Iranian Journal of Health and Environment

Evaluation of stability and maturity indices during composting process from a mixture of poultry waste and sawdust by windrow method

Amir Hossein Nafez

Background and Objective: It is important to determine the quality of the compost to use compost properly. The aim of this study was to determine the effect of mixing ratio of bulking agent on stability and maturity indices in poultry waste compost.
Materials and Methods: Two piles of sawdust mixture with poultry wastes and volume ratios of 1:1 (W1) and 2:1 (W2) were prepared by Windrow method and a pile containing poultry manure was used as control (W0). In order to determine the stability and maturity indices in compost, the most important physicochemical and biological parameters were studied.
Results: The thermophilic phase lasted about 7 weeks for W1 and about 4 weeks for W2. The initial C/N ratios in the W0, W1 and W2 were 27.10, 31.40 and 56.24, respectively, which eventually reached less than 20. The reduction of organic matter in the three piles was 8.30%, 62.59% and 85.53%, respectively. The thermophilic phase caused a sharp decrease in the population of indicator and pathogenic microorganisms in all piles. The highest dehydrogenase activity in W1 pile was 2.95 mgTPF/gDW.h and by decreasing temperature until the last day, its value decreased to 0.29 mgTPF/gDW.h.
Conclusion: The best ratio for mixing sawdust with poultry manure was 1:1 (v:v). Microbial and enzymatic activities are useful parameters for monitoring poultry composting process and determining the rate of compost stability, and the use of this compost in agriculture will improve soil quality.

Self-organizing map neural network application in detecting the extent of intentional pollution in the urban water distribution network

Naser Mehrdadi

Background and Objective: Water distribution networks are prone to terrorist attacks by injecting toxic substances, due to their vastness and availability. The main objective of this paper was detecting the extent of intentional pollution in the urban water distribution network by self-organizing map (SOM).
Materials and Methods: The existing hydraulic condition of the water distribution network covered by reservoir No. 4 in Tehran was modeled as a pilot. Possible injection scenarios of contamination in different parts of the water distribution network were performed using qualitative analysis of the water distribution network, using the EPANET analyzer engine and coding in R software environment. Artificial neural network of SOM was used to find the contamination range for the injection of arsenic at different times and places in the distribution network.
Results: The concentration of contamination at a certain point decreased over time and a high correlation was observed between time and concentration. The extent of contamination depended on the consumption of subscribers and consequently, the time of contaminat injection. The results of the artificial neural network model showed that the method developed in this research was 91% accurate and was able to determine the extent of contamination in the water distribution network at high speed.
Conclusion: SOM can be used as a complement to the water quality monitoring and pollution detection system in the urban water distribution network to determine the extent of pollution when detecting potential pollution in the shortest possible time, and as an alternative to quantitative-qualitative modeling of the water network.

Performance of microbial desalination cell for wastewater treatment and desalination: continuous operation mode

Azam Ebrahimi

Background and Objective: With increasing population growth and water pollution, fresh water supply sources are declining and can not meet today's human needs. Thus, energy conversion systems with high efficiency and low pollution such as desalination microbial cell have been considered. Therefore the aim of this research was to investigation the efficiency of microbial desalination cell (MDC) for desalination and treatment of salt wastewater.
Materials and Methods: To address this issue, the decision was taken to use saline synthetic wastewater with different initial salt concentrations (2, 5, 7 and 10 g/L NaCl) and, different hydraulic retention times (1, 2, 3 and 72 h) in open circuit voltage (OCV) and closed circuit voltage (CCV) continuous mode.
Results: The results showed that highest EC removal was 11.2% and 14.3% with 10 g/L NaCl in open and closed circuit mode, respectively. Maximum COD removal of 68.7% was achieved in CCV mode that was obtained at 10 g/L NaCl. Additionally, Escherichia coli, Bacillus, Enterobacter, Staphylococcus aureus, Pseudomonas and Citrobacter were diagnose as effective bacteria in decomposing wastewater.
Conclusion: The obtained results proved that MDC desalination microbial cell technology is Emerging technology that has many unknown aspects; however, it is expected to be an appropriate technique for wastewater treatment and desalination.

Frequency and ecological risk of microplastics and mesoplastics in the soil of residential areas near Tehran landfill in 2021

Sakine Shekoohiyan

Background and Objective: Among the emerging contaminants, microplastics threaten public health. This study aimed to determine microplastic and mesoplastics in soil of residential areas adjacent to Tehran Landfill and assess its ecological risk.
Materials and Methods: The present descriptive cross-sectional study was conducted on 20 shallow and deep soil samples from residential areas near the Tehran landfill in July 2021. The microplastics were floated in NaCl and ZnCl₂ solutions, and the mesoplastics were separated manually. The identification of physical and chemical properties of polymers was performed by stereomicroscope and FTIR analysis, respectively.
Results: The average amount of micro-plastics in shallow and deep soils estimated 76±34.98 and 24.7±19.79 particles/kg_soil, respectively. The average amount of mesoplastics obtained 5.25±2.91 and 3.55±1.09 particles/kg_soil, in shallow and deep soils, respectively. Paired-samples T-test showed significant differences between shallow and deep soil in terms of plastic particles (p<0.001). The most abundant microplastic particles were the fragment-shaped with the particle size of 0.1-0.5 mm and LDPE polymer types with the percentage of 37.75, 44.64, and 46.15, respectively. Mesoplastic particles, the 0.5-1 cm film-shaped particles and LDPE polymer types with the percentage of 62.76, 61.46, and 50.7 were found as the most prevalent. Microplastics and mesoplastics' potential ecological risks value in all sampling points was less than 150, indicating low ecological risk.
Conclusion: Despite the low PERI of microplastics and soil mesoplastics in residential areas, the E_rⁱ index for LDPE was high. Thus, Ecological risk is probable if control measures are not taken against plastic pollution.

Knowledge level of Tehran barbers about waste and their performance in waste management in 2021

Mahmood Alimohammadi

Background and Objective: barbershops are one of the most important public places for beauty activities, which requires attention to health issues (personal and environmental), and non-compliance with health standards and procedures can be a threat to public health. The level of awareness and performance of employees can affect the management of waste production. This study aimed to investigate the level of knowledge of personnel about waste production and performance in southern Tehran in 2021.
Materials and Methods: This descriptive cross-sectional study was conducted in southern Tehran with a statistical sample of 330 places. In this study, a questionnaire was used which comprised of three sections; demographic information, the level of awareness and performance of personnel, and the information was completed after interviews with hairdressers. Data were analyzed by Kolmogorov-Smirnov, Chi-square, Pearson correlation coefficient, one-sample t-test, and Mann-Whitney using SPSS software (IBM-v.26).
Results: The average scores of awareness and performance of individuals in waste management were 43.18 and 48.27, respectively, and based on the results of qualitative analysis, the scores of awareness and optimal performance of individuals in waste management were 53.6% and 72%, respectively. Also, 46.6% and 28% of the participants obtained unfavorable scores on knowledge and practice in waste management, respectively. People's knowledge about the management of waste produced in hairdressers had a significant relationship with gender, history of health education, history of health crimes, education and performance of people about the management of waste produced in hairdressers with gender and history of health education. There was no significant relationship between knowledge and practice with other variables.
Conclusion: Barbershop is a place where paying attention to environmental health is effective in promoting community health and disease control. Ignoring this issue can lead to the spread of various diseases. In general, the results of this study showed that the level of awareness is effective in the performance of barbers regarding the management of waste production. Additionally, health education was known effective in the level of awareness and performance of hairdressers in this field, so the improtant roles of these variables should taken into consideration.

Efficiency of ferrate/peroxymonosulfate advanced oxidation process in removing chlorpyrifos pesticide from aqueous solution after pretreatment with ferric chloride coagulant

Hassan Aslani

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.

Analysis of polycyclic aromatic hydrocarbons in surface soil of agricultural lands in Hamedan, Iran

Soheil Sobhanardakani

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.

Greenhouse gas emission inventory and quantifying regional compatible mitigation plans-horizon 2030 (case study: Guilan province, Iran)

Ali Ahmadi Orkomi

Background and Objective: Greenhouse gas emission estimation and submitting a regular national report on climate change has been underway since 2003. Given the importance of this issue, estimating emissions at the provincial level and assessing local emission management capacities will make the country more agile in reporting and emission control.
Materials and Methods: The greenhouse gas emission in four sectors as energy, industry, agriculture, forestry and other landuse and wastes and all sub-sectors of these areas was determined in Guilan Province. The annual emission has been estimated using the 2019 activity data and the IPCC (Intergovernmental Panel on Climate Change) software.
Results: The gross and per capita greenhouse gases’ emission of the province are 18.5 Mt and 7.31 tons per year carbon dioxide equivalent, respectively, so that the annual ecological supply of forests to capture greenhouse gases is estimated at 2 Mt. The thermal power plants, residential consumption (except electricity) and transportation sectors are the major emission sectors in the province with 36, 23 and 19% share, respectively. Out of four scenarios, the wind farms development scenario (nominal capacity 3 GW) and 10% energy savings in the residential sector reduce greenhouse gas emissions by 9% and 2.9%, respectively. The cumulative impact of all the proposed scenarios by 2030 will also lead to a 13% reduction in emissions compared to the current situation.
Conclusion: Considering the existing capacities in the clean power generation and energy saving in the residential sector, it is possible to reduce the emission of greenhouse gases by 13% by 2030. Since the proposed scenarios are regionalized and do not depend on management decisions in other provinces, they have good feasibility. Consequently, if clean power generation plans are established in other provinces and energy consumption management in the transport sector is applied at the national scale, it may be expected that the country's minimum commitments (4% reduction compared to 2010) will be met.

Adsorption of silica from aqueous solution onto magnesium oxide nanoparticle: kinetic and equilibrium studies

Maryam Fayazi

Background and Objective: With increasing water pollution, serious water shortages and increased pressure to save water, recycling and reuse of water has attracted more attention in various industries. Removal of silica from cooling water is essential for recycling and reuse of water. The aim of this study was to remove silica from water using magnesium oxide nanoparticles (MgO) synthesized by chemical deposition method.
Materials and Methods: Synthetic nanoparticles were successfully determined using field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FTIR) and X-ray diffraction (XRD). To determine the optimal adsorption conditions the batch system, the effect of important parameters such as pH (2-8), contact time (0-150 min), initial concentration of silica solution (50-1000 mg/L), adsorbent amount (0.01-0.14 g) and temperature (25-60 ˚C) were studied.
Results: Under optimal conditions, an almost removal of 200 mg/L silica solution was achieved in 60 min reaction time. Equilibrium data were analyzed using the Langmuir and Freundlich isotherms. The adsorption process can be well described by the Langmuir model, and the maximum adsorption capacity was calculated as 75.76 mg/g. Synthetic data were analyzed using pseudo-first-order and pseudo-second-order equations. The pseudo-second-order model showed good agreement with the obtained data (R² = 0.9949).
Conclusion: Due to the high potential of magnesium oxide nanoparticles in silica removal, it can be a good candidate for the removal of silica and industrial wastewater treatment.

Concentration of potentially toxic elements in black tea imported to Iran: a potential risk assessment study

Zoha Heidarinejad

Background and Objective: The aim of this study was to investigate the concentration of potentially toxic elements (arsenic, lead, copper, cadmium and mercury) in black tea imported to southern Iran and to assess the risk of carcinogenic and non-carcinogenic exposure to consumers.
Materials and Methods: For this purpose, 94 samples of black tea from 15 brands imported from India in 2021 were selected. Heavy metals concentrations were measured using an atomic absorption spectrometer (GBC model SAVANTAA). After determining the concentration of heavy metals in black tea samples, health risk assessment was determined using Montocarlo simulation technique.
Results: According to the results, the average concentrations of heavy metals namely arsenic, lead, copper, cadmium and mercury were 0.03±0.02, 0.02±0.16, 15.67±7.69, 0.02±0.01 and 0.006±0.005 mg/kg, respectively. The hazard quotient (HQ) of the heavy metals arsenic, lead, copper, cadmium and mercury were 1.07×10^-2, 6.37×10^-3, 3.45×10^-5, 2.05×10^-2 and 7.19×10^-4, respectively.
Conclusion: Therefore, according to the findings, it can be concluded that the concentrations of potentially toxic elements (arsenic, lead, copper, mercury and cadmium) in black tea were consistent with the standard level of Iran and World Health Organization. Additionally, the average carcinogenic risk index for arsenic metal was 4.49×10^-6, which is much lower than the acceptable level of carcinogenic risk (10^-6). Therefore, the concentrations of five potentially toxic elements in the studied black tea did not show any significant risk for consumers.

Evaluation of the performance of Tehran drinking water treatment plants in removing nanoplastics and microplastics

Roya Mafigholami

Background and Objective: Microplastics can have harmful effects on living things, including humans. These particles have been identified in all water, soil, and food sources. Among these, freshwater resources are more important, because they are considered a water source for humans through drinking water treatment plants (DWTPs). Therefore, this study investigates the performance of Tehran DWTPs in removing these particles.
Materials and Methods: In this study, the performance of three DWTPs in Tehran in removing these particles was investigated. In most studies worldwide, particles larger than 1 µm were examined, but in this study, nanoplastic particles smaller than 1 µm, as well as the effect of the warm and cold seasons of the year on the concentration of these particles were also examined.
Results: According to the results of the study, the amount of micro and nanoplastic particles at the inlet of treatment plants in the warm season of the year was 2569 ± 309 to 3918 ± 425 MP/L, and the output was 1492 ± 32 to 2279 ± 146 MP/L, which indicates an increase in these particles in the warm season. As a result, the studied treatment plants were only able to remove 32.1 to 59.9% of these particles. In addition, using electron microscopy, MPs were classified into three categories in terms of appearance: fiber, fragment, and film. This study completes the knowledge of MPs in this area.
Conclusion: Based on the results of this study, Tehran DWTPs have poor performance in removing these particles.

Investigation of Pb and Cd concentrations in drinking water samples of Gorgan water supply network: preparation of zoning maps by geographic information system

Mina Ghahrchi

Background and Objective: With the expansion of urbanization and the development of industry, environmental pollution, including sources of drinking water to heavy metals, has become a global problem. Therefore, the present study was conducted to measure the concentration of lead and cadmium in the water of Gorgan distribution network.
Materials and Methods: This is a descriptive cross-sectional study in which the concentrations of heavy metals lead and cadmium were measured in 25 different stations of the Gorgan drinking water distribution network from April to September 2018 by atomic absorption device. Statistical analysis was used from SPSS ver 22 software. Also, zoning maps based on the concentration of these two metals were prepared by Geographic Information System (GIS) software.
Results: The results of measuring the lead and cadmium concentration showed that all measured values are less than national and international standards. In general, the average concentrations of lead and cadmium were 4.38 and 0.1 μg/L, respectively. The results of Kruskal-Wallis test showed that there was a significant difference (p <0.01) between the concentrations obtained from lead metal in different months. Additionally, the distribution map of this lead and cadmium exhibited that in the central areas and some border areas, the concentration of these two metals is higher.
Conclusion: According to the obtained results, it can be seen that the concentration of heavy metals lead and cadmium in the water of Gorgan distribution network is within the permitted standards.