Original Article
Sajjad Bahrami; Ahad Sotoudeh; Naser Jamshidi; Mohammad Reza Elmi
Volume 16, Issue 3 , October 2018, Pages 1-24
Abstract
Introduction: Development of various industries, despite providing human welfare, has potential risks for mankind. Due to its extensive operations and activity and also the potential risk for humans and the environment, the petrochemical industry is considered a high-risk industry. The purpose of this ...
Read More
Introduction: Development of various industries, despite providing human welfare, has potential risks for mankind. Due to its extensive operations and activity and also the potential risk for humans and the environment, the petrochemical industry is considered a high-risk industry. The purpose of this study was to assess and prioritize the risks resulting from process activities in Kermanshah petrochemical complex using two approaches (i.e., the traditional and fuzzy FMEA method). Material and methods: The present study was an analytical-field research that has been conducted in Kermanshah petrochemical complex for 10 months. In this study, the product lines (urea and ammonia) were investigated and also a team of five experts was formed. In addition, an initial list of the most important risks and hazards in the environmental field was prepared and then, by using Brainstorming and Delphi Technique, the list was corrected. Finally, environmental risk assessment in the form of traditional and fuzzy FMEA methods was evaluated. Results and discussion: According to the results, 38 risks were identified by traditional FMEA. The highest priority risk was related to hydrogen and ammonia gas emissions when the ammonia unit was out of service by RPN number of 491. The lowest priority risk belonged to ammonia effluents by RPN number of 28. Also, the highest risks to air pollution, as well as the causes of the risks were related to defects in the system and connections. The results of input fuzzification and output FMEA method showed that among the 15 identified risks in the petrochemical complex, the highest number of fuzzy priority in the health section was related to noise pollution (0.75), in the safety section was falling from the heights (0.75), and in the environmental sector for the reduction of ecological resources (0.613). Conclusion: Comparing these two approaches suggest that the traditional FMEA is powerful in the early stages of risk assessment process, and on the other hand, the fuzzy approach is more flexible and user-friendly in the stage of prioritizing the risks.
Original Article
lotfali Kozegarkaleji; Arman Moslemi; Mohammad Moradi; Hossein Rafie Mehr; Abbas Amini Zadeh
Volume 16, Issue 3 , October 2018, Pages 25-44
Abstract
Introduction:
The concept of sustainable development is expanding internationally, and therefore scientists have provided several quantitative and qualitative models for measuring the sustainable development of communities and cities. One of these tools, which attracts more attention in the scientific, ...
Read More
Introduction:
The concept of sustainable development is expanding internationally, and therefore scientists have provided several quantitative and qualitative models for measuring the sustainable development of communities and cities. One of these tools, which attracts more attention in the scientific, political and educational levels, is the assessment of ecological footprint. According to this method, the development is considered unsustainable, when the ecological footprint is higher than the biomass of the region. The ecological footprint approach has been used to measure the sustainability of major cities around the world, such as London, Liverpool, and Paris. The aim of this research is to measure the stability of Tabriz city using the ecological footprint method.
Material and methods:
In this research, descriptive-analytical and quantitative methods were used. The data of this research are mainly quantitative. The population under study included all households living in Tabriz. All data were obtained either from documents (e.g., library and electronic databases) or during field works. In this study, cluster random sampling method was used. The city of Tabriz was categorized into 10 regions based on municipalities and from each region several blocks were selected by sortition. A syncretistic ecological footprint method (a combination of inductive and deductive methods) was used to calculate the ecological footprint in the urban areas. The data necessary for initial analyses were obtained using the country’s statistical data. These include energy consumption, forestry, and its utility.
Results and discussion:
To determine the ecological footprint of Tabriz, data from food, carbon dioxide emissions from transportation, heating from natural gas, water, electricity, and the amount of waste was used. The results show that the city of Tabriz requires an average of 10.86 trillion hectares of land per year for landfill. The required area to absorb the carbon derived from the consumption of the natural gas for each citizen and the whole population is 135 square meters and 20,795 hectares, respectively. The electric power footprint of each citizen of Tabriz is 0.17 hectares. Finally, the water consumption footprint of Tabriz city is 0.020 hectares.
Conclusion:
The results of this study indicate that the ecological footprints of Tabriz city in categories such as food products, transportation, heating from natural gases, water, electricity, and the land needed for waste disposal were 3.30 hectares. Our results suggest that the city of Tabriz relies on a region beyond East Azarbaijan Province to meet its biological needs and sustainability. The amount of consumables in Tabriz shows that food with 2.73 hectares has the highest share compared to other factors. The lowest amount of area needed for waste disposal was 0.77 square meters per person. Since Iran's biocapacity is 0.8 hectares, the ecological footprint of 3.30 hectares in Tabriz city indicates that the city allocated 125.4 times more than its share of the country's biological capacity to itself.
Original Article
Maryam Larijani; Mahdieh Rezaee
Volume 16, Issue 3 , October 2018, Pages 45-64
Abstract
Introduction:
Light plays an important role in human life, however, the development of light sources which is meant for human comfort, sometimes causes them discomfort. Excessive and unnecessary lighting in shopping centers (i.e., light pollution), especially in the commercial segments of the cities, ...
Read More
Introduction:
Light plays an important role in human life, however, the development of light sources which is meant for human comfort, sometimes causes them discomfort. Excessive and unnecessary lighting in shopping centers (i.e., light pollution), especially in the commercial segments of the cities, can be harmful to people's health including the sellers, customers and passersby. The level of knowledge and awareness of people about light pollution and its adverse effects on the attitude and behavior of people have been proven to be very important. Therefore, in this study, the influence of education about light and light pollution on the level of shopkeepers’ knowledge and behavior on the matter was investigated in Nahavand city.
Material and methods:
In this study, we exploited a quasi-experimental design and collected data using questionnaires. The validity of the questionnaire was approved by experts and its reliability was confirmed with Cronbach's alpha. The statistical population of this study was 40 shopkeepers in Gheisarieyeh Street of Nahavand city, which were selected based on investigator’s judgment and then were randomly categorized in control and testing groups. Pre-tests were done and then seven hours training were performed for experimental groups and finally, a post-test was applied. The obtained data were analyzed with Kolmogorov–Smirnov test, independent-samples t-test, student’s paired-samples t-test, and analysis of covariance tests (ANCOVA).
Results and discussion:
The results of ANCOVA and t-test showed that the mean score of awareness and behavior variables were significantly different between experimental and control groups after training (with 95% confidence). The effect size of training for shopkeepers' awareness variables including the light pollution concepts and dimensions of economic, health, safety, environmental and social were, respectively, 37%, 51%, 59%, 25%, 60% and 19%. P-value for behavior variable was 0.000 which was lower than 0.05.
Conclusion:
This study showed that education on light and its related subjects (e.g., light pollution) may be useful in increasing awareness and promoting the behavior of shopkeepers. Therefore, increasing public knowledge in order to change the behaviors of sellers and shopkeepers, especially those active in night hours, is of great importance.
Original Article
Parisa Kazemi; Fatemeh Shariati; Abdolkarim Keshavarz Shokri
Volume 16, Issue 3 , October 2018, Pages 65-78
Abstract
Introduction: There are numerous indices used to determine water quality, among which the National Sanitation Foundation (NSF) index is one of the most functional ones. The aim of the present study was to evaluate the water quality of Langroud River using NSF Water Quality Index (NSFWQI), where 10 parameters ...
Read More
Introduction: There are numerous indices used to determine water quality, among which the National Sanitation Foundation (NSF) index is one of the most functional ones. The aim of the present study was to evaluate the water quality of Langroud River using NSF Water Quality Index (NSFWQI), where 10 parameters including water temperature, turbidity, phosphates, nitrates, dissolved oxygen (DO), fecal coliform, biochemical oxygen demand (BOD), pH, total dissolved solids (TDS), and electrical conductivity (EC) were measured. Material and methods: Seven stations were selected along the river and samples were obtained during four seasons from February 2015 to July 2015. DO, pH, turbidity, and TDS were measured by a portable device. Nitrate and phosphate were determined by spectrophotometry. The temperature was measured by a thermometer. The coliform measurement was done by the 9-tube standard method. Results and discussion: Our results showed that turbidity, temperature, nitrate, phosphate, TDS, pH, and EC had the highest amount in summer, BOD reached its highest value in the spring, the amount of fecal coliform was almost the same in all seasons, and DO had its highest amount in winter. Comparison of the values of NSFWQI at seven stations of Langroud River in different seasons showed that the second station (Darvishanbar, upstream) had the highest value (63) in the winter, and Khalkyaser station (downstream) had the lowest value (56) in the summer. Conclusion: Generally, the results showed that in all stations, the numerical values of indexes are reduced gradually from winter to summer. Interpretation of the results based on NSFWQI indicates that in Langroud River from the first station to the last one, the pollution load increased and the water quality decreased. So, the river’s water is not suitable for drinking and it should be treated before application.
Original Article
Abutaleb Sabr; Mazaher Moeinaddini; Hossein Azarnivand
Volume 16, Issue 3 , October 2018, Pages 79-100
Abstract
Introduction: In recent decades, air quality change and its risks are correlated with the expansion of urban and industrial areas and other land-use changes. One of the important effects of land use/cover changes (LUCC) is wind erosion and as a result, an increase in particulate matter (PM) concentration ...
Read More
Introduction: In recent decades, air quality change and its risks are correlated with the expansion of urban and industrial areas and other land-use changes. One of the important effects of land use/cover changes (LUCC) is wind erosion and as a result, an increase in particulate matter (PM) concentration in residential areas. For this reason, the effects of LUCC on PM concentration in Tehran’s airshed was studied. Material and methods: Data on LUCC and landscape metrics were studied in the years 1985, 2000 and 2014. Then, the relationship between LUCC and PM concentration in Tehran was investigated by trend analysis methods. To find the most important wind directions with strong effects on Tehran’s air quality, conditional probability function (CPF) and directional relative strength (DRS) were used. Results and discussion: LUCC results showed that the area of agricultural land-use has been expanded from 1985 to 2000, yet decreased from 2000 to 2014. The trend was vice versa for barren lands during the mentioned time periods. In addition, the urban area has increased in the whole period. The landscape metric results showed that landscape patches became smaller and the landscape has been fragmented. The results of the PM10 concentration trend analysis revealed that it has been increased dramatically since 2007. Comparison of the average concentration of PM10 before and after 2007 showed a significant difference. The results of CPF and DRS illustrated that no specific wind direction was detected before 2007, but afterwards both increased in specific directions (south to west), which is compatible with most LUCC and fragmented areas in these directions. Conclusion: Our results showed that specific wind directions may lead to an increase in the PM10 concentration which is compatible with LUCC directions. Therefore, LUCC could be a significant reason for the increase in PM10 concentration in Tehran.
Original Article
Vahid Nasiri; Ali Asghar Darvishsefat
Volume 16, Issue 3 , October 2018, Pages 101-118
Abstract
Introduction: A landscape is a heterogeneous and vast region consisting of a set of patches, habitats, and repetitive environmental elements. In recent studies, various metrics have been used to investigate the structure, function, and landscape pattern changes. The metrics are quantitative indices that ...
Read More
Introduction: A landscape is a heterogeneous and vast region consisting of a set of patches, habitats, and repetitive environmental elements. In recent studies, various metrics have been used to investigate the structure, function, and landscape pattern changes. The metrics are quantitative indices that describe the structural and spatial properties of the landscape. The objective of this study was to obtain information on the current status of different land use classes and the analysis of complex relationships among classes in Arasbaran region. Material and methods: In this regard, a land use/land cover (LULC) map with seven classes (i.e., high-density forest, low-density forest, agriculture, grassland, barren land, water, and urban area) was produced from Landsat 8 OLI imagery (2014) and ancillary data. Eighteen different landscape metrics including area metrics, shape metrics, isolation and proximity metrics and diversity metrics were calculated for each class and landscape level. Results and discussion: Results showed that the high-density forest and grassland form the main elements of Arasbaran landscape with 30.76% and 30.03% of the Percentage of landscape, respectively. The metrics of number and density of patches showed that grassland and low-density forest classes had the highest number of patches compared to other land use classes and so are the finest grained land use classes in the area. The largest patch index also showed that 4.76 percent of the landscape was occupied by the largest high-density forest patch. The total edge and edge density indicated that the majority of the area is covered by high-density forest and it provides the longest border with other land uses. Based on the shape metric, urban area and barren land have the most dispersion. In addition, the urban area and high-density forest are the most discontinuous and continuous land uses in the landscape, respectively. Based on the mean of Euclidean distance, the distance between the high-density forest patches is the minimum and the distance between the urban patches is the maximum metric. In total, the study area is composed of 802 LULC patches. Also, based on Shannon and Simpson diversity and uniformity metrics, the area is diverse and heterogeneous. Conclusion: Considering the fine-grained grasslands and forests with high (dis) connectivity, the dispersion of urban areas, and the extent of agricultural lands, an increasing rate of changes in the land use can be estimated in the future. The future changes can be as removing small patches of grassland and forests, and expansion of the urban and agricultural classes.
Original Article
Pooya Arbab; Bita Ayati; Mohammad Reza Ansari
Volume 16, Issue 3 , October 2018, Pages 119-134
Abstract
Introduction:
Many pollutants in industrial wastewaters, such as dyes, can't be removed easily by the conventional physical, biological and chemical purification processes, because of their complexity and intractability. Therefore, it is necessary to find an effective treatment technology that can degrade ...
Read More
Introduction:
Many pollutants in industrial wastewaters, such as dyes, can't be removed easily by the conventional physical, biological and chemical purification processes, because of their complexity and intractability. Therefore, it is necessary to find an effective treatment technology that can degrade complex bio-refractory molecules or can breakdown them into smaller molecules which can be further degraded by conventional methods. Cavitation is one such recent technique which has been extensively studied for the treatment of complex wastewater due to its ability of generating highly reactive free radicals. Hydrodynamic cavitation has a potential of application on larger scale due to its capability in generating hydroxyl radicals at ambient condition, easy scale up and less material cost making it more economical to employ. The purpose of this study was application of hydrodynamic cavitation process for removing Reactive Black 5 and optimization the affecting parameters (pH, inlet pressure, hole diameter and initial concentration of dye) based on the amount of efficiency and energy consumption.
Material and methods:
In this research, removal of Reactive Black 5 with the use of hydrodynamic cavitation process was studied. 8.25 liters of colored solution was examined in each test. The cavitation was produced by orifice plate and pump. In order to optimize process, various trials were performed in pH of 3 to 11 and also using different orifice plates with hole diameter of 2, 3, 5 and 7 mm at inlet pressures of 2, 3, 4 and 5 bar and dye concentration of 30, 50 and 100 ppm. Due to the constant voltage of urban electricity, the electric current was measured as an indicator of energy consumption by ammeter.
Results and discussion:
According to the results by reducing the pH, dye removal was increased and orifice plates with larger hole diameter in upper pressures had better efficiency. It was observed that increasing the initial concentration of dye resulted in decreasing dye removal efficiency. The orifice with 7 mm hole diameter at 5 bar inlet pressure yielded the highest efficiency, but by involving the amount of energy consumed and considering the process efficiency to energy consumption, the orifice with 7 mm hole diameter at 4 bar inlet pressure was chosen as the best. The pH of 3, orifice with 7 mm hole diameter at 4 bar pressure and initial concentration of 30 ppm (with regards to pump energy consumption obtained from measuring the electrical current and the efficiency of process) were selected as optimum conditions. In these conditions after 120 minutes, 38.21% dye removal was obtained using hydrodynamic cavitation.
Conclusion:
Hydrodynamic cavitation has a potential of application on larger scale due to its capability in generating hydroxyl radicals at ambient condition. It was found that the energy consumption was an effective factor in selecting the optimum conditions. By reducing the initial dye concentration and pH, dye removal was increased and orifice plates with larger hole diameter in upper pressures had better efficiency.
Original Article
Zeinab Ahmadi; Davoud Kartoolinejad; Mariam Molashahi; Masoumeh Shayanmehr
Volume 16, Issue 3 , October 2018, Pages 135-152
Abstract
Introduction:
The diversity and abundance of soil fauna in the forest have an important role in nutrient cycle, and destructive factors (e.g., fire) would cause a disturbance in the balance of soil communities. In the current study, the effect of fire on biodiversity, richness, abundance, fresh biomass ...
Read More
Introduction:
The diversity and abundance of soil fauna in the forest have an important role in nutrient cycle, and destructive factors (e.g., fire) would cause a disturbance in the balance of soil communities. In the current study, the effect of fire on biodiversity, richness, abundance, fresh biomass and trophic levels of soil-dwelling invertebrates in Galandroud forest were investigated and discussed.
Material and methods:
This research was conducted in districts 20 and 21 of series 11 from watershed 48 of Natural Resources and Watershed Management Department of Nowshahr. Ten 30×30 cm quadrates with 30 cm depth were randomly placed in both fired and control forests (20 quadrates in total) across two distinct using hand-sorting methods. The soils were collected into a pan, and transferred to the laboratory for identification and measuring the fresh biomass after separating the fauna into plastic bags. Then, the fresh biomass of soil animals was separately measured using a digital balance (with an accuracy of 0.0001 g) and then identified at family and order levels. The PAST software was used to calculate the dominance, biodiversity and richness indices of the soil fauna. Statistical comparisons were done with independent sample t-test using SPSS software. Moreover, the trophic levels of the soil fauna were determined and the abundance and biomass of each five main trophic groups were investigated within two fired and control forests.
Results and discussion:
Among the identified macrofauna, the earthworms were the most abundant. The abundance of almost all species was more in the control forests rather than the fire-burned ones, except for coleopteran beetles and the ants. The total biomass of trophic levels did not show any significant difference between the two forests, while it’s amount in the burned and control forests was 2.35 and 1.70 g.m-2,respectively. Among detritivore biomass, the biomass of earthworms and coleopteran beetles increased, while it decreased for millipedes, slaters, and Diplura in the burned forests compared to the control. According to the similar studies that have been done so far, most faunal assemblages have shown a negative response to the fire in the short term, and then their populations revived or even increased compared to the control area.
Conclusion:
The results revealed that almost all indices did not show a significant difference between fired and control forests after 5 years, with an exception for evenness and dominance. These findings reflect the restoration of the forest and soil fauna communities and return to the conditions before the fire. However, comparison of the faunal population at trophic levels showed that detritivores in the burned forests experienced the most reduction among all groups and damaged the most from the fire.
Original Article
Mahmood Sinaei; Mehran Loghmani; Mehdi Bolouki
Volume 16, Issue 3 , October 2018, Pages 153-166
Abstract
Introduction:
Aquatic ecosystems, particularly marine and coastal areas, are exposed to various environmental pollutions (e.g., organic and heavy metals pollution), which are caused by natural phenomena as well as human activities in aquatic environments. The aim of this study was to evaluate the concentration ...
Read More
Introduction:
Aquatic ecosystems, particularly marine and coastal areas, are exposed to various environmental pollutions (e.g., organic and heavy metals pollution), which are caused by natural phenomena as well as human activities in aquatic environments. The aim of this study was to evaluate the concentration of heavy metals in water and brown algae Polycladia indica as a bioindicator along the northern coast of the Makoran Sea and compare their concentrations with global standards and previous studies.
Material and methods:
For this purpose, concentrations of heavy metals (i.e., cadmium (Cd), copper (Cu), zink (Zn), lead (Pb), nickel (Ni), chromium (Cr)) were assessed in P. indica and water samples in ten stations along the northern shores of Makoran Sea in the autumn of 2017. Samples were transferred to the laboratory and heavy metals were measured by atomic absorption spectroscopy (AAS).
Results and discussion:
In brown algae samples, Zn had the highest concentration within the whole area followed by Cr, Ni, Cu, Pb, and Cd, respectively. For water samples, the concentration of Cr was the highest followed by Zi, Ni, Cu, Pb, and Cd. One way-ANOVA test showed significant differences in the concentration of metals between sampling stations (p < 0.05). The concentration of heavy metals in water samples was lower than the global standards. Strong correlations were found between the examined heavy metals, indicating the lack of diversification of pollution sources in the northern coasts of the Makoran Sea and the uniformity of the geochemical composition of the coastal geology units of the sampling regions.
Conclusion:
The results of this study indicate the high affinity of P. indica towards the absorption of heavy metals, and therefore, this species can be considered as a bioindicator of heavy metals contamination in the northern shores of the Makoran Sea.
Original Article
Marziyeh Aghasi; Naser Mehrdadi
Volume 16, Issue 3 , October 2018, Pages 167-180
Abstract
Introduction:
Fish processing industry produces huge amounts of solid waste and wastewater. This wastewater consists of preliminary processing of the raw fish, washing the plant, and raw offal products (e.g., blood and viscera). The high-fat content of industrial wastewater causes problems in treatment ...
Read More
Introduction:
Fish processing industry produces huge amounts of solid waste and wastewater. This wastewater consists of preliminary processing of the raw fish, washing the plant, and raw offal products (e.g., blood and viscera). The high-fat content of industrial wastewater causes problems in treatment and disposal and raises environmental crises. The purpose of this study is to select the best method for organizing a wastewater treatment in fish processing plant based on the most widely used wastewater management technologies worldwide.
Material and methods:
This research was done by the AHP method. Based on the general conditions in fish wastewater treatment plants in industrial estates and expert judgments, and by using technical, economic, environmental, and administrative criteria, the processes were carried out. Treatment of wastewater included trickling filter, aeration lagoon, anaerobic digestion, and active sludge. The obtained results were assessed by the Expert Choice software.
Results and discussion:
According to our results, the best method was the active sludge method with a score of 0.417 and after that, aeration lagoon, anaerobic digestion and trickling filter with a score of 0.284, 0.264 and 0.052, respectively, were the best choices based on the expert's opinion.
Conclusion:
According to the technical, managerial, environmental and economic criteria and sub-criteria, this study showed that the best method for wastewater treatment in a fish processing plant was the active sludge.
Original Article
Sara Abbaszadeh; Shahindokht Barghjelveh
Volume 16, Issue 3 , October 2018, Pages 181-202
Abstract
Introduction: The paradigm of “Ecology in City” became an active approach in the early 1950s in Asia and Europe. In the paradigm of “Ecology of City”, the planning process of solving the urban landscape systems’ complex environmental problems relies upon a comprehensive ...
Read More
Introduction: The paradigm of “Ecology in City” became an active approach in the early 1950s in Asia and Europe. In the paradigm of “Ecology of City”, the planning process of solving the urban landscape systems’ complex environmental problems relies upon a comprehensive knowledge of ecological principles and of ecological networks. As in the process of planning the urban landscape systems’ ecological networks, the physical system of urban structures has a quadruple characterization of ecological heterogeneity: “structural”, “procedural”, “temporal” and “spatial”, it characterizes that in the study of urban planning there is a need for a deeper knowlwdge of urban structures and of ecological networks they provide. Overall, the urban structures’ ecological networks provide a physical system for the flow of mater, energy and information. On the other hand, “urban ecology” merely adds an emphasis on human ecosystems in general, which include organisms, the physical environment and conditions, the human population and its social structures and processes, and the built and technological components. Therefore, the main objective of this research is to apply the principles of landscape ecology and of ecological networks in the process of planning the urban landscape systems’ physical structures. Material and methods: The methodology of this research is divided into two main sections:1) analyzing the conceptual framework of the research in explaining the structural planning of ecological networks, and 2) programming the physical structure of Tehran's landscape system in coordination with the ecological trends of its landscape system, and the management system of the desired changes in the structural pattern of ecological networks. In this research, we used the LCM model (Land Change Modeler), which depicts the modeling of the changes in urban land use from the past to the present and future, and GIS (Geographic Information System) software. Results and discussion: The damage to ecological networks has caused a dam in biological processes and loss of cycles of matter and energy in the creation of eco-sociological landscape systems. This eventually has led to simplification, fragmentation, and deficiency of urban landscape systems, resulting in negative effects on the level of coordination between the four aspects of heterogeneities and their impact on human health and the environment. The generated maps in three consecutive times indicate a significant decrease in vegetation cover and landscape fragmentation in Tehran's physical system and, consequently, an increase in the magnitude of manmade structures during urban development processes, especially in the next ten years. In this regard, two issues have been considered: 1) establishing an analytical relationship between the research’s proposed conceptual framework and the data obtained from the physical system of Tehran's landscape system, and 2) analyzing the current trend of urban changes, predicting the effects of the city's physical development on local ecological networks, and the proper planning of changes for the structural pattern of Tehran's physical system. Conclusion: The analysis of Tehran’s landscape system is based on a framework proposed by current research’s conceptualization of three scientific approaches, including: “biology”, “ecology”, and “landscape ecology”. In addition of clarifing the living process of an urban landscape system’s “biological”, “social” and “spatial” characteristics, it takes into account the process of planning urban ecological networks, based on an applied strategies in reducting the ecological disturbances of Tehran’s urban landscape system.
Original Article
Shahrzad khoramnejadian; Shirin Khoramnejadian
Volume 16, Issue 3 , October 2018, Pages 203-216
Abstract
Introduction: Plastic wastes are becoming a major problem all around the world. Degradation of synthetic polymers takes a long time, and so they remain in the environment for many years. Plastic packagings are one of the main sources of solid wastes. Using biodegradable plastic may be a solution to this ...
Read More
Introduction: Plastic wastes are becoming a major problem all around the world. Degradation of synthetic polymers takes a long time, and so they remain in the environment for many years. Plastic packagings are one of the main sources of solid wastes. Using biodegradable plastic may be a solution to this problem. Mixing synthetic polymers with biopolymers is one way to produce biodegradable plastics. Another way to degraded plastic materials is photodegradation. Photodegradable plastics could be used in packaging industries because a huge amount of packaging plastics are being thrown away in nature. Material and methods: In this research, photodegradable and biodegradable compounds of starch and linear low-density polyethylene were prepared. Samples with different levels of starch (i.e., 3.7, 7.4, 10, 15, and 20 %wt) with a constant amount of 5% PE-g-MA were prepared. PE-g-MA used as coupling agent. The mechanical properties of polymer sample were done by santam instrument. Water absorpton of starch base polymer were evaluated. Soil burial tests shown the biodegradability of samples in the nature. starch-based polymer was exposed to mold growth to simulate biotic degradation. Photodegradability of samples were measured by exposure them to sunlight for 3 months. In order to determine bacterial degradability, samples were exposed to aspergilus niger for 84 days. Results and discussion: The tensile strength and Young’s modulus were decreased by the increase in starch content of the samples. The results of water absorption of the samples showed that when the starch percentage was higher, the water absorption was significantly increased. After being buried in soil for 11 months, the weight of the blends was decreased by increasing the starch level, which is an indication of biodegradation. The weight loss after removal of starch was probably caused by soil microorganisms. If the amount of starch is low, the compound would be affected by the low-density polymer matrix and unavailable to soil microorganisms. The more the samples remained in the soil, the more consumption of polymer chain by microorganism happened. Mold growth on polymeric samples confirmed the biodegradability of LLDPE/starch sheets. Mould biodegradation depends on microorganisms and their metabolism. Conclusion: According to the results, the blends are biodegradable and photodegradable and so are applicable in packaging industries. Soil burial is a simple simulation of the landfill. These blends are suitable for packaging goods.
Original Article
Saman Rostami; Hasan Amini-Rad; Ozeair Abessi
Volume 16, Issue 3 , October 2018, Pages 217-232
Abstract
Introduction: During the last years, oil and gas exploration, extraction and refinery activities caused a lot of damage to the sensitive environment of the Persian Gulf. In the current study, the Pars Special Economic Energy Zone in the northern Persian Gulf was investigated, where oil and gas explorations, ...
Read More
Introduction: During the last years, oil and gas exploration, extraction and refinery activities caused a lot of damage to the sensitive environment of the Persian Gulf. In the current study, the Pars Special Economic Energy Zone in the northern Persian Gulf was investigated, where oil and gas explorations, extractions, refineries and export infrastructures are concentrated. Each year, large amounts of petroleum-related pollutants discharge into the Persian Gulf in this region. In this research, the spatial distribution and the origin of oil-associated hazardous pollutants i.e., Polycyclic Aromatic Hydrocarbons (PAHs) in Assaluyeh Port were investigated. Material and methods: Fifteen samples of the surface sediment of the study area were collected in March 2016, using the Van Veen Grab sampler in five half lines perpendicular to the coast in phases one to five of the Pars Special Economic Energy Zone. Samples were packed in aluminum foils and transferred to the laboratory. Using freeze-drying process, the water was removed from the samples. Pollutants tend to accumulate in fine sediment particles due to the high specific surface area of these particles, and therefore, fine-grained particles (≥63 μm) were separated by physical screening. Finally, 16 compounds of PAHs, which are known as the toxic compounds by the U.S. Environmental Protection Agency (USEPA), were analyzed with gas chromatography-mass spectrometry. Total concentrations of the compounds were measured and their spatial distribution was illustrated using ArcGIS software. The origin of the observed Aromatic Hydrocarbons was also estimated using some indices. Results and discussion: Total concentrations of the 16 compounds ranged from 46.6 to 84.7 ng/g dry weight in the sampling stations. The source of compounds was identified using certain petrogenic multiple indices. Furthermore, the environmental risk of the presence of these compounds was estimated using the sediment quality guidelines of the state of Florid. It was shown that except for Naphthalene and Acenaphthene, concentration levels of other PAHs were lower than the threshold level, which is the concentration that destructive biological effects in benthic communities is rarely expected. Conclusion: Total concentrations of 16 PAH compounds in the study area showed that the concentration of no compound exceeded the concentration of Effects Range, so it can be concluded that the possibility of harmful effects on benthos communities and other organisms in the food chain and also humans at the top of the chain is low. Considering the high rates of sedimentation and erosion and also the fossil origin of the pollutants, it seems that contaminations are continuously being buried under the new layers of sediment in the study area. Therefore, the continuing source of pollution could not cause serious contamination in the surface sediment of the region.
