مجله محیط زیست و توسعه فرابخشی
پیاپی 81 (پاییز 1402)

Polycyclic aromatic hydrocarbons (PAHs) are introduced into the environment by human activities and are deposited in the river bed. These compounds are among environmental pollutants and are extremely harmful to human health and other living things even in very small amounts. For this reason, determining the concentration of these pollutants is very important to evaluate the quality of river water. About a hundred compounds of PAHs that have been identified by the Environmental Protection Agency. They have 16 major harmful and pathogenic compounds, and for this reason, they have been introduced as pioneering pollutants. For this purpose, in the present study, the concentrations of PAHs were determined in the Karun River.

In this study, 19 samples of PAHs were collected along the Karun River from Cham Golak in the north of Khuzestan to Choibedeh in the south of Khuzestan in 2022. The collected samples were immediately stored in glass bags at a temperature of -10°C and transported to the laboratory. Until the time of extraction, the samples were dried in a freeze dryer and then kept in a freezer at -50°C. Before the extraction operation, all the samples were powdered and passed through a sieve with mesh less than 0.63. After determining the amounts of each of the desired PAHs, using Dionex™ ASE™ 3, it was determined whether the PAHs has fuel or petroleum origin. Finally, the concentrations of the obtained PAHs were compared with the American Sediment quality guidelines. In this standard, two risk categories, ERL and ERM, are considered for sediment pollution.

Based on the average concentration of studied PAHs, Benzo (b) fluoranthene and phenanthrene were the most polluted in proportion to concentration among all studied PAHs. The concentration of Benzo (k) fluoranthene, Fluorene, Pyrene and Indeno (1,2,3-c,d) pyrene was also more than 1 μg.kg-1 of sediment, which was high compared to the average concentration of other PAHs. Other PAHs had an average concentration of less than 0.80 μg.kg-1. The minimum concentration of hydrocarbons varied between 0.01-2.15 μg.kg-1 and their maximum concentration between 0.05-8.97 μg.kg-1 of sediment. The results of skewness (-0.75<SKW<3.0) showed that there were many spatial variations for all pollutants, but Anthracene with a skewness of 0.3 has the most spatial changes, with the highest concentration in the south of the Karun River, and Benzo (b) fluoranthene has the skewness equal to -0.75, then, the highest pollutant concentration was in the north of Karun River. Except for the four hydrocarbons Benzo (b) fluoranthene, Benzo (k) fluoranthene, Indeno (1,2,3-c,d) pyrene and Benzo (g,h,i) perylene, the concentration of the other pollutants in the Karun River is lower than the Sediment Management Standard (SQS) limits (

The origin of the pollutant’s evaluation showed that in the north of the Karun River, there was more fuel pollution, but in the center and south of this river, both fuel and oil sources were observed. These results showed that air pollution had a greater effect on increasing the concentration of hydrocarbons in the sediments of this river. In addition, the fuel of boats in the Ahvaz to Abadan area can be an important factor in increasing PAHs pollution with fuel origin. Therefore, although PAHs pollution was observed in this river, it was not at a critical level in terms of concentration.

Fossil fuel consumption has warmed the earth by releasing greenhouse gases. Abnormal climate changes, rising sea levels, melting glaciers and other climate phenomena have attracted global attention. Greenhouse gas emissions are considered as the main cause of climate change and global warming. The largest percentage of greenhouse gases is carbon dioxide gas. The spread of pollution is one of the most important problems of countries It is one of the problems of the present century. Iran is among the ten countries with the highest carbon dioxide emissions in the world, and measures have been taken to reduce carbon dioxide emissions in this country, which have not led to a reduction in carbon dioxide emissions in this country.

The purpose of this research is to investigate energy consumption, carbon dioxide emissions and economic growth using the directional non-cyclical graph approach for the period of 1990-2018 for the country of Iran. The data was obtained annually from the World Bank. Pearson's correlation test and Granger's causality test were investigated for variables of economic growth, capital, open trade, carbon dioxide emissions and energy consumption. For the first time, this research examines the causal relationship between energy consumption, carbon dioxide emissions and economic growth with the approach of a directed non-cyclic diagram.

According to the results of this research, there is a significant correlation in the variables of carbon dioxide emission, open trade, energy consumption, capital formation and GDP. The highest correlation coefficient belongs to GDP and carbon dioxide emissions and the lowest correlation coefficient is related to gross domestic production and open trade. According to the results of the Granger causality test, causality from GDP to carbon dioxide emissions, causality from carbon dioxide emissions to energy consumption, causality from GDP to energy consumption, Causality from capital to energy consumption, causality from capital to GDP, The cause of carbon dioxide emissions to open trade. Causality from energy consumption to open trade, causality from capital to open trade and so on There is causality from GDP to open trade. Iran has a relative advantage in energy consumption due to its huge resources of oil and gas, which has caused the emission of pollutants by the gross domestic product.

According to the results in Iran, there is causality from gross domestic product to energy consumption and carbon dioxide emissions, which shows that Iran does not need to reduce its economic growth in order to reduce carbon dioxide emissions. It indicates that energy consumption and carbon dioxide emissions in Iran will not lead to economic growth. Iran can follow a conservative energy policy and a policy to reduce carbon emissions in the long term without creating obstacles and reducing economic growth. Economic growth has led to the emission of pollution and it is possible to pursue economic growth without the emission of pollution by using sustainable development policies. The causality is from economic growth to energy consumption, trade and capital. According to the directed acyclic diagram (DAG), the Granger causality test was investigated in the variables of economic growth, open trade, capital, carbon dioxide emissions and energy consumption. According to the results of this research, Granger causality has started from economic growth to other variables.

Aquaculture includes the propagation and husbandry of aquatic plants, animals, and other organisms for various purposes, including commercial, recreational, and scientific use, which has gained significant attention in recent times. However, its uncontrolled development like any other production activity, can have adverse environmental effects, Thus, the removal of water pollutants is crucial. This study aimed to investigate the impact of a mechanized water disinfection device that uses ultraviolet (UV) radiation at different doses to reduce microorganisms in the effluent of rainbow trout farms.  Also, the efficiency of the device in deactivating pathogens was investigated in different flow rates and water turbidity levels.

The study was conducted in a rainbow trout farm with a 30-ton capacity, located in Kiyar County, approximately 30 kilometers from the center of Chaharmahal and Bakhtiari province. The UV device, at various doses (60, 120, 180, and 240 mW/cm2 = joule), was applied to the farm's effluent, considering different levels of turbidity and flow rates (ranging from 2.5 to 25 liters per second). Water samples were collected both before and after the installation of the UV disinfection device. Subsequently, the average counts of total coliforms, fecal coliforms, fungi, and yeast were calculated with three replications. Probit regression was utilized within the SPSS software environment, with a statistical significance level of 0.001, to examine changes in the removal percentage of microorganisms at different UV doses. Graphs were created using Microsoft Excel 2016 software.

The findings indicated that increased water flow rates and water turbidity reduced the efficiency of removing the targeted microorganisms. The findings indicated that increased water flow rates and water turbidity reduced the efficiency of removing the targeted microorganisms. Moreover, higher UV doses led to a higher removal percentage of total coliforms, fecal coliforms, fungi, and yeast. For instance, at a dose of 56 mJ/cm2, the total counts of total coliforms, fecal coliforms, fungi, and yeast decreased by 1.7, 3.2, 0.7, and 0.86 logs, respectively. However, complete removal of yeasts required significantly higher UV doses, depending on water flow rates and turbidity (up to a maximum of 240 mJ/cm2). Additionally, the results of the probit regression indicated that at doses of 40.50 mJ/cm2, 20.22 mJ/cm2, 30.31 mJ/cm2, and 14.36 mJ/cm2, approximately fifty percent of the yeast population (P<0.001), fungi (Z=13.5, P<0.001), fecal coliform (Z=22.77, P<0.001), and total coliform (Z=6.8, P<0.001) would be removed.

In summary, this research demonstrated that at a dose of 20 mJ/cm2, the gradual elimination of microorganisms begins, but at doses higher than 120 mJ/cm2, the intensity of elimination decreases. Therefore, adjusting the doses of ultraviolet radiation based on the water quality of fish farms can help maintain system health and subsequently increase productivity. The insights obtained from this study can be valuable for commercial water treatment systems and recirculating aquaculture systems. More studies are needed for the efficiency of removing viruses in water by UV rays. It is recommended to construct a sediment pond and employ various water filtration methods, including sand filters, before utilizing ultraviolet rays. This approach aims to decrease the presence of suspended particles in the water and enhance the efficiency of the disinfection system.

Plants play a key role in the balance of ecosystems and therefore are vital for the sustainability of the environment. Any knowledge about the plant species of a region is considered the basic principle for other research and can be a starting point for future supplementary studies. Biodiversity is one of the important aspects of life, especially considering the climate and land use. Destruction of the environment and natural resources has caused the extinction of plant and animal species and consequently, the reduction of biodiversity in the world. Given that today humans are facing numerous environmental issues and threats to biodiversity, the best way to save biodiversity and understand its values is to continuously evaluate and monitor natural habitats. The present study was conducted with the aim of investigating and analyzing plant biodiversity in the Plang-Dareh protected area in Qom province, as well as determining the endemism and conservation status of plant species in the area. The results obtained from this research can be used to explain the role of protected areas in the preservation and maintenance of genetic resources, environmental health and the development of appropriate management-protection plans. Palang-Dareh protected area is located southwest of Qom province. In order to make a contribution to the flora of the region during periodic visits, plant samples were collected in the growing seasons for two consecutive years. Any information about collected samples was noted, and the samples were pressed and dried. Plant species were identified using relevant Floras. In addition to determining the endemic and conservation status of plant species, the life form of plants was determined based on the Raunkier method and the chorology of plant species in the study area was determined using Zohari and Leonard classification. In order to evaluate the biodiversity of vegetation along an altitude gradient, the height (a.s.l.) in the study area was divided into three zones (1600-1900, 1300-2200, 1600-1900 meters). Systematic-random sampling was done from different altitude zone of the study area and biodiversity indices were calculated. Based on our results there are 171 plant species belonging to 126 genera and 46 families in the studied area. The family Asteraceae is the richest plant family in Palang-Dareh. In terms of life form, 45% of the species belong to hemicryptophytes and 22% to therophytes. The chorology of the species showed that more than 65% of the flora of the Palang-Dareh protected area belong to the Irano-Turanian chorotype and 12% belong to the Irano-Turanian and Mediterranean phytogeographical regions. 15% of the identified species are endemic to Iran and some plants are on the list of vulnerable or endangered species. The evaluation of biodiversity indices in different altitude zones revealed that the species diversity and species richness indices have reached their maximum in the intermediate altitude zone and the species diversity decreases with increasing altitude. Having comprehensive knowledge about the vegetation of an area is an essential and the first step in solving ecological issues such as biodiversity conservation, natural resources management and, assessment of environmental conditions. The dominance of a dry climate as well as over-grazing and unauthorized human activities have led to the high prevalence of certain plant species (known as indicators of destruction) and also therophytes in the studied area. Enjoying diverse vegetation and suitable natural habitats, protected areas have an essential role in biodiversity conservation. Based on our results some endemic plants of the area have vulnerable or endangered conservation status so that, more precise conservation plans should be put on the agenda.

Coastal areas worldwide hold significant social and economic importance. These areas, in addition to providing essential ecosystem services, have considerable potential for activities such as tourism, industry, and transportation, contributing significantly to the economic and social development of countries. Given that coastal areas are among the most complex ecosystems, they require monitoring and planning for enhanced protection. Timely and accurate identification of land use changes, which form the basis for better understanding human-nature interactions, provides the necessary groundwork for the efficient management and utilization of coastal resources.

The present study aims to investigate land use and land cover changes in the Chabahar coastal areas for four periods, including the years 1368, 1378, 1388, and 1398, using Landsat satellite time series data. Land cover mapping was performed through preprocessing and processing stages, followed by classification using a combined method. The accuracy of the produced maps was assessed using error matrix, Kappa index, and overall accuracy, which were greater than 80% and 0.8, respectively. Land use changes were analyzed using landscape metrics.

The results indicated that barren land had the highest land use percentage in all studied years. Saline and barren land cover decreased by 398.28 and 75.7 hectares, respectively, from 1368 to 1398, while aquatic land cover increased by 115.3 hectares in 1398 compared to 1368. The analysis of vegetation cover also revealed that this land use, along with human-made structures, consistently allocated the smallest area in all periods, gradually increasing. The accuracy assessment of land cover classification showed high accuracy in the produced maps, with the highest and lowest accuracy rates in 1368 (93.25%) and 1398 (85.6%), respectively. In 1398, the number of patches for aquatic land, vegetation cover, and human-made structures increased (830, 2662, and 4, respectively) compared to 1368 (146, 2386, and 1, respectively), while the number of saline and barren land patches decreased in 1398 (643 and 761, respectively) compared to 1368 (720 and 1060, respectively).

The study results demonstrated considerable changes in the Chabahar coastline over the past 30 years. The findings indicated a significant increase in vegetation cover from 1368 to 1398 (from 116.34 to 202.30 hectares), contributing a total of 85.96 hectares to land use. This increase in vegetation cover can be attributed to agricultural expansion. The detection results of changes in human-made areas also showed substantial growth (133.18, 205.74, 228.29, and 411.42 in 1368, 1378, 1388, and 1398, respectively) during the study period. Overall, it can be concluded that, based on the analysis of landscape metrics, the increase in human-made land uses and environmental changes has continued, and integrated management plans for coastal areas have not been adopted.

Protected areas are vital tools in the management and conservation of both terrestrial and marine environments. However, the conflict between conservation priorities and resource extraction from protected areas is increasing worldwide. Due to its high biodiversity, Mouteh National Park and Wildlife Refuge hold significant conservation value; nevertheless, in recent years, it has been heavily exploited due to rich mineral attractions. Consequently, the current study investigates the Cd concentration in the soil and plants in the Mouteh Basin, its transfer factor, and the influencing factors.

45 soil samples were collected from a depth of 0-30 cm, and leaf samples of the Artemisia sieberi plant were obtained at 15 locations within the plain region of the Mouteh National Park and Wildlife Refuge, which spans an area of 423 km2. The concentrations of Cd in these samples were determined using an atomic absorption spectrometer. The uptake of Cd by the plants was calculated and interpreted using the transfer factor. The Inverse Distance Weighting method in ArcGIS software was used to identify areas contaminated with Cd, with concentrations exceeding 5 mg/kg in soil and 2.0 mg/kg in plant leaves, based on the standard limits set by the WHO and U.S. EPA. Finally, linear, logarithmic, power, exponential and polynomial regression models were employed to examine the impact of road transportation on Cd pollution.

The mean Cd concentrations in plants and soil (mg/kg) were found to be 0.39 ± 0.11 and 2.97 ± 0.15, respectively. The highest soil concentration of this element was recorded in the central areas of the region, reaching 15.00 ± 0.69 mg/kg. This concentration gradually decreased towards the southern parts of the region. The highest concentration of Cd in the leaves of Artemisia sieberi was observed in the northern sections of the region, at 0.62 ± 0.05 mg/kg, while the lowest value was recorded in the central part (0.32 ± 0.05 mg/kg). The transfer factor of Cd ranged from 0.005 to 0.544, with a mean of 0.934. According to the standard limit of 5 mg/kg for Cd in soil, an area equivalent to 20.80% of the region was identified as Cd-contaminated. However, considering the permissible limit of 0.2 mg/kg in plants, a significant portion of the vegetation cover in the area (more than 95%) was found to be contaminated with Cd. The best regression model was achieved in the exponential form with a coefficient of determination of 0.301, indicating that road transportation is one of the most significant human factors contributing to the increase in Cd pollution in the Mouteh soil and plant species Artemisia sieberi.

The exploration of gold and the establishment of multiple mines in the Mouteh region, as well as the construction of highways in the northern province of Isfahan, have led to significant threats to the ecosystem and species of this area. Based on the results, the soils of the Mouteh plain region have been contaminated with Cd. The high concentration of this element in soils near the roads and its decrease with increasing distance from the road are indicators of the impact of road transportation on soil pollution. Therefore, preventing the construction of transportation routes in areas with rich biodiversity, improving the quality of fuels and vehicles, and reducing traffic congestion are among the most important measures for protecting the environment and reducing pollution from potentially toxic elements in natural areas.

The pastures of the country are one of the main sources of production and provide an important part of the fodder needed by livestock. In the Zagros region, these resources are very important. Also, due to high destruction in Lorestan province, grazing projects are of great importance in this province. Therefore, due to the importance of protecting natural resources, developing strategies for the protection and exploitation of these resources and identifying the components hindering participation are felt as a fundamental necessity. People's participation in any project guarantees the implementation and sustainability of that project. This issue is more important in the protection of natural resources, because issues related to the environment and natural resources are intertwined with the lives of communities, and the success of any kind of program will require the participation of these communities.

The main problem faced by the planners of the General Department of Natural Resources and Watershed Management of Lorestan province is the non-participation of pastoralists in the implementation of pastoral plans, considering their effective role in maintaining and revitalizing pastures, which has made such programs unsuccessful. Is. Therefore, the main goal of this research is to investigate the causes of the non-participation of the users with an emphasis on education from the point of view of experts in this province. The collection of data and information in this research was done through 20 questionnaires from experts of the whole province of Lorestan) and in order to analyze the data of this study, Spss21 and Expert Choice11 software were used.

The results showed that structural, managerial, and economic barriers are three important factors preventing non-participation. The summary of the results of this research shows that in order to improve the conditions of pastures with the approach of more participation of the users for the studied area and similar areas, the abilities and opinions of the users and experts should be used. Considering the position that the village and the villagers have in the dynamics of the country's economy, such as helping the economic growth, controlling the inflation rate, increasing the employment rate and activity, they can be a suitable platform for agricultural, livestock, industrial and service products, preserving the environment and security, and cultural norms. and social, to provide security and border guarding. Therefore, drawing a road map that determines the role of villages in the planning system of the country is of special importance. Meanwhile, training is always considered as a sure way to improve performance quality and solve management problems, and its lack is one of the basic issues. Training is a fundamental task for better management and a continuous and permanent process. The results also showed that the lack of training is one of the important factors preventing the participation of users. Therefore, by implementing educational programs, holding gatherings and exhibitions, this participation can be increased and improve pastures.

The summary of the results of this research shows that in order to improve the conditions of pastures with the approach of more participation of the users for the study area and similar areas, the capabilities and opinions of the users and experts should be used in order to prepare, plan and implement plans based on their needs, priorities and desires. Pasture management should be provided and, in the future, we can witness the improvement of pasture management as well as the protection, modification and revival of pastures along with the increase of livestock production with the least problems at the level of any customary system as economic-social units.

Soil resources play an important role in providing the necessary material goods for humans and other organisms and also deliver multiple ecosystem services that are essential for life on earth. They have also served for a long time as an important green infrastructure in protecting agricultural and forest landscapes by providing plants a foothold for their roots and holding the necessary nutrients for their growth. In addition, soils can provide various ecosystem services such as contaminant immobilization, rainwater control, carbon sequestration, and habitat provision that are directly beneficial for humans. Services provided by ecosystems for humans are called ecosystem services. Soil retention, which refers to the potential of ecosystems for controlling soil erosion and conserving soil, is classified in the class of regulating services.    

The InVEST Sediment Delivery Ratio (SDR) model was used in InVEST Software to quantify soil retention and erosion. The required inputs for implementing this model include land use maps, K-factor (soil erodibility), R-factor (rain erosivity), C-factor (land use and land cover or LU/LC), P-factor (support practices), DEM (digital elevation model), and the biophysical table. 

Based on the results, the potential of soil loss and sediment transport in the study area ranged from zero to 248.18 t/pixel and from zero to 57.25 tons per pixel, respectively. Soil retention is also estimated in a range from zero to 124.85 tons per pixel in the studied area. The largest amount of soil loss happened in sub-basin number 14 with 13716400 t/year and the smallest in sub-basin number 4 with 416594 t/year. Most of the ecosystem service of soil retention belonged to sub-basin number 13 with 4304414 t/ha/ year and the least to sub-basin number 4 with 5645 tons/ha/year.

The dense forests in the northernmost part of Semnan Province provide the most part of the ecosystem service of soil retention with more than 36 t/ha and the desert areas, the salt lake, and the salt marsh the least. Based on this, the province's forests, including dense, semi-dense, sparse and thin forests, contribute to the maintenance of soil in the province by a total of 4269166 tons per year. Also, good pastures maintain more than 18 tons per hectare of the province's soil every year, and the total function of soil maintenance by all types of pastures in the province, including good, medium and poor pastures, is 9395160 tons per year. Since the area covered by the pastures is 18 times more than that by the forests, we can say that most of the ecosystem service of soil retention is provided by the pastures due to the geographical distribution of this service in the province, despite the fact that forests are more capable in soil conservation than pastures. The orchards and rainfed agricultural land rank third and fourth, respectively, in soil retention with 7.86 and 2.15 tons of soil/ha, respectively. However, man-made land uses such as urban areas decrease this ecosystem service because they are usually accompanied by removing or reducing the vegetation. The urban areas are located in the northern part of the study area, and they have negative impacts on this ecosystem service. Therefore, protection of the forest and rangeland covers in the province is vitally important for the continued conservation of the ecosystem service of soil retention.