Ecological Risk Assessment of Potentially Toxic Elements in Urban Soils Based on Deterministic and Stochastic Models (Case Study: City of Hamedan, Iran)

Document Type : Research Paper

Authors

Department of Environmental Sciences, Ha.C., Islamic Azad University, Hamedan, Iran.

Abstract

Background and Objectives: Ecological risk assessment of potentially toxic elements in urban soils and scientific-practical recommendations for reducing environmental risks have attracted widespread attention as a necessary measure to protect and promote sustainable urban development. In this regard, determining the priority of control factors in ecological risk management of potentially toxic elements of urban soil is of great importance in order to develop and accurately prioritize preventive measures and effective strategies for protecting the health of the urban ecosystem based on the importance and necessity of their implementation. Therefore, this study was conducted with the aim of determining the priority of control factors in ecological risk management of potentially toxic elements (As, Pb, Cu, and Mn) in urban soils of Hamedan city in 2023.
Materials and Methods: In this study, a total of 135 urban surface soil samples were collected from 15 sampling sites from three different functional regions (i.e., commercial, residential, and industrial). Following sample preparation and acid digestion, the concentrations of the analyzed elements were determined using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Statistical analyses were done using SPSS software. Additionally, the potential ecological effects of the studied elements on ecosystem health, the modified ecological risk factor (MEr) and modified ecological risk index (MERI) were calculated. Also, a stochastic ecological risk assessment based on Monte Carlo simulation was performed using Crystal Ball software with 10,000 iterations and a 95% confidence level.
 
Results: The results from determining the content of the elements showed that the highest average content of As and Cu (mg/kg) with 6.91 and 30.9, respectively, belonged to the industrial areas and for Pb and Mn with 31.2 and 293 (mg/kg), respectively, belonged to the commercial areas, revealing the effect of various urban activities and land uses on the spatial variations of the PTE contents. The average MERI index of the elements was equal to 406, indicating the occurrence of very high ecological risk in the study area. The results of the ecological risk assessment based on the stochastic model showed that 100% of the ecological risk values in the study area were in the "very high" risk range. The results of the sensitivity analysis showed that arsenic as a key influencing factor has the greatest impact on ecological risk in the study area. The results showed that the stochastic model compared to the deterministic model significantly improved and increased the accuracy and performance of ecological risk assessment.
Conclusion: The results showed that arsenic, as the main and key factor in the occurrence of ecological hazards, was the priority metalloid pollutant for the control and management of the ecological risk of the studied elements in the soil of Hamedan city. Therefore, control of emission sources and regular and periodic monitoring of soil arsenic content with the aim of reducing risk is recommended to ensure the health of the urban ecosystem and protect sustainable urban development.

 

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Main Subjects

References

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Iranian Journal of Soil Research
Volume 40, Issue 2
September 2026
Pages 147-166

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