Iranian Journal of

Background and Objective: Water quality is one of the issues that is of great importance to economic and social development due to the high costs of providing healthy drinking water and its risk to human health and the environment. For instance, although only a short time has passed since the construction of the Shirin-darreh dam, the problems arising from its exploitation have challenged the environmental sector and the health of the water.
Materials and Methods: Water quality is affected by complex processes and various variables. Accordingly, NSFWQI input variables at monthly intervals collected at the dam reservoir during December 2011 - November 2012 was used to evaluate the water quality of the reservoir based on the grey relational analysis process. The results were compared with the results of the NSFWQI method. Also, the Shannon Entropy method was used, considering the importance of weight of variables in different methods.
Results: The results showed that the water quality in the grey analysis method from November 2011 to May 2012 and in the NSFWQI method from October 2011 to April 2012 was moderate and in the remaining months was bad. In the grey analysis method, the highest reservoir value was related to Station 3 and month of February 2012 with a value of 64.2 and the worst water quality was related to Station 4 and month of August 2012 with a value of 39.2. Also, In NSFWQI method, the highest reservoir value was related to station 3 and month of February 2012 with a value of 68.7, and the worst water quality was related to Station 1 and month of August 2012 with a value of 39.1.
Conclusion: Although there was no significant difference between the two methods, due to the greater adaptability of the results of the gray analysis method with the weather events and upstream conditions of the dam, this method is recommended. Due to the relative inadequacy of Shirin-darreh reservoir water in some months, it is essential that the source of pollutants from upstream areas is identified. After identification of the hotspots and preparation of the critical areas map, the appropriate control measures could be implemented.
 

Background and Objective: Chlorpyrifos (CPF), an organophosphate pesticide, has been widely used in the agricultural industry and may cause environmental damage. The present study aimed to evaluate the potential application of Fe(VI) and Fe(VI)/PMS processes for oxidation of CPF in water after pretreatment with ferric chloride coagulant.
Materials and Methods: This study was performed in two phases including coagulation and flocculation process and advanced oxidation process (AOP). In the first phase, the coagulation process was performed for turbidity removal by ferric chloride (FeCl₃). In this phase, using a central composite design (CCD) with R software, the combined effect of four variables including initial turbidity, initial pH, coagulant dose and contact time was investigated. The supernatant from this process was transferred to the next phase for further analysis. In the AOP phase, the effect of Fe(VI) and Fe(VI)/PMS oxidants were investigated separately.
Results: In the first phase (coagulation and flocculation), FeCl₃ showed the highest efficiency (95.79%) at alkaline pH (pH=8). In the next phase (AOP), the results showed that the degradation efficiency of Fe(VI)/PMS process was higher compared to sole Fe(VI) process at all pHs. Also, by examining the reaction kinetics, it was found that after the coagulation process by FeCl₃, the removal rate in the Fe(VI)/PMS process is 1.5 times higher than the Fe(VI) process.
Conclusion: Due to the high removal efficiency and higher degradation rate of Fe(VI)/PMS process, this technique can be used as a relatively effective method in removing chlorpyrifos from aqueous solution.
 

Background and Objective: One of the main ways of transmitting diseases is drinking water, so the safety of drinking water is an important issue for consumers, water suppliers, operators, and health officials. This study was conducted to identify and semi-quantitative evaluation and prioritization of risks in the drinking water supply system of Bostan Abad city.
Materials and Methods: In order to evaluate and document the key elements of WSP and identify the steps that need improvement, the quality assurance tool of the water safety plan (WSP-QA TOOL software) was used, and then based on the guide of the water safety plan from the WHO and the International Association Water safety, WSP team formed. Then the water supply system of Bostan Abad city from the farthest point of the basin to the last consumption point was inspected and described.
Results: The results showed that the highest number of risks are in the water supply sources, distribution network, and point of consumption, respectively. Also, the most vulnerable part of the system was identified as the disinfection unit and storage tanks due to biological and chemical contamination caused by equipment failure and improper preparation of chlorine solution.
Conclusion: In summary, it can be said that carrying out the necessary reforms can play an effective role in reducing the risk potential in times of crisis, which should be given serious attention by water industry officials.
 

Background and Objective: Nowadays, recycling is one of the ways to save mankind from the mass of waste it produces, and waste separation from the source is the first and most important link in the field of urban waste recycling. Since the necessity and basis of recycling is people's participation in separation plans from the source, the present study was conducted to investigate the awareness, attitude, and performance of the people of Mazandaran province regarding the source separation of household waste in 2021.
Materials and Methods: The present study was a descriptive-analytical and cross-sectional study, and the tool used in it was a researcher-made questionnaire including three dimensions of knowledge, attitude, and performance, the link of which was provided online to qualified people. The qualitative content validity of this questionnaire was confirmed by 8 environmental health experts in the field of the research subject. The reliability of the tool was also estimated through the Retest Method. Furthermore, the values of Cronbach's alpha coefficient for the three dimensions of awareness, attitude, and performance were calculated. In the following, the samples were selected in virtual groups based on the available sampling method and through the distribution of the questionnaire link online. Analysis of variance was used to compare the mean scores in the levels of variables, Pearson's correlation test was used to examine the relationship between the scores of awareness, attitude, and performance dimensions, and linear regression was used to examine the effect of independent variables. Finally, the data was analyzed in SPSS software (version 22).
Results: For the entire study population (305 people), the range and mean score of awareness were 0-6, and 5.03±1.18 respectively, the range and mean score of attitude were 17-85 and 61.01± 9.45, and the range and mean score of performance were 6-30 and 11.43±5.19, respectively. Also, there was a significant correlation between the mean scores of the dimensions of awareness and attitude (correlation coefficient=0.70), awareness and performance (correlation coefficient=0.68), and attitude and performance (correlation coefficient=0.63).
Conclusion: The results of this study, which was conducted to measure the knowledge, attitude, and performance of the people of Mazandaran province regarding the separation of household waste from the source and waste recycling, and with a survey of 305 households in this province, showed that although the most of people have a piece of proper knowledge and attitude related to the importance of separation and recycling of solid waste, they have not participated much in the plans of waste separation from the source. Therefore, in order to increase the level of people's performance, it is recommended to develop incentive programs in the field of source separation, including awarding prizes or applying discounts on waste charges, as well as providing suitable containers for waste separation to households for free by the municipality to encourage waste separation.
 

Background and Objective: The adverse health effects of polycyclic aromatic hydrocarbons (PAHs) have received significant attention in recent years. This study aimed to measure the concentration of PAHs associated with fine particles and assess the health risks posed by these compounds.
Materials and Methods: A total of 38 air samples were collected from the central part of Isfahan city using a particle sampler equipped with an inlet to capture particles smaller than 2.5 µm (PM_2.5). The samples were analyzed using GC-MS, and molecular ratios were used to identify potential sources of PAHs. Additionally, a Monte Carlo simulation was employed to perform a probabilistic risk assessment of carcinogenic and non-carcinogenic effects of PAHs for two groups:  children and adults.
Results: Out of the 16 priority PAH compounds, seven compounds were identified, with average concentrations ranging from 0.003 to 17.8 ng/m³. Molecular ratios indicated that pyrogenic sources were the main contributors to PAHs in the air. The median carcinogenic risk for children and adults was estimated to be 3.1×10^-8 and 5.99×10^-8, respectively. The median non-carcinogenic risk for PAH compounds was estimated at 3.08×10^-1.
Conclusion: The probabilistic risk assessment revealed that the PAHs concentrations associated with fine particles do not pose a significant risk to exposed individuals. However, it is important to note that this study focused solely on the risk assessment of PAHs associated with fine particles. A comprehensive risk assessment of all PAHs present in the atmosphere is, therefore, recommended.
 

Background and Objective: This study aimed to assess the chemical and microbial quality of sludge generated at the Khoy wastewater treatment plant using an SBR process, and to compare the results with established agricultural standards.
Materials and Methods: In this study, monthly sludge samples were collected and analyzed using standard EPA methods, including the 15-tube technique for coliforms, flotation for Ascaris eggs, and acid digestion for heavy metals. Data were analyzed using SPSS v.25 and statistical analyses included Pearson correlation tests.
Results: The analyzed sludge exhibited an acceptable pH (7.14) and a high organic carbon content (27.32%). However, its elevated salinity (9891 µS/m) and low C/N ratio (6.38) indicated biological instability and limitations for direct agricultural application. The concentrations of heavy metals—including arsenic (10.27 mg/kg), copper (134.86 mg/kg), and zinc (530.93 mg/kg)— exceeded Iran’s national standards. Heat-map analysis confirmed a significant correlation between salinity, and the levels of chloride (Cl^-), and sulfate (SO₄^2-). Despite its nutritional value, the sludge is not recommended for direct agricultural use without prior treatments such as stabilization, salinity reduction, and pathogen removal.
Conclusion: Despite the substantial nutrient content of the sludge, including nitrogen, phosphorus, and organic carbon, its direct application in agriculture faces serious limitations due to high salinity, an imbalanced C/N ratio, severe microbial contamination (e.g., nematode eggs), and the exceedance of permissible levels for several heavy metals. Safe utilization of this sludge requires corrective treatments such as stabilization, disinfection, desalination, and regular monitoring of heavy metal concentrations.