فصلنامه پژوهش در بهداشت محیط
سال هفتم شماره 3 (پاییز 1400)

Air pollution is one of the most important environmental problems in the last century that threatens human health and particulate matter is one of the deadliest types of air pollution.This study was done to choose the best interpolation algorithm in the spatial distribution of PM2.5 suspended particles in Mashhad in 1395by different spatial models.

PM2.5 particulate concentrations was collected from 21 active air quality measuring stations in different parts of Mashhad and IDW, Ordinary Kriging (OK) and Universal Kriging (UK) interpolation models were evaluated to spatially investigate the air pollution situation in Mashhad. The root mean square error (RMSE) was used to compare the models and select the best model, and the Standardized RMSE was used to choose the most optimal conditions for running the OK and UK models.

The results showed that the highest seasonal average of PM2.5 pollutants in 1395 was related to autumn (40.84 µg/m3) and the lowest was related to spring (27.78 µg/m3). Also, the east to north area of Mashhad is in a more unfavorable situation in pollution concentration than the western areas of the city. Comparison of models using RMSE index also showed that OK model due to having the lowest amount of RMSE for seasonal average and annual concentration of suspended particles PM2.5 has a lower error in the predicted values than the measurement, so it has better conditions for intermediation.

This research eventually led to the production of maps of PM2.5 Pollutants situation in the whole city of Mashhad, which is very useful in order to identify high-risk areas in the city and use useful measures to reduce air pollution in those areas.

Heavy metals contamination of soils is one of the main environmental problems. Heavy metals are considered as one most dangerous groups of pollutants because of their toxicity and stability. The biological and ecological importance of heavy metals is due to their characteristics of polluting, their toxicity, persistence and bioaccumulation. The aim of this study was to investigate the spatial distribution of heavy metals in region Dehnow Shandiz (North West of mashhad).

In the present study, 20 soil samples (10-30 cm depth) collected and total concentration of As, Cd, Co, Cr and Ni were measured using Atomic absorption spectrophotometer device. Also, some other soil properties including PH, Organic carbon, CEC and soil texture proportions were measured.

The results showed that the average concentrations of As, Cd, Co, Cr and Ni in the study area were 10.87, 0.26, 14.8, 56.6 and 68.2 mg/kg respectively. Also the results of statistical analysis showed that the standard deviations of As, Cd, Co, Cr and Ni in the study area were 1.97, 0.16, 1.32, 19.47 and 17.39 respectively.

The results indicate that the average concentration of Ni in the soil of study area were higher than the standard of the Environmental Protection Organization of Iran and As, Cd, Co and Cr were lower than the standard. The presence of serpentinite soils has increased the concentration of nickel in the region.

The impact of various types of waste produced in the system, transportation and treatment of waste, and diversity of pollutants due to waste collection are some standard problems that communities, including Iran, are straggling with. The city of Tehran, as the capital of Iran, produces more than 7,000 tons of waste per day, and if this volume of waste is not properly managed, it will release excessive emissions into the environment.

In this research, a superstructure model for solid waste management was presented, with an approach to achieve the maximum avoided emissions. Optimization was done by normalizing the output of the emissions and then categorizing and sorting the data.

We examined 31250 different scenarios and based on the obtained results, the best scenario in terms of emission optimization was scenario 21303. Based on this scenario, organic materials, paper, and wood undergo anaerobic digestion while plastics, glass, and metals enter a recycling system. In this case, the amount of emissions avoided is equal to -837027 kg of carbon dioxide equivalent per day.

Anaerobic digestion of organic materials, paper, and wood and recycling of plastics, glass, and iron can be selected as a sustainable model for the current waste management system in Tehran. In this case, the amount of emission avoided will be very high and it can be considered the best environmentally friendly option.Keywords: Superstructure, Optimization, Waste Management, Emissions, Tehran

Due to the adverse effects of sewage sludge and environmental problems of organic waste, today, composting is proposed as a new method for the reuse of sludge to safely dispose of sludge and organic waste. The purpose of this study was to review the co-composting of wastewater treatment plant sludge and various organic wastes, as a strategy to reduce environmental and agricultural pollution.

In the present study, articles from Scopus, Springer, Web of Science, and PubMed databases in English, and google scholar in Persian, were searched and parameters such as pH, carbon to nitrogen ratio, moisture content, and process time were studied. The keywords included "co-compost", "wastewater treatment sludge", "organic wastes", "environmental pollution", "agricultural", and "agriculture".

From 2011 to 2020, 14 articles were found with the mentioned keywords. However, 24 items that did not have the keywords “wastewater treatment sludge”, as well as five books and six items related to wastewater, were excluded from the study. To improve the composting process, we can increase the quality of the product by reducing the size of the raw material and using bulking materials to reduce the processing time, as well as measuring and controlling the pH, carbon to nitrogen ratio, and daily moisture content.

In most previous studies, bulking agents and particle size reduction were used to increase compost aeration and reduce the processing time. The most important parameter influencing the co-composting process was the adjustment of pH and temperature. The composting process, with reducing environmental adverse effects of the sludge produced by the treatment plant and organic waste, as an environmentally friendly process, increases the health and well-being of the community.

Helicobacter pylori is the most common gastrointestinal pathogen infecting more than half of the world's population. Helicobacter pylori is a bacterium that causes gastrointestinal ulcers (chronic gastritis), stomach cancer, lymphoma, and adenocarcinoma. This study aimed to apply the Polymerase Chain Reaction (PCR) for investigating Helicobacter pylori in the tap water of selected hospitals in Tehran in 2020.

In this study, 22 tap water samples and six well water samples were randomly gathered from the selected hospitals in different areas of Tehran from September 5 to November 20, 2020. The samples were collected in sterile bottles according to the procedure detailed in national standard methods. In this study, Helicobacter pylori was evaluated using Polymerase Chain Reaction (PCR) and surface culture. Data analysis was done by SPSS18 software.  

This study showed Helicobacter pylori in two samples (10.3%) by PCR. The mean values of Helicobacter pylori in tap water and well water samples were 0.18 ± 0.85 and 0.67±1.63, respectively. The mean values of heterotrophic plate count in tap water and well water samples were 0.00 ±0.00 and 7.83±2.10, respectively. The mean values of coliforms, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, and Streptococcus faecalis in tap water were 0.00 ±0.00.

Helicobacter pylori has high persistence in the aquatic environment due to resistance in harsh environments and its absence will be an indicator of proper environmental health. So, according to our results, infection control and preventive strategies to reduce the risk of exposure to Helicobacter pylori for safe water supply are purposed to public health authorities. The evaluation of the biological quality of water (heterotrophic bacteria, coliforms, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, and Streptococcus faecalis), physicochemical quality of water, and Helicobacter pylori in water is among the strengths and innovations of this research.

Waste disposal and accumulation in the environment is well known as an environmental and human health problem that, in addition to environmental aesthetic issues, is a threat to the mental, physical, and emotional health of citizens. Despite the positive effects of the COVID-19 outbreak on the environment, it has also had negative effects on the environment. This study aimed to pathologically analyze the environmental behavior of citizens in District 3 of Ardabil with emphasis on littering during the COVID-19 pandemic and taking into account four criteria (lack of facilities, dirty environment, anonymity, and habit of littering). 

This research is applied in terms of purpose and descriptive-analytical in terms of method. Excel and SPSS software (to estimate the average answers to the questionnaire) were used to analyze the data. To measure the environmental behaviors of the citizens of the studied areas, the relevant indicators were used with the entropy weighting method and the target areas were classified using decision-making techniques. Finally, the Copeland integration technique was used to achieve the final prioritization.

Based on the findings of various decision-making techniques, the Molayosef and Molabashi neighborhoods were in the most unfavorable situation with the lowest score and ranked first in terms of waste distribution, and the Rezvan neighborhood was in the last rank with the highest score and had the best status.

Since many citizens consider the lacked or poor waste disposal services as one of the important reasons for littering behavior, therefore, providing health-care and education infrastructure in the city is very important to encourage community members toward responsible environmental behaviors.

Hospital waste is the second most hazardous waste after radioactive waste. Although this waste threatens the health of citizens and the environment, disagreements between responsible organizations have made the management of hospital waste a serious problem. Inefficient management of this waste and the increase of its volume due to the spread of the coronavirus disease have increased the need to study this issue. So, this issue in the country requires accurate scientific, practical, and technical frameworks calculated according to the waste management law and relevant executive regulations. Therefore, in this study, to improve the inter-organizational problems of waste management, the conflicts and contradictions between the stakeholders of this issue were studied and structured.

In this paper, participants were first identified using the journey-making method. Then, by drawing a power-interest diagram, the role of each participant was determined, and the main actors were identified. Next, the problem of hospital waste management actors was structured by the drama theory. 

The results showed that according to the priorities and decision options of the five main actors at the negotiating table, there are many problems of non-cooperation and conflict between them. The most conflict is formed between waste organizations and hospitals and the most important type of problem between organizations is the problem of rejecting each other's options.

Conflicts caused by rejection dilemmas can be considered the best type of conflict that can be improved by compromise and cooperation of organizations with each other. In this situation, these conflicts can be turned into cooperation by negotiating, flexibility, compromise, and of course, innovation in offering newer options.

This study was conducted to evaluate the knowledge, practice, and attitude of food health and safety in foodservice centers in Kermanshah province during the outbreak of COVID-19.

This research is a cross-sectional study. A questionnaire was used to collect data. To determine the reliability, the questionnaire was completed twice in one week. The questionnaire was organized into four sections including demographic information, knowledge section, attitude section, and performance section. In the first part, demographic information included gender, age, level of education, income, health, and satisfaction. In the second part, 7 two-option questions on knowledge were used. In the third part, 12 questions were used with a 5-point Likert scale, and in the performance part, 10 questions were considered with a 5-point Likert scale.

Observing the principles of health and food safety can minimize the possibility of contamination of food with any pathogen, especially the new coronavirus. In this regard, the mean score of the respondents' attitudes (67.51 ± 3.5) was estimated. This mean was estimated to be equal in the health sector (51.48 ± 3.7) and the safety sector (58.19± 6.7). Therefore, the safety sector score was higher than the health sector score. The mean performance score of the respondents (72.45± 4.1) was estimated. This mean was estimated to be equal in the health sector (49.31 ± 2.1) and the safety sector (65.2± 7.7). Therefore, the safety sector score was higher than the health sector score. The mean score of respondents' knowledge (54.6± 71.8) was estimated. This mean was estimated to be equal in the health sector (49.31± 2.1) and the safety sector (35.11± 5.7). Therefore, the score of the health sector was higher than the safety sector score.

The results of this study showed that the knowledge, practice, and attitude of food health and safety in foodservice centers in Kermanshah province at the time of the outbreak of COVID-19 were relatively weak. Most of the respondents were not sufficiently aware of the microorganisms in the hands and nose, the importance of hand hygiene before and during food preparation and serving, the temperature of hot food storage, and the status of microorganisms in the refrigerator. This lack of awareness can create the condition for cross-contamination and increased growth of food-borne microorganisms during the outbreak of COVID-19.