Showing 48 results for Dust
Sh Khaledan, L Taghavi, P Paykanpour Fard,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Population explosion and human ever-increasing demands has been resulted in industrialization which its mismanagement led to land pollution and consequently irreversible harm to nature and living organisms. Thus, it is an important measure to investigate the role of industrial centers in soil pollution.
Materials and Methods: We studied Mobarakeh Steel Industrial Complex and surface soil samples were taken in a regular grid with a dimension of 2 km of a 10 km buffer zone. 49 samples were taken from different sites. Soil parameters such as texture, pH and salinity were analyzed and concentrations of heavy metals including lead and cadmium were measured using flame atomic absorption spectrometry.
Results: Data analysis in the GIS environment using geostatistical techniques showed that a spherical model is a good model to investigate the spatial variability of lead and cadmium. The lowest and highest lead concentrations were 88.50 and 71.26 mg/kg and that of Cd was 6 and 26.1 mg/kg, respectively. No significant relationship between the heavy metals and soil properties (p>0.05). However, the correlation between two elements was significant (p<0.001). Among the various parameters, it was realized that wind direction played a great role in the distribution of lead and cadmium in the area.
Conclusion: The results showed the role of the industrial complex in the environmental pollution. The hot spot for lead was eastern and southwestern parts of the steel complex and for Cd it was in eastern and western parts. Proper management and more accurate monitoring are necessary to protect the environment in the complex industry.
R Shokohi, A Shabanloo, F Zamani,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Nitrophenols are among the most common and toxic compounds in industrial effluents that 2, 4 dinitrophenol (2, 4-DNP) is the most toxic compound in this group. The object of this study was to optimize the removal of 2, 4-DNP by thermally activated persulfate using a central composite design.
Materials and Methods: This study was performed on a batch thermal reactor with a volume of 4 L. In this study, a central composite design (CCD) with RSM method was used for designing and optimizing the operation parameters such as initial pH of solution, potassium persulfate concentration and temperature. The effect of 2, 4-DNP concentration and reaction time at optimum conditions were also investigated.
Results: The results indicated that the degradation rate of 2, 4-DNP was enhanced by increasing the concentration of persulfate and reducing temperature and pH. The optimum conditions for the highest degradation efficiency (99%) were as initial concentration 10 mg/L, reaction time 30 min, temperature 60 °C, Potassium persulfate concentration 10 mmol/L, and pH 5. At the optimum conditions, when 2, 4-DNP concentration was increased to 50 mg /L, the 2, 4-DNP degradation rate decreased to 73%.
Conclusion: This study indicated that the heat-activated PS oxidation could be an efficient approach for decomposition of 2, 4-DNP. Temperature was the most influential variable in this regard (p<0.0001).
S Mazloomi, A Esmaeili - Sari, N Bahramifar, M Moeinaddini,
Volume 10, Issue 2 (9-2017)
Abstract
Background and Objective: Street dust is considered as one of the important sources of particulate matters and heavy metals in the atmosphere. The goal of this study was to assess the heavy metals pollution in street dust of Tehran and evaluate their ecological risk.
Materials and Methods: The sampling of street dust was carried out in two areas at the east and west of Tehran. After preparation of samples, the concentration of heavy metals was measured by ICP-MS. The pollution level of heavy metals in the street dust was assessed using geo-accumulation index (Igeo), pollution index (PI), integrated pollution index (IPI), enrichment factor (EF) and ecological risk index (RI).
Results: The results of the calculations of the indices showed that the street dust in both studied areas was non-polluted with Li, Al, Ti, V, Cr, Mn, Fe, Ni, Sr and Ba. The origin of these elements was mainly natural sources. However, Cd, Cu, As, Zn, Sn and Pb had medium to high level of contamination. These elements had a very high to extremely high enrichment in both areas. Their origin was mainly anthropogenic sources. The ecological risk index indicated a moderate ecological risk for the east and a low ecological risk for the west area.
Conclusion: The higher level of lead in the East is the main reason of higher ecological risk of this area. Therefore, the heavy metals pollution of the street dust, especially lead and its enterance into the environment, should be considered in this area.
R Bagheri, S Sobhanardakani, B Lorestani,
Volume 10, Issue 3 (12-2017)
Abstract
Background and Objective: In countries such as Iran that are facing with water scarcity and water crisis, paying attention to the quantity, quality and sustainable use of water resources is very significant. Petrochemical processes discharge pollutants into the environment, contaminating surface water resources. Therefore, treatment of the wastewater of these industries is necessary. Due to the capabilities of AHP process such as generalization, consideration of various parameters, multi-dimensional selection and quantifying the qualitative parameters by experts, the current study was carried out to select the best wastewater treatment alternative for HDPE plant of petrochemical research and technology company-Arak center based on AHP in 2016.
Materials and Methods: In this study, both sequencing batch reactors (SBR) and extended aeration activated sludge (EAAS) systems based on environmental, technical-functional, economic and management criteria's according to the expert's opinion were weighted. Then, the paired comparisons of the selected wastewater treatment systems for each criterion were developed. Finally, the results were analyzed to select the best wastewater treatment systems for HDPE unit of petrochemical industries using Expert Choice 11 Software.
Results: The results showed that the SBR wastewater treatment system was the best method for the wastewater treatment of HDPE plant of petrochemical research and technology company-Arak center as compared with the ESSA system. Also, consistency ratio was ranged from 0 to 0.10 in all emphases. Based on the results of the sensitivity analysis, the SBR system had the highest priority of economic and environmental criteria. The ESSA system had the highest priority of technical-functional and management criteria.
Conclusion: Based on the results, although ESSA method requires more maintainance and management than the SBR method, due to increasing requirement for the compliance of the output effluent quality with permissible limits and the need for less land for the establishment of the treatment plant, the SBR method was selected to be the most suitable process for HDPE plant wastewater treatment.
M Fahiminia, H Jafri Mansoorian, R Shaikh Bigloo, S Bahari, A Eskandari,
Volume 10, Issue 4 (3-2018)
Abstract
Background and Objective: Today, workshop industries play an important role in urban development by creating effective employment in urban areas. It has been stated that these small industries can cause environmental pollution. The purpose of this study was to investigate and analyze the contaminations caused by the workshops in Qom in 2016.
Materials and Methods: The present study was descriptive-analytic-cross sectional. First, all of the city's businesses were listed in 67 relevant :::::::union:::::::s. After identifying the polluting businesses, a total of 223 classes of all :::::::union:::::::s were randomly screened. Sewage, solid waste, air, sound, soil and landscape pollution were investigated. According to 15 specialists and using Expert Selection software, each pollution type and rating of each class were weighed and determined.
Results: The results showed that the wastewater, solid waste, air, noise, and landscape pollution with a score of 0.399, 0.259, 0.169, 0.097, and 0.027, respectively, are important. Accordingly, in terms of the total contamination of the studied occupational units, authorized dealers of car sales, carwash, guest house, carpet cleaning, bath, brick plants, chalk plants, gemstones, chelokbaby, mosaic making, lathes and blacksmans, iron doors and window making, general blinds and shuttering, ceramic making, wood processing industry, mechanical, polishing with a total score of 1, 0.889, 0.881, 0.872, 0.709, 0.644, 0.644, 0.641, 0.62, 0.609, 0.582, 0.569, 0.552, 0.546, 0.518, 0.499, and 0.499 had unfavorable status, respectively.
Conclusion: In order to reduce the environmental pollution caused by these businesses, continuous monitoring and inspections should be carried out in the short term. Moreover, the polluting industries should be relocated out of the city in the long term.
N Ghanavati,
Volume 11, Issue 1 (6-2018)
Abstract
Background and Objective: The aim of the present study was to investigate risk of heavy metals on human health including (Pb, Zn, Cu, Cr, Cd, Ni, V, As and Co) in street dusts in Abadan.
Materials and Methods: 30 dust samples were collected from sidewalks of main streets of Abadan and analyzed by inductively coupled spectroscopy (ICP-OES) method.
Results: The mean concentration of the heavy metals was as follows: Pb (59.13), Zn (287.50), Cu (112.97), Cr (50.30), Cd (0.52), Ni (56.77), V (35.83), As (10.7) and Co (7.33) (mg/kg). The concentration of all of the heavy metals, except V, in the dust samples was several times higher than the field concentration (concentration in the earth's crust). The average value of the potential ecological risk of the heavy metals V, Cr, Zn, Ni, As, Cu and Pb was low and had a low potential ecological risk. Cd had a moderate potential ecological risk. Also, based on the average value of Risk Index, the samples were at medium risk. Cumulative non-carcinogenic hazard of all the heavy metals in the street dust was higher for children than adults. This indicates that children are more at risk for heavy metals than the adults. In both age groups, Cr had the highest risk of carcinogenicity and Pb had the lowest risk.
Conclusion: The results indicated that the main source of the heavy metals in the study area is anthropogenic sources such as traffic, industrial facilities and burning of fossil fuels.
Mr Jelokhani-Niaraki, F Hajiloo, L Hasanzade,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Noise pollution causes many physiological, psychological, economic and social effects on human life. This issue is more important in the environment of industrial workplaces. This research aimed to adopt the functions of GIS for evaluating and spatial analysis of noises in industrial environments.
Materials and Methods: At the initial step, the spatial data for industrial halls were collected and stored as map layers into GIS database. Then, the noise pollution data sampled. The data, including the locations and values of sound pressure levels, were used for the relevant spatial analyses.
Results: The analyses included: the estimation of sound pressure levels in different areas of halls and at the given distance from machines, determination of noisy areas, development of sound noise risk map, interpolation of sound pressure level data, prioritization of the sound sources (i.e., machines) for a given point, prediction of sound pressure levels by moving machines, and optimal site selection and distribution of machines. The mean of noise pressure level was 95 dB for knitting hall, 93 dB for spinning hall 1 and 88 dB for spinning hall 2.
Conclusion: GIS plays a key role in the assessment of noise pollution in industrial workplaces. It is an appropriate tool to store, analyze, manage, and present all types of sound pressure spatial data. Specifically, the use of such system provides spatial intelligence and could help monitor, detect, control, and solve real word sound noise pollution issues.
M Moradi Baseri, H Kamani, Sd Ashrafi, E Bazrafshan, F Kord Mostafapour,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: Street dust is an important factor in urban pollution which consists of soil, particulate matters and heavy metals. At present, over half of the world’s population lives in urban areas. Therefore, this study aimed to investigate health risks of heavy metals in street dusts in Zahedan.
Materials and Methods: The samples of street dust were collected in Zahedan. After preparation, the samples, were injected to ICP-MS for determination the amount of Hg and Cu. According to the measured concentrations, Hazard quotient (HQ) and hazard index (HI) were calculated to evaluate the health risk assessment.
Results: Results showed that Hazard quotient for both Hg and Cu was less than 1 for children and adult. HQ for Hg and Cu was in order of HQingestion >HQdermal >HQinhalation> HQvapour for adults and HQvapour > HQingestion > HQdermal > HQinhalation for children. HI was also less than 1.
Conclusion: The value of HQ showed that inhalation of mercury vapor and ingestion were the main routes of exposure to Hg for children and adults. The non-carcinogenic risk was within the safe value (HI <1) in this study.
Ghr Siyahati Ardakani, M Mirsanjari, Hr Azimzadeh, E Solgi,
Volume 11, Issue 3 (12-2018)
Abstract
Background and Objective: The establishment of pelletizing and steel industries in Ardakan suburbs has increased the pollutants such as heavy metals into the environment. The purpose of this study was to investigate the contamination of the area soil by heavy elements around these industries using the pollution index (PI), comprehensive pollution index (NIPI), accumulation index (Igeo) and enrichment index (EF).
Materials and Methods: 57 soil samples were prepared by systematic-random sampling from 0 to 5 cm depth and levels of As, Cd, Cr, Mo, Ni, Pb, V and Zn were analyzed by ICP-OES.
Results: The highest and lowest mean of Igeo (0.49 and 0.36) and PI (2.16 and 1.17), were related to nickel, and the highest EF was calculated for Zn at about 25.1 and the lowest were detected for molybdenum approximately that was 17.1. The EF index of lead, vanadium and zinc, which was 15.8%, 5.3% and 1.8%, respectively, classified the study area in a medium enrichment class. Hot spots of lead, vanadium, nickel and zinc was at the nearest distance to these industries and downstream of wind direction.
Conclusion: Indicators of Igeo and EF showed a low level of soil pollution. The PI and NIPI indices in most stations were classified in medium pollution class, and the highest of these indicators was related to the surface soil of station 30, which was located near the steel industry. Therefore, it can be concluded that the activities of these industries had affected the soil contamination of the study area.
M Moradzadeh, Kh Ashrafi, M Shafiepourmotlagh,
Volume 11, Issue 4 (3-2019)
Abstract
Background and Objective: Hydrocarbon processing industries are considered as potential sources of volatile organic compounds (VOCs) due to their specific nature. These compounds can directly or indirectly through producing secondary pollutants have adverse effects on the health of individuals. Therefore, identification of them is an important step in the formulation of control programs. This study aimed to identify the type and amount of the most important volatile organic compounds in the South Pars region.
Materials and Methods: In this study, industrial processes located in the region were investigated and information was gathered for estimation of VOCs emissions. The emission was estimated over a one-year period and was ranked according to three criteria including emission, health hazards and ozone production potential.
Results: The results showed that the greatest emission was due to equipment leakage and storage tanks (64%), cooling towers (21%) and flaring (11%). The 171 VOCs were determined in Plum of these processes and propylene had the greatest contribution (21%). The alkenes had the highest share in total mass (41%) and ozone production (78%). By weighting the list based on the three criteria mentioned above, formaldehyde is the most important emitted VOC and the main sources of it were olefins and aromatic units.
Conclusion: This method can be a useful tool for identifying effective organic compounds in such areas. Here, the optimum control strategy is mitigating of emission of formaldehyde from the aromatic and olefins processes. The next priority is to control propylene, ethylene and butylene emission sources.
M Khalaji, Sa Hiseini, R Ghorbani, N Agh, H Rezayi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Nutrient-rich effluents (mainly nitrogen and phosphorus) may lead to algae blooms and many harmful effects in aquatic environments. Micro-algae have been more effective among the various methods used for the removing of nutrients from wastewater. Microalgae Chlorella vulgaris has specific characteristics such as rapid growth, resistant to systems manipulation, simple and inexpensive production technology, as well as the rapid uptake of nutrients such as phosphate and nitrate.
Materials and Methods: In the present study, two concentrations of chlorella vulgaris microalgae (13 and 26 million cells/mL) were injected into dairy effluent, diluted using distilled water by 25, 50 and 75%, and the amount of nutrient removal and microalgae growth were examined during the growth period.
Results: Results indicated that different concentrations of algae at various percentages of dilution (25, 50, 75%) had a significant effect on the removal of nutrients and algal growth (p<0.05). The absorption of nutrients (nitrate, phosphate and ammonia) were 57.01, 51.84 and 43.15 percent respectively that containing lower density of initial algae compared to the treatments of 2nd group (29.15, 51.84 and 43.15 percent) with higher algae concentration. In both algal concentrations, the highest percentage of phosphate and ammonia adsorption were in dilution of 25% effluent and the highest percentage of nitrate adsorption were in the first group with 50% dilution and in the second group with 75% dilution.
Conclusion: The more percentage of nutrients (nitrate, phosphate, ammonia) was eliminated compared to the second group (26 million cells / mL) when the microalgae concentration (group I) was 13 million cells / mL. Absorption of nutrients was decreased by increasing the concentration of microalgae. Regarding to the percentage of nitrate adsorption, the higher absorbance in the dilution was occurred at the highest concentration of algae.
S Shojaee Barjoee, Hr Azimzadeh, A Mosleh Arani,
Volume 12, Issue 4 (2-2020)
Abstract
Background and Objective: Non-biodegradation in nature and creation of adverse health effects in humans is important features of heavy metals. The main objective of this study was to determine the level of contamination, carcinogenic and non-carcinogenic risks of falling dust containing heavy metals on residents around the industrial areas of Ardakan. Another objective was to identify potential sources of heavy metal release into the environment.
Materials and Methods: In this cross-sectional analytical study, the falling dust was collected in summer around Tile and Ceramic, Khak-e-chini, sand and gravel and glass industries by installing 35 Inverted Frisbee traps with artificial grass cover. The concentration of Cd, Ba, Cu, Ni, Cr, Mn and V were measured by ICP-MS. Probable sources of the heavy metal of the dust were evaluated using Pearson correlation coefficient and cluster analysis. Ecological risk indices for determining the level of contamination and proposed relationships proposed by the US Environmental Protection Agency were used to assess the carcinogenic and non-carcinogenic risks.
Results: The highest and lowest mean concentrations of heavy metals were measured for Cd and Ba, respectively. The results of Pearson correlation analysis and cluster analysis revealed three anthropogenic and also natural sources for heavy metals of the falling dust. According to the Ecological Risk Potential Index, Cd in 45.10% of the samples was in a very high class and in 54.88% of the samples was a high class. Pollution class of the ecological risk index of all the heavy metals was medium to high. The carcinogenic risk of Cr and Ba in children and adults was estimated to be higher than 10–4. In both age groups, the Hazard index for each metal was less than 1 and its sum was measured as 1.29 for children and 0.16 for adults.
Conclusion: Cd increases the ecological risk of the falling dust in the area. Ther heavy metal carcinogenic risk results showed that the concentrations of Cr and Ba were higher than standard. Also, the non-carcinogenic risk was higher in children than in adults.
Saeed Sotoudeheian, Behnaz Shirazi Rumenan,
Volume 13, Issue 2 (8-2020)
Abstract
Background and Objective: During the last few years, air pollution and increasing levels of particulate matters (PMs) have become major public health issues in the megacity of Tehran. The high cost of constructing and maintaining air pollution monitoring stations has made it difficult to achieve adequate spatial-temporal coverage of PM data over various regions. In this regard, the use of remote sensing data such as aerosol optical depth (AOD) can be a simple and cost-effective way to overcome the problem.
Materials and Methods: Due to the weakness of univariate linear relationship of PM10-AOD under normal conditions, this relationship has been studied for the time periods of dust storm occurrence during 2007-2010 in Tehran. Satellite product with spatial resolution of 3 and 10 km obtained from MODIS sensor were used to fit the models.
Results: Results showed that the best performance of univariate model was achieved for 5 km radius of AOD extraction and daily mean of PM10 concentrations (r = 0.55). Moreover, the use of meteorological auxiliary variables and the development of multivariate linear regression model have improved the performance of the model (r = 0.64). The final model also exhibited accurate capability for prediction of high PM10 concentrations during dusty days.
Conclusion: Overall, the obtained univariate linear relationships of PM10-AOD was stronger during dusty episodes than those of normal conditions, suggest a higher correlation between AOD and PM10 from dust activities as compared with PM10 originating from other sources. Furthermore, the final developed model could be used to predict daily level of PM10 concentrations during dusty episodes.
Hamid Karyab, Faeze Karyab,
Volume 13, Issue 3 (11-2020)
Abstract
Background and Objective: Since industrial waste management requires accurate knowledge of quantity and quality of solid wastes, this study was conducted to assess quantitative and qualitative characterization of industrial solid waste in Qazvin province, Iran and investigate its related pattern management.
Materials and Methods: Based on the guideline of Iranian Environment Protection Organization, industries were classified into 10 groups. Then according to the abundance of industries in each group, 276 industries and 4 wastewater treatment plants were selected. The Basel Convention criterion was used to identify special solid wastes. Quantitative and qualitative characteristics and management pattern of industrial wastes were determined by referring to the industries and completing a researcher-made questionnaire.
Results: The total types of identified industrial solid wastes were 1726. According to the guideline of Basel Convention, 33.7% of identified wastes were classified as special wastes. The total amount of solid wastes was 38826 ton/month. The maximum solid wastes production was in the chemical industries with 14,380 ton/month. The recovery and recycling rates were 8.96 and 6.44%, respectively, and 36.44 % of industrial waste was sold directly.
Conclusion: The results of the study showed that the management of industrial solid wastes in Qazvin province does not follow a specific pattern. In addition, the quantity and the composition of solid wastes in the study area is a serious potential for environmental pollution and threatening human health. Therefore, it is necessary to establish a center responsible for industrial wastes management and design a centralized industrial waste disposal system.
Abdolmotaleb Seid Mohammadi, Ghorban Asgari, Reza Shokoohi, Parastoo Shahbazi,
Volume 13, Issue 3 (11-2020)
Abstract
Background and Objective: Considering the importance of alkalinity in pH regulation and its buffering role, in this study, the effect of inlet wastewater alkalinity on the efficiency of the anaerobic unit of the wastewater treatment plant. Moreover, a superior chemical compound in providing alkalinity to wastewater was investigated.
Materials and Methods: This study was performed in the treatment plant to determine the relationship between input alkalinity and removal efficiencies of COD, BOD5 and TSS. In order to determine the optimal alkali material for superb anaerobic wastewater performance, four common chemical substances including, NaOH, Na2CO3, Ca(OH)2 and MgO were selected and examined using One Factor At Time (OFAT) test method.
Results: According to the results maximum removal efficiencies were obtained 62, 66.6 and 71.2% for COD, BOD5 and TSS, respectively under alkaline condition of 1260 mg/L CaCO3. Furthemore, the optimal dose to supply one unit of alkalinity by Na2CO3, Ca(OH)2 and MgO were 0.53, 0.54 and 0.3 mg/L, respectively. These values were obtained 5 min contact time and mixing rate of 150 rpm. However, for NaOH the optimal dose supply was obtained 0.35 mg/L for 3 min contact time and mixing rate of 100 rpm.
Conclusion: In conclusion, the performance of anaerobic baffled reactor is highly related to the supply of influent alkalinity to the reactor. In addition, the use of MgO can be considered as a suitable alkaline substance to neutralize acidic wastewater and provide alkalinity for ABR system.
Forough Tajiki, Hossein Mohammad Asgari, Isaac Zamani, Farshid Ghanbari,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: Considering the fact that Iran is located in semi-arid climate and the harmful effects of dust storms on different ecosystems, this study aimed to identify and locate dust storms using fungal bio-aerosols (spores) and HYSPLIT model in southwestern region of Iran.
Materials and Methods: MODIS satellite images and HYSPLIT model were used to investigate the temporal changes of dust masses entering the Khuzestan province. Sampling was carried out from dust storms in Abadan and Khorramshahr cities and from the soil of the dried parts of Hur al-Azim and Shadegan wetlands in a two-month period (from May to July 2019).
Results: The results of numerical modeling show that Abadan and Khorramshahr cities were affected by dust storms of internal origin (from Hur-al-Azim wetland). After isolation of bioaerosols from air and soil samples, a total of 6 fungal genera were identified in soil samples and 6 genera in dust samples of internal origin by PCR-Sequencing method. Talaromyces, Alternaria, Penicillium and Aspergillus were identified as the predominant genera fungi in soil and air samples.
Conclusion: With 70% similarity of fungi found in soil and air samples, it can be concluded that the main source of fungi in Abadan and Khorramshahr is Hur al-Azim wetland.
Fatemeh Bagheri, Mehri Rezayi,
Volume 14, Issue 1 (5-2021)
Abstract
Background and Objective: The aim of this study was to investigate dust origin particulate (PM2.5) in Mashhad city in a long period of time (2014-2019) based on unhealthy days. Furthermore, changes in meteorological parameters and their relationship with dust storms have also been investigated.
Materials and Methods: In order to locate dust pollution hotspots in mashhad air, first, information about unhealthy days of Mashhad city in a 5-year period was obtained from the site of Mashhad Pollutants Monitoring Center and then HYSPLIT model was used to locate air pollution hotspots caused by particulate matter. To verify the results, the outputs obtained from this model were also compared with the DREAM8b model.
Results: By examining the meteorological parameters and its relationship with the outputs obtained from THEHYSPLIT and DREAM8b models, the maximum wind speed and relative humidity were obtained in autumn. There was no rainfall in the studied days (19 days) and the highest temperature was related to summer, indicating the relationship between the occurrences of polluted days due to particulate matter less than μ 2.5, wind speed and relative humidity in autumn. The results of the two models showed that the southern and northeastern regions of Mashhad city had the highest source of dust particles during the studied days.
Conclusion: Although in previous articles, the origin of dust in Mashhad city was announced outside the geographical boundaries of the province, long-term investigation at low altitude (below 10m) showed that local origin of dust have an essential role in air pollution in Mashhad city under unstable atmospheric conditions. Inappropriate use of agricultural lands and severe changes in land use often in the northern region and implementation of construction projects such as the southern belt of Mashhad city play essential roles in increasing PM2.5 particles in the air of Mashhad. This finding shows the importance of decision making for the implementation of soil stabilization projects etc... at the local level.
Moslem Rahimi, Maryam Mohammadi Rouzbahani, Khoshnaz Payandeh, Ahad Nazarpour, Ebrahim Panahpour,
Volume 14, Issue 2 (9-2021)
Abstract
Background and Objective: Due to the spread of dusty air and the transfer of these particles to the cities of Khuzestan province, it is very important to study the status of these particles in terms of heavy metal pollution and their pollution status.
Materials and Methods: In this study, the concentrations of Cr, Cu, Zn, Pb, Ni, Mn, Mg and Fe in the air of 4 cities of Khuzestan province (Ahvaz, Dezful, Mahshahr and Abadan) in dusty and dust-free conditions over a period of 9 months (autumn, winter and spring) were measured in 2018-2019. Due to the spread of dusty air and the transfer of these particles to the cities of Khuzestan province, it is very important to study the status of these particles in terms of heavy metal pollution and their pollution status.
Results: 48 samples in contaminated conditions and 48 samples in non-contaminated conditions were collected at the specific points and exact times using a High Volume sampling pump with a flow rate of 110 L/min for 6 hours. Metal concentrations were measured using ICP. Except for Ni, Mn and Mg, the mean concentration of other studied metals were higher at dusty conditions as compared with their values in non-dusty conditions (p < 0.05). In dusty and non-dusty air conditions the order of heavy metals based on their concentrations were obtained as following: Zn> Mg> Mn> Ni> Cr> Pb> Fe> Cu and Mg> Mn> Ni> Pb> Fe> Cr, respectively. This result shows that the origin of zinc and copper metals and the increase in chromium concentration in polluted air are due to the entering of dust and pollution transfer from the outside area into cities. The cities of Ahvaz, Dezful, Mahshahr and Abadan were highly enriched in terms of heavy metals pollution either in dusty or non-dusty conditions.
Conclusion: The findings of this study showed that despite low concentration of heavy metals in airborne dust particles in clear and dusty air, high health risks of metals such as zinc in cities of Khuzestan province, especially Mahshahr are probable. Further investigation showed that particles are generally derived from intra-city or provincial activities, which call for more attention due to the drought conditions that attributes to more dust formation.
Farah Rashadi, Nahid Navidjouy, Ali Ahmad Aghapour, Mostafa Rahimnejad,
Volume 14, Issue 3 (12-2021)
Abstract
Background and Objective: Microbial fuel cell (MFC) is a new green technology that uses the catabolic ability of microorganisms to produce bioenergy while simultaneously removing organic matter and other wastewater contaminants. Electrode material is one of the factors affecting the performance of microbial fuel cells. The aim of this study was to investigate the performance of microbial fuel cells in COD removal and bioenergy production from synthetic and real beverage wastewater.
Materials and Methods: In this research, a two-chamber microbial fuel cell with Nafion membrane and aerated cathode was set up using two electrodes made of carbon felt and flat graphite after being contacted by synthetic wastewater with a concentration of COD 5000 mg/L and real beverage wastewater. Organic matter removal efficiency and voltage, power density and maximum current were determine.
Results: Experimental results showed that maximum COD removal efficiency of 92 % was achieved in synthetic wastewater and with a carbon felts electrode. In this condition, maximum voltage, power density and output current density of 469 mV, 175.28 mW/m2, and 855 mA/m2, were obtained, respectively. However, by using real industrial wastewater (beverage), maximum removal efficiency of COD, voltage, power density and output current density, related to carbon felt electrodes were obtaines as 84 %, 460 mV, 91/65 mW/m2, and 635 mA/m2, respectively.
Conclusion: The findings showed that synthetic wastewater outperforms microbial fuel cells in terms of bioelectric production and organic matter removal as compared to real wastewater (beverage). The reason for the decrease in the cell performance might be the presence of solids and other confounding pollutants in real wastewater.
Zeinab Alizadeh, Kavoos Dindarloo, Mohsen Heidari,
Volume 14, Issue 3 (12-2021)
Abstract
Background and Objective: Heavy metal (HM) pollution of settled dust on the interior surfaces of elementary schools may affect the health of young students; hence, the health risk of such pollution should be assessed. Therefore, the aims of this study were to measure the content of heavy metals in the settled dust in the indoor of elementary schools in Bandar Abbas and to assess the attributed health risks.
Materials and Methods: In this study, dust samples were collected from the interior surfaces of elementary schools in Bandar Abbas. Settled dust samples were digested using aqua regia solution and then their metals contents were measured using ICP-OES. To assess the health risk attributed to this pollution, daily intake doses through ingestion, inhalation and skin absorption routes were estimated. Then, non-carcinogenic and carcinogenic risks were calculated considering the daily intake doses and toxicity factors.
Results: The average concentrations of arsenic, cadmium, cobalt, chromium, nickel and lead in settled dust were 5.45, 0.58, 11.44, 69.72, 83.95 and 66.72 mg/kg, respectively. The non-carcinogenic risk level for all metals was below threshold, while the carcinogenic risk level for arsenic (2.18×10-6) exceeded the threshold.
Conclusion: This study showed that the settled dust in elementary schools of Bandar Abbas is polluted with various levels of heavy metals. Health risk assessment showed that the exposure to dust containing heavy metals in the elementary schools of Bandar Abbas does not pose significant non-carcinogenic risk, but the carcinogenic risk of As exceeded the threshold limit and should be considered.
