Mahmood Alimohammadi - Academia.edu (original) (raw)

Papers by Mahmood Alimohammadi

Journal of Advances in Environmental Health Research, 2014

Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and c... more Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and copper (Cu)] were investigated in four common edible vegetables including coriander, dill, radish root and radish leaf grown at periurban sites in Sanandaj, Iran. A total of 120 composite samples of vegetables were taken from ten vegetable farms during six months from May to October 2012. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the levels of heavy metals. The results showed that Pb and Cr concentrations exceeded the safety limits given by Food and Agriculture Organization (FAO) or the World Health Organization (WHO) for human consumption with the exception of copper and cadmium that were lower than the permissible leveling in all of the samples. Furthermore, the results showed that there was a significant variation in the levels of these metals among the examined vegetables (P < 0.001). DI values for Pb, Cu, Cr and Cd could be 0.1, 1.5, 0.94 and 0.004 mg per day, respectively. As respect, DI values for Pb and Cd were also below the international guideline bases. Although Pb level was higher than the permissible standard, it seems that daily intake of these vegetables may not have detrimental health hazards to consumers.

مجله مراقبتهاي باليني, Dec 16, 2013

ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonat... more ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonation, ultraviolet radiation, membrane processes, etc. Water disinfection using irradiation techniques is new in water treatment industry which has been developed recently. The aim of the present study was to investigate radio frequency (RF) efficiency for the inactivation of total coliform (TC), fecal coliform, and heterotrophic bacterial count of water pellets. Tap water samples were taken from School of Public Health, Tehran University of Medical Sciences and irradiated using hydropad device, steam KLEAR model S-38 (1.2 W and frequency of 120-200 kHz). Microbial concentration was measured in cycles 1, 5, 10, 15, 20, 25, 30, 35, and 40 in 1 and 2 h contact time. Indicator bacteria were counted using plate count method and multiple fermentation tube technique. According to the microbial results, after 40 cycles and without chlorine residual, TC, fecal coliform, and heterotrophic bacteria were reduced by 86, 90, and 85%, while after 15 cycles and 0.8 mg/l chlorine residual, removal rate was 89, 91, and 89%, respectively. Furthermore, it was observed that after 2 h of contact time, TCs, fecal coliforms, and heterotrophic plate count were reduced by 78.2, 80, and 60%, respectively. Although RF efficiency in water disinfection has not been studied, our findings suggested its possible use due to more than 75% efficiency. From the standpoint of practical use, more studies should be done, especially to find a fine synergist agent, determining power, frequency, and suitable contact time and also the method should be modified.

Iranian journal of public health, 2014

Desalination and Water Treatment, 2016

Journal of Advances in Environmental Health Research, Sep 6, 2014

Iranian Journal of Health and Environment, Jul 15, 2014

Background and Objectives: Doogh is considered as one of the traditional drink in iran and other ... more Background and Objectives: Doogh is considered as one of the traditional drink in iran and other nations like Eastern Europe, Middle East and Asia. in the past the "doogh" was applied to a product which remained after dilution of full fat yoghurt with water and fat separation using the musk. Nowadays Doogh has have physical, chemical, physico-chemical, microbial and sensory characteristics and standards. in this study the microbial quality of four famous brands produced in iran was assessed. Materials and Methods: This is a cross-sectional study. Totally, 126 samples were selected from the foodstuff suppliers using random sampling .in order to determine Staphylococcus aureus, Baird Parker Agar (recognition test) and coagulase test (confirmation test) were used. Results: The results were analyzed using SPSS, and T-Test and one way ANOVA were performed. The results showed that in view of contamination there is Significant differences between the months, the brands and the types of doogh (p<0.05). Conclusion: According to the results and due to probable presence of Entrotoxin, the analyzed brands can be potent risk to consumer's health.

Journal of Environmental Health Science and Engineering, 2015

In this study, a central composite design (CCD) was used for modeling and optimizing the operatio... more In this study, a central composite design (CCD) was used for modeling and optimizing the operation parameters such as pH, initial tetracycline and persulfate concentration and reaction time on the tetracycline degradation using sono-activated persulfate process. The effect of temperature, degradation kinetics and mineralization, were also investigated. The results from CCD indicated that a quadratic model was appropriate to fit the experimental data (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) and maximum degradation of 95.01 % was predicted at pH = 10, persulfate concentration = 4 mM, initial tetracycline concentration = 30.05 mg/L, and reaction time = 119.99 min. Analysis of response surface plots revealed a significant positive effect of pH, persulfate concentration and reaction time, a negative effect of tetracycline concentration. The degradation process followed the pseudo-first-order kinetic. The activation energy value of 32.01 kJ/mol was obtained for US/S2O8 (2-) process. Under the optimum condition, the removal efficiency of COD and TOC reached to 72.8 % and 59.7 %, respectively. The changes of UV-Vis spectra during the process was investigated. The possible degradation pathway of tetracycline based on loses of N-methyl, hydroxyl, and amino groups was proposed. This study indicated that sono-activated persulfate process was found to be a promising method for the degradation of tetracycline.

With the rapid growth of urbanization, the discharge of industrial, agricultural and municipal wa... more With the rapid growth of urbanization, the discharge of industrial, agricultural and municipal wastewater into water resources is increasing. Cyanobacteria are a dominant component of the phytoplankton that causes problems in water reservoirs. The aim of this study is to evaluate the performance of bacteria in the removal of cyanobacteria algae from water reservoirs. In this study, a biological method with four types of bacteria was applied for algae removal. First of all, species of cyanobacteria were identified, and then their specific medium BG-11 was prepared. The species of bacteria (Pseudomonas aeroginosa, Enterobacter aerogenes, Klebsiella oxytoca, and Citrobacter freundii) were used for removing cyanobacteria for a period of 0 to 10 days. Variables such as chlorophyll a, nitrate, phosphate, dissolved oxygen, heterotrophic plate count, and algal cell count were measured during the study period. The results of the present study showed that P. aeroginosa and C. freundii were effective for the removal of chlorophyll a in the first five to six days of the study period with removal efficiency of 63.5 and 56.59% respectively. The other parameters such as phosphate, nitrate, and algal cells decreased relatively. This method is relatively efficient and effective for removing algae from water resources and can be used for removing nutrients and cyanobacteria algae from water resources.

Journal of Environmental Health Science and Engineering, 2015

Background: Mercury is considered as a toxic heavy metal in aquatic environments due to accumulat... more Background: Mercury is considered as a toxic heavy metal in aquatic environments due to accumulation in bodies of living organisms. Exposure to mercury may lead to different toxic effects in humans including damages to kidneys and nervous system. Materials and methods: Multi-walled carbon nanotubes (MWCNTs) were selected as sorbent to remove mercury from aqueous solution using batch technique. ICP instrument was used to determine the amount of mercury in solution. Moreover, pH, contact time and initial concentration of mercury were studied to determine the influence of these parameters on the adsorption conditions.

Environmental science and pollution research international, Jan 11, 2015

Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the large... more Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the largest wastewater treatment plant in the Middle East. Active sampling was carried out around four operational units and a point as background. The results showed that the aeration tank with an average of 1016 CFU/m(3) in winter and 1973 CFU/m(3) in summer had the greatest effect on emission of bacterial bioaerosols. In addition, primary treatment had the highest impact on fungal emission. Among the bacteria, Micrococcus spp. showed the widest emission in the winter, and Bacillus spp. was dominant in summer. Furthermore, fungi such as Penicillium spp. and Cladosporium spp. were the dominant types in the seasons. Overall, significant relationship was observed between meteorological parameters and the concentration of bacterial and fungal aerosols.

Environmental Science and Pollution Research, 2015

Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the large... more Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the largest wastewater treatment plant in the Middle East. Active sampling was carried out around four operational units and a point as background. The results showed that the aeration tank with an average of 1016 CFU/m 3 in winter and 1973 CFU/m 3 in summer had the greatest effect on emission of bacterial bioaerosols. In addition, primary treatment had the highest impact on fungal emission. Among the bacteria, Micrococcus spp. showed the widest emission in the winter, and Bacillus spp. was dominant in summer. Furthermore, fungi such as Penicillium spp. and Cladosporium spp. were the dominant types in the seasons. Overall, significant relationship was observed between meteorological parameters and the concentration of bacterial and fungal aerosols.

Iranian Journal of Environmental Health Science & Engineering, 2012

Sonolysis and photochemical degradation of different compounds such as chlorinated aliphatic hydr... more Sonolysis and photochemical degradation of different compounds such as chlorinated aliphatic hydrocarbons are among the recent advanced oxidation processes. Perchloroethylene is one of these compounds that has been mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation, andphotochemical oxidation by ultra violet ray and hydrogen peroxide were investigated. Three different initial concentrations of perchloroethylene at different pH values, detention periods, and concentrations of hydrogen peroxide were investigated. Head space gas chromatography with FID detector was used for analyses of perchloroethylene. This research was performed in 9 months from April through December 2011. Results showed that perchloroethylene could be effectively and rapidly degraded by ultrasonic irradiation, photochemical oxidation by ultra violet ray, hydrogen peroxide and a combination of these methods. Kinetics of perchloroethylene was strongly influenced by time, initial concentration and pH value. Degradation of Perchloroethylene increased with decrease in the initial concentration of perchloroethylene from 0.3 to 10 mg/L at all initial pH. The results showed an optimum degradation condition achieved at pH = 5 but did not affect significantly the perchloroethylene destruction in the various pH values. Kinetic modeling applied for the obtained results showed that the degradation of perchloroethylene by ultrasound and photo-oxidation followed first order and second order model. The percentage of removal in the hybrids reactor was higher than each of the reactors alone, the reason being the role of hydroxyl radical induced by ultrasound and photochemical reaction.

Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and c... more Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and copper (Cu)] were investigated in four common edible vegetables including coriander, dill, radish root and radish leaf grown at periurban sites in Sanandaj, Iran. A total of 120 composite samples of vegetables were taken from ten vegetable farms during six months from May to October 2012. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the levels of heavy metals. The results showed that Pb and Cr concentrations exceeded the safety limits given by food and agriculture organization (FAO) or the world health organization (WHO) for human consumption with the exception of copper and cadmium that were lower than the permissible leveling in all of the samples. Furthermore, the results showed that there was a significant variation in the levels of these metals among the examined vegetables (P < 0.001). DI values for Pb, Cu, Cr and Cd could be 0.1, 1.5, 0.94 and 0.004 mg per day, respectively. As respect, DI values for Pb and Cd were also below the international guideline bases. Although Pb level was higher than the permissible standard, it seems that daily intake of these vegetables may not have detrimental health hazards to consumers.

ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonat... more ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonation, ultraviolet radiation, membrane processes, etc. Water disinfection using irradiation techniques is new in water treatment industry which has been developed recently. The aim of the present study was to investigate radio frequency (RF) efficiency for the inactivation of total coliform (TC), fecal coliform, and heterotrophic bacterial count of water pellets. Tap water samples were taken from School of Public Health, Tehran University of Medical Sciences and irradiated using hydropad device, steam KLEAR model S-38 (1.2 W and frequency of 120-200 kHz). Microbial concentration was measured in cycles 1, 5, 10, 15, 20, 25, 30, 35, and 40 in 1 and 2 h contact time. Indicator bacteria were counted using plate count method and multiple fermentation tube technique. According to the microbial results, after 40 cycles and without chlorine residual, TC, fecal coliform, and heterotrophic bacteria were reduced by 86, 90, and 85%, while after 15 cycles and 0.8 mg/l chlorine residual, removal rate was 89, 91, and 89%, respectively. Furthermore, it was observed that after 2 h of contact time, TCs, fecal coliforms, and heterotrophic plate count were reduced by 78.2, 80, and 60%, respectively. Although RF efficiency in water disinfection has not been studied, our findings suggested its possible use due to more than 75% efficiency. From the standpoint of practical use, more studies should be done, especially to find a fine synergist agent, determining power, frequency, and suitable contact time and also the method should be modified.

The objective of this study was to evaluate the presence of perchloroethylene (PCE) and trichloro... more The objective of this study was to evaluate the presence of perchloroethylene (PCE) and trichloroethylene (TCE) in dry cleaning shops in Tehran, Iran. PCE and TCE are two most prevalent solvents in dry-leaning shops. Air and effluent samples were collected in October to December 2011 from 10 dry-cleaning shops. Analyses were performed by head-space gas chromatography technique. Gas chromatography with FID detector is used for analysis. Mean PCE levels in the air of ten dry-cleanings ranged from 42.7 to 516 μgL -1 with maximum level of 960, PCE mean levels in the effluent ranged from 186.5 to 292.9 μgL -1 with maximum level of 326. Mean TCE levels in the air effluents ranged from 29.5 to 543.7 μgL -1 with maximum 964 and 25.5 to 29.75 μgL -1 with maximum level of 37 μgL -1 respectively. The survey of the PCE and TCE in dry-cleaning shops in Tehran shows that both air and effluent have been contaminated by PCE and TCE. These solvents have several negative health effects. Health educat...

Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addit... more Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addition, it can deteriorate the performance of water treatment process including coagulation, adsorption, and membranes. NOM also reacts with chlorine in the chlorination process and may form disinfection by-products. The present study was carried out in laboratory-scale in a batch system using a cylinder shape reactor with effective volume of 2 L. The initial NOM concentrations during the study period were 10, 25, and 50 mg/L. After specific time intervals, samples were taken from the reactor and filtered. Finally, the NOM removal according to total organic carbon (TOC) content of the samples that were analyzed with a TOC analyzer. The results showed that the highest NOM removal efficiency for three initial concentrations 10, 25, and 50 mg/L were 91, 94, and 82%, respectively. These removal efficiencies were obtained at pH 7, contact time of 20 min, and electrical current of 0.1 A. The elec...

Sonolysis and photodegradation of various compounds such as chlorinated aliphatic hydrocarbons ar... more Sonolysis and photodegradation of various compounds such as chlorinated aliphatic hydrocarbons are the recent advanced oxidation processes. Perchloroethylene (PCE) is one of these compounds mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation and photooxidation by UVC were investigated. Head space gas chromatography with FID detector was used for analyses of PCE. Results showed that PCE could be effectively and rapidly degraded by ultrasonic irradiation, photooxidation by UVC and combination of these methods. The order of studied reactions for degradation PCE has been determined.

Journal of Environmental Health Science and Engineering, 2013

Fungi are usually presented in indoor environments and cause of many diseases. The aim of this de... more Fungi are usually presented in indoor environments and cause of many diseases. The aim of this descriptive study was to investigate the level of fungal contamination in hospital rooms. Sampling was conducted with an Andersen one-stage viable impactor (Quick Take-30) and counting plates containing a fungus-selective medium. A total of 120 air samples from ten hospital environments were performed. Airborne fungi concentrations were determined 72-120 hours after sampling. Total mean concentration of detected fungi in the hospital rooms was 55 ± 56 (mean ± SD) cfu/m 3 . The findings of the fungal concentration in the various hospital rooms revealed different levels of contamination: the lowest mean counts (37 ± 17 cfu/m 3 ) were observed in NS 1 (Nursing Stations 1), and the highest (97 ± 217 cfu/m 3 ) were reported in Orthopedics Operating Room (OOR). The most common fungal genus isolated were Penicillium (70%), Aspergillus (14%), Cladosporium (12%), Alternaria (2%) and others (2%). The obtained results showed that fungal concentrations in the present study were nearly high and these conditions should be considered as a risk factor for patients and other persons in the hospital.

Journal of Advances in Environmental Health Research, 2014

Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and c... more Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and copper (Cu)] were investigated in four common edible vegetables including coriander, dill, radish root and radish leaf grown at periurban sites in Sanandaj, Iran. A total of 120 composite samples of vegetables were taken from ten vegetable farms during six months from May to October 2012. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the levels of heavy metals. The results showed that Pb and Cr concentrations exceeded the safety limits given by Food and Agriculture Organization (FAO) or the World Health Organization (WHO) for human consumption with the exception of copper and cadmium that were lower than the permissible leveling in all of the samples. Furthermore, the results showed that there was a significant variation in the levels of these metals among the examined vegetables (P < 0.001). DI values for Pb, Cu, Cr and Cd could be 0.1, 1.5, 0.94 and 0.004 mg per day, respectively. As respect, DI values for Pb and Cd were also below the international guideline bases. Although Pb level was higher than the permissible standard, it seems that daily intake of these vegetables may not have detrimental health hazards to consumers.

مجله مراقبتهاي باليني, Dec 16, 2013

ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonat... more ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonation, ultraviolet radiation, membrane processes, etc. Water disinfection using irradiation techniques is new in water treatment industry which has been developed recently. The aim of the present study was to investigate radio frequency (RF) efficiency for the inactivation of total coliform (TC), fecal coliform, and heterotrophic bacterial count of water pellets. Tap water samples were taken from School of Public Health, Tehran University of Medical Sciences and irradiated using hydropad device, steam KLEAR model S-38 (1.2 W and frequency of 120-200 kHz). Microbial concentration was measured in cycles 1, 5, 10, 15, 20, 25, 30, 35, and 40 in 1 and 2 h contact time. Indicator bacteria were counted using plate count method and multiple fermentation tube technique. According to the microbial results, after 40 cycles and without chlorine residual, TC, fecal coliform, and heterotrophic bacteria were reduced by 86, 90, and 85%, while after 15 cycles and 0.8 mg/l chlorine residual, removal rate was 89, 91, and 89%, respectively. Furthermore, it was observed that after 2 h of contact time, TCs, fecal coliforms, and heterotrophic plate count were reduced by 78.2, 80, and 60%, respectively. Although RF efficiency in water disinfection has not been studied, our findings suggested its possible use due to more than 75% efficiency. From the standpoint of practical use, more studies should be done, especially to find a fine synergist agent, determining power, frequency, and suitable contact time and also the method should be modified.

Iranian journal of public health, 2014

Desalination and Water Treatment, 2016

Journal of Advances in Environmental Health Research, Sep 6, 2014

Iranian Journal of Health and Environment, Jul 15, 2014

Background and Objectives: Doogh is considered as one of the traditional drink in iran and other ... more Background and Objectives: Doogh is considered as one of the traditional drink in iran and other nations like Eastern Europe, Middle East and Asia. in the past the "doogh" was applied to a product which remained after dilution of full fat yoghurt with water and fat separation using the musk. Nowadays Doogh has have physical, chemical, physico-chemical, microbial and sensory characteristics and standards. in this study the microbial quality of four famous brands produced in iran was assessed. Materials and Methods: This is a cross-sectional study. Totally, 126 samples were selected from the foodstuff suppliers using random sampling .in order to determine Staphylococcus aureus, Baird Parker Agar (recognition test) and coagulase test (confirmation test) were used. Results: The results were analyzed using SPSS, and T-Test and one way ANOVA were performed. The results showed that in view of contamination there is Significant differences between the months, the brands and the types of doogh (p<0.05). Conclusion: According to the results and due to probable presence of Entrotoxin, the analyzed brands can be potent risk to consumer's health.

Journal of Environmental Health Science and Engineering, 2015

In this study, a central composite design (CCD) was used for modeling and optimizing the operatio... more In this study, a central composite design (CCD) was used for modeling and optimizing the operation parameters such as pH, initial tetracycline and persulfate concentration and reaction time on the tetracycline degradation using sono-activated persulfate process. The effect of temperature, degradation kinetics and mineralization, were also investigated. The results from CCD indicated that a quadratic model was appropriate to fit the experimental data (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001) and maximum degradation of 95.01 % was predicted at pH = 10, persulfate concentration = 4 mM, initial tetracycline concentration = 30.05 mg/L, and reaction time = 119.99 min. Analysis of response surface plots revealed a significant positive effect of pH, persulfate concentration and reaction time, a negative effect of tetracycline concentration. The degradation process followed the pseudo-first-order kinetic. The activation energy value of 32.01 kJ/mol was obtained for US/S2O8 (2-) process. Under the optimum condition, the removal efficiency of COD and TOC reached to 72.8 % and 59.7 %, respectively. The changes of UV-Vis spectra during the process was investigated. The possible degradation pathway of tetracycline based on loses of N-methyl, hydroxyl, and amino groups was proposed. This study indicated that sono-activated persulfate process was found to be a promising method for the degradation of tetracycline.

With the rapid growth of urbanization, the discharge of industrial, agricultural and municipal wa... more With the rapid growth of urbanization, the discharge of industrial, agricultural and municipal wastewater into water resources is increasing. Cyanobacteria are a dominant component of the phytoplankton that causes problems in water reservoirs. The aim of this study is to evaluate the performance of bacteria in the removal of cyanobacteria algae from water reservoirs. In this study, a biological method with four types of bacteria was applied for algae removal. First of all, species of cyanobacteria were identified, and then their specific medium BG-11 was prepared. The species of bacteria (Pseudomonas aeroginosa, Enterobacter aerogenes, Klebsiella oxytoca, and Citrobacter freundii) were used for removing cyanobacteria for a period of 0 to 10 days. Variables such as chlorophyll a, nitrate, phosphate, dissolved oxygen, heterotrophic plate count, and algal cell count were measured during the study period. The results of the present study showed that P. aeroginosa and C. freundii were effective for the removal of chlorophyll a in the first five to six days of the study period with removal efficiency of 63.5 and 56.59% respectively. The other parameters such as phosphate, nitrate, and algal cells decreased relatively. This method is relatively efficient and effective for removing algae from water resources and can be used for removing nutrients and cyanobacteria algae from water resources.

Journal of Environmental Health Science and Engineering, 2015

Background: Mercury is considered as a toxic heavy metal in aquatic environments due to accumulat... more Background: Mercury is considered as a toxic heavy metal in aquatic environments due to accumulation in bodies of living organisms. Exposure to mercury may lead to different toxic effects in humans including damages to kidneys and nervous system. Materials and methods: Multi-walled carbon nanotubes (MWCNTs) were selected as sorbent to remove mercury from aqueous solution using batch technique. ICP instrument was used to determine the amount of mercury in solution. Moreover, pH, contact time and initial concentration of mercury were studied to determine the influence of these parameters on the adsorption conditions.

Environmental science and pollution research international, Jan 11, 2015

Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the large... more Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the largest wastewater treatment plant in the Middle East. Active sampling was carried out around four operational units and a point as background. The results showed that the aeration tank with an average of 1016 CFU/m(3) in winter and 1973 CFU/m(3) in summer had the greatest effect on emission of bacterial bioaerosols. In addition, primary treatment had the highest impact on fungal emission. Among the bacteria, Micrococcus spp. showed the widest emission in the winter, and Bacillus spp. was dominant in summer. Furthermore, fungi such as Penicillium spp. and Cladosporium spp. were the dominant types in the seasons. Overall, significant relationship was observed between meteorological parameters and the concentration of bacterial and fungal aerosols.

Environmental Science and Pollution Research, 2015

Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the large... more Bioaerosol concentration was measured in wastewater treatment units in south of Tehran, the largest wastewater treatment plant in the Middle East. Active sampling was carried out around four operational units and a point as background. The results showed that the aeration tank with an average of 1016 CFU/m 3 in winter and 1973 CFU/m 3 in summer had the greatest effect on emission of bacterial bioaerosols. In addition, primary treatment had the highest impact on fungal emission. Among the bacteria, Micrococcus spp. showed the widest emission in the winter, and Bacillus spp. was dominant in summer. Furthermore, fungi such as Penicillium spp. and Cladosporium spp. were the dominant types in the seasons. Overall, significant relationship was observed between meteorological parameters and the concentration of bacterial and fungal aerosols.

Iranian Journal of Environmental Health Science & Engineering, 2012

Sonolysis and photochemical degradation of different compounds such as chlorinated aliphatic hydr... more Sonolysis and photochemical degradation of different compounds such as chlorinated aliphatic hydrocarbons are among the recent advanced oxidation processes. Perchloroethylene is one of these compounds that has been mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation, andphotochemical oxidation by ultra violet ray and hydrogen peroxide were investigated. Three different initial concentrations of perchloroethylene at different pH values, detention periods, and concentrations of hydrogen peroxide were investigated. Head space gas chromatography with FID detector was used for analyses of perchloroethylene. This research was performed in 9 months from April through December 2011. Results showed that perchloroethylene could be effectively and rapidly degraded by ultrasonic irradiation, photochemical oxidation by ultra violet ray, hydrogen peroxide and a combination of these methods. Kinetics of perchloroethylene was strongly influenced by time, initial concentration and pH value. Degradation of Perchloroethylene increased with decrease in the initial concentration of perchloroethylene from 0.3 to 10 mg/L at all initial pH. The results showed an optimum degradation condition achieved at pH = 5 but did not affect significantly the perchloroethylene destruction in the various pH values. Kinetic modeling applied for the obtained results showed that the degradation of perchloroethylene by ultrasound and photo-oxidation followed first order and second order model. The percentage of removal in the hybrids reactor was higher than each of the reactors alone, the reason being the role of hydroxyl radical induced by ultrasound and photochemical reaction.

Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and c... more Concentration and daily intake (DI) of heavy metals [lead (Pb), chromium (Cr), cadmium (Cd) and copper (Cu)] were investigated in four common edible vegetables including coriander, dill, radish root and radish leaf grown at periurban sites in Sanandaj, Iran. A total of 120 composite samples of vegetables were taken from ten vegetable farms during six months from May to October 2012. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to estimate the levels of heavy metals. The results showed that Pb and Cr concentrations exceeded the safety limits given by food and agriculture organization (FAO) or the world health organization (WHO) for human consumption with the exception of copper and cadmium that were lower than the permissible leveling in all of the samples. Furthermore, the results showed that there was a significant variation in the levels of these metals among the examined vegetables (P < 0.001). DI values for Pb, Cu, Cr and Cd could be 0.1, 1.5, 0.94 and 0.004 mg per day, respectively. As respect, DI values for Pb and Cd were also below the international guideline bases. Although Pb level was higher than the permissible standard, it seems that daily intake of these vegetables may not have detrimental health hazards to consumers.

ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonat... more ABSTRACT The most common used methods for water disinfection were chemicals like chlorine, ozonation, ultraviolet radiation, membrane processes, etc. Water disinfection using irradiation techniques is new in water treatment industry which has been developed recently. The aim of the present study was to investigate radio frequency (RF) efficiency for the inactivation of total coliform (TC), fecal coliform, and heterotrophic bacterial count of water pellets. Tap water samples were taken from School of Public Health, Tehran University of Medical Sciences and irradiated using hydropad device, steam KLEAR model S-38 (1.2 W and frequency of 120-200 kHz). Microbial concentration was measured in cycles 1, 5, 10, 15, 20, 25, 30, 35, and 40 in 1 and 2 h contact time. Indicator bacteria were counted using plate count method and multiple fermentation tube technique. According to the microbial results, after 40 cycles and without chlorine residual, TC, fecal coliform, and heterotrophic bacteria were reduced by 86, 90, and 85%, while after 15 cycles and 0.8 mg/l chlorine residual, removal rate was 89, 91, and 89%, respectively. Furthermore, it was observed that after 2 h of contact time, TCs, fecal coliforms, and heterotrophic plate count were reduced by 78.2, 80, and 60%, respectively. Although RF efficiency in water disinfection has not been studied, our findings suggested its possible use due to more than 75% efficiency. From the standpoint of practical use, more studies should be done, especially to find a fine synergist agent, determining power, frequency, and suitable contact time and also the method should be modified.

The objective of this study was to evaluate the presence of perchloroethylene (PCE) and trichloro... more The objective of this study was to evaluate the presence of perchloroethylene (PCE) and trichloroethylene (TCE) in dry cleaning shops in Tehran, Iran. PCE and TCE are two most prevalent solvents in dry-leaning shops. Air and effluent samples were collected in October to December 2011 from 10 dry-cleaning shops. Analyses were performed by head-space gas chromatography technique. Gas chromatography with FID detector is used for analysis. Mean PCE levels in the air of ten dry-cleanings ranged from 42.7 to 516 μgL -1 with maximum level of 960, PCE mean levels in the effluent ranged from 186.5 to 292.9 μgL -1 with maximum level of 326. Mean TCE levels in the air effluents ranged from 29.5 to 543.7 μgL -1 with maximum 964 and 25.5 to 29.75 μgL -1 with maximum level of 37 μgL -1 respectively. The survey of the PCE and TCE in dry-cleaning shops in Tehran shows that both air and effluent have been contaminated by PCE and TCE. These solvents have several negative health effects. Health educat...

Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addit... more Natural organic matter (NOM) affects some qualitative parameters of water such as color. In addition, it can deteriorate the performance of water treatment process including coagulation, adsorption, and membranes. NOM also reacts with chlorine in the chlorination process and may form disinfection by-products. The present study was carried out in laboratory-scale in a batch system using a cylinder shape reactor with effective volume of 2 L. The initial NOM concentrations during the study period were 10, 25, and 50 mg/L. After specific time intervals, samples were taken from the reactor and filtered. Finally, the NOM removal according to total organic carbon (TOC) content of the samples that were analyzed with a TOC analyzer. The results showed that the highest NOM removal efficiency for three initial concentrations 10, 25, and 50 mg/L were 91, 94, and 82%, respectively. These removal efficiencies were obtained at pH 7, contact time of 20 min, and electrical current of 0.1 A. The elec...

Sonolysis and photodegradation of various compounds such as chlorinated aliphatic hydrocarbons ar... more Sonolysis and photodegradation of various compounds such as chlorinated aliphatic hydrocarbons are the recent advanced oxidation processes. Perchloroethylene (PCE) is one of these compounds mainly used as a solvent and degreaser. In this work, elimination of perchloroethylene in aqueous solution by ultrasonic irradiation and photooxidation by UVC were investigated. Head space gas chromatography with FID detector was used for analyses of PCE. Results showed that PCE could be effectively and rapidly degraded by ultrasonic irradiation, photooxidation by UVC and combination of these methods. The order of studied reactions for degradation PCE has been determined.

Journal of Environmental Health Science and Engineering, 2013

Fungi are usually presented in indoor environments and cause of many diseases. The aim of this de... more Fungi are usually presented in indoor environments and cause of many diseases. The aim of this descriptive study was to investigate the level of fungal contamination in hospital rooms. Sampling was conducted with an Andersen one-stage viable impactor (Quick Take-30) and counting plates containing a fungus-selective medium. A total of 120 air samples from ten hospital environments were performed. Airborne fungi concentrations were determined 72-120 hours after sampling. Total mean concentration of detected fungi in the hospital rooms was 55 ± 56 (mean ± SD) cfu/m 3 . The findings of the fungal concentration in the various hospital rooms revealed different levels of contamination: the lowest mean counts (37 ± 17 cfu/m 3 ) were observed in NS 1 (Nursing Stations 1), and the highest (97 ± 217 cfu/m 3 ) were reported in Orthopedics Operating Room (OOR). The most common fungal genus isolated were Penicillium (70%), Aspergillus (14%), Cladosporium (12%), Alternaria (2%) and others (2%). The obtained results showed that fungal concentrations in the present study were nearly high and these conditions should be considered as a risk factor for patients and other persons in the hospital.