فهرست مطالب saeed parastar

Yarrow is a member of the Asteraceae family, utilized extensively in the field of medical sciences. Among the medicinal plants, one may encounter few specimens like the aforementioned plant, which enjoys widespread distribution across various regions of the globe and boasts a diverse array of uses that contribute to its renown. The aim of the present study was the synthesis of Yarrow extract evaluation of its antibacterial effects on a group of intestinal bacteria and comparing its antibacterial properties with phenol.

In this experimental study, Yarrow plant extract was extracted with the hydroalcoholic method. The aerial parts of Achillea ageratum plant with herbarium number 1753 were prepared from the slopes of Ardabil mountains and after determining the identity, the extract of this plant was extracted by hydroalcoholic method. In this method, after preparing the plant and drying the aerial parts of the plant, 10 g of it was crushed in a sterile mortar, then it was poured into an Erlenmeyer flask, and 50 mL of 100% ethanol was added to it. After 24 hours of mixing in a magnetic stirrer using a Buchner funnel with Whatman filter paper and a vacuum pump, the remaining components of the plant were separated. Then, a certain amount of distilled water (20 ml) was added to the desired solution and placed again in the magnetic stirrer whose temperature was set at 80 degrees Celsius, so that the alcohol was completely removed from the reactor. The Antibacterial effect of yarrow extract was performed by disc diffusion method and micro broth dilution on standard species of Enterobacteriaceae families including the standard bacterial strains of Klebsiella pneumoniae (ATCC:10031), Escherichia coli (ATCC:23591), Shigella dysentery (ATCC:25922) and Enterobacter aerogenes (ATCC:13048). All experiments were performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.

In the present study, the growth rate of bacteria decreased by increasing the concentration of yarrow extract. The MIC of Yarrow plant extract for Klebsiella pneumonia and Enterobacter aerogenes was obtained in %6.25 and for Shigella dysentery and Escherichia coli was obtained in %12.5 and %25, respectively. Also, the MBC of extract for Shigella dysentery, Klebsiella pneumonia, and Enterobacter aerogenes bacteria was obtained in 25%, and for Escherichia coli it was obtained in 50%. The results of MIC and MBC show that the most sensitive bacteria to yarrow extract among the studied bacteria is Enterobacter aerogenes and the most resistant is Escherichia coli. The diameter of the inhibition zone for Shigella dysentery, Escherichia coli, Klebsiella pneumoniae, and Enterobacter aerogenes bacteria was obtained at 19, 18, 20, and 23 mm, respectively. In this experiment, Enterobacter aerogenes bacteria were the most sensitive and Escherichia coli was the most resistant among the investigated bacteria. Comparative investigation of the antibacterial properties of yarrow extract with phenol, showed that yarrow extract had a lower killing effect than phenol at 5, 10, and 15-minute contact time. In this test, the most resistant bacteria are Shigella dysentery and the most sensitive bacteria are Escherichia coli and Enterobacter aerogenes. The reason that the type of resistant and sensitive bacteria was slightly different in the method of comparing the antibacterial effect of yarrow extract with phenol with the results of MIC, MBC, and non-growth halo diameter is related to the reduction of contact time of the extract with bacteria.

The results of the present research show that the hydroalcoholic extract of the yarrow plant is very effective in the removal of gram-negative intestinal bacteria. Also, the hydroalcoholic extract of the yarrow plant is more effective in removing gram-negative bacteria than phenol

Transmission of leachate from municipal solid waste landfills can potentially threaten ecosystems and human societies when the landfill has no system for collecting and treating leachate. Leachate produced from landfills finds its way through the soil to groundwater and surrounding surface waters, leading to pollution of water resources. This study aimed to investigate the effects of leachate from Khalkhal landfill (a city in Ardabil province, northwestern Iran) on the quality of groundwater and surrounding surface water. During 2019-2020, 4 wells (one control well located upstream of the landfill and three wells located downstream of the landfill) and two stations of the surface water resource of the Herochai river were spots for sampling. First, we did sampling during high and low rainfall seasons in accordance with the standards. Second, we analyzed the values of some physical, chemical, and biological quality parameters according to standard methods. The sampling of the soil texture was conducted following ASTM D 422 standards. Then, the soil was analyzed at Reference Laboratory of Water, Soil, and Plant in Ardabil province. The value of most parameters measured in the water of downstream wells was lower than the limit recommended by the Iranian and World Health Organization, indicating no limitation for drinking and agricultural uses. The quality of the Herochai river water was also relatively undesirable in terms of turbidity and total coliform in some samples. Additionally, consistent with the study results, no difference was observed between high and low rainfall seasons. According to the results obtained from different parameters, Schuler and Wilcox diagrams, and landfill water pollution index (LWPI), the quality of upstream and downstream water resources of Khalkhal municipal solid waste landfill was not much different. In other words, the landfill did not affect water.

Bisphenol A (BPA) is one of the toxic environmental pollutants that can be entered into aquatic ecosystems by raw wastewaters. In the current study, electrocoagulation used in the treatment of water and wastewater in a wide range was investigated for the removal of BPA.
All the experiments were conducted in a batch system. The effect of operating parameters such as pH, BPA concentration, electrolyte concentration, distance between electrodes, current intensity, and reaction time were evaluated. Experiments were carried out at laboratory temperature (25 °C), potential difference 30 V.
According to the results, the optimal condition were follows: BPA concentration 10 mg/L, current intensity 1500 mA, pH=7, and distance between electrodes 0.5 cm. The removal efficiency was ranged 60 to 90 percent.
It can be concluded that the electrocoagulation process using iron electrodes in the optimal condition can acceptably remove BPA from aqueous solutions.

 Phthalates (e.g., diethylhexyl phthalate) act as one of the endocrine disruptive compounds and can have adverse effects on different biological pathways including hormonal receptors, affecting the synthesis, secretion, or metabolism of hormones. The aim of this study was, method development of the dispersive liquid-liquid microextraction (DLLME), to determine the monoesters of diethylhexyl phthalate in children and adolescents in Isfahan city, Iran. 

 This study was conducted in 2016 (during a year) on 242 children and adolescents, aged 6–18 years, living in Isfahan, Iran. In this method, acetonitrile and chlorobenzene were used as disperser and extractant, respectively, to extract the investigated monoesters. The analytes were determined by gas chromatography–mass spectrometry. 

 Acetonitrile (as disperser) and chlorobenzene (as extractant) were used for monoester phthalates extraction (750 μl of acetonitrile and 80 μl of chlorobenzene). The results indicated that the recovery and relative standard deviation (RSD) of the utilized method were 55–109 and 6.3%–13.2%, respectively. The limit of detection and limit of quantification (LOQ) of the method were 0.024–0.088 and 0.05–0.48 μg/L, respectively. Monoethylhexyl phthalate (MEHP), monoethyl oxo-hexyl-phthalate (MEOHP), and monoethyl hydroxyl-hexyl-phthalate (MEHHP) were observed in 99.6%, 95.87%, and 96.28% of the studied samples, respectively. The mean concentration of MEHP, MEOHP, and MEHHP in the study population was 151.7 ± 143.8, 258.26 ± 143.07, and 194.17 ± 147.3 μg/L, respectively. 

 Acetonitrile (as disperser) and chlorobenzene (as extractant) were suitable solvents for phthalate monoesters extraction in method development of DLLME. On the other hand, the mean concentrations were very high values in comparison with other similar studies that require the attention and legislation regarding limitation of the application of phthalate compounds.

Locating landfills in urban areas is one of the most important issues in urban planning because of the effect on economy, ecology, and environment, therefore the right management and principled landfilling of solid waste is the major concern all over the world especially in the developed countries. In locating landfills, different criteria should be considered. In the present study, locating sites for solid landfill of two industrial suburbs in Natanz using Analytic Hierarchy Process (AHP) was investigated so as to present optimal solutions. Three places were investigated as suggested sites and seven factors like distance from the industrial suburb, ease of access, cost of site preparation, access to covering soil, wind direction, soil penetration, and groundwater direction were considered in the decision-making process. Super Decisions software was mployed to create hierarchy network, compare criteria and sub criteria, and finally choose better choice. Based on the results, the third choice located in northeast of Shojaabad suburb and southeast of Ooreh suburb (almost between two suburbs) was selected as the best choice to bury the industrial wastes of these suburbs with score of 0.618 based on the software results. The incompatibility rate was 0.069.

 This study was aimed to determine national sanitation foundation water quality index (NSFWQI), sodium adsorption ratio (SAR) and some other parameters such as electricity conductivity (EC) and sodium percent (%Na) to investigate the quality of the Jajrood and the Damavand rivers, the mix of them and Mamloo dam. 

 The tested parameters were pH, dissolved oxygen, biochemical oxygen demand, total solids, nitrate, phosphate, turbidity, temperature, fecal coliform, EC, Na, potassium (K), calcium and magnesium. The used indices were NSFWQI, SAR, %Na and magnesium hazard. 

 average WQI for the Jajrood river (S1), Damavand river (S2), mix of S1 and S2(S3) and the Mamloo dam (S4) were 71.7 (good), 64.5 (medium), 70.6 (medium) and 77.3 (good), respectively. According to USA Laboratory Diagram and Wilcox diagram, all the sampling points were in C3-S1(very good to good classes), C2-S1(good to permissible classes) categories. 

 According to the results, the water of sampling points is unsuitable for direct human consumption. However, for the S1, S2 and S3 as drinking water, advanced treatment may be needed. For S4 as a drinking water source, conventional treatment may be necessary. All the sampling points are suitable for irrigation purposes under normal conditions.

Mercury is one of the three heavy metals which are listed on top of the US EPA,s list for toxic and hazardous material with priority for human health. The aim of this study was to evaluate the situation of environmental and occupational human contamination with mercury in Iran. All studies conducted in Iran which had measured mercury levels in humans in Iran, were searched by electronic databases including Iranmedex, SID, Magiran, Google Scholar, Web of Knowledge, Science Direct and PubMed. Due to the heterogeneity of the study results, meta analysis was not performed on the results. After searching the databases, fourty seven articles were found. From these, 44 were chosen and evaluated. Although contamination with mercury is not high in Iran, but occupational exposure is considerable and contamination in specific groups such as dentists is high. Considering the high exposure to mercury in some occupational groups, using personal protective equipment and proper ventilation at workplaces should be emphasized. Also periodic monitoring of mercury exposure and medical examination of related workers is necessary. In order to decrease environmental exposure, it is suggested that legislations for routine monitoring of mercury in food and using composites without mercury be practiced.

Pollution of water resources to nitrate is an environmental problem in many parts of the world. This problem possibly causes diseases such as methemoglobinemia, lymphatic system cancer and Leukemia. Hence, nitrate control and removal from water resources is necessary. Considering that application of nanomaterials in treatment of environmental pollutants has become an interesting method, in this research use of Ag-doped TiO2 nanoparticles synthesized through photodeposition produced under UV irradiation was studied for removal of nitrate from aqueous solutions. Three nitrate concentrations of 20, 50, and 100 mg/L were considered. In order to determine the effect of Ag-doped TiO2 nanoparticles on nitrate removal, dosages of 0.1, 0.4, 0.8 and 1.2 g/L nanoparticles were used; pH range of 5-9 was also considered. The effect of Ag-doped TiO2 nanoparticles both in darkness and under UV irradiation was studied. Moreover, the presence of chloride and sulfate anions on the system removal efficiency was investigated. The optimum performance of nitrate removal (95.5%) was obtained using nitrate concentration of 100 mg/L, in acidic pH and 0.8 g/L Ag-TiO2. Increase of nanoparticle dosage up to 0.8 g/L, increased the removal efficiency, but for 1.2 g/L dosage of nanoparticles, the removal efficiency decreased. Maximum reduction performance without nanoparticles, under UV irradiation and under darkness conditions were 32% and 23.3%, respectively. In addition, we found that presence of sulfate and chloride anions in aqueous solution reduced efficiency of nitrate removal. Results of this study showed that Ag-doped TiO2 nanoparticles may be efficiently used for nitrate removal from aqueous solutions.