Iranian Journal of Health and Environment

Design of three-dimensional magnetically modified graphene oxide nanoparticles for humic acid removal from aqueous media

Amir Hossein Javid

Background and Objective: Humic substances are a group of high molecular weight, heterogeneous organic macromolecules formed through biological and geochemical reactions. They are recognized as one of the main precursors of by-products in water treatment processes. Humic acid compounds create various issues in water and soil treatment industries, necessitating their effective removal from water sources. Due to their small size and their ability to separate environmental pollutants, magnetic nanoparticles are used in the treatment of toxic and hazardous pollutants and in remediating contaminated environments. This study aimed to investigate the removal efficiency of humic acid using a three-dimensional magnetic nanoadsorbent and to identify the optimal conditions for removal.
Materials and Methods: First, three-dimensional magnetic graphene oxide was synthesized, and then surface modification was carried out with allyl amine/allyl glycidyl ether. The characteristics of the synthesized magnetic nanoadsorbent were determined using field emission scanning electron microscopy and the surface charge zero point. The removal of humic acid from aqueous solutions on magnetic nanoadsorbent was assessed based on pH, nanoadsorbent dosage, contact time, and temperature, with optimal conditions identified using the Taguchi method. Additionally, the adsorption isotherms, kinetics, and thermodynamics of humic acid adsorption on the magnetic nanoabsorbent were determined, with data analyzed through linear regression and determination coefficients for isotherm comparisons. The reusability of the nanoadsorbent in the humic acid adsorption mechanism was also examined. Experimental studies was conducted on well water samples from Tehran and Manjilabad (Karaj).
Results: The analyses confirmed the structural characteristics and properties of the synthesized adsorbent. Optimal removal of humic acid was achieved at pH 6, an adsorbent dosage of 0.02 g, a contact time of 120 minutes, and a temperature of 25°C, resulting in a 98% removal efficiency. Results indicated that humic acid adsorption followed the Langmuir isotherm, with kinetics corresponding to a pseudo-second-order model, yielding correlation coefficients of 0.9969 and 0.9968, respectively. Thermodynamic data showed that humic acid adsorption by the nanoadsorbent is an endothermic and favorable process.
Conclusion: The use of this nanoadsorbent in removing humic acid from aqueous solutions can be considered as an efficient method. Magnetic nanoabsorbents offer the advantages of easy separation from suspensions using a magnetic field, potential recovery through various methods, and reusability.

Chemical speciation and bioavailability of potentially toxic elements in agricultural soils (case study: south of Hamedan province)

Mehrdad Cheraghi

Background and Objective: Evaluating the chemical speciation and bioavailability of heavy metals, along with identifying the effective parameters influencing their bioavailability, plays a key role in soil management and the improvement of agricultural lands. Therefore, this research was conducted to determine the origin, chemical speciation, and bioavailability of potentially toxic elements (PTEs) in the agricultural soils of the southern cities of Hamedan province.
Materials and Methods: In this study, 90 surface soil samples were randomly collected from a depth of 0–20 cm in agricultural lands. After preparing the samples in the laboratory, the elemental content was measured using an atomic absorption device. Texture characteristics, acidity (pH), salinity (EC), calcium carbonate content, organic matter, and exchangeable cations were determined using methods proposed by the Environmental Protection Organization. The relationships between the bioavailability of heavy metals and these characteristics were investigated using Spearman's correlation test.
Results: The average concentrations of manganese, cadmium, iron, cobalt, chromium, copper, nickel, antimony, and arsenic in the three studied cities were 267.63, 0.19, 4.20, 20.65, 90.49, 35.86, 70.84, 3.78, and 17.82 mg/kg, respectively. Sequential extraction results showed that manganese, copper, and nickel had the highest bioavailability, with concentrations of 6.76, 2.91, and 3.77 mg/kg, respectively. More than 70% of the bonds between heavy metals and soil were in resistant and residual fractions, indicating that heavy metals in the soil have a natural background.
Conclusion: The bioavailability of heavy metals in the soil environment is low, suggesting minimal potential for these metals to enter water, soil, and crops, and thus does not pose significant concern.

Modification of anaerobic composting process using natural clinoptilolite zeolite on the quality of physical and chemical properties

Mohammad Hossien Saghi

Background and Objective: Composting is a sustainable solution for recycling organic solid waste (OSW). Various compounds can be used to enhance the quality of compost. This study aimed to investigate the effects of zeolite on the physical and chemical characteristics of compost produced through the anaerobic process.
Materials and Methods: This analytical study was conducted in 1402 at Kimia Sabzevar Company, located 5 km from Rudab Road. Cow manure and natural clinoptilolite zeolite were used in varying proportions (0%, 5%, 10%, 15%, and 20% of the total reactor volume) to prepare fertilizer via the anaerobic method. After 30, 45, and 60 days, a total of 90 samples were collected and sent to the laboratory for analysis. Parameters such as pH, electrical conductivity, temperature, carbon-to-nitrogen ratio, and nitrate content were measured to evaluate the quality of the fertilizer product.
Results: The results showed that in the early stages, pH changes were less pronounced in treatments with varying zeolite percentages, ranging from 7.9 to 8.57. The addition of zeolite in the composting process influenced temperature dynamics, with higher zeolite percentages maintaining elevated temperatures. Moreover, the nitrate content increased by 15% during the process.
Conclusion: The findings indicate that adding zeolite to fertilizer enhances temperature stability, accelerates the composting process, and reduces the time required for fertilization. Additionally, zeolite improved the physicochemical properties of the fertilizer produced through the anaerobic process.

Determining the amount of pesticides and toxins in drinking and agricultural water resources and health risks assessment: a case study of Fasa city, Iran

Navid Alinejad

Background and Objective: Monitoring pesticide concentrations in drinking water resources is crucial for enhancing water quality and public health. Therefore, periodic assessments of pesticide levels in these resources are essential to safeguard consumer health.
Materials and Methods: This study aimed to assess the concentrations of six pesticides—malathion, diazinon, glyphosate, paraquat, deltamethrin, and cypermethrin—in agricultural water resources as well as in urban and rural water distribution networks in Fasa city in 2023. Pesticide levels were monitored in 25 drinking water samples and 6 agricultural water samples.
Results: The results show that pesticide concentrations are higher in agricultural water compared to drinking water and distribution networks. Specifically, the concentrations of malathion and diazinon in agricultural water resources are significantly higher than in drinking water, with levels potentially up to eight times greater. The total risk index for samples from agricultural water sources ranges from 0.89 to 1.36, indicating a comparable risk to that of drinking water.
Conclusion: The health risk assessment of malathion, diazinon, glyphosate, paraquat, deltamethrin, and cypermethrin in drinking water resources suggests no immediate threat to public health. However, due to the elevated pesticide levels in agricultural water resources, ongoing monitoring of water sources near agricultural areas is recommended.

Developing an advocacy document for management of pesticide residues in agricultural products in Iran

Reza Saeedi

Background and Objective: The use of chemical pesticides is essential for integrated pest management; however, their improper application can lead to significant health and environmental consequences. This study aimed to develop an advocacy document for managing pesticide residues in agricultural products in the country, supported by the Academy of Medical Sciences of the Islamic Republic of Iran.
Materials and Methods: The study comprised the following steps: (1) formation of a committee to develop the advocacy document, (2) assessment of pesticide residue levels in agricultural products, (3) evaluation of the management of pesticide residues in the country, (4) drafting the advocacy document, and (5) proposing executive recommendations to improve the current situation.
Results: The systematic review and meta-analysis revealed that approximately 19% of agricultural products in the country exceeded the maximum residue level (MRL) set by the Codex Alimentarius Commission, a relatively high rate compared to other countries. While existing laws and regulations provided a clear framework for pesticide residue management and outlined stakeholder responsibilities, there was insufficient allocation of resources and support for policymakers, executives, beneficiaries, and the general public. The advocacy document identified stakeholder roles and defined five goals to enhance stakeholder engagement and foster intersectoral collaboration. The five key recommendations to improve the current situation were: (1) clarifying the current status of pesticide residue management, (2) setting quantitative goals for programs, (3) ensuring adequate budget and resource allocation, (4) leveraging expert opinions effectively, and (5) improving the performance of beneficiaries.
Conclusion: To ensure the implementation of these recommendations and achieve the goals outlined in this document, it is recommended to establish an advocacy committee on pesticide residue management in agricultural products. This committee should include representatives from all responsible organizations within the Ministry of Health, Treatment, and Medical Education.

Photocatalytic degradation of rhodamine B dye from aqueous media using imide conjugated polymer photocatalyst under visible light

Nader Bahramifar

Background and Objective: Dyes are significant pollutants that pose serious hazards to humans, animals and other organisms. They are not biodegradable through aerobic treatment processes, making their removal from industrial wastewater through photocatalytic processes essential. This research aimed to synthesize an imide-conjugated polymer photocatalyst for the first time and evaluate its effectiveness in removing Rhodamine B dye from aqueous solutions.
Materials and Methods: In this applied research, an imide conjugated polymer was synthesized and employed as a photocatalyst for the removal of Rhodamine B from aqueous solutions. The polymer was characterized using Scanning Electronic Microscopy (SEM), Transmission electron microscopy (TEM), Atomic force microscopy (AFM), X-Ray Diffraction (XRD), Thermogravimetric Analysis, Fourier transform infrared spectroscopy (FTIR), and Diffuse reflectance spectroscopy (DRS) methods. The study also assessed the influence of variables, including pH (4-9), photocatalyst concentration (0.01-0.04 g/L), and contact time (0-120 min), on the removal efficacy of Rhodamine B.
Results: The findings indicated that removal efficiency increased to 99% at a contact time of 45 minutes and a photocatalyst concentration of 0.02 g/L. The optimal pH for Rhodamine B removal was found to be 7.
Conclusion: The imide conjugated polymer proved to be an effective and accessible photocatalyst for the removal of rhodamine B from industrial wastewater under visible light.

A study on the performance of the wastewater treatment plant in Charmshahr industrial estate and the potential of reuse for effluent and disposal sludge

Hatam Godini

Background and Objective: Wastewater produced in industrial estates is crucial to address due to the wide range of pollutants it contains. The objective of the present study was to investigate the performance of the Chamshahr Industrial Estate Wastewater Treatment Plant for effluent and sludge reuse.
Materials and Methods: In this descriptive and comparative study, the quality of raw industrial wastewater, effluent, and sludge from the wastewater treatment plant of the Chamshahr Industrial Estate was investigated over three periods at monthly intervals. Additionally, archival quality data for wastewater, effluent, and sludge from 1402 to 1403 were analyzed. The results were compared with the standards and guidelines of Iran, WHO, FAO, USEPA, and others. The wastewater treatment method employed a combination of chemical sedimentation and aerated lagoons with return sludge.
Results: The volume of wastewater produced in this industrial estate was 15,000 m³/day, primarily originating from leather and tanning industries (6,100 m³/day), which exhibit high pollution intensity. The treatment plant's efficiency in removing BOD, COD, and TSS was 62±24%, 72±19%, and 84±13%, respectively. However, due to the concentration of heavy metals, such as chromium in the wastewater (0.28 mg/L) and sludge (353.5 mg/L), the treatment method was unable to meet existing standards and guidelines. Furthermore, the salt content in the effluent (43,300 mg/L) and sludge (202,000 mg/L) was excessively high, rendering it unsuitable for disposal or reuse without further treatment.
Conclusion: The performance of the wastewater treatment plant fails to meet the standards and guidelines for environmental discharge and the reuse of effluent and sludge. Therefore, the final effluent and sludge require additional treatment to enable reuse and prevent environmental pollution.

Modeling of the impact of land use patterns on groundwater quality indices (TDS, SAR) in Qazvin plain

Eisa Solgi

Background and Objective: The Qazvin Plain, one of the key agricultural regions in Iran, faces significant challenges affecting the quality of its water resources. These challenges include changes in land use (LU) and the expansion of activities such as agriculture and industry. Assessing, modeling, and predicting total dissolved solids (TDS) and the sodium absorption ratio (SAR) in groundwater—two critical parameters influencing water resource usability—can play a pivotal role in managing water quality in the region.
Materials and Methods: This study aimed to investigate and model the relationship between LU and water quality parameters. TDS and SAR values were first mapped using the inverse distance weighting (IDW) interpolation method. Land use in the Qazvin Plain was then classified using Landsat 8 satellite imagery and the supervised maximum likelihood classification method. Finally, geographic weighted regression (GWR) was employed to model and examine the spatial relationship between the LU distribution patterns in the Qazvin Plain and the groundwater quality parameters.
Results: The coefficient of determination (R²) for the relationship between SAR and LU was 0.74, while for TDS and LU, it was 0.81. These findings highlight a significant influence of LU changes on groundwater quality parameters in the study area.
Conclusion: The results demonstrate a strong correlation between LU and groundwater quality parameters. Moreover, the application of GWR proved effective in capturing spatial variations and providing accurate tools for analyzing these relationships. This approach can be instrumental in the sustainable management of water resources in the Qazvin Plain.

Evaluation of pollution and environmental toxicity of potentially toxic elements in street dust of city of Hamedan, west of Iran

Bahareh Lorestani

Background and Objective: Street dust, as both a source and sink of pollutants, is considered a reliable indicator for assessing atmospheric pollution. Therefore, this study aimed to evaluate the pollution levels and environmental toxicity of arsenic (As), zinc (Zn), lead (Pb), cadmium (Cd), and copper (Cu) in street dust in the city of Hamedan in 2023.
Materials and Methods: A total of 108 street dust samples were collected from 12 sampling sites, including residential, commercial, and industrial regions, during the spring, summer, and fall seasons. The concentrations of the analyzed elements were determined using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Additionally, pollution indices (PI), integrated pollution index (IPI), and mean effects range median quotient (mERM-Q) were calculated.
Results: The highest average concentrations of the analyzed elements in street dust were observed in the industrial regions and the fall season for As (5.79 mg/kg), Zn (405 mg/kg), Cd (0.758 mg/kg), and Cu (84.8 mg/kg). For Pb, the highest average concentration (110 mg/kg) was found in commercial regions during the fall season. PI values indicated pollution levels for As, Zn, Pb, Cd, and Cu ranging from "moderate" to "very high." The average IPI values varied between 2.52 and 3.90, reflecting "high" pollution conditions across all sampling sites and seasons. Furthermore, the average mERM-Q values suggested a 21% probability of elemental toxicity in the analyzed street dust samples.
Conclusion: The findings highlight the influence of human activities, seasonal variations, and emission source fluctuations on street dust pollution. To mitigate pollution, it is recommended to identify and control the release sources of these elements, particularly in regions with higher pollution levels.

Synthesis, characterization, and modification of hairy nanocrystalline cellulose adsorbent for using in carbon dioxide adsorption process

Maryam Tahmasebpoor

Background and Objective: The global increase in energy consumption has led to a rise in carbon dioxide emissions, causing significant and often irreparable damages such as global warming. This study investigates the adsorption capacity of hairy nanocrystalline cellulose as a novel adsorbent and seeks to enhance its performance in carbon dioxide capture by modifying it with two types of amines: monoethanolamine and diethanolamine.
Materials and Methods: Hairy nanocrystalline cellulose was synthesized through oxidation and amine modification. The formation of chemical groups and sample morphology was analyzed using Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Additionally, thermogravimetric analysis was performed at two temperatures (25 and 50 °C) and two concentrations (10% and 90% carbon dioxide in nitrogen) to evaluate the adsorption capacity of the samples.
Results: The results showed that at 25 °C and a carbon dioxide concentration of 90%, the adsorption capacities of hairy nanocrystalline cellulose, cellulose modified with 20% by weight of monoethanolamine, and cellulose modified with 20% by weight of diethanolamine were 1.74, 2.5, and 1.96 mmol/g, respectively. These findings indicate that modifying the adsorbent with monoethanolamine increased its carbon dioxide adsorption capacity by approximately 44%, while modification with diethanolamine resulted in a 13% improvement.
Conclusion: The findings suggest that hairy nanocrystalline cellulose, particularly in its modified forms, holds significant promise as a novel and effective adsorbent for carbon dioxide capture.

Spatial variablities and health impact assessment of ambient PM2.5 in Tehran during 2023-2024

Mohammad Sadegh Hassanvand

Background and Objective: The present study was designed to investigate the spatial and temporal (hourly, daily, monthly, and seasonal) variations in ambient fine particulate matter (PM_2.5) concentrations in Tehran from 21 March, 2023, to 19 March, 2024, and estimate the number of premature deaths attributable to PM_2.5.
Materials and Methods: Hourly PM_2.5 data were obtained from 41 air quality monitoring stations across Tehran. Subsequently, 29 validated stations were identified for assessing spatial changes in pollutant concentrations and estimating the associated health effects. The latest version of the AirQ+ software (version 2.2.4) was employed to estimate health impacts attributable to PM_2.5. Additionally, updated baseline data and the population of Tehran were used to assess the health effects of air pollution.
Results: The annual average concentration of ambient PM_2.5 in Tehran over the study period was approximately 32 µg/m³ for the entire city. At validated monitoring stations and across neighborhoods, the concentrations ranged from 20.8–47.5 µg/m³ and 22.2–46.3 µg/m³, respectively. These levels were approximately 4 to 9 times higher than the World Health Organization's (WHO) annual air quality guidelines and 2 to 4 times higher than the NAAQS. The number of deaths attributable to long-term exposure to ambient PM_2.5 in adults aged 30 and above in Tehran during the study period was estimated to be 9,321 (95% confidence interval: 7,232–10,313) for concentrations exceeding 5 µg/m³.
Conclusion: The results of this study highlight that ambient PM_2.5 concentrations in Tehran over the study period consistently exceeded the WHO air quality guideline and the NAAQS. Furthermore, a comparison of pollutant concentrations across all validated monitoring stations and neighborhoods reveals that residents in all parts of Tehran experienced poor air quality. However, concentrations were significantly higher in some areas, particularly the central and southern parts of the city, compared to the northern regions.

Equilibrium and kinetic investigation of solophenyl dye removal from aqueous solution using cellulose adsorbents

Shahriar Mahdavi

Background and Objective: Dyes are among the most widespread pollutants found in industrial wastewater. The aim of this study is to investigate the potential of vineyard wood waste as a green adsorbent for the removal of polyazo solophenyl dye from aquatic environments.
Materials and Methods: In this laboratory research, two forms of adsorbents modified with H₂SO₄ and NaOH were used. Data obtained from dye adsorption in synthetic solutions were fitted to isotherm, kinetic, and thermodynamic models, with all calculations performed using Excel software. Zeta potential analysis, along with FTIR, BET, and FESEM-EDS instrumental analyses, was conducted to determine the properties of the adsorbent. Additionally, the desorption rates of the adsorbents were analyzed.
Results: The results showed that the highest color removal efficiency for the adsorbent modified with H₂SO₄ was achieved at a contact time of 180 minutes and a reaction temperature of 50 °C, while for the adsorbent modified with NaOH, the highest efficiency was observed at a contact time of 105 minutes and a reaction temperature of 25 °C. For both adsorbents, the optimal pH was 4, and the optimal adsorbent dosage was 1 g. The adsorption data for both modified adsorbents followed the pseudo-second-order kinetic model, while the equilibrium data aligned with the Freundlich and Temkin isotherm models. The adsorption capacities were found to be 22.27 mg/g and 9.87 mg/g for the adsorbents modified with acid and base, respectively, under optimal conditions.
Conclusion: This study introduces a novel, low-cost adsorbent derived from natural waste for water pollution removal, transforming the current approach into a cost-effective and eco-friendly solution.