University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Enhancing the Removal Efficiency of Organic Load, Phosphorus, and Ammonia in the Sequencing Batch Reactor (SBR) Wastewater Treatment by Employing Electrochemical Technology Enhancing the Removal Efficiency of Organic Load, Phosphorus, and Ammonia in the Sequencing Batch Reactor (SBR) Wastewater Treatment by Employing Electrochemical Technology 1 17 102379 10.22059/jes.2025.371371.1008474 FA Zahra Abolhasanzadeh Department of Water and Wastewater Treatment , Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran,Iran Gagik Badalians Gholikandi Department of Water and Wastewater Treatment , Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran,Iran Journal Article 2024 01 23 Objective: Advanced wastewater treatment plays a vital role in reducing environmental pollution and safeguarding water resources, particularly as industrialization and urban development continue to accelerate globally. Among the various treatment technologies available, electrochemical processes have emerged as a promising and innovative option, largely due to their effectiveness in eliminating resistant and hard-to-treat contaminants. These technologies not only offer high treatment efficiency and scalability but also exhibit strong potential for integration with traditional treatment systems, making them a practical enhancement to current infrastructure. Key goals of wastewater treatment include achieving high removal rates of organic pollutants, consistently meeting regulatory thresholds for nutrients like nitrogen and phosphorus in the effluent, and improving the overall operational efficiency of treatment processes, thus ensuring long-term sustainability and effectiveness in environmental management. Method: This study evaluates the integrated treatment strategy by examining the removal efficiencies of key pollutants, including organic matter, phosphorus, and ammoniacal nitrogen, alongside measurements of sludge volume index (SVI) and energy consumption across a voltage range of 1 to 15 volts. To ensure both practical relevance and methodological robustness, experiments were conducted using a combination of real and synthetic wastewater samples. Results: The findings revealed that applying voltages below 5 volts significantly enhanced the removal of organic contaminants, achieving up to a 1.5-fold improvement relative to conventional treatment systems. Notably, the system attained a peak organic load removal efficiency of 98% at an applied voltage of 3 volts. In parallel, phosphorus removal efficiency reached 99%, while ammoniacal nitrogen removal was observed at 69% within the 1–5 volt range. Beyond pollutant elimination, the incorporation of electrochemical technology notably improved sludge characteristics. The most substantial decrease in SVI occurred at 15 volts, reducing sludge volume to one-third of that observed in traditional sequencing batch reactor (SBR) systems over an equivalent operational period. Additionally, the system demonstrated favorable energy performance, with maximum energy consumption under optimal operating conditions measured at 1.78 kWh per cubic meter of treated wastewater. Conclusions: The findings of this study indicate that enhancing the conventional biological wastewater treatment system through the simultaneous application of the electrochemical method leads to increased efficiency in the removal of organic load, phosphorus, and ammonium, particularly at voltages below 5 V. Furthermore, the results suggest that, under optimal operating conditions, the integration of the electrochemical method reduces retention time, significantly improves the sludge volume index (SVI), and optimizes energy consumption, making the process more sustainable, environmentally friendly, and economically viable in the long term. Objective: Advanced wastewater treatment plays a vital role in reducing environmental pollution and safeguarding water resources, particularly as industrialization and urban development continue to accelerate globally. Among the various treatment technologies available, electrochemical processes have emerged as a promising and innovative option, largely due to their effectiveness in eliminating resistant and hard-to-treat contaminants. These technologies not only offer high treatment efficiency and scalability but also exhibit strong potential for integration with traditional treatment systems, making them a practical enhancement to current infrastructure. Key goals of wastewater treatment include achieving high removal rates of organic pollutants, consistently meeting regulatory thresholds for nutrients like nitrogen and phosphorus in the effluent, and improving the overall operational efficiency of treatment processes, thus ensuring long-term sustainability and effectiveness in environmental management. Method: This study evaluates the integrated treatment strategy by examining the removal efficiencies of key pollutants, including organic matter, phosphorus, and ammoniacal nitrogen, alongside measurements of sludge volume index (SVI) and energy consumption across a voltage range of 1 to 15 volts. To ensure both practical relevance and methodological robustness, experiments were conducted using a combination of real and synthetic wastewater samples. Results: The findings revealed that applying voltages below 5 volts significantly enhanced the removal of organic contaminants, achieving up to a 1.5-fold improvement relative to conventional treatment systems. Notably, the system attained a peak organic load removal efficiency of 98% at an applied voltage of 3 volts. In parallel, phosphorus removal efficiency reached 99%, while ammoniacal nitrogen removal was observed at 69% within the 1–5 volt range. Beyond pollutant elimination, the incorporation of electrochemical technology notably improved sludge characteristics. The most substantial decrease in SVI occurred at 15 volts, reducing sludge volume to one-third of that observed in traditional sequencing batch reactor (SBR) systems over an equivalent operational period. Additionally, the system demonstrated favorable energy performance, with maximum energy consumption under optimal operating conditions measured at 1.78 kWh per cubic meter of treated wastewater. Conclusions: The findings of this study indicate that enhancing the conventional biological wastewater treatment system through the simultaneous application of the electrochemical method leads to increased efficiency in the removal of organic load, phosphorus, and ammonium, particularly at voltages below 5 V. Furthermore, the results suggest that, under optimal operating conditions, the integration of the electrochemical method reduces retention time, significantly improves the sludge volume index (SVI), and optimizes energy consumption, making the process more sustainable, environmentally friendly, and economically viable in the long term.

https://jes.ut.ac.ir/article_102379_20940d9cea03482df61e3a0118919ef6.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Construction of Urban Heat Island Network Based on Morphological Network Analysis and Graph Theory Construction of Urban Heat Island Network Based on Morphological Network Analysis and Graph Theory 19 40 102380 10.22059/jes.2025.385006.1008547 FA Mahdis Sadat Department of Environmental Planning, Management and HSE,, Faculty of Environment, University of Tehran, Tehran, Iran Mahmood Zoghi Department of Environmental Planning, Management and HSE,, Faculty of Environment, University of Tehran, Tehran, Iran Esmail Salehi Department of Environmental Planning, Management and HSE,, Faculty of Environment, University of Tehran, Tehran, Iran Journal Article 2025 01 17 Objective: The increase in ecological vulnerability in cities due to rising temperatures has received much attention in recent years. Accurate identification of the urban heat island network is very important for effectively reducing its impact. In many studies, the impact of heat island connectivity on these networks has been largely ignored. This study was conducted to fill this research gap by creating an urban heat island network based on the connectivity perspective to understand the structural characteristics of the effect of this network and evaluate it in order to determine the priority level for implementing temperature reduction measures in the Tehran metropolis. Method: To achieve the above goal, after analyzing the ground surface temperature, areas with high temperatures were identified. Then, morphological spatial pattern analysis, morphological structure evaluation, and recognition of the importance of heat island sources were carried out. In the next stage, the resistance level against thermal diffusion was constructed, and, then, using the minimum cumulative resistance method, heat transfer corridors were identified and analyzed. Results: The findings of this study identified 29 strong heat island cores in Tehran with a relatively scattered distribution, 8 of which showed very high heating power. 31 corridors connected these islands, 10 of which had the potential to increase temperatures significantly. In addition, in terms of spatial distribution, the heat island network fragments in Tehran were more densely located in the western and southern areas. The high density of heat islands in the western part of Tehran made planning to combat them more difficult and increased their influence. Also, the very dense islands located in the southwest of Tehran led to the identification of short heat corridors in this part of the city, which justified the increase in temperature. On the other hand, the results showed that the cores had the largest share in the heat island network in Tehran, which indicated the size of the heat islands and their regional distribution in the study area. Conclusions: In this study, special attention has been paid to the structural characteristics of the urban heat islands of the study area and their degree of importance. This approach is simpler than previous methods of determining the size or density of blue-green spaces to achieve cooling effects. This framework can be used as a strategic measure to prevent the coalescence and expansion of urban heat islands and to avoid the unplanned increase of blue-green spaces aimed at reducing temperatures in urban areas. Objective: The increase in ecological vulnerability in cities due to rising temperatures has received much attention in recent years. Accurate identification of the urban heat island network is very important for effectively reducing its impact. In many studies, the impact of heat island connectivity on these networks has been largely ignored. This study was conducted to fill this research gap by creating an urban heat island network based on the connectivity perspective to understand the structural characteristics of the effect of this network and evaluate it in order to determine the priority level for implementing temperature reduction measures in the Tehran metropolis. Method: To achieve the above goal, after analyzing the ground surface temperature, areas with high temperatures were identified. Then, morphological spatial pattern analysis, morphological structure evaluation, and recognition of the importance of heat island sources were carried out. In the next stage, the resistance level against thermal diffusion was constructed, and, then, using the minimum cumulative resistance method, heat transfer corridors were identified and analyzed. Results: The findings of this study identified 29 strong heat island cores in Tehran with a relatively scattered distribution, 8 of which showed very high heating power. 31 corridors connected these islands, 10 of which had the potential to increase temperatures significantly. In addition, in terms of spatial distribution, the heat island network fragments in Tehran were more densely located in the western and southern areas. The high density of heat islands in the western part of Tehran made planning to combat them more difficult and increased their influence. Also, the very dense islands located in the southwest of Tehran led to the identification of short heat corridors in this part of the city, which justified the increase in temperature. On the other hand, the results showed that the cores had the largest share in the heat island network in Tehran, which indicated the size of the heat islands and their regional distribution in the study area. Conclusions: In this study, special attention has been paid to the structural characteristics of the urban heat islands of the study area and their degree of importance. This approach is simpler than previous methods of determining the size or density of blue-green spaces to achieve cooling effects. This framework can be used as a strategic measure to prevent the coalescence and expansion of urban heat islands and to avoid the unplanned increase of blue-green spaces aimed at reducing temperatures in urban areas.

https://jes.ut.ac.ir/article_102380_8edaec9ae1d9a31a4d6726c1317442d4.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Habitat Management of Mugger Crocodile (Crocodylus palustris) through Regional- Scale Niche Modeling for Practical Conservation Planning Habitat Management of Mugger Crocodile (Crocodylus palustris) through Regional- Scale Niche Modeling for Practical Conservation Planning 41 58 102381 10.22059/jes.2025.385203.1008549 FA Malihe Erfani ‎Department of Environmental Sciences, Faculty of Natural Resources, University of Zabol‎, ‎Zabol, Iran Abdolrassoul Salmanmahiny ‎Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan ‎University of Agricultural Sciences and Natural Resources, Gorgan, Iran‎ Journal Article 2024 12 04 Objective: Macro-environmental variables influence the distribution of species on a regional scale, and bioclimatic variables are the most important among them. The mugger crocodile (Crocodylus palustris), which is a keystone species and the only crocodile in Iran, needs freshwater habitats to survive in regions with low precipitation. Also, every temperature fluctuation in the nest location impacts the sex ratio of its offspring. Consequently, the continuity of survival of this cold-blooded species is fundamentally influenced by climatic conditions rather than other ecological conditions on a regional scale. Therefore, this study was conducted on habitat modeling of the mugger crocodile using historical bioclimatic variables on a regional scale. Methods: In the present study, habitat suitability modeling for the mugger crocodile was conducted using maximum entropy modeling (MaxEnt) and bioclimatic variables extracted from the KGClim_V1 climate model database. Bioclimatic variables were screened based on their correlation and the variability of each dataset, as assessed through standard deviation (SD), ultimately leading to the selection of seven from an initial dataset of twelve variables. Using species presence data as the dependent and bioclimatic variables as independent variables, the MaxEnt model was executed with 15 repetitions to identify potentially suitable areas for the species at regional scale based on the average results from the repetitions. Results: The modeling results indicated that the highly suitable habitat areas were located near the observation points of the species. This finding reflected a significant gain associated with a high area under the curve (AUC) value of 0.938. The jackknife test identified the most effective climatic variables, including PWM, PWMwint, and Tavg. According to the logarithmic response curves of this species to rainfall bioclimatic variables, suitable habitat areas were predicted to be in regions with low rainfall. By comparing the results with those of other studies, it was concluded that different scales of biological, ecological, geographical, and human factors influence the species distribution. Therefore, predicting species distribution across multiple spatial scales is essential for a more accurate valuation of the relationships among these variables. Conclusions: The findings of this study showed the necessity of integrated watershed management, especially in upstream areas, to ensure the survival of mugger crocodile downstream. Accordingly, a hierarchical modeling approach was recommended for future studies utilizing environmental variables at different scales. This approach is based on modeling macro factors separately from local-scale influences. In this context, micro and macro-scale studies are both important; however, their integration may pose problems because of inconsistency in spatial resolution and the scale of their effect on the species. Objective: Macro-environmental variables influence the distribution of species on a regional scale, and bioclimatic variables are the most important among them. The mugger crocodile (Crocodylus palustris), which is a keystone species and the only crocodile in Iran, needs freshwater habitats to survive in regions with low precipitation. Also, every temperature fluctuation in the nest location impacts the sex ratio of its offspring. Consequently, the continuity of survival of this cold-blooded species is fundamentally influenced by climatic conditions rather than other ecological conditions on a regional scale. Therefore, this study was conducted on habitat modeling of the mugger crocodile using historical bioclimatic variables on a regional scale. Methods: In the present study, habitat suitability modeling for the mugger crocodile was conducted using maximum entropy modeling (MaxEnt) and bioclimatic variables extracted from the KGClim_V1 climate model database. Bioclimatic variables were screened based on their correlation and the variability of each dataset, as assessed through standard deviation (SD), ultimately leading to the selection of seven from an initial dataset of twelve variables. Using species presence data as the dependent and bioclimatic variables as independent variables, the MaxEnt model was executed with 15 repetitions to identify potentially suitable areas for the species at regional scale based on the average results from the repetitions. Results: The modeling results indicated that the highly suitable habitat areas were located near the observation points of the species. This finding reflected a significant gain associated with a high area under the curve (AUC) value of 0.938. The jackknife test identified the most effective climatic variables, including PWM, PWMwint, and Tavg. According to the logarithmic response curves of this species to rainfall bioclimatic variables, suitable habitat areas were predicted to be in regions with low rainfall. By comparing the results with those of other studies, it was concluded that different scales of biological, ecological, geographical, and human factors influence the species distribution. Therefore, predicting species distribution across multiple spatial scales is essential for a more accurate valuation of the relationships among these variables. Conclusions: The findings of this study showed the necessity of integrated watershed management, especially in upstream areas, to ensure the survival of mugger crocodile downstream. Accordingly, a hierarchical modeling approach was recommended for future studies utilizing environmental variables at different scales. This approach is based on modeling macro factors separately from local-scale influences. In this context, micro and macro-scale studies are both important; however, their integration may pose problems because of inconsistency in spatial resolution and the scale of their effect on the species.

https://jes.ut.ac.ir/article_102381_fce46ae29c1f527a0cf8efb1ce82f531.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Assessment of Potential Health Risks Caused by Heavy Metal Accumulation in Rice Crops of Ramhormoz Farms, Iran Assessment of Potential Health Risks Caused by Heavy Metal Accumulation in Rice Crops of Ramhormoz Farms, Iran 59 73 102382 10.22059/jes.2025.387054.1008558 FA Abbas Kord Zanganeh Department of Environment Sciences and Engineering, Faculty of Natural Resources, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran Hamid Reza Pourkhabbaz Department of Environment Sciences and Engineering, Faculty of Natural Resources, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran Ali Reza Pourkhabbaz Department of Environment Sciences and Engineering, Faculty of Agriculture, University of Birjand, Birjand, Iran Journal Article 2025 01 04 Objective: Given that rice is one of the most important food sources for humans, monitoring contaminants in this crop is essential to safeguarding consumer health. Due to the expansion of vast rice cultivation areas across various parts of Ramhormoz, Iran, it is necessary to conduct a health risk assessment of heavy metals in irrigation water sources and rice products. Method: To determine the concentration of heavy metals, three composite samples were collected from each of the irrigation water sources, including wells, springs, and rivers, as well as from the rice products irrigated by each of the mentioned water resources separately. Subsequently, all water samples were digested with 65% nitric acid and the rice samples were digested with 70% perchloric acid, sulfuric acid, and 70% nitric acid, and analyzed by an atomic absorption spectrometer. The health risk index was applied to determine the impact of heavy metals on consumer health. Results: The results showed that the highest average concentrations of heavy metals in river water samples were as follows: cadmium (0.049 mg/L), lead (0.149 mg/L), zinc (0.304 mg/L), and iron (76.150 mg/L). There was a significant difference at the 1% level between cadmium levels in well water and river water samples compared to the WHO standard (0.01 mg/L). For this metal, there was also a significant difference at the 5% level in spring and well water samples compared to global standard levels. Also, there was a significant difference at the 1% level for Lead in spring and river water samples compared to the global standard (0.05 mg/L) and for zinc in well, spring, and river water samples compared to the global standard (5 mg/L). There is a significant difference (p < 0.05) in the level of iron metal in the water of these three water sources compared to the World Health Organization's standard. Comparison of the water samples obtained from these three sources to the global standard indicated that the highest average concentrations of these metals in rice irrigated with river water were: cadmium (0.0030 mg/kg), lead (0.279 mg/kg), zinc (0.963 mg/kg), and iron (317.25 mg/kg). According to the results, the average daily intake of elements and the health risk index indicated that in all samples, the health index for Lead for children was above one, which was deemed hazardous for consumption. Conclusions: According to the results of the present study, the main reason for the high concentration of the heavy metals was found to be the discharge of wastewater from agricultural lands and various surrounding industries into water resources in the region. Therefore, given the presence of certain heavy metals in the rice crop and the high health risk index, its consumption, particularly for children, should be restricted. Objective: Given that rice is one of the most important food sources for humans, monitoring contaminants in this crop is essential to safeguarding consumer health. Due to the expansion of vast rice cultivation areas across various parts of Ramhormoz, Iran, it is necessary to conduct a health risk assessment of heavy metals in irrigation water sources and rice products. Method: To determine the concentration of heavy metals, three composite samples were collected from each of the irrigation water sources, including wells, springs, and rivers, as well as from the rice products irrigated by each of the mentioned water resources separately. Subsequently, all water samples were digested with 65% nitric acid and the rice samples were digested with 70% perchloric acid, sulfuric acid, and 70% nitric acid, and analyzed by an atomic absorption spectrometer. The health risk index was applied to determine the impact of heavy metals on consumer health. Results: The results showed that the highest average concentrations of heavy metals in river water samples were as follows: cadmium (0.049 mg/L), lead (0.149 mg/L), zinc (0.304 mg/L), and iron (76.150 mg/L). There was a significant difference at the 1% level between cadmium levels in well water and river water samples compared to the WHO standard (0.01 mg/L). For this metal, there was also a significant difference at the 5% level in spring and well water samples compared to global standard levels. Also, there was a significant difference at the 1% level for Lead in spring and river water samples compared to the global standard (0.05 mg/L) and for zinc in well, spring, and river water samples compared to the global standard (5 mg/L). There is a significant difference (p < 0.05) in the level of iron metal in the water of these three water sources compared to the World Health Organization's standard. Comparison of the water samples obtained from these three sources to the global standard indicated that the highest average concentrations of these metals in rice irrigated with river water were: cadmium (0.0030 mg/kg), lead (0.279 mg/kg), zinc (0.963 mg/kg), and iron (317.25 mg/kg). According to the results, the average daily intake of elements and the health risk index indicated that in all samples, the health index for Lead for children was above one, which was deemed hazardous for consumption. Conclusions: According to the results of the present study, the main reason for the high concentration of the heavy metals was found to be the discharge of wastewater from agricultural lands and various surrounding industries into water resources in the region. Therefore, given the presence of certain heavy metals in the rice crop and the high health risk index, its consumption, particularly for children, should be restricted.

https://jes.ut.ac.ir/article_102382_2af4cc8385e035e24defeb5bee6cee95.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Quantitative Revelation of Regime Shifts in the Social-Ecological System of Zayandeh-Rud: Application of the Ball in the Basin Metaphor Quantitative Revelation of Regime Shifts in the Social-Ecological System of Zayandeh-Rud: Application of the Ball in the Basin Metaphor 75 95 102383 10.22059/jes.2025.388271.1008570 FA Majid Rahimi Social Business Institute, University of Tehran, Tehran, Iran. Mehdi Ghorbani Department of Reclamation of Arid and Mountainous Regions, Faculty of Natural Resources, University of Tehran, Karaj, Iran. Journal Article 2025 01 15 Objective: Interactions between human societies and natural ecosystems characterize social-ecological systems (SES), which, in turn, illustrate the dynamic interconnections among resources, land use, and water management. The goal of this research was to analyze and quantitatively disclose regime shifts in the social-ecological system of Zayandeh-Rud, which is one of Iran's important water sources, through the ball in the basin metaphor. Method: The research method involves the collection and analysis of time series data on surface water flow, water quality, groundwater levels, and agricultural land area. Using the sequential t-test method, regime shifts in the data were identified, and the obtained results and identification of critical thresholds assisted in this process. These critical threshold points were used to numerically calculate the depth of the basins in the ball in the basin metaphor. Then, through visualizing the regime shifts using this metaphor, different states of the studied systems and alternative stable states in these systems were analyzed. Results: The findings indicated that in the surface water subsystem regime, shifts were not identified in the Eskandari and Qaleh Shahrokh stations. In five other stations, at least one instance of regime shift was observed in the time series of surface water flow. Additionally, the analysis of Gavkhuni Wetland indicated the occurrence of regime shift in this wetland. In the surface water quality subsystem, no shifts were identified in the three upstream stations, while at least one regime shift was recognized in five other stations. Groundwater analysis showed the occurrence of regime shift with a decline in static levels in all 16 studied aquifers. Moreover, in the agricultural system, an increase in land areas was observed in the upstream region of the Zayandeh-Rud dam, accompanied by a decrease downstream and east of Isfahan. The results of applying the ball in the basin metaphor demonstrated that in the initial regime of all time series, resilience erosion led to shifts to other regimes. Additionally, the decline in resilience in some current regimes also indicated the system's movement toward another innovative regime. Conclusions: Regime shifts in the Zayandeh-Rud River Basin social-ecological systems arise from the complex interactions of human factors, together with natural factors, whose effects are majorly felt in the ecosystem and the local community; hence, a comprehensive analysis is vital. The excessive exploitation of natural resources resulting from human activity, particularly population growth and increased urbanization, has caused significant water quality degradation. It is also important to add that climate change and the increasing incidences of drought have further aggravated declining groundwater levels, which, in turn, have diminished the resilience of these ecosystems. Identification of threshold points and analysis of regime shifts enable managers to formulate effective management strategies and conserve the resilience of ecosystems. Objective: Interactions between human societies and natural ecosystems characterize social-ecological systems (SES), which, in turn, illustrate the dynamic interconnections among resources, land use, and water management. The goal of this research was to analyze and quantitatively disclose regime shifts in the social-ecological system of Zayandeh-Rud, which is one of Iran's important water sources, through the ball in the basin metaphor. Method: The research method involves the collection and analysis of time series data on surface water flow, water quality, groundwater levels, and agricultural land area. Using the sequential t-test method, regime shifts in the data were identified, and the obtained results and identification of critical thresholds assisted in this process. These critical threshold points were used to numerically calculate the depth of the basins in the ball in the basin metaphor. Then, through visualizing the regime shifts using this metaphor, different states of the studied systems and alternative stable states in these systems were analyzed. Results: The findings indicated that in the surface water subsystem regime, shifts were not identified in the Eskandari and Qaleh Shahrokh stations. In five other stations, at least one instance of regime shift was observed in the time series of surface water flow. Additionally, the analysis of Gavkhuni Wetland indicated the occurrence of regime shift in this wetland. In the surface water quality subsystem, no shifts were identified in the three upstream stations, while at least one regime shift was recognized in five other stations. Groundwater analysis showed the occurrence of regime shift with a decline in static levels in all 16 studied aquifers. Moreover, in the agricultural system, an increase in land areas was observed in the upstream region of the Zayandeh-Rud dam, accompanied by a decrease downstream and east of Isfahan. The results of applying the ball in the basin metaphor demonstrated that in the initial regime of all time series, resilience erosion led to shifts to other regimes. Additionally, the decline in resilience in some current regimes also indicated the system's movement toward another innovative regime. Conclusions: Regime shifts in the Zayandeh-Rud River Basin social-ecological systems arise from the complex interactions of human factors, together with natural factors, whose effects are majorly felt in the ecosystem and the local community; hence, a comprehensive analysis is vital. The excessive exploitation of natural resources resulting from human activity, particularly population growth and increased urbanization, has caused significant water quality degradation. It is also important to add that climate change and the increasing incidences of drought have further aggravated declining groundwater levels, which, in turn, have diminished the resilience of these ecosystems. Identification of threshold points and analysis of regime shifts enable managers to formulate effective management strategies and conserve the resilience of ecosystems.

https://jes.ut.ac.ir/article_102383_2e60c0f291ab36014bfa22efa3935c71.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Evaluation of the Impact of Urban Form on Urban Heat Islands: A Comparative Study of Residential Areas of Mashhad, Iran Evaluation of the Impact of Urban Form on Urban Heat Islands: A Comparative Study of Residential Areas of Mashhad, Iran 97 119 102384 10.22059/jes.2025.378604.1008514 FA Fateme Mirzaeiyan 1. Department of Urban Planning, Faculty of Architecture and Urbanism, University of Ferdowsi, Mashhad, Iran Iman Ghalandarian Department of Urbanism, Faculty of Architecture and Urbanism, Ferdowsi University of Mashhad. Maryam Talaei Department of Architecture, Faculty of Architecture and Urbanism, University of Ferdows, Mashhad, Iran Journal Article 2024 07 17 Objective: The rapid growth and expansion of urban areas have caused extensive replacement of natural land surfaces with impermeable buildings and urban materials. This process increases thermal energy absorption and results in elevated temperatures, contributing to the Urban Heat Island (UHI) effect—a significant temperature difference between urban areas and their adjacent rural regions. The primary objective of this study is to examine how different urban morphological characteristics, including spatial configuration, building height, street orientation, and urban canyon geometry, influence urban microclimatic conditions. The focus is on cold semi-arid climates, where thermal comfort is often compromised, to identify effective urban design strategies to mitigate UHI and improve outdoor thermal conditions. Method: A mixed-method research approach was adopted, involving a systematic review, morphological classification, and numerical environmental simulation. Additionally, a systematic analysis using VOS viewer software was conducted to explore the evolution of research trends related to urban form and thermal comfort, covering publications from 1973 to 2023. Subsequently, six distinct urban fabric types were selected from residential areas in Mashhad, Iran, categorized by spatial configuration (compact versus scattered) and building height classes (low-rise, mid-rise, high-rise). The microclimate of each typology was simulated using ENVI-met 5.1/6, a sophisticated 3D modelling tool that estimates variables such as air temperature, surface temperature, wind speed and direction, solar radiation, shading patterns, sky view factor (SVF), and height-to-width (H/W) ratios. Simulations were performed for three representative dates—summer solstice (June 21), winter solstice (December 21), and a moderate season (April 15), each covering a full diurnal cycle. Results: The results revealed that compact urban forms generally contributed to lower daytime air temperatures due to increased shading from dense building arrangements and higher H/W ratios. However, very compact layouts tended to reduce natural ventilation, limiting nighttime cooling. Urban canyons with low SVF reduced solar exposure during the day but trapped heat at night, decreasing overall thermal comfort after sunset. Proper alignment of streets parallel to prevailing wind directions enhanced airflow and cooling, whereas perpendicular orientations impeded ventilation. Notably, some scattered high-rise configurations created localized cooling zones due to increased wind penetration, particularly in cruciform building layouts. Conclusions: The study highlighted the importance of integrating climatic considerations into urban form design. It concluded that an optimal balance of building density, canyon geometry, and alignment with wind flow could effectively mitigate UHI impacts in cold semi-arid climates. These findings offer valuable evidence-based recommendations for urban planners and policymakers aiming to enhance thermal comfort and sustainability in rapidly urbanizing regions. Objective: The rapid growth and expansion of urban areas have caused extensive replacement of natural land surfaces with impermeable buildings and urban materials. This process increases thermal energy absorption and results in elevated temperatures, contributing to the Urban Heat Island (UHI) effect—a significant temperature difference between urban areas and their adjacent rural regions. The primary objective of this study is to examine how different urban morphological characteristics, including spatial configuration, building height, street orientation, and urban canyon geometry, influence urban microclimatic conditions. The focus is on cold semi-arid climates, where thermal comfort is often compromised, to identify effective urban design strategies to mitigate UHI and improve outdoor thermal conditions. Method: A mixed-method research approach was adopted, involving a systematic review, morphological classification, and numerical environmental simulation. Additionally, a systematic analysis using VOS viewer software was conducted to explore the evolution of research trends related to urban form and thermal comfort, covering publications from 1973 to 2023. Subsequently, six distinct urban fabric types were selected from residential areas in Mashhad, Iran, categorized by spatial configuration (compact versus scattered) and building height classes (low-rise, mid-rise, high-rise). The microclimate of each typology was simulated using ENVI-met 5.1/6, a sophisticated 3D modelling tool that estimates variables such as air temperature, surface temperature, wind speed and direction, solar radiation, shading patterns, sky view factor (SVF), and height-to-width (H/W) ratios. Simulations were performed for three representative dates—summer solstice (June 21), winter solstice (December 21), and a moderate season (April 15), each covering a full diurnal cycle. Results: The results revealed that compact urban forms generally contributed to lower daytime air temperatures due to increased shading from dense building arrangements and higher H/W ratios. However, very compact layouts tended to reduce natural ventilation, limiting nighttime cooling. Urban canyons with low SVF reduced solar exposure during the day but trapped heat at night, decreasing overall thermal comfort after sunset. Proper alignment of streets parallel to prevailing wind directions enhanced airflow and cooling, whereas perpendicular orientations impeded ventilation. Notably, some scattered high-rise configurations created localized cooling zones due to increased wind penetration, particularly in cruciform building layouts. Conclusions: The study highlighted the importance of integrating climatic considerations into urban form design. It concluded that an optimal balance of building density, canyon geometry, and alignment with wind flow could effectively mitigate UHI impacts in cold semi-arid climates. These findings offer valuable evidence-based recommendations for urban planners and policymakers aiming to enhance thermal comfort and sustainability in rapidly urbanizing regions.

https://jes.ut.ac.ir/article_102384_5035c89da856f25fe2c185eaec6b731e.pdf

University of Tehran Journal of Environmental Studies 1025-8620 51 1 2025 06 10 Spatial Economic Valuation of Multiple Ecosystem Services in Semnan Province, Iran Spatial Economic Valuation of Multiple Ecosystem Services in Semnan Province, Iran 121 144 102385 10.22059/jes.2025.390063.1008583 FA Fatemeh Mohammadyari Department of Environmental Engineering, Faculty of Natural Resources and Earth Sciences, Shahrekord University, Shahrekord, Iran Ardavan Zarandian Environmental assessment and risks group, Research Center for Environment and Sustainable Development, Department of Environment, Iran. Majid Ramezani Mehrian Department of Environmental Studies, The Institute for Research and Development in the Humanities (SAMT), Tehran, Iran Roya Mousazadeh Research Group of Environmental Economics, Research Center for Environment and Sustainable Development (RCESD), Department of Environment, Tehran, Iran Journal Article 2025 02 09 Objective: In recent years, many environmental economic valuation studies have been conducted without considering the spatial distribution of ecological goods and services, focusing instead on the existence of natural assets. Consequently, the estimated economic value is extended to the entire study area, which is not quite accurate, as different locations possess a diverse range of assets, goods, and services that should be categorized separately. Hence, in many cases, environmental assessments lack the necessary effectiveness in decision-making processes. The present study aims to estimate the economic value of multiple ecosystem goods and services in Semnan Province, Iran, with particular attention to their spatial distribution, offering a more accurate representation of ecological contributions across the region. Method: In this study, eight ecosystem services, namely food supply, forage production, aquaculture, water production, soil conservation, carbon sequestration, and habitat preservation, were quantified using GIS-InVEST-ROS models. Each service was then valued using appropriate methods, including the market price method, replacement cost method, social cost of carbon method, and benefit transfer method, based on the modeling outputs. Ultimately, to ensure the relevance of these estimates in current economic terms, adjustments were made using national inflation indicators, primarily the GDP deflator and domestic price indices. Results: The results indicated that the total value of production services in Semnan Province amounted to USD 521,973,155.17, while the total value of other services, including regulatory, supporting, and cultural, was USD 8,677,364,627.58. In fact, 94.3 % of the total ecosystem service value in this province was attributed to non-production services. Habitat quality and carbon sequestration services had the highest and lowest economic values in the region, with USD 8,679,933,224.14 and USD -1,146,837.93, respectively. Additionally, the total annual economic value of selected ecosystem services in Semnan Province was estimated at USD 9,199,337,093.10. Conclusions: The concept of ecosystem services can provide a useful tool for more integrated and sustainable planning, management, and restoration of degraded ecosystems. The application of an integrated economic-ecological valuation system, emphasizing the ecosystem services approach and incorporating the economic valuation of relevant services into the development and environmental protection decision-making processes, can outline a comprehensive framework for integrating valuation outcomes into decision-making. This integrative approach can lead to informed decision-making and a balance between development and environmental conservation. Based on the results, it is recommended that planners and policymakers pay attention to the value of ecosystem services in economic development programs and integrate ecosystem service valuation approaches into spatial planning within Semnan Province. This would ensure that ecological values are systematically considered in land use and development planning. Objective: In recent years, many environmental economic valuation studies have been conducted without considering the spatial distribution of ecological goods and services, focusing instead on the existence of natural assets. Consequently, the estimated economic value is extended to the entire study area, which is not quite accurate, as different locations possess a diverse range of assets, goods, and services that should be categorized separately. Hence, in many cases, environmental assessments lack the necessary effectiveness in decision-making processes. The present study aims to estimate the economic value of multiple ecosystem goods and services in Semnan Province, Iran, with particular attention to their spatial distribution, offering a more accurate representation of ecological contributions across the region. Method: In this study, eight ecosystem services, namely food supply, forage production, aquaculture, water production, soil conservation, carbon sequestration, and habitat preservation, were quantified using GIS-InVEST-ROS models. Each service was then valued using appropriate methods, including the market price method, replacement cost method, social cost of carbon method, and benefit transfer method, based on the modeling outputs. Ultimately, to ensure the relevance of these estimates in current economic terms, adjustments were made using national inflation indicators, primarily the GDP deflator and domestic price indices. Results: The results indicated that the total value of production services in Semnan Province amounted to USD 521,973,155.17, while the total value of other services, including regulatory, supporting, and cultural, was USD 8,677,364,627.58. In fact, 94.3 % of the total ecosystem service value in this province was attributed to non-production services. Habitat quality and carbon sequestration services had the highest and lowest economic values in the region, with USD 8,679,933,224.14 and USD -1,146,837.93, respectively. Additionally, the total annual economic value of selected ecosystem services in Semnan Province was estimated at USD 9,199,337,093.10. Conclusions: The concept of ecosystem services can provide a useful tool for more integrated and sustainable planning, management, and restoration of degraded ecosystems. The application of an integrated economic-ecological valuation system, emphasizing the ecosystem services approach and incorporating the economic valuation of relevant services into the development and environmental protection decision-making processes, can outline a comprehensive framework for integrating valuation outcomes into decision-making. This integrative approach can lead to informed decision-making and a balance between development and environmental conservation. Based on the results, it is recommended that planners and policymakers pay attention to the value of ecosystem services in economic development programs and integrate ecosystem service valuation approaches into spatial planning within Semnan Province. This would ensure that ecological values are systematically considered in land use and development planning.

https://jes.ut.ac.ir/article_102385_b2cfdbd975d665ffebfade772c6e98f5.pdf