Environmental Sciences
Year:2018 | Volume:15 | Issue:4 |Papers Count:15

Introduction: Soil pollution by heavy metals has become an environmental problem due to their long-term sustainability and ecologically harmful effects. In soils contaminated by heavy metals, establishing plants with the ability to grow in affected areas, adapt and uptake heavy metals is both scientifically and economically beneficial.Materials and methods: In the current study, soil and plant samples were taken using a systematic random sampling approach within a 500, 1250 and 2000 meter radius of the centre of Kiasar cement factory in Mazandaran Province. For each distance, three plant species (such as Astragalus, Artemisia and Convolvulus) and their adjacent soils were sampled in three replications resulting 54 samples (27 plant and 27 soil samples). The concentrations of Pb, Cu, and Zn in the samples were determined using an ICP-OES Device and data analyzed statistically using a randomized complete block design.Results and discussion: Analysis of variance results in this study showed that the amount of heavy metals in the soil was higher than those obtained in plant species tissues (p£0.05). The mean comparison of data showed that distance from factory had a significant affect on copper and lead concentrations in both soil and plant tissues (p£0.05). While the copper concentration increased in both the soils and plant tissues, the amount of lead decreased with the increasing distance. The distance had no significant effect on zinc concentration in soil samples, but there were significant differences in plant species tissues and they do not follow the regular process. The correlation of heavy elements between plant species and soils showed that Astragalus andArtemisiahad a significant correlation with copper (r=0.7) and lead (r=0.5), but convolvulus only had a significantly positive correlation with Zn.Conclusion: Due to the high potential of Astragalus and Artemisia species in up-taking the heavy metals, these species can be used in refining contaminated areas with same ecological conditions.

Introduction: Growth of industrial activities and increasing emissions are giving greater attention to environmental problems in the world. Unpleasant (malodorous) smells can be classified as pollutants that have a negative impact on the quality of life. About one-third to half of animal products unusable for humans are used as raw materials in the processing and recycling industry. One of the most important features of slaughterhouse rendering plants is the release of volatile compounds and unpleasant odours, which disturb workers and people living adjacent of this industry. The purpose of this study was to evaluate an electronic nose system as a tool for displaying vapours from a slaughterhouse rendering plant, selecting an array of appropriate sensors and determining the fingerprint for this pollutant unit.Material and methods: Batch cooking was carried out at a temperature of 140 ° C under 3 bar pressure for four hours and uniformly stirred at a speed of 20 rpm (ISIRI 2389, 1995). A total of 30 liquid samples, each one with volume of 10 ml, were obtained from condensed vapours of batch cooker. Samples were transferred to the laboratory located at the Agricultural Machinery Department of the University of Tehran, and an electronic nose system was used for analysis and investigation. The electronic nose system was based on metal oxide semiconductor (MOS) sensors and included an array of six gas sensors. The principal component analysis (PCA) method was used to evaluate the sensors and select appropriate array of sensors.Results and discussion: Observation of the sensor’s response up until steady state with the aim of reducing consumption of time and oxygen, showed that 30 seconds to reach sensors to their baseline (baseline time), 100 seconds to contact the vapours with sensors (injection and response time) and 40 seconds to clear the sensors (purging time) were suitable. Correlation analysis of the sensors showed that some of the sensors had a correlation higher than 0.85. The analysis of variance distribution of the two primary principal componentsshowed that these two components comprised more than 99% of the total variance, and the primary component (PC-1) comprised over 98% of the total variance. The highest effect on the first component was related to the MQ135 sensor, after that the MQ136, MQ9, MQ131, MQ5 and, finally, MQ3 sensors were effective. The analysis of the principal components showed that MQ135 and MQ136 sensors, having a high sensitivity to ammonia, hydrogen sulphide and benzene, were the most suitable sensors for detecting the unpleasant smell released from the poultry slaughterhouse waste batch cooking (rendering plant). Selection of the MQ135 and MQ136 sensors as an array can be used to distinguish between pollutants from poultry rendering plants and pollutants released from other industries, and these sensors can be used to determine the fingerprint of the odour emitted from poultry rendering plants.Conclusion: According to the results of this research, the electronic nose system with arrays of MQ135 and MQ136 can be used to monitor and control the quality of pollutants from poultry rendering plants. Also, with referring to this fact that unpleasant odours as part of air quality control have no standard definition in Iran, an electronic nose system could be used to control the air quality in terms of the presence of unpleasant odours in the environment.

Introduction: Invasive fishes are a major threat to biodiversity of aquatic ecosystems. Tilapia species are invasive due to their reproductive, diet and behavioural characteristics and high resistance to environmental conditions, pollution and diseases. So far, two exotic species Coptodon zillii and Oreochromis aureus, as well as a native species Iranocichla hormuzensis of these species, have been reported from Iran. In recent years, exotic tilapia species have invaded Iran and its neighbouring countries inland waters and have had significant ecological and economic impacts. The aim of this study was to conduct a preliminary survey on the status of exotic tilapia species in Khuzestan Province, Iran.Materials and methods: The present study was carried out from November 2014 to September 2015 to determine the abundance of tilapia species (C. zillii and O. aureus) in the Shadegan Wetland and some local fish markets in Khuzestan Province. In addition, we the evaluated presence or absence of the species in some cyprinid fish farms in the province.Results and discussion: The results showed that the catchment and supply of C. zillii is high and the species is one of the dominant fish in Shadegan Wetland. In this study, although O. aureus was not caught from Shadegan Wetland, observations showed that it has dispersed to other areas, especially in rivers, and its abundance is being increased. The tilapia species especially C. zillii are pests in some fish farms and a reduction of fish production has been noted. The presence of the species in some fish hatcheries has increased the possibility of their transfer to other regions.Conclusions: At the moment, it seems that the best course of action to take action against tilapia is to prevent them from entering other water bodies (especially through aquaculture). The continuous studies to determine various aspects of the introduction, potential range prediction, and regular monitoring should also be also considered. Overall, a compilation method and also ecologically sustainable water management, reduction of water contaminants and decrease of fishing pressure on native species should be adopted for controlling and reducing of these species.

Introduction: In recent years, zero-valent iron has drawn a great deal of attention in wastewater treatment and ground water remediation. It can effectively remove priority water contaminants, but there are some disadvantages in the use of nZVI particles, such as a high tendency to agglomerate, lack of stability, secondary iron pollution, separation and recovery of the fine nZVI particles after utilization. Using supporting material for nZVI is a promising way to solve these problems. Clay minerals as abundant natural resources are appropriate candidates to act as supporting materials. In this study, the use of fibrous clays-supported nZVI composite for the remediation of contaminated aqueous solutions will be discussed.Materials and methods: Sepiolite and Palygorskite nano zero-valent iron composites were made using green tea extract. In order to determine the sorption capacity of nZVI, sepiolite and palygorskite composites for phosphorous, cadmium and nickel based on isotherm models, different concentrations of these ions were equilibrated with the composites in 1% suspensions for 24 hours. After adsorption, the supernatant liquids were filtered and the residual pollutant concentrations were determined.Results and discussion: Results showed that Langmuir and Freundlich were the best models for describing p sorption on both composites. The estimated maximum adsorption capacity of the Sep-nZVI and Pal-nZVI using the Langmuir model (qmax) was 11.38 mg P/g and 8.57 mg P/g. The cadmium adsorption data for both sorbents was best fitted to the Langmuir, Fruendlich and Dubinin–Radushkevich models. Results clearly demonstrated the much higher Cd sorption potential of sepiolite compared with palygorskite. The sorption capacities (qmax) of Sepiolite-nZVI and palygorskite nZVI composites for Ni were 11.14 and 32.3 mgr/gr, respectively. The Ni sorption affinity (KL) of palygorskite nZVI was also greater than that of Sepiolite-nZVI. The favourability of a sorption system can be predicted by the constant separation factor RL. In the currentstudy, RL values for palygorskite nZVI and Sepiolite-nZVI were greater than zero and less than unity, indicating favourable sorption of P, Cd and Ni onto the two composites.Conclusion: Fibrous clays and nano zero-valent iron can be used as efficient sorbents for phosphorus removal from urban wastewater and the removal of cadmium and nickel from industrial wastewater due to their environmentally friendly nature and high performance in pollutant removal.

Introduction: Urban planning for women can be seen as a kind of advocacy-based planning that recalls forgotten rights and the silence of women in the city. Urban space planning for women draws its original idea from feminist ideas. The theory of sustainable urban development focuses on the prevention of urban and regional environmental pollution, reducing local, regional and national production capacity, supporting recycling, failing to support harmful development, and bridging the gap between rich and poor. Sustainable urban development is a multifaceted phenomenon that considers environmental conservation, social justice and economic dynamism with optimal resource utilization. Urban and regional planning with a special futuristic perspective needs to be developed for the future of the city and analyzed using statistics and information. By using the facilities and reducing limitations through presenting a precise and comprehensive plan, that takes account of environmental considerations, can provide for sustainable urban development. Considering the importance of women's well-being and women's vulnerability, the issue of urban security with a gender approach has been investigated in this research. In this regard, the present study aims to evaluate urban planning with the approach of women to formulate a sustainable development pattern in Tehran.Materials and methods: The method of this research is descriptive-survey and, according to the research method, all women in Tehran have been considered in this study. The estimated size of the community is about one hundred thousand people. Using randomized systematic cluster sampling, 384 women in Tehran were selected as a statistical sample. After collecting data, a researcher-made questionnaire was used to analyze the statistical data using SPSS software. The Kolmogorov-Smirnov test was used to test the normal distribution of the main variables.Results and discussion: The results indicate that, women do not have much to gain in planning for sustainable development and they are not included in the socio-economic approach, planning approach, or participationplanning and security approach to sustainable development in Tehran. Also, the results of the research showed that urban security is important for sustainable development, but women have a minimal role in this regard. Today, the world faces the fact that women can no longer be considered as hidden in the development process.Conclusion: The role and capacities of women in the success of developing countries will lead to state-level policymakers to make women inferior to the fence. It is also one of the most effective areas for promoting gender equality empowering women by educating them about imbalance and equality in power, and empowering women to manage their lives.

Introduction: Despite past improvements in air quality, very large parts of the population in urban areas breathe air that does not meet European standards let alone the health-based World Health Organisation Air Quality Guidelines. Over the last 10 years, there has been a substantial increase in findings that particulate matter (PM) air pollution is not only exerting a greater impact on established health endpoints, but is also associated with a broader number of disease outcomes.Materials and methods: Recently, relatively sound research has been done on the understanding of the nature of particles and their role in creating problems in humans. A comprehensive study of this research and the analysis of the results, along with the comparison of the results of the research on health impact assessment, were evaluated in Tehran.Results and discussion: Data strongly suggest that the effects have no threshold within the studied range of ambient concentrations, can occur at levels close to PM2.5 background concentrations, and that they follow a mostly linear concentration-response function. Having firmly established this significant public health problem, an enormous effort has been made to identify what it is in the ambient PM that affects health and to understand the underlying biological basis of this toxicity by identifying mechanistic pathways-information that, in turn, will inform policy makers how best to legislate for cleaner air. Another intervention in moving towards a healthier environment depends upon achieving the right public attitude and behaviour through the use of optimal air pollution monitoring, forecasting and reporting that exploits increasingly sophisticated information systems.Conclusion: Improving air quality is a considerable but not an intractable challenge. Translating the correct scientific evidence into bold, realistic and effective policies undisputedly has the potential to reduce air pollution so that it no longer poses a damaging and costly toll on public health.

Introduction: Population growth and the increase of water demand in the different sectors of agriculture, drinking water, industry, health, groundwater resources have led to a lot of pressure. This issue along with severe and prolonged droughts has created conditions for the country, particularly in arid and hyper arid areas, whereby it has encountered serious challenges in the field of water quantity and quality. In this study, the qualitative changes in the trend of drought and water resources in the Hamadan-Bahar plain, one of the most important agricultural centres in Iran, has been considered.Materials and methods: Twenty-three wells were sampled across the plain, on September 2015 and, in order to evaluate the strategic parameters in the study, standard methods were used. All anions and cations in the water along with fluoride, nitrate and nitrite were measured.Results and discussion: The results showed a reduction of groundwater level decline by an average of 1 metre per year and the parameters measured indicated adverse changes in the quality of underground water sources. The maximum measured nitrite and nitrate, respectively, was 74.8 and 0.41 mg/L for the area. About 27% of the samples collected were close to the national standard of 43 milligrams per litre, while the average was critical at the border; however, the average total for nitrates was 24.2 mg/L. The amount of fluoride in most cases was lower than the international standard. In some cases the amount of sulfate flowing through the city’s sewage system was also standard.Conclusion: Considering the results, it can be concluded that the only fundamental method for preventing dangerous consequences of falling water table levels and reducing the quantity and quality of undergroundwater resources is to ensure correct and legal water consumption to avoid the uncontrolled withdrawal of groundwater.

Introduction: Urbanization and population growth and their rapid development across the world have led to a major demand for the food security and self-sufficiency in terms of food production in many cities. Accordingly, activities based on urban agriculture using different traditional methods (e.g. planting on the ground surface with a soil bedding) or modern ones (e.g. rooftop gardening with hydroponic cultivation methods) have emerged and numerous studies regarding these methods have been accomplished. Likewise, a large number of farms in urban areas have come into existence worldwide. Nonetheless, there are yet various challenges in developing this type of agriculture. Moreover, only a few studies have been carried out to monitor the health and hygiene condition of the food produced in such places, especially in terms of air pollutant accumulation. The objective of this research was to study the hygiene of the plants cultivated in an urban environment (rooftops and courtyards), and to determine the accumulation rates of pollutants in the eggplant fruit (Solanum Melongena var. depressum (L.)) and bell peppers (Capsicum fruitescens var. grossum (Mill.)).Materials and methods: Two types of vegetables; bell pepper and eggplant were cultivated in the rooftop and courtyard of a five-storey building in the 7th district of Tehran. The seeds were planted on the basis of a completely randomized design system using six replications. In order to compare the health of these fruits with those of the fruits cultivated in the countryside, similar samples of the same products were grown on farms located in the environs of Varamin and Karaj cities. Densities of heavy metals such as molybdenum, chrome, copper and manganese (Mn, Mo, Cr and Cu) found in bell pepper and eggplant fruit cultivated in the urban areas of Tehran were compared with amounts found in fruits cultivated on the farms located outside towns. Additionally, the amounts of the heavy metals lead and cadmium (Cd, Pb) in the samples related to the city ofTehran were compared to European Union Standards and the Iranian National Standard. The sample digestion was carried out using microwave and, in order to analyse and measure the results, the ICP-MS device was used. Data was analysed using SAS and Microsoft Excel software and the comparison of means was done through standard error.Results and discussion: The resultant data demonstrate that the densities of heavy metals in the most of the fruits grown in city showed were significantly higher (in the range of 5%) than those of plants grown in countryside, except for the content of chrome in eggplant which is higher in the samples from farms located in the countryside than those of both urban areas. Moreover, the heavy metal pollution of copper in both eggplant and bell pepper from the farms located in countryside were higher than the samples of the rooftop. The chrome density in the eggplants cultivated in farmland was 1.56 times more than that of the courtyard plants, and 1.58 times more than those grown on the rooftop. Densities of copper in the eggplant and bell pepper of countryside farm are, respectively, 1.22 and 1.24 times more than the rooftop samples. Furthermore, except for lead content (Pb) being observed at the three different levels of 0.18, 0.63 and 0.14 milligrams per kilogram of dry weight (mg/kgDW) in some samples, respectively, for rooftop eggplants, rooftop bell peppers and courtyard bell peppers which showed significant variances to the permissible limits (in the range of 5%), other samples indicated acceptable amounts of lead and cadmium with respect to the European Union Standard and Iranian National Standard (under the limits of 5%).Conclusion: In general, it can be concluded that all the samples cultivated in the urban areas of 7th district of the city of Tehran were healthy in terms of allowable amounts of the heavy metal cadmium. These density ratios fully complied with international standards, and were similar to those of the samples cultivated in the countryside. In contrast, most of the aforementioned samples contained impermissible amounts of the heavy metal lead. Likewise, the densities of other heavy metals included in the products of urban farms were much higher than those grown on the city exteriors. This difference may well be the impact of the effects of heavy traffic flow, geographic position and the unsuitable climatic conditions on the air quality of urbanized areas.

Introduction: Irankuh Pb-Zn mine is located 20 km Southwest of Isfahan in the Zayandehrud River drainage basin. Shale and carbonate are the host rocks of the ore deposits formed from high concentrations of Pb and Zn. Weathering and erosion of the host rocks of ore deposits, waste water and waste materials arising from mining have a potential for heavy metal pollution of running water, ground water and agricultural soils. The main objectives of this investigation were to study the total concentration of Zn, Pb, Ni, Cu, Co, Ag, and Cd in the shale deposits of the mine, and the physicochemical factors on their distribution and pollution.Materials and methods: For measuring heavy metal values, twenty samples were taken from the shale deposits. For distinguishing the shale-forming minerals, thin sections were prepared and studied with a polarizing microscope. The rock forming clay minerals, after preliminary treatments (heating at 550oc, ethylene glycol solvation), were detected by XRD and the organic carbon, calcium carbonate and Eh/pH of the shales were then measured. Heavy metal values in the sample were measured by AAS after mineralization. The correlation coefficient of organic carbon and manganese with metals and also metals-metals were calculated. For comparison of the heavy metal concentration relative to their natural amount (in shale), the enrichment factor was applied.Results and discussion: The dark grey to olive-coloured shales in the studied area consisted of clay to fine silt size. Quartz, biotite, muscovite, feldspar and clay minerals comprise the non-opaque minerals of the shales while the clay minerals are illit (60-70%), kaolinite (9-27%) and chlorite (7-22%), respectively. Sphalerite, pyrite and galena are the main opaque minerals in the mine. The mean OC content of the shale is about 2% (0.35-5.5%) with less than 1% calcium carbonate. The pH of the samples is nearly neutral (6.8-7.8) and they have an oxidizing to nearly reducing Eh (18 to -100 v).Conclusion: The average concentration of heavy metals in the shales were Zn=128.05>Pb=42.55>Ni=35.24>Cu=24.18>Co=7.4>Ag=3.33>Cd=0.79 in ppm, respectively. A highly positive correlation between Ag-Pb-Cd, Cd-Zn-Pb and Co-Ni-Mn and also a positive correlation between Zn with organic carbon demonstrate geochemical convenient conditions for concentration of the metals. The calculated enrichment factor has revealed extremely high enrichment for Ag and average for Cd. Other elements are depleted in the sediments. Due to the relative high concentration of the metals and extent of the shales in the study area, activation of the heavy metals under suitable conditions can be a potential source for environmental contamination in the groundwater and runoff water of the basin.

Introduction: The goitred gazelle, which is classified as a vulnerable species (VU) by IUCN has a very wide distribution across the Middle East, Pakistan, Central Asia, China and Mongolia. A few ecological studies have been conducted on some aspects of goitred gazelle, such as population dynamics, habitat selection, daily activity, and social organization. However, little is known about the population dynamics of Goitred gazelle in Iran. Among the artiodactyls in Golestan National Park, goitred gazelles have shown the most vulnerability to the poaching and increasing frequency and intensity of habitat destruction. The objective of this study was to determine the population dynamics of goitred gazelle in different areas of Golestan National Park.Materials and methods: Fieldwork was carried out in Golestan National park, Iran. The transect line sampling method was used to survey the population dynamics of goitred gazelle, during the survey at each of the 24 transects, over three visits conducted between February 2016 and July 2016. Data (number of individuals, sex and age of gazelles) were collected at each of 24 transects. To calculate the density of gazelles we used the DISTANCE 6.0 programme. Differences in the lambing rate were evaluated using the non-parametrical Kruskal-Wallis and Mann-Whitney U-test. All the statistical tests were performed using Minitab 15 and Ecological Methodology software.Results and discussion: Results of the density analysis showed that goitred gazelles had the largest and the smallest population sizes in Kohne Mirzabaylu and Rabat, respectively. The sex ratio varied from 1.33 to 1.86; moreover, results of the sex ratio showed that the Almeh and Soulgerd populations had the best sex ratio. The number of middle-aged and older males was low in all gazelle populations which means that a high proportion of females prone to fertility were unable to mate. Many management strategies offer an increase in mature males in the population which results in increases in the reproduction rate of females (Bender, 2002). Due tothe low numbers of qualified females (6 years old and older), a considerable number of females could not mate. This means the males spend more time gathering the females and warding off rival males and, consequently, the female reproduction rate decreases. Yearlings (male and female) and very old gazelles (more than 11 years old) comprised the highest and the lowest percentages of the gazelle population, respectively. The highest percentage of lambs occurred in the Soulgerd and Kohne Mirzabaylu populations. This pattern of age class in lambs was due to high security in the vicinity of these two areas from wildlife guard stations. There was no significant difference among different areas in lambing rate. This pattern was consistent with Varasteh (2004).Conclusion: According to this study conducted on the sex and age structure, lambing rate, and density of gazelles in comparison with the past, it is quite obvious that the current trend of population dynamics is in decline and this is an alarm that indicates the need for urgent action to reduce the speed of population decline and for careful and long-term planning to management of gazelles populations.

Introduction: Urbanization creates significant changes in global ecosystems, while urban agro-ecosystems can provide valuable and desirable ecosystem services for human society. Understanding these services and taking them into account is necessary for the urban management of both today’s society and future generations.Materials and methods: This study was conducted in 2015 in Mashhad parks. To evaluate services like carbon sequestration, oxygen production and pollutant removal, plant data in plots was entered in itree software and their values were calculated according to international gas tax and also social values. In order to evaluate services such as diversity in landscapes, water storage, soil formation, biological pest control and cultural services, a questionnaire was designed using a choice experiment method and the average of willingness of landscape experts to pay was analyzed.Results and discussion: The urban forest of Mashhad has tree cover of 41.6 percent; the three most common species are Acer negundo (17.4%), Platanus orientalis (15.6%) and Robinia pseudoacacia (11.7%). The percentage of young trees was greater than others and, so, the ecosystem services of parks come mostly from younger trees. The population of exotic tree species was more than native ones, with most exotic tree species having their origins in North America (at 44.1%) and 15.9% with Asian origins. The gross carbon sequestration of trees was 1.0387 tons per hectare per year, most of which belonged to Platanus orientalis. Oxygen production was 0.24656 and pollutant removal was 0.041 ton/ha/year, with carbon storage per hectare at 22.769 tons. Results showed that the value of regulatory services like (carbon sequestration, oxygen production and pollutant removal) in Mashhad parks was 4 million Rials annually per hectare and carbon storage was 61 million Rials per hectare. As the atmosphere is a huge source of oxygen, this gas was not calculated in the monitory valuation. The amount of oxygen production in all parks was 290 tons which can provide for theneeds of 115 persons. Species richness was 38 with a value of 22 million Rials. Total value of other regulatory services such as (landscape diversity, water storage, soil formation, biological pest control and cultural services) was negative and, of these services, the responders only have a willingness to pay 365 million Rials per ha annually for cultural and water storage services. From this amount, 240 million Rials was for cultural services and 133 thousand Rials was for water storage. There was no willingness to pay for the other serviceswhich they consider to be part of the Municipality’s tasks.Conclusion: More budget is needed for increasing ecosystem services and for saving the urban ecosystem.

Introduction: Lining is one of the most important components of waste landfills, whose main function is to limit the penetration of leachate from waste from the landfill base. Since the cost of a lining system is a significant part of a landfill’s total cost, therefore, it is necessary to design the compacted clay lining with environmental and economic considerations equally in mind, which requires identification of factors affecting the construction cost of clay lining.Materials and methods: For this purpose, using a performance-based approach, the factors affecting the technical design and hydraulic performance of clay linings in preventing leachate leakage, four variables include of trench height, trench lifespan, land price and distance from the soil loan, have been identified as the variables affecting the cost of clay lining construction. Using the HYDRUS one-dimensional model, the appropriate lining thickness was determined in the scenarios of 30, 60, 180, 360, 720 and 1080 days for the trench lifespan. Then, by defining design scenarios based on the effective variables, the cost of different parts is estimated.Results and discussion: Investigating the cost variations shows that increasing the height of the trench in different parts leads to lower costs of construction. While changes in the cost of lining construction over the lifespan of the trench initially had a downward trend, it then showed an incremental pattern. The variation in total cost is affected by land cost variations and indicates the importance of land prices in assessing the overallcosts of constructing the lining. Also, an increase in the distance from the loan increases the cost of lining construction significantly and, if suitable soil for lining can only be located more than 100 km from the site, then the use of a Geosynthetic clay lining is more cost-effective. The trench lifetime can be considered as a variable with less design constraints, depending on the cost of other parts.Conclusion: Investigating the costs in different parts of compacted clay lining construction shows the necessity for economic modelling and creation of cost functions for the optimal design of compacted clay linings in every area.

Introduction: It is no longer acceptable to design an unchangeable plan, especially in landscape architecture where end-users should be at the centre of any design. Much literature discusses the influence of public involvement in the landscape design process and its necessity in contemporary life. However, the implementation of public participatory design has proved to be challenging and even problematic in many cases in the world. The initiated, civic leaders and professional experts generally develop and manage open space planning and design with a relatively limited level of public participation considering what is possible. The range of creativity from those who participate is limited for a range of reasons, premises and constraints; these will be discussed in the literature review. The need exists for landscape architects to work from an understanding of the ranges of participation and the ranges of creativity that can be elicited in order to deliver sustainable designs. For several decades the theories of public participation were discussed in Europe and North America, but the application of this in many other countries remained under-researched. Of specific interest in this article, public participatory design was used in Iran for the past few centuries (until a few decades ago) as a common solution. Although this practice has continued in many villages, public participation is not often practised in Iran’s cities anymore, and the few attempts at using it were not successful. So the aim of this article is to identify the obstacles to public participation specifically in Iran, and to classify these barriers by Iranian architectural designers.Materials and methods: A mixture of qualitative and quantitative methods has been used in this study. First, the main obstacles were extracted from the literature, then they were classified into five groups, namely technical, cultural, social, economic and political. After classifying the obstacles, these were assessed by interviewing Iranian landscape designers, with the help of the Delphi method. The Delphi method is astructured communication technique or method, originally developed as a systematic, interactive forecasting method which relies on a panel of experts. The experts answer questionnaires over two or more rounds. After each round, a facilitatoror agent of change provides an anonymous summary of the experts’ forecasts from the previous round as well as the reasons they provided for their judgments. Thus, experts are encouraged to revise their earlier answers in light of the replies of other members of their panel. It is believed that, during this process, the range of the answers will decrease and the group will converge towards the ‘correct’ answer. Finally, the process is stopped after a predefined stop criterion and the mean or median scores of the final rounds determine the results. In this research, the Delphi panel comprised ten landscape architects, six architects and four urban designers who work in laboratories and companies which depend on landscape architecture. Their assessment emerged in a table and its content validity ratio (CVR) was calculated and interpreted.Results and discussion: The main obstacles extracted from the literature were classified into five groups: technical, cultural, social, economic and political. Each of these groups contained a few obstacles and there are twenty-two elements in total. Technical obstacles included finding the right members to represent people and end-users, the age at which people participate in the design process, lack of expert knowledge and experience in public participatory landscape design, lack of people’s knowledge and experience in public participatory landscape design, inefficiency of public participatory landscape design methods, uncertainty over how people ideas and decides affect the last decision and the design, and the lack of a free and comfortable relationship between end-users, employers and designers. Executive obstacles included increasing arguments between participants of public participatory landscape design, inefficiency of implementing systems and the time-consuming nature of public participatory design. Cultural obstacles included unwillingness of people, employers and designers to involve in a participatory design process. Social obstacles included lack of free time in contemporary society, divergent orientations and interests of contemporary society, the separation of contemporary society from social activity, lack of popular power to prove what they want in participatory design process, selfishness in contemporary society and prioritization in decision-making which depends on social outreach. Economic obstacles included the high expense of participatory design process. Political obstacles included nervousness about public participation and wrong and inefficient policies. Finally, technical and political groups of obstacles achieved the highest rank in respect of expert opinions. From among twenty-two obstacles, respectively, the unwillingness of employers to involve in a participatory design process, the age at which people participated in the design process, the lack of a free and comfortable relationship between end-users, employers and designers, wrong and inefficient policies, and lack of popular power to prove what they want in participatory design process were distinguished as the most important obstacles.Conclusion: Based on the research foundations, we presented a few suggestions to improve the participatory design process in Iran. On the one hand, the unwillingness of employers to be involved in a public participatory design process was distinguished as the first and main barrier. In Iran, the main employer of public landscape designers is the Government. On the other hand, wrong and inefficient policies were distinguished as the third barrier and, in Iran, this refers to governmental regulations. So, from these statements the important role of Government and its regulations in improving the participatory design process emerges and it shows that there is a need for promotion and revision of governmental regulations and policies. Developed countries, in contrast, have special regulations and policies which encourage public participatory landscape design and guide the process to be more efficient.

Introduction: Carnivores have always been exposed to threat-inducing processes because of their placement at the top of the food pyramid. Nowadays, approximately 65% of carnivores are listed as Critically Endangered (CR) or Vulnerable (V) on the IUCN Red List of threatened species. On a global scale, in the order Carnivora the Hyaenidae family is the smallest with only four species. Hyaena hyaena is the only member of the Hyaenidae family found in Iran, and is listed as Near Threatened (NT) in the IUCN Red List. The current study was aimed at modelling the species distribution of the striped hyaena (Hyaena hyaena), which is wide in Iran.Materials and methods: Using nineteen layers of so-called Bioclimatic variables, the correlations between those variables were analyzed and then highly correlated variables were excluded from the modelling process. Finally, eight species distribution models from the sdm package (GLM, GAM, BRT, SVM, RF, MARS, CART, and FDA) in R software were used. Given that the output of species distribution models is, unavoidably, often uncertain, one possible solution is to estimate the d ifference between projections and, to reduce the uncertainty, the use of an ensemble prediction system instead of using a single modelling method. Therefore, after determining the potential habitats of the Hyaena hyaen a using those eight mentioned models and by using the ensemble prediction system, the best regions for the distribution of this species in Iran were estimated.Results and discussion: The results of this study showed that annual mean temperature, seasonal precipitation and precipitation during the warmest season have the greatest influence on the distribution of Hyaena hyaena. In general, the FDA, GAM, BRT, CART and GLM models are fairly reliable, the MARS model is very reliable, and SVM and RF models are completely reliable. The results showed that the GLM, GAM, BRT, MARS, CART, RF models demonstrated that the suitable areas for Hyaena hyaena are generally the central regions ofIran, while the SVM and FDA models predicted the southern margin of the Caspian sea as containing the best regions for the distribution of this species.Conclusion: The difference in the predictions of each model makes confirms the uncertainty between the models which confirms the necessity of using the ensemble method. The results of the ensemble model showed that the most suitable regions for the Hyaena hyaena species distribution are the semi-arid and central steppe regions of Iran.