Biotechnology & nanotechnology
Mahta Majdnia; Maryam Sadrnia; Fatemeh Shahbazi; Nooshin Sohrabi
Abstract
Introduction: One of the best ways to remove toxic metals is to use bacteria resistant to these metals with biological purification process. The aim of this research is to isolate bacteria resistant to tin, copper, chromium and nickel from industrial wastewater and their molecular identification.
Materials ...
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Introduction: One of the best ways to remove toxic metals is to use bacteria resistant to these metals with biological purification process. The aim of this research is to isolate bacteria resistant to tin, copper, chromium and nickel from industrial wastewater and their molecular identification.
Materials and methods: First, wastewater contaminated with heavy metals was collected from electroplating factories located in Tehran province. The wastewater sample was cultured on LB Agar containing certain concentrations of heavy metals and the grown bacteria were isolated. On the grown bacteria, the minimum growth inhibitory concentration (MIC) of heavy metals was determined by the microbroth dilution method. Genomic DNA of two strains with the highest level of resistance, purity and polymerase chain reaction was performed with the help of specific primers. The PCR product was sequenced and ribotyping was done.
Results: 9 gram positive and negative bacilli and gram negative coccobacilli were isolated from wastewater containing heavy metals. Two Gram-negative bacillus strains showed the highest resistance to heavy metals in the MIC test. Based on the sequencing results, these two strains were identified as Enterobacter and Pseudomonas.
Conclusion: Two strains with the highest resistance to four metals were isolated from the effluent of electroplating factories and phylogenetic evaluation was performed. These bacteria can be used in the biological treatment of wastewater containing heavy metals.
Health and environment
Mohammad Hasan Kowsari; MohammadHossein Saghi; ayoob rastegar; Somayeh Sotude
Volume 29, Issue 1 , May and June 2022, , Pages 65-76
Abstract
Background: Even in engineered landfills in developed countries, leachate production cannot be avoided and it contains different types of heavy metals. Therefore, landfills are one of the main sources of increased concentrations of heavy metals in the soil. The purpose of this study was to evaluate the ...
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Background: Even in engineered landfills in developed countries, leachate production cannot be avoided and it contains different types of heavy metals. Therefore, landfills are one of the main sources of increased concentrations of heavy metals in the soil. The purpose of this study was to evaluate the severity of contamination of soils around Sabzevar landfill with heavy metals and to prepare a soil contamination map with heavy metals.Methods: Samples of surface and deep soils were collected in 18 stations according to the type of soil and distance from landfill Sabzevar. The concentrations of heavy metals Arsenic, Zinc, Lead, Chromium, Copper, Mercury and Cadmium were analyzed by ICP-OES. The intensity of soil contamination was assessed using Index Geoaccumulation Potential ecological risk index.Results: The mean concentrations of Arsenic, Zinc, Lead, Chromium and Copper in surface soil, respectively are, 6.013, 41.04, 6.31, 26.77 and 31.45 mg/kg of Mercury and Cadmium, respectively, 60.79 and 61.60 μg/kg, respectively. But the mean concentration of Arsenic, Zinc, Lead, Chromium and Copper in depth soil, respectively are, 5.75, 38.33, 6.25, 22.68 and 31.04 mg/kg, Mercury and Cadmium, respectively, 66.57 and 59.98 μg/kg, the value of all proportion to Natural background values are higher.Conclusion: Based on estimates of Igeo and RI indices for heavy metals Arsenic, Lead, Zinc, Chromium and Copper in the soil showed no contamination but for Mercury and Cadmium showed severe contamination.
Health and environment
Ramezan Sadeghi; Mehraban Sadeghi; Rahman Abdizadeh; Morteza Sedehi; Morteza Hashemzadeh Chaleshtori; Shahrbanou Parchami Barjui; Mohammad Rasoul Asadi Amirabadi
Volume 28, Issue 6 , January and February 2022, , Pages 982-994
Abstract
Backgrounds: Similar to some organic materials the heavy metals are not easily removed from the environment because of the toxic nature and form a class of stable and non-biodegradable pollutants. These elements enter the nature and the food chain as a result of natural activities such as eruptions of ...
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Backgrounds: Similar to some organic materials the heavy metals are not easily removed from the environment because of the toxic nature and form a class of stable and non-biodegradable pollutants. These elements enter the nature and the food chain as a result of natural activities such as eruptions of volcanoes and human activities such as mining, producing industrial and urban wastewaters and applying pesticides.Materials and Methods: In this study, chrome (VI) -resistant bacteria were isolated from the industrial wastewater taken from Isfahan Mobarakeh Steel Complex. The isolated strains were identified and their resistance to chromium was determined and the strain with the highest resistance to chromium was used for its bioremediation.Data were analyzed using descriptive statistics and one way ANOVA.Results: The results of this study led to the identification of five chrome resistant strains that the Micrococcus luteus SEHD031RS bacterium was detected as the best chrome resistant strain due to the minimum inhibitory concentration of 140 mgL-1 and minimum bactericidal concentration of 152 mgL-1. In this study, the highest chromium removal rate of 82.5% was obtained at pH 4, concentration of 30 mgL-1 and 96 hours.Conclusion: The results of this study indicate that the Micrococcus luteus SEHD031RS strain can be used as an effective microorganism in removing chromium from industrial wastewater or environmental bioremediation.
Health and environment
Mohsen Yazdani; Hosein Alidadi; Aliakbar Dehghan; Mojtaba Davoudi; Mahmood Dankoob; Mahmoud Taghavi; Reza Ataei; Aliasghar Navaei
Volume 26, Issue 1 , March and April 2019, , Pages 153-159
Abstract
Pistachio hull, a by-product of Pistachio processing, is a source of environmental pollution and can cause the health problems. Therefore, it must be treated by proper, sanitary and economical manners. One of the basic parameters for compost valuation is determine the amount of heavy metals. The objective ...
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Pistachio hull, a by-product of Pistachio processing, is a source of environmental pollution and can cause the health problems. Therefore, it must be treated by proper, sanitary and economical manners. One of the basic parameters for compost valuation is determine the amount of heavy metals. The objective of the present study was to determiner the concentration of heavy metals (pb, Cd, cr, Zn, Ni, Cu ) in the compost produced from mixed Pistachio Hull and livestock and Compare levels of heavy metals with the limits of international and internal standards.Material & Methods: This study is a descriptive cross-sectional that in sampling was two-stage in September 2014 and October 2015 A total from 2 composting pile , Compound sampling based ,26sample were selected. After digestion of the samples, the concentrations of metals( Pb ,Cd, Zn,Cr,Cu,Ni) by means of atomic absorption analysis and the concentration of a component in the sample based on mg / kg dw were reported.
Health and environment
Elham Aseman; Hosein Sayyaf
Volume 24, Issue 3 , July and August 2017, , Pages 165-171
Abstract
Background: The use of living and nonliving bio sorbents to removal of heavy metals andtoxic compounds from aqueous solutions and industrial wastewaters has revealed considerable highly potential of green algae for adsorption. Spirogyra porticalis is filamentous algae that can often form flimsy green ...
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Background: The use of living and nonliving bio sorbents to removal of heavy metals andtoxic compounds from aqueous solutions and industrial wastewaters has revealed considerable highly potential of green algae for adsorption. Spirogyra porticalis is filamentous algae that can often form flimsy green aggregates in freshwater ponds, rivers and streams. The present study aimed to determine the capability of powdered s. porticalis to remove chromium from aqueous solutions. Materials and Methods: Biosorption of Cr (VI) from synthetic aqueous solutions by powdered filamentous green algae Spirogyra porticalis was investigated as an effect of various parameters including pH, biomass dosage, initial Cr (VI) concentration and contact time in laboratory scale batch. In order to do the statistical analysis, repeated measure testand one-way analysis of variance using SPSS 16.0 software was applied and P< 0.05 was considered as significant level. Results: The findings showed that the removal of Cr (VI) increased with the increasing algal dosage, metal concentration, contact time and decreasing pH. Maximum biosorption capacity was observed at pH 3.0 and 1 g/L of biomass in 60 min from a solution containing 40 mg/L initial concentration of Cr (VI). Under the optimum conditions, the removal percentage of chromium (VI) was found to be 70%. Conclusion: The results of the study indicated that the powdered filamentous green algae s. porticalis can be used as an available, affordable and efficient biomaterial even in low dosages to remove Cr (VI) from industrial acidic wastewater and aqueous solutions.
Health and environment
Seyed Ali Mazhari; Faezeh Haghighi
Volume 24, Issue 4 , July and August 2017, , Pages 281-291
Abstract
Background: Agricultural soils irrigation by urban sewage is a key factor to increase soil pollution and environmental risks. Heavy metals are one of the most important sewage pollutants which may produce different diseases.
Methods: The specified locations were selected for surface soil sampling to ...
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Background: Agricultural soils irrigation by urban sewage is a key factor to increase soil pollution and environmental risks. Heavy metals are one of the most important sewage pollutants which may produce different diseases.
Methods: The specified locations were selected for surface soil sampling to investigate the effect of sewage irrigation on the soil and vegetation (parsley) composition in the south of Sabzevar area. The heavy metals concentration and trace elements composition of whole samples were determined by ICP-MS. The heavy metals bioavailability was measures by DTPA method. The heavy metals concentration in DTPA extracted solution and parsley samples were defined by FAAS method.
Results: Ni and Cr concentrations in the non-polluted soils are more than standard limits. These high concentrations have been generated by enriched parental materials. In addition to Ni and Cr, polluted soils have potential environmental risk because of high concentration of Ag, Cd, Co and Zn. The DTPA results showed that non-polluted soils, unlike polluted soils, have low bioavailability. The vegetables cultivated on the polluted soils have several times higher heavy metal concentrations than non-polluted samples. These vegetations show higher Cr bioavailable value than FAO/WHO standard.
Conclusion: Heavy metal concentration has been increased by long time sewage irrigation in the southern Sabzevar soils. These heavy metals are environmentally harmful. Nickel content of vegetables cultivated on polluted soils have high HRI (>1) index which indicates high health risk for consumers.
Afshin Takdastan; Mehdi Jolanejad; Abdolkazem Neisi; Mehrnosh Abtahi; Sahand Jorfi
Volume 23, Issue 4 , September and October 2016, , Pages 698-705
Abstract
Background Chromium and cadmium are two heavy metals having adverse effects on the health and environment, which are released to environment by waste streams. Because of high solubility, they are absorbed by living organisms and through food chain accumulate in human body. This study aimed to determine ...
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Background Chromium and cadmium are two heavy metals having adverse effects on the health and environment, which are released to environment by waste streams. Because of high solubility, they are absorbed by living organisms and through food chain accumulate in human body. This study aimed to determine the efficiency of the polyferric sulfate (PFS) in removing of Cr6+ and Cd2+ from aqueous solutions.Methods & Materials This study was investigated in bench scale using a jar test apparatus. The effect of pH (4-11), dose of coagulants (10-200 mg/l), initial amount of metals (1-100 mg/l) and settling time (15-9 min) were investigated. Cr and Cd concentration were determined by atomic absorption spectroscopy.Results The result showed that the maximum removal efficiency was 52.82% for Cr and 93.13% for Cd, at pH values of 6 and 9, coagulant dosage of 100 and 50 mg/l, respectively, and settling time for 30 min. Conclusion Coagulation and sedimentation by use of polyferric sulfate can be considered as an efficient process for removal of Cd and pretreatment of Cr.
Mohammad Miri; Seyede Mojgan Mosavi Bideli; Mehdi Mokhtari; Hamideh Ebrahimi Aval
Volume 23, Issue 3 , July and August 2016, , Pages 392-397
Abstract
Background Vegetables are important components of a healthy and proper diet. The main route of entry of heavy metals into the body is through the foods, especially vegetables. Because the use of wastewater for irrigation has become a common practice, and the standards in this regard are not met, especially ...
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Background Vegetables are important components of a healthy and proper diet. The main route of entry of heavy metals into the body is through the foods, especially vegetables. Because the use of wastewater for irrigation has become a common practice, and the standards in this regard are not met, especially the products that are consumed raw materials like vegetables can threaten public health. Therefore, in this study, the concentrations of heavy metals (lead, cadmium, arsenic) in vegetables distributed in green groceries of Yazd City, Iran were measured.Materials & Methods This research was a cross-sectional study. Over 2 months, 40 samples of vegetables (parsley, coriander, leek, and lettuce), (20 samples in each month) were randomly selected from Yazd greengroceries and prepared according to the standard method for determining the concentration of heavy metals by atomic absorption spectrometry. Data analysis was performed using SPSS and Excel. Finally, the obtained data were compared with the standards of the World Health Organization and Food and Agriculture Organization.Results The average values of the studied heavy metals in vegetables were different. Parsley had the highest total concentration of heavy metals (518 mg/kg), and lettuce had the lowest total concentration of heavy metals (305 mg/kg).Conclusion The concentration of heavy metals was more than WHO and FAO standards. Probably soil or water that is used for vegetable growth has a lot of heavy metals and is not standard for vegetable irrigation. Therefore, controlling policies from respective organizations are of necessity.
Ghasem Kiani Feizabadi; Amir Hossein Mahvi; Mohammad Hadi Dehghani; Ramin Nabizadeh; Morteza Barani
Volume 22, Issue 1 , March and April 2015, , Pages 57-65
Abstract
Background: Leachate, including various pollutants such as heavy metals, is generated during collection, trasportation and disposal of solid waste as well as composting process. Lack of control, disregarding the leachate treatment and heavy metals removal cause environmental pollution. This study was ...
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Background: Leachate, including various pollutants such as heavy metals, is generated during collection, trasportation and disposal of solid waste as well as composting process. Lack of control, disregarding the leachate treatment and heavy metals removal cause environmental pollution. This study was aimed to investigate the efficiency of heavy metals removal from Isfahan composting leachate, using the following coagulants ferric chloride, poly ferric sulfate and poly aluminium chloride.
Materials and Method: In this experimental study, leachate samples were collected from the Isfahan composting leachate´s collection ponds. At first, leachate characteristics including TSS, BOD, COD and pH as well as the following heavy metals: Cd, Cr, Zn, Cu and Ni were measured according to the standard methods. Jar-test experiments were carried out to examine the effects of changing coagulants' dosage (0.5, 1, 1.5, 2, 2.5 and 3 g/L) and pH values (4, 5, 6, 7, 8, 9, 11 and 12) on the removal of heavy metals. As a result, the effective dosage, optimum pH and the most convenient coagulant were identified.
Results: Investigating the average concentration of mentioned heavy metals, Zn had the highest concentration in leachate (6.2 mg/L) followed by Ni, Cu, Cr and Cd with the concentrations of 2.15, 0.62, 0.48 and 0.21 mg/L, respectively. The optimum pH for precipitation of the metals using poly aluminium chloride, Ferric chloride and poly ferric sulfate was 7, 10 and 11, respectively. Optimum concentration of the three mentioned coagulants was 1.5, 1.5 and 2 g/L, respectively. Poly ferric sulfate with 70% to 87% of heavy metals and 50% of COD removal has the highest efficiency, followed by poly aluminium chloride with 65% to 85% and Ferric chloride with 75% to 80% of heavy metals removal.
Conclusion: Among the three mentioned coagulants, poly ferric sulfate is the most effective followed by poly aluminium chloride and ferric chloride, respectively. Since poly ferric sulfate and poly aluminium chloride are more expensive compared to other coagulants, economic estimations need to be done according to their efficiency to choose the best coagulant.
Afshin Takdastan; Azadeh Tashrifat; Roya Mafi Eslami; Azadeh Eslami
Volume 21, Issue 4 , September and October 2014, , Pages 665-674
Abstract
Background: Chromium is one of the toxic heavy metals that exist in trivalent and hexavalent forms in aqueous systems. Hexavalent chromium is highly toxic, carcinogenic and corrosive in nature. Adsorption is an effective method in chromium removal. The aim of this study is investigation of the hexavalent ...
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Background: Chromium is one of the toxic heavy metals that exist in trivalent and hexavalent forms in aqueous systems. Hexavalent chromium is highly toxic, carcinogenic and corrosive in nature. Adsorption is an effective method in chromium removal. The aim of this study is investigation of the hexavalent chromium removal using sugarcane bagasse from synthetic solutions and determining of the sorption kinetics.
Methods: The impact of pH, temperature, contact time, Adsorbent concentration and paricle size on chromium removal was carried out. Langmuir and Freundlich adsorption isotherms with sorption kinetics were investigated. Experiments were carried out with Tagochi method using Qualitik4.
Finding: The maximum chromium removal was achieved in pH=2, temperature of 50C ,500 m adsorbent size, adsorbent concentration of 20g/l equal to 90.1%. Altogether adsorption capacity was increased with increasing temperature and adsorbent concentration and decreased with increasing pH. Adsorbent particle size does not an important effect on removal efficiency. Sugarcane bagasse adsorption kinetics in chromium removal followed by second- order reaction and were in good agreement with Langmuir isotherm.
Conclusion: the results showed appropriate adsorption capacity for sugarcane baggase in hexavalent chromium removal as a significant pollutant.
Roshanak Rezaei Kalantary; Ahmad Allah-Abadi; Mehdi Farzadkia; Ayyob Rastgar; Ahmad Joneidi Jafari; Abdolmajid Gholizadeh
Volume 19, Issue 3 , September and October 2012, , Pages 277-286
Abstract
Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients ...
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Background: Leaching of nutrients and heavy metals from municipal solid waste compost leads to accumulation of certain elements in soil layers, causing underground water pollution. The objective of this study was to investigate the effect of compost on leaching and adsorption of heavy metals and nutrients (sodium, potassium, and sulfate) from silt-loamy soils. Materials and Methods: In this empirical, applied study, three polyethylene columns (height 50 cm, inner diameter 10 cm), filled with sandy clay loam soil, were randomly selected. Then, 10 kg of compost per square meter were sprayed onto the columns, and leachates exiting the columns were routinely analyzed for pH, electrical conductivity, sulfate, sodium, potassium, lead, chromium, and cadmium. Data analysis was performed with Excel and SPSS software using Kruskall-Wallis test. Results: The data showed that the use of enriched and unenriched compost leachate decreased pH (from 7.43±17.0 to 6.7±0.25 and 7.07±0.11, respectively) and increased the electrical conductivity (EC) (from 1.8±0.3 mSiemens/m to 3.7±0.12 and 12.87±0.41 mSiemens/m respectively). Leakage of metals in the unenriched treatments was not significantly different from the control (p>0.78), but leakage with three metal-enriched compost applications was significant compared with control (p