نشریه علوم محیطی
سال سیزدهم شماره 3 (پیاپی 49، پاییز 1394)

The kinetics of release of heavy metal ions zinc, lead, nickel, copper and cadmium from the depth of 0 to 10 cm of downstream river sediment located in Hamedan Province, polluted with nitrate salt of these metals, were studied using the leaching column method. The rate of desorption of heavy metals from polluted sediments was initially rapid and, then, gradually declined over time; the behavior of Pb was different and it was released in a gradual and continuous manner. In general, the release of heavy metals from clayey sediments polluted by an inorganic source conformed to a two-site model of first order kinetics; however, the release of Zn, Cd and Pb from sediment (1) and Pb from sediment (2) could also be adequately accounted for by a single-site model. The average coefficients of determination and RMSE for metals in the first order kinetics were 0.905 and 0.054 for a single-site model and for a two-site model were 0.986 and 0.046, respectively. Considering the total heavy metal content of sediments, the cumulative quantity of leached metals was low, indicating a high retention capacity of the sediments for heavy metals. This statement can be elucidated by the low values of the apparent coefficient of desorption in the first order kinetics model.

The Gachsaran evaporate formation is extensively exposed in East of Khozestan Province and the gypsum rocks in this formation show karstification. This paper has studied the development and environmental impact problems of gypsum karst in Ramhormoz and Meaedavood cities based on field study, laboratory and software studies. Structural factors such as joints, fractures and faults and the extraction of groundwater are the main agents in the development of karst gypsum. Due to the dissolution of gypsum, there is an increase in TDS and sulfate ions and a decrease in the quality of surface water and groundwater. The extraction of groundwater and lowering of the water table have increased the dissolution rate of gypsum and created a sinkhole. During recent years, a large number of sinkholes have been formed suddenly in the gypsum but, fortunately, have not caused any damage. Dissolution of the gypsum has caused an increase in the salinity of soil and expansion of saline land in Ramhormoz plain. As a result of the dissolution process, the resistance of rock decreases and cracks and fractures develop for the passage water, creating abundant slope instability in the Jareh Dam reservoir.

The 16th district of Tehran city was selected for investigating the condition of trees in urban areas. A qualitative and quantitative study was conducted on the stands of two species, namely European elm (ulmus carpinifolia) and Persian elm (ulmus carpinifolia var.umberaculifera), in two forms of stand and line. One hundred trees for each kind (separately) were measured after selecting the stands. After having chosen the lines, first one tree was randomly selected and, then, the next tree would selected and the fourth one. Following this, quantitative parameters (including diameter at breast height, tree height, crown height and average of crown diameter) and qualitative parameters (including the health of crown, the die back, canker, and pests and multi-branching) were measured. According to the results we can say that, according to quantitative characteristics, the European elm has a better desirability rather than the Persian elm, while the Persian elm has healthier crown, lower die back and fewer pests than the European elm in terms of qualitative characteristics; the European elm has more limited multi-branching than the Persian elm but no significant differences were discovered in canker. Thus, for the development of green areas in lines and where the objective is to design an aesthetic landscape, it is better to use Persian elm and, when establishment of forest planting and improvement of quantitative characteristics is desired (stands), European elm may be a better option.

One of the new approaches in the management of water resources is according to the principle of comparative advantage and trade in virtual water. This is based on the view that it can be considered a specialty area in which the water products and the products produced in wet areas, or imported from other countries, enter areas that are less water. In this study, the approach in Gilan Province has been studied. On this basis, the central question of this study would be what form the trade model of virtual water in this province takes and, in order to answer this question, an extended input-output table was used. Accordingly, the direct and total water consumption for 40 activities at the provincial level has been considered. The results showed that Guilan Province, with net exports of 636 and 811 million cubic meters of water at the level of economic activity and agriculture, respectively, has been a net exporter of virtual water, while the province's industries and mines have been net importers of virtual water. Based on the information obtained in this study, it is possible through a change in the composition of economic activity (to increase the proportion of activities with high added value and reduce the share of activities with the highest intensity of water use) to hold the added value of Guilan Province and establish an improved trade balance for water.

Due to the breadth of the subject and its interaction with social and economic issues, forest resource management is a metaorganizational plan application which requires public participation. Due to an increasing population size and the high dependency of forest dwellers on forest resources, this valuable resource has faced destruction and a decline in terms of quantity and quality and is in danger of disappearing. The purpose of this study was to investigate factors affecting the participation of rural forest dwellers towards management of Oshtorankooh Forest in Doroud. The study was undertaken by using a descriptive-correlation method. The population size was 543 households and, according to the Krejcie and Morgan Table, 226 family heads were studied as a sample by using stratified random sampling method. Statistical analysis was done through SPSS software. The research tools included a questionnaire whose validity was confirmed by a group of professionals. A pilot study was conducted during which the Cronbach's alpha test was calculated to determinate the reliability of data collection instrument. Multiple regression analysis showed that the use of educational tools and resources, attitude to participation, age, cooperation and interaction experience in rural areas, education level and annual income, could explain 0.51 of the variation of participation. Results of path analysis showed that the variable of the use educational tools and resources had the most effect and the awareness of the importance of forests had the least effect on the participation rate in forest management. Based on the findings, some executive recommendations have been presented.

The prevention of pollution of marine ecosystems is very important for the sustainable use of resources. Given the persistence of pollutants in the aquatic food chain, the likelihood of damage to all living organisms is high, including humans who are at the top of the food chain. n-alkanes were used as an indicator of the origin and changes in organic substances. The present study was aimed at determining the origin and concentration of these compounds in the eggs of four sea-bird species (White-cheeked Sterna repressa, Bridled Sterna anaethetus, Greated Crested and Lesser Created T. bengalensis Terns) on Shidvar Island in July 2013. n-alkanes were mostly determined in the range of n-C14 - n- C35, and their total obtained concentrations in the sampled eggs of White-cheeked, Bridled, Greated Crested and Lesser Created Terns were also in the range of 41.39-86.32, 22.88-53.19, 21.82- 54.94 and 59.47-95.46 (μg.mg-1 lipid), respectively. However, the concentrations of these compounds in eggs of the White-cheeked and Lesser Created Terns were higher than the Greater Crested and Bridled Terns. Diagnostic ratios of CPI, Pr/Ph, n-C17/Pr, n- C18/Pr and U/R, in addition, n-alkanes in all the samples were mostly recognized as originating from petrogenic compounds and, so, the most important causes involved are presumably contamination from oil refineries which have been established on Lavan Island closed to Shidvar Island. The presence of oil pollutants cause by oil spills in the Persian Gulf, shipping, the discharge of ballast water from ships to this area is also an important source.

With increasing public concern about food quality and health of society in conjuction with destruction of natural resources, there has been recently much more attentions about organic farming in most developed and developing countries. This study aims to investigate the effect of mix marketing on development of pomegranate exports of Saveh, southwest of Tehran, to international markets providing the opportunity for improving the existing situation Accordingly, some questionnaires were distributed among exporters and manufacturers having some experiences in export. Assumptions were examined base on a t-student with single groups and Friedman test with a margin of error of 5%. The results showed that the most important factors effecting the pomegranate exports in the mix marketing are price element, product element, distribution element and the element of promotion, respectively. The results also revealed that the lack of knowledge of producers, lack of supporting the manufacturer particularly during the transition period as well as failure to support guarantee buying at a higher price are among those impediments for the development of organic pomegranate area in the region.

Alborz markazi wildsheep is a migrant species that has several seasonal home rang. This species is classified as vulnerable in red list of IUCN and is classified as a protected animal based on environment conservation law in iran ،Therefor conservation of this species and itshabitats is important in regional and international levels. Analysis relation between species and their environment has ever been a important issue that it is base of modelling. In research we used maximum entropy approach in1392 in Tehran by recorded 350 present points gathered in summer and winter to environmental variables representing geographical and anthropogenical factors of the study area. of summer suitable habitat is 204629 ha and winter suitable habitat is 204471 ha. . in order to survey validation model we used cross validation. Acording to result of studing standard devation of slope and elevation classification, distance of water resource maximum play and orientation minimum play in summer model and in winter model slop and elevation and about orientation sun maximum play and orient east and south minimum play in model.

In this research we tried to investigate the respond of high part of Zagros Mountains to past climate change by studying a 300cm core was extracted from Lake Gahar. This region is as an important biome of oak forest of Iran. Then the aim of this investigation is to detect past climate condition by palynology and climate modeling. According to the pollen diagram of Lake Gahar, four main local pollen assemblage zones during Holocene consisting of two older zones GHA(depth of 300 to 290 cm), GHB (290 to 110 cm depth) and two more new zones GHC (depth 110 to 50 cm) and GHD (depth 50 to 0 cm) were identified. We also reconstructed the annual mean precipitation and temperature data over 40000 years by MCM (Macrophysical Climate Model). The results showed that two zones GHA and GHB beyond depth 300-110cm indicate vegetation of forest- steppe with dominant species of oak trees however Quercus pollen is evident in all zones. It seems that the abrupt decreasing of arboreal pollen, especially Quercus at a depth of 50 and 60 cm at the boundary between the two zones GHC and GHD is associated with unfavorable conditions for plant growth during this period. There are also upland herbs pollen types such as Poaceae crealia types and polygonium can be considered as evidence of the destruction of the region as a result of anthropogenic effects and heavy grazing and farming operations. It is also approved the existence of consecutive period of cold/wet and warm/dry period in the past climate of Gahar region by comparing the results of this study with results from other lakes in the northwest of Iran.

One of the best ways to prevent groundwater contamination is to identify aquifer vulnerability areas, monitor spatial quality changes and, then, manage water resource exploitation and land uses. In this study, aquifer vulnerability has been studied by using a DRASTIC model in SARKHON. Thus, the geographic information system (GIS) has been used to provide an aquifer vulnerability map and seven hydro-geological factors influencing vulnerability have been studied. The results show that 70% of the area affected has moderate vulnerability, 27.5% has high vulnerability and 2.5% has low vulnerability. In both of the sensitivity analysis methods, the map removal and single parameter was assessed. The DRASTIC vulnerability index was most responsive to both sensitivity analysis methods and shows the effect of vados zone results from a single parameter sensitivity analysis of the study area. This shows a depth of parameter, the most important criterion in assessing the vulnerability of but, unexpectedly, the lower impact on the vulnerability of the study area, weight and a significant difference of about 12% with the weight theoretical. Nitrate ion measurements were taken from multiple wells (water and agricultural) and were used in order to verify the measurement accuracy of the model. The results indicate the high accuracy of the model for the area studied.

During recent decades, Tehran County has faced a considerable growth in urban dwellers. This huge rate of urbanism and subsequent use of land for urban habitation, without taking the environmental potentials into account, has caused serious consequences and has led to environmental destruction in Tehran and a disruption of the balance between the county and the environment. Urban river valleys, as one of the elements of ecological structure of cities, can play an efficient role in creating a balance between the human-made city structure and nature, but their widespread use has caused a hyper-pressure on the natural environment resulting in the waste of natural elements such as trees, vegetation, water pollution, etc. Thus, providing and increasing recreational places, planning natural environments in order to save and revive natural ecosystems and the optimum exploitation of them appears to be absolutely vital. This paper is descriptiveanalytical and is based on a SWOT strategic analysis combinational model and the QSPM strategic planning model. This research has explored the process of planning for reviving the natural environment of river valleys in Tehran County and has taken Darakeh river valley as a case study. Performing field studies and reviewing records, it provides some strategies in order to plan for reviving the natural environment of this river valley based on existing facilities and opportunities, limitations and threats. The results of the research shows that the selected QSPM strategy is of the highest priority among the other five strategies, namely the selective strategy, protection strategy, reviving strategy, strengthening vegetation strategy and natural settlements strategy, with an attraction score of 6.048.

Habitat is one of the significant factors for species protection and determining the pattern of wildlife species distribution and their habitat selection is an important part of managing wildlife and its habitat. So, the purpose of this study is to investigate the habitat selection of Gazella subgutrrosa in Kalmand Conservation Area. Sampling was carried out using random steady transects 200 meters long by 2 meters wide and with two replications during five field investigations. When dung groups were observed, a 10*10 plot was placed in the center of the dung masses and the environmental variables were measured. Then, dung was removed for further monitoring and the transects were investigated every 45 days. The results showed that there is a significant difference among three plant communities in terms of dung group density. The most and the least utilization by deer was related to Artemisia-lactuca and other Artemisia communities, respectively, but there is no significant difference between Artemisia and Artemisia-Salsola communities in terms of habitat use. The Artemisia-lactuca community had the least distance to the nearest post and the Artemisia-Salsola community had the least distance to the nearest water sources and the road. The Artemisia community also had the least distance to the nearest farm. There was no significant difference between the two seasons in terms of dung group density in plant communities. It seems that Artemisia-lactuca community provided better refuge (because the Astragalus species is part of this community), greater safety (because of being near to the post), and more food and water resources (because of the presence of Artemisia and Astragalus species) for Gazella subgutrrosa compared to the other communities.

The land surface has experienced significant land use and land cover changes especially with regard to the human built environment. Land use changes is an important component in understanding the interactions between human activities and the environment, so analyzing these changes from the past to the future on the basis of a dynamic approach is necessary. In this research, land use maps for Malekan County in East Azerbaijan (Iran) for the years 1987, 2000 and 2014 were extracted, respectively, using Landsat TM, ETM+ and OLI using RS and GIS techniques. Land use changes detected over the past 27 years were analyzed. The CAMarkov model was used to predict the land use pattern for 2024. Results show that agricultural land and human built areas increased but bare land decreased during the period 1987-2014. The simulated land use map for 2024 indicates an incremental trend in agricultural land (from 24.53% to 25.67%) and also in human built areas (from 2.69% to 3.75%) during 2014-2028. These results can play useful role to improve land use management strategies in the study area.