نشریه مهندسی بهداشت محیط
سال نهم شماره 1 (پیاپی 34، پاییز 1400)

Nowadays, the increase in population growth rate and followed by anthropogenic activities such as urbanization, industrialization, mining and agriculture practices continuously increase the amount of heavy metals in the environment especially groundwater resources. Therefore, qualitative assessment of groundwater resources is of great importance for maintaining public health and for this reason, this study was conducted to qualitative assessment of groundwater resources of Asadabad Plain using WQI, Cd, HPI, HEI, PoS and MI indices in 2018.

In this descriptive cross-sectional study, 120 groundwater samples were collected from 20 stations in the spring and the summer seasons and their temperature, pH and EC values were measured on-site. In the laboratory, the values of physicochemical parameters were determined according to the standard methods. Also, the content of heavy metals was determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). All statistical analyses were performed using SPSS software.

The results showed that the average concentrations of Na, PO4-, Cl-, Ca, Mg and NO3- (mg/L) in samples of the spring season were 21.8, 0.230, 0.170, 69.0, 21.1 and 19.3, respectively; and in the summer season were 8.14, 0.190, 0.160, 75.3, 15.6 and 19.8, respectively. Also, the average concentrations of As, Fe, Zn, Pb, Cd, Cr, Cu, Mn and Ni (μg/L) in samples of the spring season were 5.10, 1.61, 0.970, 7.82, 0.230, 1.25, 3.58, 0.360, and 1.30; and in the summer season were 21.4, 1.62, 1.24, 7.63, 0.200, 1.00, 6.73, 0.430, and 1.01, respectively, and except for As in samples of the summer season, the average concentrations of all elements in groundwater samples of both seasons were lower than the maximum permissible concentration (MPC) established by WHO for drinking water. In addition, water quality index (WQI), pollution index (Cd), heavy metal pollution index (HPI), heavy metal evaluation index (HEI), quality index (PoS) and heavy metal index (MI) of samples of the spring season with values of 18.2, -7.53, 9.86, 1.64, 298 and 1.64, respectively, indicate the quality of groundwater were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "low pollution" and " slightly affected" classes and in the summer season with values ​​of 17.9, -5.94, 9.86, 3.05, 602, 3.05, respectively, were categorized in "excellent and very good", "low pollution", "low pollution", "low pollution", "high pollution" and "moderately affected" classes.

Although only the average values of As in groundwater samples of the summer season were higher than the MPC, management of the use of agricultural inputs such as pesticides, chemical and organic fertilizers and municipal wastewater for irrigation to maintain the quality of groundwater resources of the study area is recommended.

Metronidazole antibiotic is belong to the nitroimidazole family. Non degradability, high solubility in water, toxicity, carcinogenicity and mutagenicity are important concerns related to antibiotics. Therefore, the aim of this study is to apply the new advanced oxidation process of UV/zinc oxide/sulfite (UZS) to degrade metronidazole from aqueous solutions.

In this study, the effect of pH, sulfite to zinc oxide ratio, initial metronidazole concentration and contact time on the performance of the UV/sulfite/zinc oxide process in the degradation of metronidazole was studied. The residual concentration of metronidazole was measured by HPLC (Cecil model 4900 CE).

The results showed more than 90 % antibiotic is degraded at pH = 12 and the molar ratio of sulfite to zinc oxide 1 to 3 after 5 min of the reaction. Although the antibiotic degradation rate in the UZS process was very high, based on the GC-MASS analysis, the mineralization rate was not sufficient. The several metabolites were detected in the UZS process effluent and the degradation pathway was proposed based on the identified metabolites. It was observed the kinetic coefficient of robs (mg/L. min) to degrade the metronidazole by UZS was 6.92 time and 15 time of UV/zinc oxide and UV alone processes, respectively.

According to the results, the UV/zinc oxide/sulfite process, due to the higher robs value as well as the higher efficiency value ​​than those of the UV/zinc oxide and UV alone processes, can be considered as a suitable and economical option in the degradation of metronidazole antibiotic and the similar compounds.

The selection of municipal solid waste landfills is significant because it controls environmental pollution and its problems. Since site selection is a time-consuming and multifaceted process involving various socio-economic and environmental parameters, it requires expert opinion, extensive information resources, and multi-criteria methods. Therefore, this study was carried out for landfill site selection of municipal solid waste of city of Kermanshah combining SWARA technique and Copras method using GIS in 2019.

In this descriptive study, the Copras method and SWARA technique were selected as multi-criterion decision-making methods (MCDM) were used. Also, the environmental and socio-economic criteria including height above sea level, geographical direction, slope, distance from the protected areas, distance from the agricultural areas, land use, distance from the road, distance from the airport, distance from railway lines, distance from transmission lines, surface and groundwater resources, distance from residential areas, distance from faults, type of vegetation and soil type were evaluated by seven environmental specialists.

 The results of the SWARA method showed that the water resources criterion with a final weight of 0.300 is the most important criterion. Also, the type of soil and the distance from agricultural lands with a final weight of 0.202 and 0.119, respectively are the others. While, slope, distance from transmission lines and distance from fault with final weights of 0.020, 0.015 and 0.015 were the least important criteria for site selection. Besides, the results of the Copras method showed that the southwestern areas of the city of Kermanshah had better conditions for disposal of municipal solid waste due to their characteristics such as distance from residential areas and agricultural lands, suitable slope, and proper road access. Thus, the "Shah Vali" site with an approximate area of 90 ha was suggested as a landfill for municipal solid waste in city of Kermanshah for the next 20 years.

 In general, based on the results obtained, SWARA and Copras methods, due to their novelty, high flexibility, and accuracy in presenting the results, could be an excellent alternative to the other conventional weighting methods. Consequently, we can confident to their final proposed options, which have suitable characteristics of the landfill. Finally, given that landfill site selection is one of the most critical environmental issues in metropolitan areas, consider other criteria such as demographic parameters and the application of newer multi-criteria decision-making methods such as ARAS and MULTIMOORA in site selection studies are recommended.

Long-term used of sewage sludge and fertilizer causes accumulation of heavy metals in the soil, which may lead to excessive absorption of these elements by plants and consequently entering these toxic metals into the human and animal food chain. Therefore, this study was conducted to investigate the effects of bio-organic and chemical fertilizers application on the absorption of macronutrients and heavy metals in Lepidium sativum.

In this descriptive study, the experiment was carried out in a completely randomized design with three replications in the environment and greenhouse conditions. Fertilizer treatments included chemical fertilizer treatment (diammonium phosphate), anaerobically digested sludge compost, sludge compost without digestion and raw sludge at the weight of 28, 57 and 115 g and control treatment. Finally, the concentrations of heavy metals Pb, Cd, Hg and As and macronutrients including phosphorus, nitrogen and carbon in the leaf of L. sativum were measured using ICP-OES. All statistical analysis was performed using SPSS version 21.

The results showed that the maximum mean concentrations of As and nitrogen in L. sativum vegetables were 0.592 and 10.2 mg/kg in 115 g raw sludge treatment, the maximum mean concentration of Cd, Hg, Pb, carbon and phosphorus elements in L. sativum were 0.956, 0.701, 1.25, 98.5 and 10.3 mg/kg, respectively in 115 g treatment raw diammonium phosphate fertilizer. The results of variance analysis showed that there was a significant difference between fertilizer, sludge and control treatment and there was a significant difference between amounts 28, 57 and 115 g from fertilizer treatment in L. sativum in terms of concentration of heavy metals and macronutrients (p < 0.050).

In conclusion, it was concluded that increasing the amount of fertilizer and sludge in the soil leads to an increase in the concentration of heavy metals and macro nutrients in L. sativum. Therefore, in the use of fertilizers and sludge for agricultural lands, it is necessary to pay attention to this issue. It was also found that the highest uptake of heavy metals and macronutrients in L. sativum was related to raw sludge treatment and diammonium phosphate fertilizer, which is indicating better quality of compost with respect to chemical fertilizer and raw sludge.

Monitoring and supervising public water systems correctly by health workers in rural areas can reduce the prevalence of waterborne diseases. Through educational interventions in Shahreza city, we are aiming to improve health workers' knowledge and increase their ability to apply what they have learned about monitoring and supervising rural water supply systems.

As a training course and as an intervention, Shahreza's health workers took part in this study. We used a checklist of water supply systems completed by health workers to collect information about their level of knowledge, their pre-test results, and other relevant information about the current situation. After identifying the lack of knowledge of health workers, the topics the training course should cover were compiled. Following the training course, a post-test was administered to health workers, and checklists completed by the workers before and after the intervention were compared. Using SPSS22 software and paired t-tests and Wilcoxon tests, the data were analyzed, and the effects of the educational intervention measured.

Before and after the educational intervention, the mean scores were 46.2±8.6 and 88.4±8.2, respectively, which indicated a significant difference (P value<0.001). The average risk percentage of all water supply systems decreased from 35.4±5.2 to 19.27±7.6% after the educational intervention, which indicates that the average risk percentage was significantly lower after the intervention than before the intervention (P value<0.001).

This study found that the educational interventions improved both the performance and knowledge of health workers, as well as reducing the risk associated with water supply systems in the rural area.

In case of ignition and explosion of oil depot, it will cause a lot of human and financial losses because there is a large population around it. . Therefore, understanding how fire spread and fire modeling by using CFD software to predict the outcome of accidents and their potential effects are very helpful .This research examines for the first time dangerous and unexpected scenarios of explosion and ignition in oil sites using advanced Fluent and monitoring software in the country and seeks to preserve the life and financial assets of the areas around the oil depot.

This study is a descriptive-analytical research that was conducted in 1399 in one of the country's oil depots. Hurly formula and Ansys Fluent 15 software were used to estimate the energy rate from burning tanks, flame height and burning time of oil tanks. In this method, effective factors by dividing the case area into smaller elements and applying boundary conditions for boundary nodes were determined

Energy and temperature due to burning materials in all tanks is about 139072.7 kW and 4000 degrees Kelvin. In case of ignition and explosion of oil, ambient temperature will be added about 70 degrees Celsius. Residential areas closer to the oil depot, including the grain depot, barracks and prison, Razkan Noo residential areas, parts of Banafsheh residential town and the railway area along this route will be more affected by this increase in temperature. The maximum burning time of the tank is six and a half hours and the minimum time was estimated at about 5 hours. The highest flame was calculated to be 70.60 meters.

The results of this study showed that if a fire occurs in the tanks. Different areas, including residential and industrial, are in the path of spreading pollution caused by fire. Due to the distance and severity of pollution produced, it can cause many financial and human losses. The results of this study showed that if a fire occurs in the tanks. Various areas are in the path of spreading pollution caused by fire, including residential and industrial, Due to the severity of pollution produced and the extent of areas involved it is predictable human and financial losses.

Refineries produce about four percent of the global carbon dioxide emissions, close to one billion tons per year. Globally, the refining sector is the third largest producer of carbon dioxide after the electricity generation and cement industry.This greenhouse gases is a major cause of global warming and climate change and is a serious threat to human health and the environment. One way to reduce this greenhouse gas into the atmosphere is to reduce carbon dioxide by reversing this gas in the fuel cycle.The Fluid Catalytic Cracking unit (FCCU) is one of the emissions sources of this greenhouse gas in Abadan Refinery,which produces 230 tons per hour of combustion gases,it has 12.7% mole of carbon dioxide. Identifying the sources of carbon dioxide emissions in Abadan Refinery and simulating the chemical absorption of this greenhouse gas and converting it into methanol fuel is one of the objectives of this study.

In this research, the concentration of carbon dioxide emitted from the emission sources of Abadan Refinery has been measured by Testo 350-XL and GC. Due to the fact that the concentration of carbon dioxide in the combustion gases of the FCC unit was the highest amount, so the chemical absorption of carbon dioxide from the combustion gases of this unit by 30 wt% diethanolamine solvent and converted into methanol during a hydrogenation reaction has been simulated with Aspen Hysys software. Finally, the economic calculations of the project were performed.

The overall efficiency of chemical absorption of CO2 in the simulation with software is 92% and the purity of captured CO2 is 94.6%. With this method, 1003 ton per day of carbon dioxide in FCC unit can be absorbed and recovered and also converted into methanol product. In the simulation of the conversion of recovered carbon dioxide into methanol, the amount of 686 ton per day of methanol with a purity of 99.8% was obtained. The economic calculations of the project show that the cost of reducing emissions per ton of carbon dioxide is $ 19. The internal rate of return on the project is 22% and the net present value of the project is $ 92 million. The return time on investment of this project is 3 years.

Diethanolamine has a high efficiency in absorbing carbon dioxide from combustion gases.By chemical absorption method with this amine, carbon dioxide pollutant can be recovered from combustion gases that produced in refineries and used as an inexpensive feed to produce methanol fuel.This method, in addition to creating added value, prevented the emission of this greenhouse gas into the environment.

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants that due to their characteristics including bioaccumulation potential and persistence in the environment; can pose adverse effects on human and environmental health. Therefore, this study was performed to analysis, source identification and health risk assessment of PCBs in surface soil samples collected from some land types of northern, eastern and western parts of city of Tehran in 2019.

In this descriptive cross-sectional study, a total of 45 surface soil samples were collected from 15 sampling sites including business districts, residential areas, cultural and educational areas, public green space and roadside. After extraction of analytes, the gas chromatography/mass spectrometry (GC–MS) method was used to determination of PCBs in the soil specimens. All statistical analyses were performed using the SPSS software.

Based on the results obtained, 13 congeners of PCBs were detected in the analyzed soil samples. Also, the minimum, maximum and mean concentrations of ∑13PCBs (µg/kg) were 0.031, 23.1 and 6.77, respectively. Moreover, the results of principal component analysis (PCA) and significant distribution of low molecular weight homologues of PCBs in the analyzed soil samples indicated that the presence of PCB compounds in the soil samples would be connected with combustion processes in the soil. Besides, since among the detected PCBs, the TEF values only established for PCB189, therefore, exposure to contaminated soil with this congener could be lead to a "very low level of carcinogenic risk".

Given that PCBs have adverse effects on the environment and human health, detection, content determination, source identification and periodic monitoring of these compounds in different mediums especially water and soil for human and environmental health maintenance are recommended