Iranian Journal of

Background and Objective: Heavy metals are the most frequent pollutants of urban soils. In general, human health and especially children are directly at risk if the soil is being accidentally ingested orally or nasally. Therefore, this study was conducted to assess potential ecological risk index (RI) of Pb, Cd, Cr and Cu in surface soils of urban parks in Tehran City in 2016.
Materials and Methods: A total of 60 surface soil samples were collected from Mellat, Laleh, Velayat, Ekbatan and Pirouzi parks. The heavy metals contents in samples were determined using ICP-OES after acid digestion of soil samples. Also, RI of heavy metals was determined. All statistical analyses were performed according to the Shapiro-Wilk test, One-Way ANOVA, One Sample T-Test and Pearson Correlation Coefficient.
Results: The lowest and highest contents of the metals (mg/kg) with an average of 0.52 ± 0.25 and 153.81 ± 31.83 were related to Cd and Pb, respectively. Pb and Cu were higher than MPL. Also, the highest surface soil contamination was related to Velayat Park located at the south of Tehran. The value of RI was 99.16 and therefore the soil contamination was categorized in low ecological risk.
Conclusion: Although the value of RI categorized as low ecological risk, due to mean concentrations of Pb and Cu were higher than MPL, control of soil-contamination sources, periodic monitoring of surface soil in the urban parks where citizens spend most of their free time. Additionally, it should be avoided to construct urban parks close to the regions with high traffic intensity.
 

Background and Objective: Ethylene oxide (EO) is a very toxic and dangerous substance with a high potential for explosion and fire. Ethylene oxide units are among the most hazardous units in petrochemical industries. This study was designed to analyze and model the consequences of ethylene oxide storage tanks explosion in one of Iran's petrochemical industries.
Materials and Methods: In this study, the consequences of the ethylene oxide storage tanks explosion in a petrochemical industry was identified and analyzed. This study was conducted in 2017 using PHAST software version 6.54. For this study, two climate conditions including the first climate conditions (spring and summer) and the second climate conditions (autumn and winter) were considered.
Results: The results of the modeling for the first and second climate conditions showed that there were possibility of severe damages due to the explosion consequences up to 204 and 256 meters, respectively. In addition, based on the criteria for assessing the consequences of accidents associated with damage levels, such as the explosion wave, the wind speed and direction due to the sudden release scenario and the numerical results related to the modeling, the consequence of this scenario in the second climate conditions (autumn and winter) was higher than the first climate conditions (spring and summer).
Conclusion: The findings of the study indicated that, in addition to the high risk of explosion of ethylene oxide storage tanks, the modeling scenarios in different climate conditions have different consequences. Thus, more attention should be paid to safety of these equipment as risk centers in the petrochemical industry and similar industries.
 

Background and Objective: Monitoring of traffic emissions is a good way to build a safe ecosystem for living organisms. Therefore, the present study was conducted to assess the feasibility of using Achillea wilhelmsii and Cardaria draba located along the suburban roads of Hamadan for Zn, Pb and Ni removal by their aerial and underground organs in 2020.
Materials and Methods: In this descriptive study, after selecting 3 sampling stations, a total of 126 plant samples and 63 soil samples were collected. In the laboratory, the samples were prepared, and were then digested with acid. Subsequentely, the concentration of each heavy metal was measured by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Moreover, bioconcentration factor (BCF), bioaccumulation factor (BAF), transfer factor (TF) and metal accumulation index (MAI) were also calculated. Statistical analyses of the results were performed using SPSS statistical software.
Results: The mean values of BCF and BAF in both A. wilhelmsii and C. draba for all tested elements were greater than 1. On the other hand, A. wilhelmsii showed TF greater than 1 for zinc while C. draba showed TF greater than 1 for zinc and lead. The highest mean values of MAI in unwashed and washed shoots and roots of A. wilhelmsii were 98.48, 64.87 and 72.38, respectively.
Conclusion: Based on the calculated average values of BCF, BAF and TF of each elements, it can be argued that A. wilhelmsii and C. draba species have the potential of phytoextraction and Phytostabilization of the measured heavy metals and can be used for biomonitoring and bioremediation from soil and air in the heavy metals polluted areas.

Background and Objective: Soils and sediments contamination with trace and toxic elements lead to potential ecological risk and adverse effects on human health and so have been the cause of increasing concern worldwide. Therefore, this study was carried out to potential ecological risk assessment of As, Cd, Ni and V in surface sediments of Khazar Abad, southern parts of Caspian Sea in 2019.
Materials and Methods: In this descriptive cross-sectional study, a total of 36 surface sediment samples were collected from 12 sampling sites. After samples preparation, the elemental contents were determined using ICP-OES. Also, potential ecological risk factor (Eⁱ_r) and cumulative potential ecological risk index (RI) were calculated. All statistical analyses were performed by SPSS software.
Results: Based on the results obtained, the mean contents of As, Cd, Ni and V in analyzed samples were found to be 12.7, 0.191, 35.0, and 31.9 mg/kg, respectively. The computed values of Eⁱ_r  showed that factor values were decreased in the order Cd > As > Ni > V. Additionally, the mean values of RI with 53.7 indicated that all the examined elements have the "low potential ecological risk".
Conclusion: Accordingly, although the examined elements have shown a low potential ecological risk, cadmium with 46.4% and arsenic with 45.4% mean values of RI can cause for concern. Therefore, source identification and management of organic and inorganic pollutants and also periodic monitoring of water and sediments as the sink of environmental pollution are recommended.

Background and Objective: Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants produced by anthropogenic activities that contaminate all environmental matrices, including soils, and can enter the food chains. Therefore, this study was conducted for the analysis of PAHs compounds content in agricultural soils of Hamedan city, west of Iran, in 2021.
Materials and Methods: a total of 36 surface soil specimens were collected from 12 sampling sites in agricultural soils and after extraction of analytes based on the soxhlet method, the gas chromatography/mass spectrometry (GC–MS) method was used for the determination of PAHs compounds in the samples. Furthermore, soil samples were further analuzed for the amounts of pH, electrical conductivity (EC), and total organic carbon (TOC). Statistical analysis was performed using SPSS software.
Results: Results showed that 16 PAHs (∑16PAHs) total concentrations ranged from 435 to 3292 µg/kg with an average value of 1806 µg/kg. PAHs with higher molecular weight (≥ 4 rings) were dominant in PAHs profiles accounting for 78%. Based on the results, the mean concentrations of all 16 PAHs were lower than MPC established by MHWaS. Furthermore, the mean concentrations of Pyr, B(a)A, Chy, B(b)F, B(k)F­, B(a)P, and B(ghi)P were higher than the MPC established by the Iranian Department of Environment.
Conclusion: Based on the results obtained, as the mean contents of some PAHs were higher than the MPC, therefore, periodic monitoring of soil contamination with PAHs is recommended for the environmental and human health aspects.
 

Background and Objective: Amoxicillin (AMX) is one of the commonly used commercial antibiotics due to its high resistance to bacteria and its large spectrum against a wide variety of microorganisms, which it´s existence in the wastewater from pharmaceutical industries and hospital effluents causes unpleasant odor, skin disorder, and microbial resistance among pathogen organisms, and it can lead to the death of microorganisms which are effective in wastewater treatment. Therefore, this study was conducted to investigate of removal efficacy of AMX from aqueous solutions using GO@Fe₃O₄@CeO₂.
Materials and Methods: In this descriptive study, GO@Fe₃O₄@CeO₂ was synthesized and then used as a photocatalyst for the removal of AMX from aqueous solution. GO@Fe₃O₄@CeO₂ was characterized using X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), SEM-EDX elemental analysis, Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometry (VSM) methods. Additionally, the influence of variables including pH (3-11), amount of photocatalyst (0.006-0.04 g), contact time (0-150 min), and temperature (25-55 °C) was assessed on the efficacy of AMX removal. 
Results: The results indicated that removal efficiency increased up to 90 min contact time, 0.02 g of photocatalyst, and at the temperature of 25 °C. The optimum pH for AMX removal was 10.
Conclusion: GO@Fe₃O₄@CeO₂ could be an effective and available photocatalyst for the removal of AMX from industrial wastewater under UV light.

Background and Objective: Antibiotics are emerging pollutants that enter the human environment through pharmaceutical, hospital, and urban wastewater. Therefore, this study was conducted to investigate of removal efficacy of tetracycline (TC) from aqueous solutions using GO@Fe₃O₄@β-CD.
Materials and Methods: In this descriptive study, GO@Fe₃O₄@β-CD was synthesized and then used as an adsorbent for the removal of TC from aqueous solution. GO@Fe₃O₄@β-CD was characterized using X-ray diffraction (XRD), Scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometry (VSM) methods. Also, the influence of variables including pH (3-9), amount of adsorbent (0.003-0.050 g), contact time (0-100 min), and temperature (25-55 °C) so assessed on the efficacy of TC removal. 
Results: The results of TGA analysis showed that GO@Fe₃O₄@β-CD nanoparticles were resistant to temperatures up to 400 °C. Also, the results indicated that β-cyclodextrin was uniformly dispersed on the surface of GO@Fe₃O₄.
The results indicated that removal efficiency increased up to 60 min contact time, 0.01 g of adsorbent, and decrease temperature to 25 °C. The optimum pH for TC removal was 7.0. Also, under these conditions, the adsorption process followed the Langmuir adsorption isotherm with a correlation coefficient of 0.992 and the pseudo-second-order kinetic model with a correlation coefficient of 0.997, 0.999, and 0.998. The maximum adsorption capacity of the prepared adsorbent was 357 mg/g.
Conclusion: The GO@Fe₃O₄@β-CD could be an effective and efficient adsorbent for the removal of TC from industrial wastewater.
 

Background and Objective: Monitoring and remediation of metal contaminants in aquatic ecosystems is of particular importance to estimate, control, and reduce the level of threats to alive creatures and humans. Therefore, this study was conducted to evaluate metal contamination of surface sediments and the ability to monitor and bioremediation of iron, lead, and copper by aerial and underground tissues of Typha Latifolia and Nasturtium microphyllum located along the aquatic ecosystem of the Lar River, Tehran, Iran in 2021.
Materials and Methods: In this descriptive study, after selecting four sampling sites, 48 plant samples and 12 sediment samples were collected. After preparation and acid digestion of the samples in the laboratory, the contents of the elements were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES). Also, pollution index (PI), pollution load index (PLI), bioconcentration coefficient (BCF), bioaccumulation (BAF), and translocation factor (TF) were calculated. Statistical analyses of the results were performed using SPSS statistical software.
Results: The highest values of Fe, Pb, and Cu (mg/kg) in sediment samples were 11.8 ± 0.665, 0.915 ± 0.030, and 0.710 ± 0.026, respectively, and belonged to station 4; and in plant tissues 11.4 ± 1.25, 0.578 ± 0.180, and 0.298 ± 0.095, respectively, and were belonged to the roots of T. Latifolia. The PI values showed that the pollution of Fe, Pb, and Cu was "low" and the average PI values for the elements followed the descending order of Pb > Cu > Fe. The average values of PLI also vary from 0.003 to 0.006, indicating the quality conditions of "no pollution" in all the studied stations. On the other hand, T. Latifolia had a BCF > 1 and TF < 1 for Fe.
Conclusion: Based on the results obtained, it can be concluded that T. Latifolia is a suitable species for stabilizing Fe in sediments and could be used to monitor and remediate potentially toxic elements from polluted aquatic ecosystems.
 

Background and Objective: Monitoring of pollutants in urban ecosystems is of particular importance. Therefore, this study was conducted to evaluate the capability of Robinia pseudoacacia and Pinus elderica for biomonitoring of Pb, Cr and Ni in urban areas of Hamedan in 2023.
Materials and Methods: A total of 36 soils and 72 plant samples were collected from 12 sites. The contents of elements were determined using ICP-OES. Also, the values of PI, PLI, BAF, and CR indices were computed. 
Results: The highest values of Pb, Cr, and Ni (mg/kg) in soil samples with 72.2, 67.5 and 101 values belonged to the commercial, industrial, and commercial sites, respectively. The highest average content of analyzed elements in unwashed and washed leaves/needles for Pb both belonged to the commercial areas; for Cr and Ni, all belonged to the industrial areas. The average values of PI followed the descending order of Cr > Ni > Pb. The average values of PLI varied from 1.22 to 1.34. Moreover, BAF values of Pb, Cr, and Ni of R. pseudoacacia leaves and P. elderica needles were found to be in the range of 0.100-1.00. Also, the highest mean values of CR of Pb and Cr were both found in P. elderica; and the highest mean value of CR of Ni was found in R. pseudoacacia.
Conclusion: R. pseudoacacia and P. elderica could be used as suitable and efficient species for monitoring and remediation of toxic elements from soil and air in polluted ecosystems.