فصلنامه سلامت و محیط زیست
سال چهاردهم شماره 2 (پیاپی 52، تابستان 1400)

Due to the water shortages and the presence of industrial pollutants in water resources, wastewater treatment, especially colored wastewater, is essential. The aim of this study was to treat wastewater containing Methylene Blue dye using activated carbon nanocomposite/zinc oxide nanoparticles (ZnO/AC) obtained from canola oil waste by green method.

In the present study, the effect of different parameters (pH, Methylene Blue concentration, adsorbent amount, temperature and contact time) on the adsorption of Methylene Blue was investigated. Design of Experiment 7 software (Response Surface Method (RSM)) was used to evaluate the influence of various parameters on Methylene Blue removal.

The results of the predicted experiments showed that the highest adsorption of Methylene Blue is at pH = 10, temperature 70 °C, contact time of 50 min, initial adsorption concentration of 10 mg/ L and adsorbent amount of 0.05 g. Under optimal conditions, ZnO/AC adsorbent was able to remove 98.22% of Methylene Blue from the aqueous medium.

Appropriate to the high potential of ZnO/AC nanocomposite in the removal of Methylene Blue pigment, it can be a good candidate for the removal of dye contaminants and wastewater treatment of textile factories.

Access to safe water is critical for protecting human health. Turbidity is one of the main physical parameters that affect the quality of water from both health and aesthetical points of view. Therefore, waters should be treated based on the standards set for turbidity before consumption. This study was performed to determine the performance of a bench-scale baffled filter system for removing the turbidity, microbial population, and total organic carbon (TOC) from the contaminated water.

  A lab-scale Plexiglas baffled filter consisting of five compartments with a total working volume of 2 L was designed and constructed. The polyurethane foam cubes were used as filter media. The effect of turbidity (10, 50, and 100 NTU) and surface overflow rate (SOR: 7.5, 10 and 15 m/h) was investigated on the performance of the developed system.

A direct relationship between turbidity, TOC, and microbial density was observed in the inlet water. The efficiency of the baffled filter in the removal of turbidity and the period of the filter operation run both enhanced as the SOR was either decreased or the inlet turbidity was increased. In addition, almost complete removal of TOC from the inlet water was noticed.

The results of the present study indicated that the baffled filter system with sponge media can be a novel and effective method for the removal of turbidity, microbial contaminants and TOC from the natural surface water.

Milk is one of the most important components of human food. In recent decades, the continued use of pesticides has led to contamination of soil, water, air and milk and caused public concern in the community. Long-term exposure to pesticide residuals in the food chain can be harmful. Therefore, there is a need to control environmental conditions in order to improve its healthy and sustainable food processing practices.

 In this study, 30 samples of raw milk were randomly collected in October 2020, from milk collection centers in Urmia and the residual pesticides were determined using gas chromatography–mass spectrometry (GC-MS).

 Organochlorine pesticides were detected in some raw milk samples. The highest concentrations of Lindane (γ-HCH) were detected with the values ranging from 0.3 to 0.6 mg/kg in 5 milk samples. Atrazine was detected in 15 samples with the values ranging from 0.8 to 1.33 mg/kg and alachlor was found in 13 samples with the varied range of 0.35 to o.5 mg/kg. Organochlorine pesticide concentrations were higher than maximum residue level (MRL) in all contaminated milk samples according to the values mentioned by the European Union.

This study showed that atrazine, lindane and alachlor were higher than MRL according to European Commission (EC). However, other organochlorine pesticides such as Heptachlor, Aldrin and hexachlorocyclohexane (HCH) isomers (α, β and γ) were not detected.

The aim of this study was to evaluate the chemical and microbial quality of bottled water in Iran and to calculate the water quality index (WQI).

Different brands of bottled water (4 samples from 71 brands) were randomly collected from the market. Chemical and microbial characteristics of the samples were examined and determined. Finally, the calculations related to the WQI index were performed and the water samples were classified as excellent, good, poor, very poor and unsuitable.

None of the samples exhibited concentration of heavy metals beyond Iranian water standards, and the concentration of sulfate (SO4), chloride (Cl) and fluoride (F) did not exceed international standards. However, in some samples, nitrite (NO2) and nitrate (NO3) concentrations were higher than recommended standards. With Regard to other water quality parameters, 8% to 89% of the samples exhibited concentration higher than the values provided on the water bottle label. 5 species of different bacteria were found in 15 water samples. According to the WQI index, about 63% of the samples were of excellent quality. Also, the water quality of 34% and 3% of the samples fell in good and poor quality categories, respectively. None of the bottled water samples was of very poor quality.

The quality of bottled water investigated in this study was generally suitable, but due to the wide range of bottled water in Iran based on brand and seasons, continuous evaluation of water treatment methods in companies and careful monitoring of chemical and microbial quality of bottled water in all seasons is recommended.

In assessing the risk of community related poisonings due to insecticide use a practical and effective tool is needed to evaluate insecticides Therefore, the present study aimed to investigate the reliability and validity of exposure patterns to insecticides.

In this study, after performing validity, translation of the final version of the questionnaire was prepared based on the agreement of experts in accordance with the study population. In the next step, the reliability validity of the study was investigated. Finally, the questionnaire reliability was evaluated by test-retest method at a 14-day interval with the participation of 40 resident of Tehran city.

 The results of R-CVI and C-CVI were evaluated as good for all of items (between 0.91 and 0.97). The total CVI index for the whole questionnaire ranged from 0.75 to 1 in terms of proportion and transparency. On the other hand, the total coefficient of kappa for reliability of the questionnaire was obtained between 0.89 and 1.

Considering the acceptable validity and reliability level of the Persian version, this questionnaire is a valid tool and can be applied to assess the risk of insecticide use and its associated injuries in the Iranian population.

This study was conducted to investigate the long-term temporal trends and spatial variations of ambient PM10, PM2.5, O3, concentrations in Tabriz city during the years 2006-2017.

Real-time hourly concentrations of PM10, PM2.5, O3 measured at nine air quality monitoring stations (AQMSs) were obtained from the Tabriz Department of Environment (TDoE) during 2006-2017 and analyzed. Spatial and temporal variations of pollutants using the Mann-Kendall's test and Moran’s I index were analyzed.

The results of this study showed that the annual trend of PM10, PM2.5 was decreasing but remained almost constant for O3 during the study period. During some of the studied days, PM10, PM2.5 levels were exceeded greater than the WHO AQG and National standard levels. Moreover, the highest monthly mean concentrations of PM10 in October (80.3 µg/m³), PM2.5 in January (42.9 µg/m³) and O3 in June (77.8 µg/m³) were observed. Comparison between the stations indicated that the Raste Kuche station was more polluted than other stations.

Effective control planning and implementation policies are essential to improve the air quality of the Tabriz environment. Hence, information provided in this research can be used as a key step for city managers, policymakers, and health officials to reduce the health impacts of air pollution.

The most important first step in promoting environmental performance is identifying and evaluating environmental behavior. In this regard the measuring tool is considered an environmental behavior questionnaire. Validity and reliability of the questionnaire before its application is essential. Thus this research was conducted with the aim of assessing the validity and reliability of questionnaires.

The environmental behavior questionnaire containing 36 questions was designed using the literature review and expert panel opinions. Then, the validity of the questionnaire was assessed by content validity index (CVI) and content validity ratio (CVR) and its reliability was evaluated using Cronbach's alpha coefficient by 14 experts and 40 target groups. Finally, data were analyzed by SPSS 20 software.

The results showed that the questionnaire with 36 items had CVI and CVR of 0.896 and 0.726, respectively, and 4 items should be excluded from the questionnaire due to non-compliance with content validity indices. The questionnaire exhibited high internal consistency and hence was acceptable owing to the Cronbach's alpha coefficient of 0.85.

The questionnaire was designed to evaluate environmental performance of citizens and can be cited in future studies.

Due to the spread of dusty air and the transfer of these particles to the cities of Khuzestan province, it is very important to study the status of these particles in terms of heavy metal pollution and their pollution status.

In this study, the concentrations of Cr, Cu, Zn, Pb, Ni, Mn, Mg and Fe in the air of 4 cities of Khuzestan province (Ahvaz, Dezful, Mahshahr and Abadan) in dusty and dust-free conditions over a period of 9 months (autumn, winter and spring) were measured in 2018-2019. Due to the spread of dusty air and the transfer of these particles to the cities of Khuzestan province, it is very important to study the status of these particles in terms of heavy metal pollution and their pollution status.

48 samples in contaminated conditions and 48 samples in non-contaminated conditions were collected at the specific points and exact times using a High Volume sampling pump with a flow rate of 110 L/min for 6 hours. Metal concentrations were measured using ICP. Except for Ni, Mn and Mg, the mean concentration of other studied metals were higher at dusty conditions as compared with their values in non-dusty conditions (p < 0.05). In dusty and non-dusty air conditions the order of heavy metals based on their concentrations were obtained as following: Zn> Mg> Mn> Ni> Cr> Pb> Fe> Cu and Mg> Mn> Ni> Pb> Fe> Cr, respectively. This result shows that the origin of zinc and copper metals and the increase in chromium concentration in polluted air are due to the entering of dust and pollution transfer from the outside area into cities. The cities of Ahvaz, Dezful, Mahshahr and Abadan were highly enriched in terms of heavy metals pollution either in dusty or non-dusty conditions.

The findings of this study showed that despite low concentration of heavy metals in airborne dust particles in clear and dusty air, high health risks of metals such as zinc in cities of Khuzestan province, especially Mahshahr are probable. Further investigation showed that particles are generally derived from intra-city or provincial activities, which call for more attention due to the drought conditions that attributes to more dust formation.

The purpose of this study was to use the HELP model to estimate the leachate generation rate and its pattern in a landfill located in the semi-arid region of Iran.

The input data for the model were collected through fieldwork. To evaluate the accuracy of outputs, the actual amount of leachate production has been measured on-site for 10 months. In addition, sensitivity analysis was conducted to find out the most important parameters in leachate generation in the landfill.

The results showed that the model was able to estimate the rate of leachate generation with an accuracy of 75.5% and the correlation between the model's estimated values and actual values was 60%. In addition. the sensitivity analysis showed that the most important factors affecting the leachate generation in the landfill were waste moisture content and rainfall, respectively.

The model showed satisfactory performance in the prediction of leachate generation in the arid area. The model showed that the moisture content of the waste significantly contributes to leachate generation in Karaj landfill and therefore, it is suggested to identify and implement procedures to reduce the moisture content of the waste at the source of generation.

Antibiotics are hardly decomposable and resistant contaminants in the environment that according to their anti-biological properties, it is necessary to eliminate or reduce the amount of them before entering the environment. Therefore, the main goal of this research is to investigate the Fenton and Fenton-like process efficiency for the treatment of wastewater containing Spiramycin antibiotic.

The effect of independent variables including pH, contact time, oxidant concentration (H2O2), and catalyst concentration (Fe2+ and Fe3+) on the COD removal efficiency were measured using COD meter. The ranges and number of experiments were assigned by RSM (Response surface method) using design expert software.

The optimum conditions of Fenton process with treatment efficiency of 63.31% were obtained at pH 4, hydrogen peroxide concentration of 50 mg/L, Fe2+ concentration of 75 mg/L and contact time of 5 min. The optimum conditions of Fenton-like process with treatment efficiency of 51.21% were obtained at pH 3, hydrogen peroxide concentration of 60 mg/L, Fe3+ concentration of 137.5 mg/L and contact time of 32.5 min. Based on the ANOVA analysis results, the f value in Fenton method indicates that the model is significant.

According to the results, Fenton oxidation process was selected as the optimum method to remove COD from synthetic wastewater containing Spiramycin antibiotic which may be applied as an efficient method for the treatment of wastewaters containing antibiotic.

Wastewater treatment and stabilization always imposes costs and consequently a lot of energy on wastewater treatment plants. To achieve the purification and stabilization of as much sludge as possible, breaking complex components into simpler components is considered a critical step. Therefore, this study aimed to evaluate the feasibility of treating the produced sludge in the municipal wastewater treatment plant using ozonation method.

In this study, sludge was obtained from the return line of activated sludge from the wastewater treatment plant in the south of Tehran. An ozonation generator with a discharge rate of 3 L/min and an ozone concentration of 40-35 mg/L was discharged to the reactor and the residual ozone concentration was measured by iodometric method. Finally, the total suspended solids and volatile, soluble chemical oxygen demand, total organic carbon, and biochemical oxygen demand during ozonation processes were measured using the Standard Method.

The results of this study showed that the amount of TSS and VSS in the activated return sludge decreased from 4060 to 2100 mg/L and from 3300 to 1850 mg/L during the ozonation process, respectively. However, SCOD, TOC, and SBOD had an upward trend of about 18, 11.7, and 14 times in the same reaction time, respectively.

According to the results of this study, it can be concluded that the ozonation system can be proposed as a suitable process for the decomposition of sludge produced in wastewater treatment plants and increasing the biodegradability of these sludges.

Understanding the factors contributing to the mortality of COVID-19 patients can provide comprehensive information for preventive decisions and public health, and will help in better management of the epidemic. In this regard, the present study was conducted with the aim of identifying and introducing risk factors affecting the mortality of COVID-19 patients by modifiable and non-modifiable factors.

In this review study, according to the objectives of the study, related papers on risk factors affecting the mortality of COVID-19 patients were searched and collected in the international databases of Web of Science, Scopus, Embase, PubMed, and Google scholar. Then the results were extracted and reported by modifiable and non-modifiable factors.

The results showed that almost all studies conducted in this field address non-modifiable risk factors such as age, sex, and underlying diseases including cardiovascular disease, diabetes, hypertension, respiratory diseases, cancer, self-diseases, autoimmune, and neurological diseases. Although few studies have been conducted on modifiable risk factors, lack of early admission or long waiting for hospital admission, occupancy of hospital beds and ICUs, as well as lack of equipment in hospitals were associated with increased mortality in these studies.

Regarding the situation of different countries in this epidemic, improving the control of the COVID-19 epidemic and reduce the mortality rate is possible by considering modifiable factors and taking appropriate measures. According to the results of studies, allocating sufficient financial, personnel and equipment resources can be effective in reducing COVID-19 mortality. However, controlling the COVID-19 epidemic to reduce morbidity and mortality as well as its economic and social consequences is possible by integrated management in the country. Also, using the experiences and guidance of the World Health Organization and successful countries, and stability in measures with a comprehensive approach should be considered.