspection checklist. Results: 265 subjects (51.6%) passed training course and awarded certificate, while 248 subjects (48.4%) did not participate whatsoever in training courses. Mean scores of knowledge and performance in trained group were 68.1±16.1 and 70.8±10.5% and in untrained group were 62.6±15.4 and 61.8±11.6% respectively, indicating statistically significant difference (p<0.05). Comparing scores of knowledge and practice scores between employers with valid certificate (during last 3 years) with employers without certificate did not show any valuable statistically difference in score reduction. Conclusion: This study showed that hygienic training courses can be effective in improving knowledge and practice of managers and staff in food preparation and distribution centers.
J Karimi, M Sadeghi, E Fadaie, M.h Mehdinejad,
Volume 8, Issue 3 (12-2015)
Abstract
Background and Objective: Collection and disposal of waste has an important role in public health. Isolation and separation procedures at the origin is considered as one of the most important and least costly methods of isolation and separation of waste. This study was aimed to culture and educate those involved in recycling and waste reduction in the Kalaeh City using two educational methods. .
Materials and Methods: This semi-experimental study was conducted in Kalaleh City. In the social and cultural context, Kalaleh was divided into six regions. Using cluster sampling, regions were selected randomly. In each area, 120 samples were used. The first group was face-to-face trained and the second group received training through the training package. Waste collection period was 60 days. After this time, the questionnaires were again filled up and the impact of teaching methods were investigated.
Results: Face-to-face training resulted in increasing waste separation from 70.8 (before training) to 95%. Whereas, this figure in the group receiving training package increased from 57.5 (before training) to 86.7%. Waste recycling rate was between 0.6 to 1 Kg per person per week. These wastes included paper, glass, plastic, and metal containers. On average, the waste recycled in face-to-face training group and training package group was 91 and 83 Kg per week.
Conclusion: Knowledge, attitude and cooperation in waste separation increased after training in both groups. However, in the face-to-face training group, the knowledge and participation in waste separation was more compared with training package group. Continuous training and organizing waste separators could be helpful to re-use waste. It causes less pollution of the environment, reduce the transmission of diseases associated with non-systematic disposal of solid waste, reduce costs and increase awareness about the problems and issues of solid waste, and reduce the solid waste volume.
M.m Amin, M Giyahi, M Mansourian,
Volume 8, Issue 4 (3-2016)
Abstract
Background and Objectives: Perchlorate, as an emerging contaminant, has attracted notice of the most individuals and organizations. Presence of perchlorate in the human body can lead to inappropriate regulation of metabolism in adults. Moreover, due to inhibition of iodide uptake in the thyroid gland, it causes neurological and behavioral problems in infants and children. United States Environmental Protection Agency (EPA) has enacted 15 µg/L perchlorate in drinking water as a guideline value. Regarding the possible sources and potential presence of perchlorate in the environment of the study area, and the unique characteristics of this pollutant, such as extreme water solubility, high mobility in soils and stability in the environment, the status of its contamination was assessed in soil, surface water and drinking water in the study area (Khorramshahr County).
Materials and Methods: Soil and water samples were taken during February to April, 2013. Combined sampling was used for soil sample collection and the random sampling was used for water (surface and drinking water) samples. Each sample was analyzed using ion chromatography. In this study, 15 samples of surface soil and 22 samples of surface and drink water were tested for perchlorate analysis.
Results: It was found that all surface soil and water samples collected from the study area were contaminated with perchlorate and exceed the standard level. Concentration of perchlorate in surface water and drinking water was 1400-5800 and 700-5900 µg/L respectively and in surface soils was 3.3-107.9 mg/kg.
Conclusion: The assessment of perchlorate in soil, surface water, and drinking water in the study area is extremely higher than recommended standards and therefore is a threat to the health of consumers.
R.s Hajimirmohammad Ali, H Karyab,
Volume 8, Issue 4 (3-2016)
Abstract
Background and Objective: The concentration of nitrate, factors affecting the balance sheet, and the changes in an aquifer is of utmost importance. Because modeling is an efficient method to predict the concentration of ions in water resources, in this study using lumped-parameter model and Monte Carlo simulation model, the nitrate concentrations in groundwater resources of Qazvin Plain were estimated and analyzed.
Materials and Methods: A total of 19 wells in different climates of saline watershed in Qazvin Plain were selected and entry and exit routes of nitrate to these sources were analyzed using lumped-parameter model. Finally, Monte Carlo simulation was used to determine the probability of the estimated nitrate concentration in aquifer.
Results: Application of lumped-parameter model for a part of a part of groundwater resources in Qazvin Plain watershed predicted the nitrate concentration in the range of 8.12 to 15.94 mg/l. The maximum concentration was estimated in cold-dry climate with 12.8±0.04 mg/L. Moreover, it was found that the difference between the estimated nitrate concentration and factors affecting its concentration in different climates was significant (p<0.05).
Conclusion: Despite the predicted concentrations of nitrate in the study area were in accordance with the Iran national standard for drinking purposes, the cumulative probability of Monte Carlo simulation showed that the possible violation of nitrate from the safe limit of 10 mg/l in the study area is 90% (p = 0.005).
B Nadalian, M Shahriari Mogadam, G.h Ebrahimipour, B Nadalian,
Volume 8, Issue 4 (3-2016)
Abstract
Background and Objectives: Organophosphate pesticides are used most commonly for domestic, commercial, and agricultural purposes and have been found to be highly toxic. In essence, bioremediation has become one of the most important tools for removing these compounds in the environment, considering its higher efficiency when compared with the physicochemical methods.
Materials and Methods: The biodegradation efficiency of two bacterial strains (i.e. Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2) were assessed. In order to evaluate Malathion biodegradation, each sample was cultured on mineral salts medium containing Malathion as a sole carbon source. Malathion biodegradation efficiency of the strains was monitored in different culture media. The ability of bacterial isolates to degrade Malathion was studied using gas chromatography.
Results: Serratia marcescens BNA1 and Pseudomonas aeruginosa BNA2 were able to degrade Malathion. Biodegradation percentage in different treatments recorded were: BNA1+Ma (33.88%), BNA2+MA (26.45%), BNA1+BNA2+Ma (46/96%), BNA1+Ma+Tween (61.05%), BNA2+Ma+Tween (40.17%), and BNA1+BNA2+Ma+ Tween (67.79%).
Conclusion: It could be speculated that the best degradation efficiency can be yielded using mixture of strains plus a surfactant. The results of this study can be used in the bioremediation of Malathion contaminate soil after doing the pilot experiments.
Sar Mousavi, M Parvaneh,
Volume 9, Issue 2 (9-2016)
Abstract
Background and Objectives: Conventional methods of leachate treatment are inefficient due to high pollution loads and characteristics of the leachate. In recent years, an integrated method has been developed considerably. The aim of this research was to evaluate the effect of powdered activated carbon on the treatment of landfill leachate of Kermanshah City by a columnar aerobic sequencing batch reactor.
Materials and Methods: This study was carried out in three reactors having a total volume of 2000 mL and each having an effective volume of 600 mL in the bench scale. To the reactors 2 and 3 that were similar from environmental conditions and operation point of view with reactor 1 (with no carbon powder), 5 and 10 g/L of PAC were added, respectively. The effects of different doses of PAC (0, 5, 10 g/L) and hydraulic detention times (HRT = 48, 96, 144 h) were investigated in order to remove the Chemical Oxygen Demand (COD) and ammonia nitrogen (NH3-N) from the leachate. The efficiency was investigated using two -way ANOVA test in SPSS software (Ver. 16).
Results: The results of two-way ANOVA showed that there was a significant difference (P-value=0.001) between the removal efficiency of COD and NH3–N at different HRTs with different doses of PAC. The highest removal efficiency achieved at HRT=144 h for COD and NH3-N was in Reactor 1 were 50.11 ± 4.42 and 19.85 ± 1.49%; in reactor 2: 55.67 ± 1.6 and 25.7 ± 0.89%; and in reactor 3: 58.02 ± 3.99and 25.48 ± 1.7%, respectively.
Conclusion: It can be concluded that the combination of biological - activated carbon compared with the biological process, can remove COD and NH3–N of strong sewages such as landfill leachate, although achieving standard treatments using this method is not possible.
Gh Fallah Ghalhari, R Esmaili, F Shakeri,
Volume 9, Issue 2 (9-2016)
Abstract
Background and Objectives: Nowadays, indicators related to human physiology have special roles in human bioclimatic and environmental studies. One of these indices is Physiological Equivalent Temperature (PET). In the present study, trends of physiological equivalent temperature index over the past half century, which is the foundation of plans, especially in the field of health and environment, were evaluated in four climatic regions of Iran (Mashhad, Rasht, Esfahan, Tabriz and Bandar Abbas).
Material and methods: In this study, the data required to calculate the heat stress in the daily scale for 50 years during 1961-2010 were obtained from Iranian Meteorological Organization. Then, PET index at the daily scale was calculated and values greater than 35°C were identified for warm periods of the year. In the next step, the seasonal trends were analyzed by Mann-Kendall test.
Results: Changes in the frequency of days with heat stress in stations of Mashhad, Isfahan, and Tabriz have been rising during spring and summer. In other words, the greatest amount of positive change has occurred over the long-term average in these cities. The highest frequency of hot days was observed in Rasht and Bandar Abbas stations. The main reason for this subject has to do with how adjacent they were to the sea and the high rate of evaporation in such areas.
Conclusion: The 1980s-1990s have been allocated as the most days of hot stress. Upward trend of thermal stress occurring in the studied stations has increased the attention to the problem of heat stress and disease (thermal attack, fainting, muscle cramps) from the field of planning and management of the crisis.
