فهرست مطالب mojtaba davoudi

Increased waste production during patient treatment emerges as a serious issue following infectious disease outbreaks. The current study aimed to investigate the effect of the COVID-19 outbreak on medical waste production in Mashhad, Iran.

In this study, 4 referral (R) and 2 non-referral (NR) hospitals were examined. The quantity and quality of waste produced before (2018-2019) and during COVID-19 (2019-2020) were extracted from hospital records and noted in standard medical waste management checklists. Also, the number of hospital visits due to COVID-19 was determined and entered into the study by referring to the Treatment Deputy of Mashhad University of Medical Sciences.

The results showed that the mean waste production was 449.50 ± 49.45 kg/day and 436.04 ± 107.55 kg/day in 2018-2019 (before COVID-19) and 2019-2020 (during the outbreak) in R1, respectively, 3000.26 ± 227.46 kg/day and 3279.72 ± 153.00 in R2, 544.53 ± 107.10 kg/day and 666.32 ± 156.68 in R3, and 476.72 ± 15.96 kg/day and 635.41 ± 54.88 kg/day in R4. Also, the mean waste production was 219.6 ± 36.90 and 199.06 ± 49.58 kg/day in NR1 and 112.1 ± 29.55 kg/day and 108.8±59.1 kg/day in NR2 before and during COVID-19, respectively. Field surveys showed that despite the increased amount of waste production, all waste management stages, such as collection, transfer, and disposal, are being implemented in accordance with the guidelines.

The results of this study showed that the medical waste production rate is related to the prevalence of diseases. Considering the importance of medical waste management, it requires careful and correct application of national and international guidelines.

Pistachio hull, a by-product of pistachio processing, is a source of environmental pollution and can cause the health problems. Therefore, it must be treated by proper, sanitary and economical manners. One of the basic parameters for compost valuation is determine the amount of heavy metals. The objective of the present study was to determiner the concentration of heavy metals (pb, Cd, cr, Zn, Ni, Cu ) in the compost produced from mixed pistachio hull and livestock and compare levels of heavy metals with the limits of international and internal standards. This study is a descriptive cross-sectional that in sampling was two-stage in September 2014 and October 2015. Among total from 2 composting pile, compound sampling based, 26 sample were selected. After digestion of the samples, the concentrations of metals (Pb ,Cd, Zn, Cr, Cu, Ni) by means of atomic absorption analysis and the concentration of a component in the sample based on mg/kg dw were reported. The results were analyzed by using Excel and SPSS software. The heavy metals examined in the composted pistachio hull mixed with livestock waste were as follows: pb as 67.09, Cr as 49.58 Cd as 2.84, Cu as 107.95, Zn as 188.24, Ni as 79.75 (mg/kg dw), respectively. Compare the average concentration of heavy metals in samples with Iran and EPA Astandrads showing concentrations of heavy metals in all samples (except metal cu) are less than the standard limit. Based on the results, compost produced from pistachio skin and livestock waste the of heavy metals hygienic standards adhered to and usability of its environmental objectives.

Fluoride concentration in drinking water within the optimal range reduces dental caries and prevents dental fluorosis. This study was conducted to determine the level of fluoride in drinking water resources in Torbat Heydariyeh City in 2016-17. This descriptive cross-sectional study was conducted on 22 wells used to supply drinking water of Torbat Heydariyeh City. A seasonal sample of one litre was withdrawn from each well and the fluoride concentration was measured using the SPADNS standard methodwith a DR 5000 spectrophotometer. Data were analyzed by SPSS version 11 software. The concentration of fluoride in the study area was measured in the range of 0 to 0.35 mg/L with an average of 0.23 mg/L. No significant seasonal changes were observed in the fluoride concentration. In addition, there was no significant relationship between fluoride concentration and well depth. Considering the fact that observed fluoride concentrations were below the standard level, it is recommended to take measures to prevent dental caries due to fluoride deficiency such as distribution of mouthwash containing fluoride in schools and fluorination of drinking water.

This study evaluated silica aerogel as an adsorbent for phenol removal from aqueous solutions. Silica aerogel was prepared through the sol-gel process and characterized by different analyses. Then, it was used for phenol removal under various conditions of operational parameters. Also, twelve isotherm parameters were employed to describe the behavior of phenol-silica aerogel adsorption system. The chemical structural analysis confirmed -OH functional groups in amorphous SiO2 and proved the adsorption of phenol onto the surface of silica aerogel. The findings of the adsorptive behavior of silica aerogel toward phenol showed increasing pH, up to 8.5, and contact time, and adsorbent dose increased the phenol removal. The removal efficiency reached over 90% when phenol concentration was below 50 mg L-1. The reaction kinetics followed the pseudo-first order model. The isotherm study showed that equilibrium adsorption data were well-described by Freundlich and Halsey equations, among two-parameter isotherms, and Hill, Sips, and Koble-Corrigan, among three-parameter isotherms. Jovanovic and BET were the worst isotherm models for prediction of experimental equilibrium data. The maximum adsorption capacity of 75.23 mg.g-1 was calculated in phenol-silica aerogel adsorption system. The study showed silica aerogel as an efficient adsorbent to remove phenol from phenol-containing solutions.

Industrial wastewater is one of the most important sources of hazardous pollutant emissions. Having high levels of various dyes, textile wastewater is considered as one of the major environmental pollutants. The aim of this study was to compare the efficiency of almond shell ash as a natural absorbent in comparison to commercial activated carbon in removing basic red 18 dye from aqueous solutions.
Considering the parameters affecting the adsorption process, the experiments were carried out to determine the optimal conditions of basic red 18 dye removal by means of the two adsorbents. At the end, three isotherms including Langmuir, Freundlich and Bet were used to evaluate the equilibrium conditions.
The highest removal efficiencies of commercial activated carbon and almond shell ash as adsorbents were obtained %98.46 and %92.5 in alkaline pH and at 25 and 45 ͦ C respectively. For commercial activated carbon the adsorption process followed the Freundlich isotherm, while for almond shell ash, the adsorption process followed the Langmuir isotherm.
The results showed that the higher efficiency of commercial activated carbon than almond shell ash in removal of basic red 18 dye. Nevertheless, almond shell ash as a food waste can be used as a low cost adsorbent to remove dyes from textile wastewaters.

Due to their special environments, rural areas are susceptible to rodent outbreaks. Extensive damage to agricultural produce, equipment and buildings on the one hand and outbreaks of zoonotic diseases on the other are among the health and economic impacts of a rodent outbreak. Failure in controlling such events may even result in social issues, such as, village abandonment and mass migration to suburban areas. One such rodent outbreak occurred in 2015 in a village of Torbat Heydariyeh County, Razavi Khorasan province. This report explains both the root causes of the event as well as the efforts which resulted in the control of the outbreak within a couple of weeks.

 Dyes and heavy metals are hazardous pollutants often found together in wastewaters of textile industries; these pollutants have a significant ecological impact on the ecosystem and can modify the physical and chemical properties of water affecting the aquatic flora and fauna.  This fundamental-applied study was done on lab scale. Effects of various factors including dye initial concentration(5-50 mg/L), Cu initial concentration(1-10 mg/L), pH(2-10), adsorbent dose(1-8 g/L), and contact time(5-90 min) in the sorption dye and Cu were determined by using sawdust Melia Azedarach tree. The study was designed to experiments the response surface methodology. The most performance in dye and Cu removal were gained 98.03%, and 99.90% respectively. Increasing adsorbent dose showed the most positive effect, whereas initial dye concentration can cause performance falling on dye removal. Also, increasing pH showed the most positive effect, whereas initial dye concentration can cause performance falling on Cu removal. In this study, the data analysis of isotherm studies is more compatible with Langmuir model. An R2 value in Langmuir isotherm was determined 0.994 for dye and 0.9712 for Cu.  Furthermore, the kinetic results showed the best fit with pseudo-second-order model. Show the R2 value determined same and equal amounts of 9998/0 for dye and Cu. Sawdust as an effective method used in dye and heavy metal removal in aqueous solution.

School is a place for nurturing the children talents and plays a substantial role in constructing healthy people. This study conducted to compare the environmental health and safety status of governmental and non-governmental primary schools in Kashmar in 2015-2016.
This is a descriptive/cross-sectional study conducted on 31 governmental and 14 non-governmental primary schools in Kashmar city in 2015-2016. To collect data, the designed checklist approved by ministry of health was filled through interview, observation and inspection. Data were analyzed by SPSS 22 and Excel 2007 software using Fisher's exact test and Chi-squared test.
Based on the obtained results, regarding the building status, safety status, buffet status and environmental health indices, 86.51%, 83.87%, 49.7% and 95.16% of governmental schools and 77.67%, 83.68%, 78.58% and 88.57% of non-governmental schools were in suitable situation, respectively. Governmental schools were significantly better than non-governmental schools as a matter of school area and proper school plan (p˂0.05). On the other hand, non-governmental schools were significantly better in terms of buffet health than governmental schools (p˂0.05).
In conclusion, the results show that privatization do not necessarily improve environmental health indices in primary schools. To have a healthy and safe school, proper management, increase in allocated budget for schools and strict monitoring by health centers are required.

Backgrounds & Elimination of phenolic compounds which is considered as resistant pollutants to biological degradation has a great importance. This study aims to investigate the electrochemical oxidation process efficiency in removal of phenol compounds using a continuous and divided rector.
The catalytic anodes of Ti/SnO2-Sb and cathodes of iron were employed in a reactor divided into anolyte and catholyte chambers by a cellulosic separator. The influence of initial phenol concentration (14.12‒40.88 mg L‒1), retention time (32.23‒82.77 min), and current intensity (0.18‒0.42 A) on TPh removal efficiency, TPh residual concentration, and energy consumption was investigated using response surface methodology.
The results showed that TPh removal efficiency strongly depends on retention time, followed by current intensity and initial phenol concentration. The importance order of factors affecting on TPh residual concentration were distinguished as initial TPh concentration > retention time > current intensity. The energy consumption in terms of kWh m‒3 is mostly affected by retention time and then current intensity, and irrespective of initial phenol concentration. Under the optimal conditions, removal efficiency of 93.21%, residual concentration of 1 mg L‒1, and energy consumption of 34.40 kWh m‒3 is achieved.
Based on the obtained results, the electro-oxidation is a very efficient process for diminution of wastewater phenolic content, and is able to set the allowable limits to discharge to the environment.

Corrosion is one of the most complicated and costly problems related to the drinking water supply that can influence the health of consumers, the general acceptance of a water resource, and the costs of water supply. Scaling also causes problems such as clogging and head loss in drinking water networks. The aim of this study was to determine the chemical quality and stability indicators (scaling and corrosion potential) of rural drinking water supplies of Taybad city in 2015-2016.
In this descriptive/cross-sectional study, 96 water samples (from 8 wells) were gathered within 12 months and analyzed for physicochemical parameters. Then scaling and corrosion potential of water supplies was determined based on Langelier saturation Index (LSI), Ryznar Stability Index (RSI), Aggressive Index (AI), and Puckorius Scaling Index (PSI).
The results showed that the quality of some wells was below the acceptable limits in terms of TDS and hardness. However, other parameters such as fluoride, nitrite, and nitrate, were in standard range. In addition, the sampling stations were 50% corrosive and 50% scaling based on LSI, 50% corrosive and 50% neutral based on RSI, 25% scaling 75% neutral based on AI, and 37.5% corrosive, 25% scaling, and 37.5% neutral based on PSI.
According to the findings, water in the study region is not in neutral state; thus, stabilizing the water before entering the distribution network is recommended as an important measure to control scaling and corrosion phenomenon.

Mosques are among public places and like other places meeting hygiene standards is necessary. In case of not paying enough attention to this issue, mosques can be a center from which pathogens spread and endanger the health of the population. The aim of this study was to investigate the environmental health status of mosques in Tabas in 2015.
This is a cross/sectional/descriptive study conducted on 39 mosques in Tabas city in 1394 through census sampling method. To collect data, the designed checklist approved by ministry of health was filled through interview, observation and inspection. Data were analyzed using SPSS 22 and Excel 2007 software.
Despite the regular inspections of health inspectors, the environmental health status of mosques is not suitable, so that only 11.5% of personal health, 49.9% of instruments and tools. On the other hand, 77.25% of building health and 100% of other indices such as prohibition of smoking were in suitable range. Moreover, the overall mean of desirability for all indices in Tabas mosques was determined as 55.93%.
Based on the obtained results, health issues in the mosques in Tabas are in moderate condition. Regarding the importance of cleanness of mosques in Islam region, adopting essential measures such as education and more precise monitoring are expected to promote the instruments and tools health and servant's personal health.

Dyes are one of the most important pollutants in textile wastewater that are toxic, carcinogenic, teratogenic and non-biodegradable. Entering of dyes into water resources reducing the penetration of sunlight and eutrophication is occurred. Melia azedarach core and fruit is one of the inexpensive natural absorbent that has an important place in the treatment of textile wastewater.
In this study solid structure of absorbent was analyzed using Fourier transform infrared spectroscopy and Scanning electron microscope, also effect of various parameters such as initial dye concentrations (10-100 mg/l), adsorbent dosage (0.1-1.1 g/l), contact time (0-60 min) and solution pH (4-10) on the removal of dye were investigated and at the end, kinetics and adsorption isotherm were also noted by the adsorbent. The remaining of dye was analyzed by UV/VIS spectrophotometer at a wavelength of 665 nm.
Maximum removal of color, which is 85%, was in color concentration 32.5 mg/l , adsorbent dose 0.85 g/l, detention time 45 min and pH=8.5.initial concentration had the greatest impact on color removal (P=0.0001). The results showed data were explained acceptably by pseudo second-order model (R2=0.95_0.99) and Langmuir isotherm model (R2 = 0.98).
Core and Melia azedarach fruit has the ability to remove methylene blue. The optimum pH to remove the color by absorbing was in alkaline range and most textile wastewater has an alkaline pH therefore, it is an appropriate and cost-effective adsorbent to take away color from the wastewater of textile industry.

Abstract corrosion and scaling are of the most important characteristics of drinking water, affecting public health and water industry economy. The aim of the present study was to evaluate the corrosion and scaling potential of potable water supplied by Saqqez Rural Water and Wastewater Company. this was a descriptive study conducted on 142 samples taken from different parts of the distribution network during 2011-2012. All samples were analyzed for required physical and chemical parameters. The obtained results were compared with water quality standards and then, corrosion and scaling indices including Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Larson Ratio (LR), and Saturation Level (SL) were calculated. all parameters were below the allowable limits determined by national and international qualitative drinking water standards. Biennial average of 0.73, 6.51, 0.74, and 1.96 were calculated for LSI, RSI, LR, and SL, respectively. Accordingly, potable water of the surveyed region was evaluated to be scaling based on LSI and SL, stable based on RSI, and corrosive based on LR. Finally, frequency distribution of indices during the surveyed period was reported. potable water of the region was in an acceptable level in terms of corrosion and scaling potential. However, considering significant differences between values of indices in a year to another year, annual survey of corrosion and scaling potential of regional potable water is strongly recommended.

 Antibacterial effects of hydrogen peroxide and silver composition on selected pathogenic enterobacteriaceae was investigated in this study. 

 The efficacy of 30 ppb silver in 0.3% hydrogen peroxide solution for inactivation of selected Enterobacteriaceae, including Escherichia coli, Proteus mirabilis, and Klebsiella pneumoniae was assessed for 72 hours in a designated nutrient broth medium and steel surface. The bactericidal growth ability was determined for each bacterium genus by the conventional colony count method and turbidimetry via an optical density (OD) assay at 450 nm in a time interval of 24 hours. 

 Suspensions of K.pneumoniae, and P.mirabilis showed a significant OD reduction at three 24-hour intervals (CI = 0.95; P < 0.05, for both), along with blocked growth in a designated broth medium during 24 to 48 hours of exposure. The disinfectant was also significantly efficient for inactivating of the mentioned bacteria on steel surfaces after a 15-minute time exposure (CI = 0.95; P < 0.05). For E.coli, the OD decreased slightly during the initial exposure time, but increased after 24 hours. Viable E.coli cells were proved by colonies grown on the plate. A qualitative surface decontamination test showed that three pathogenic bacteria were inactivated significantly after disinfectant exposure (CI = 0.95, P < 0.05). 

 In conclusion, a combination of hydrogen peroxide and silver ions was proposed as a strong disinfecting agent both in suspensions and on the surfaces against these three important human pathogens.

Groundwater is the most important source of water supply in industries and agricultures; therefore the need to protect this valuable resource against pollution is felt more than ever. In this study, the possible impact of Yazd municipal solid waste landfill was investigated on the chemical quality of the area’s groundwater. Groundwater samples were collected from three wells around the landfill, one located at the upstream and two located at the downstream. The following parameters were measured: pH, electrical conductivity (EC), chloride (Cl-), nitrate (NO3-), total hardness, alkalinity and heavy metals including lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn). The data statistical analysis was performed by SPSS t-test and Microsoft Excel was used to draw the curves. The groundwater’s pH in downstream was significantly lower than the pH in upstream (P = 0.038). also the values of EC, Cl-, NO3-, total hardness and alkalinity were significantly higher in downstream (P < 0.05). However no increase was observed in heavy metal obtained from downstream groundwater of the landfill. The study findings indicated that the chemical quality of groundwater improves by increasing the distance from the landfill. Therefore it is better to avoid utilizing the groundwater closed to the landfill. However, the best practice is insulating the landfill’s floor to control the movement of the current contaminations into the groundwater.