Abolfazl Rahmani Sani; Ahmad Hosseini Bandehgharaei; Mahsa Naeemi; Ameneh Navidzadeh; Elham Agheli
Abstract
Background and aim:Antibiotics are a category of organic pollutants that can cause serious environmental problems through their disposal and uncontrolled release to the environment. The purpose of this study was to investigate the removal of sulfadimethoxine from aqueous solutions using carbon ...
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Background and aim:Antibiotics are a category of organic pollutants that can cause serious environmental problems through their disposal and uncontrolled release to the environment. The purpose of this study was to investigate the removal of sulfadimethoxine from aqueous solutions using carbon nanotubes.
Materials and Methods:The present work was an experimental study in which the effects of different parameters, such as PH, contact time, doses of carbon nanotubes, and different concentrations of sulfadimethoxine, on the removal of antibiotic from solutions were examined. All experiments were carried out in a 100-mL reactor at laboratory temperature (24 ± 2 ° C) using a magnetic stirrer at 350 rpm.
Results:The results showed that the maximum removal efficiency (94.5%) was occurred at pH = 6, adsorbent dosage 0.04 g, contact time of 30 min, and initial concentration of 20 mg/L. The findings on the effect of pH showed that the adsorption capacity increases with increasing pH, and at pH = 6, it reaches its maximum and then decreases again. The extent of removal was increased by increasing the dose of carbon nanotubes and the optimum amount for initial concentration of 100 mg/L (50 mL) was 0.04 g. The amount of absorption increased with increasing contact time and the maximum absorption occurred when the contact time was 30 min. The sulfadimethoxine antibiotic isotherm followed the Langmuir isotherm model (R2 = 0.9800) and the pseudo-second-order kinetic model (R2 = 0.9937).
Conclusion: The results showed that carbon nanotubes have a high potential for removal of sulfadimethoxine from aqueous solutions, due to its properties like its high surface area.
Mohammad Reza Atabaki; Ali Lotfi
Abstract
Abstract
Background and Objective:Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics ...
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Abstract
Background and Objective:Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics of polluting, their toxicity, persistence and bioaccumulation.. The aim of this study was to investigate the spatial distribution of heavy metals in the different north areas of Isfahan.
Method: In the present study, 30 soil samples (0-20 cm depth) were randomly collected and the total concentration of Pb, Cd, Zn and Cu were measured using Perkin Elmer's atomic absorption device. Also, some other soil properties including pH, EC, organic carbon, soil texture and organic matter proportions were measured. The inverse distance weighting (IDW) method was used for interpolation and mapping of the heavy metals concentration.
Findings: The results showed that the average concentrations of Pb, Cd, Zn and Cu in the study area were 47/16, 2/26, 57/35 and 22/31 mg/kg respectively. Also the results of statistical analysis showed that the standard deviations of Pb, Cd, Zn and Cu in the study area were 7.13, 0.51, 5.56 and 2.84 respectively.
Conclusion: The results indicate that the averageconcentrations of Pb and Cd in the soil of study area were higher than the global standard and Cu and Zn were lower than the global standard.
Zahra Yaghoubzadeh; Resa Safari
Abstract
Abstract
Background and objective: Biological assessment of water resources is of particular importance and the presence of pathogens in these resources affects the health of consumers. The aim of this study was to determine the bacterial contamination of water including total coliforms, fecal ...
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Abstract
Background and objective: Biological assessment of water resources is of particular importance and the presence of pathogens in these resources affects the health of consumers. The aim of this study was to determine the bacterial contamination of water including total coliforms, fecal coliforms and fecal streptococci in the Azad dam lake.
Methods and Materials: In this study, Sanandaj Azad dam water was evaluated for the indicator bacteria during one year (from May 2015 to June 2016). Sampling was performed from five stations in the areas of lake, transients and river. Statistical analysis of the obtained data was accomplished by ANOVA and Duncan tests using SPSS 18 software (P<0.05).
Results: Monthly analyzes showed that the maximum and minimum mean of total bacteria were recorded in the months of January (6.7×105 CFU / 100ml) and September, (1.6×104 CFU100ml). The maximum total mean value of total coliform was 2.3 × 104 CFU / 100ml in December and the minimum one was 62 CFU100ml in July. Neither thermophilic coliforms nor fecal streptococcus were observed in the lake of the dam in taken samples.
Conclusion: Based on the obtained results, the collected water behind the dam can be used without any purification for agricultural purposes and fish farming. However, this water supply is not suitable for drinking due to the observed microbial load.
Seyed Mostafa Tabatabaei; Ali Shahidi
Abstract
Abstract
Background & objeftive: In the Rafsanjan region of Kerman province, some sites have been considered for landfill construction. Since groundwater resources are the only source of water supply to provide water requirements in this region, the leachate leakage from landfills into groundwater ...
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Abstract
Background & objeftive: In the Rafsanjan region of Kerman province, some sites have been considered for landfill construction. Since groundwater resources are the only source of water supply to provide water requirements in this region, the leachate leakage from landfills into groundwater resources is regarded as a serious threat. The aim of this research is to study the trend of changes in the contamination concentration obtained from leachate leakage in a hypothetical landfill based on the geological and hydrogeological conditions of Rafsanjan plain in order to represent the effect of leachate leakage and contamination spread on groundwater resources.
Methods and Materials: Transmission of contamination has been studied on the basis of changes in concentration at two initial and final points of landfill by MT3DMS model daily and for 22 years period. The concentration of leachates has been considered 2 and 4 g / l, and its diffusion rate has been assumed 1.5 and 3 cm per day.
Results: The slope of the concentration increase in the propagation process and delayed diffusion at the beginning of the landfill with 2 and 4 g/l concentration and 1.5 cm rate during 15 and 17 years have an increasing trend, respectively and later it would have a decreasing trend. At the end of landfill, 90% increase in contamination will occur for 2 g/l concentration in the first five years and 4 g/l concentration in the first 9 years and it will have a fixed trend over the next few years.
Conclusion: In the various transmission processes after the penetration of the infection into the aquifer, the concentration of contamination is initially low and increasing over time and if the concentration of the contamination penetrating source and penetrating intensity are constant, the maximum concentration of aquifer pollution is fixed at a certain value. The type of transmission process has a huge impact on this constant value. So that in the propagation-diffusion process, the average in the first 5 years of this value is fixed and in a delayed state, it reaches a constant value after close to 22 years.
Ali Pakfetrat; Ali Sajjadi; Aliakbar Dehghan
Abstract
ABSTRACT
Background & Objectives: At present, one of the most important environmental issues is dental solid wastes due to its high contents of toxic, pathogen and hazardous agents. The aim of this study was to analyze the quantity and quality of dental solid waste in dental centers of Mashhad.
Materials ...
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ABSTRACT
Background & Objectives: At present, one of the most important environmental issues is dental solid wastes due to its high contents of toxic, pathogen and hazardous agents. The aim of this study was to analyze the quantity and quality of dental solid waste in dental centers of Mashhad.
Materials & Methods:In this descriptive study, 40 dental centers were studied. From each dental center, three samples were taken and analyzed at the successive working days (Sunday, Monday and Tuesday). The samples were manually sorted into 64 different components and measured by digital scale. Then, measured components were classified on the basis of characteristic and hazardous potential as well as material type. Obtained data were analyzed using a descriptive statistics software, SPSS 16.
Results:According to the results, total produced wastes in dental centers in Mashhad were 224.137 kg/day. Per capita and the average generation rate of each dental center were 106.32 g/day-patient and 5603 g/day, respectively. Potential infectious, domestic-type, chemical & pharmaceutical, and toxic wastes consisted of 41.24, 44.17, 9.89, and 4.7% of the generated waste, respectively.
Conclusion: Regarding optimal dental waste management, it is suggested that education of dentists should be done to learn waste reduction, separation and recycling in the offices along with separately collection and disposal of separated fractions of dental solid wastes according to the enacted instructions.
Keywords: Dental solid waste, Potential infectious waste, Domestic-type waste, Chemical &pharmaceutical waste, Mashhad.
Elham Asrari; Maryam Paydar
Abstract
Abstract
Background and Purpose: Air pollution problem in metropolitan’s city is made by different sources of pollutants. The proportion of air pollutants’ emissions have been increased in many cities of Iran such as Mashhad. This study aimed to investigate the relationships ...
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Abstract
Background and Purpose: Air pollution problem in metropolitan’s city is made by different sources of pollutants. The proportion of air pollutants’ emissions have been increased in many cities of Iran such as Mashhad. This study aimed to investigate the relationships between the trend of particular matter concentration changes and metrological parameters in the atmosphere of Mashhad.
Materials and Methods: In this descriptive cross - sectional study, data including temperature, sunny hours, precipitation, evaporation, moisture, speed and direction of wind were collected from 11 monitoring stations of air pollutants and Metrologic synoptic stations in Mashhad during 2010-2016. Daily average concentrations of PM10 of PM2.5) were calculated, and then relationships between pollutants and metrological data analyzed by Spss18 software.
Findings: The results showed that the maximum concentrations of particle matter occurred in October and autumn season. Numbers of unhealthy days were increased during the years of 2011-2013, decreased in 2014 - 2015 and increased again in 2016. The variations of PM10 and PM2.5 are significant with season, month and year (P <0.001). PM10 was directly related to temperature and evaporation (r=0.095). Also, there was a reverse relation among humidity and rainfall. A reverse relationship was observed between PM2.5 concentration and minimum temperature, sunny days, rainfall and wind speed; however, it was directly related to wind direction.
Conclusion: According to the obtained results in the autumn and October, the highest concentration of particulate matter was observed. Also, GIS maps showed that eastern and relatively center of Mashhad is more polluted than other areas.
Keywords: Air pollution, Mashhad, PM2.5, PM10, Meteorology data
Ghorban Vahabzadeh; Hojat Delavar; Jamshid Ghorbani; Mohammad Reza Ashrafi
Abstract
Abstract
Background and Purpose
Changing the quality of groundwater and increasing salinity of water resources are considered as a major threat for country's agricultural development, especially in arid and semi-arid lands. Preparing counter maps of salinity and salts can be an important step in the ...
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Abstract
Background and Purpose
Changing the quality of groundwater and increasing salinity of water resources are considered as a major threat for country's agricultural development, especially in arid and semi-arid lands. Preparing counter maps of salinity and salts can be an important step in the proper utilization of water resources. This research was carried out in Firoozabad plain in west of Fars province to evaluate the hydrogeochemical processes affecting groundwater quality.
Method
Preparation of the counter maps of the chemical parameters such as Electrical Conductivity (EC), chlorine and their variations along with the counter maps of variation trends of Total Dissolved Solids (TDSs), total hardness and Sodium Adsorption Ratio (SAR) in Firoozabad plain was performed using EC, NO3, TDS and hydrodynamic data of wells measured in East and West of Firoozabad plain. Preparation of similar maps was carried out using Schuler and Wilcox diagrams to produce coincidence lines.
Findings
Based on the maps of the chemical parameters in the studied areas along with variation diagrams and classifications of the data according to Wilcox and Schuler diagrams, the water classification indicated a declined quality of water for agricultural purposes in 2004 and 2011. Based on the obtained results for the drinking water classification, there were generally no significant changes in drinking quality except in 2011.
Conclusion
The amount of chlorine and electrical conductivity parameters in the Firoozabad plain increased from north and northwest to the center and eastern part of the plain and from east to center. Also, the results showed that based on the Schuler diagram from the aspect of drinking quality, the groundwater of this plain was classified into three classes: good, acceptable and moderate. However, in terms of quality for agricultural purposes, it was in C3S1, C1S1, C2S1 C3S2, C3S4 and C3S3 classes in 2011, and in C3S1, C1S1, and C2S1 classes in 2004 (first period). According to Wilcox, the water quality for agricultural purposes was decreased in 2004 and 2010. However, drinking water quality was rather stable except in 1390 which experienced a little bit decrease in quality.