آوا حیدری

Consumption of vegetables contaminated with heavy metals is dangerous for human health. The present research determined some heavy metals in Portulaca oleracea and assessed its health risk.

P. oleracea was grown in pots using soil polluted with nickel and various amounts of iron nanoparticles (0, 15, and 30 mg/kg). The concentration of heavy metals was determined by ICP-OEC after the samples were extracted. The bioaccumulation and transfer factors in plants, daily intake, and risk indicators of heavy metals for humans were all calculated.

The treatment with 30 mg/kg of iron nanoparticles resulted in the maximum concentration of nickel and iron in the roots and aerial sections of P. oleracea. The nickel and iron TF were below one for the soil-root but above one for the root-stem. For nickel and iron, the BAF in the plant was discovered to be less than one. Human consumption of P. oleracea poses minimal dangers, as indicated by HRI values that are less than 1. Compared to iron, nickel showed higher HRI values. Across all treatments, children demonstrated high HRIs for nickel and iron than adults.

There are no non-cancerous diseases for consumers, according to the hazard ratio of the investigated components in the P. oleracea, which was 1. Overall, the findings demonstrated that the HRI of heavy elements for both analyzed age groups was less than one.

One of the most fundamental global environmental challenges in the past two decades has been the issue of soil pollution and degradation. Soil, as an important environmental element, has played a significant role in food production, human health, and living organisms, but various factors, by both human and naturally have destroyed it. The exploitation of natural resources with activities such as mining and quarrying, as an anthropogenic action (caused by human activities), is one of the most important factors of human intervention in nature and also one of the environmental hazards of soil degradation, which has caused the spread of desertification. Sangan iron mines in Khaf city are the largest mines in the northeast of Iran. According to the geomorphological disturbances caused by the activity of Khaf iron ore mines and the geological composition of the region, there is a potential for causing pollution and destroying the soil around the mine. This research was conducted with the aim of evaluating the impact of mining activity on concentration of some heavy metals such as lead, iron, nickel, copper, and arsenic in the soil around the iron ore mine in Sangan area of Khaf city in Khorasan Razavi province. Realizing the polluted hotspots due to the concentration of heavy metals, as one of the important signs of soil pollution and the spread of desertification, is one of the goals of this research, and the results can be effective in making appropriate management decisions to prevent soil pollution and further destruction.

In order to conduct this research, 60 soil samples were systematically taken from a depth of 0-20 cm from two areas adjacent to the mine and control. The concentration of aqua regia extracted heavy metals was measured using an inductively coupled plasma-optical emission spectroscopy (ICP-OES). In the first stage, the results were descriptive, and in the second part, after performing tests related to the normality of the data, they were inferential using the parametric independent t-test and Pearson's correlation coefficient in the statistical environment of the SPSS software. In order to quantify the level of soil contamination with heavy metals, geochemical indices including contamination factor, pollution load index, and enrichment factor were used. The pollution load zoning map of the area adjacent to the mine as well as the average enrichment map of lead and arsenic elements were prepared using the inverse distance weighting interpolation method in the ArcGIS environment.

The results of this research showed that the average concentrations of arsenic, copper, nickel, lead, and iron elements in the area near the mine were 12.71, 25.54, 34.59, 48.64, and 38860 mg/kg and in the control area were 8.57, 15.97, 32.13, 16.96, 29110 mg/kg, respectively. The comparison of the coefficient of variation (dispersion criterion) of heavy metals showed that the highest coefficient of variation among the metals is related to the lead with a value of 42.8%, as well as the coefficient of variation for other metals in the area adjacent to the mine also has a relatively high dispersion compared to the control area. In addition, it was found in all elements except for nickel (p<0.05), which indicates a significant difference in the average concentrations between the control area and the area adjacent to the mine. The correlation between lead element and nickel, copper and arsenic variables was inverse and there was a positive and very strong correlation between iron and copper and nickel with values of 0.8 and 0.76 respectively and nickel and copper with values of 0.82. The pollution coefficient of the lead elements in the area adjacent to the mine showed moderate to significant pollution levels, which is more polluted than other elements. The pollution load in the area near the mine showed that the value of this index was greater than one in the samples closer to the mining areas, which indicates the high contamination of the surface soil with these elements. Lead and arsenic elements in the area adjacent to the mine showed moderate to relatively intense enrichment. From the examination of all the pollution indicators used in this research, as well as the positive and very strong correlation between copper and nickel, the presence of these two elements in the soil of the study area showed no pollution. The comparison of the results obtained from the analysis of soil samples in the two areas of the control and adjacent to the mine showed an increase in the concentration of heavy metals (iron, lead, and arsenic, copper) in the area adjacent to the mining.

The results obtained from the analysis of soil samples and pollution indicators in the two control areas adjacent to the Sangan iron ore mine in Khaf city showed that the presence of iron ore industrial and mining sites in the study area and the spread of its wastes and tailings by seasonal and local winds, as well as the activities of humanity and the spread of these pollutants to other areas, can be one of the main reasons for the increase in the concentration of metal pollutants in the soils of this region.

Free plastic bags have practical benefits for consumers but because of their non-biodegradability and additives, they have adverse effects on the environment. Therefore, in this study, the factors affecting people's intention and behavior for using plastic bags with the Theory of Planned Behavior and Structural Equation Modeling were investigated.

A total of 360 customers in 7 major hypermarkets in different areas of Mashhad responded the questionnaire. Data were analyzed using IBM SPSS Statistic 22 and AMOS 24 software. An extended model based on the Theory of Planned Behavior was introduced with the constructs including cognitive attitude, affective attitude, economic motivation, feedback, subjective norm, behavioral control, intention and behavior to determine the factors influencing the behavior.

The results of this study showed that more than half of the respondents to the questionnaires were women and more than 30% of them were in the age group of 25-35 years. The effect of demographic information on the intention to reduce plastic bags in hypermarkets was examined by the Anova test.  Only the age (p 0.05) effect (coefficient of 0.16) on intention to reduce plastic bag. The norm with a coefficient of 0.41 has a positive and significant effect (p <0.001) on the intention.

The results showed that the structural equation model with appropriate fit could describe the relationships between variables. The main parameters of the Theory of Planned Behavior (attitude, subjective norms, and behavioral control) significantly describe the intention of using plastic bags. Adding new variables such as feedback and economic incentives to this theory will help determine other predictors of behavior. The norm is one of the most important variables that mediate the influence of other factors such as cognitive attitude, affective attitude, economic motivation, feedback, and behavioral control on intention to using plastic bag. Although the economic incentive has an effect on intention to use free plastic bags, it is appropriate to use the intervention approach based on the model presented in this study to find a solution.

Today, air pollution, with an impact on a global scale, is an important concern of the modern world. It has many adverse effects on human health and the environment. Therefore, it is necessary to find sustainable and environment-friendly solutions that prevent the increase of pollution levels and help eliminate them. One of the newest ways to reduce air pollution and absorb particulate matter, as well as improve air quality, is to use green walls in urban spaces. The present study investigated the potential of green walls in reducing air pollutants.  

In this research, two green walls were installed at the Khayyam intersection in Mashhad for three months. Finally, the Air Pollution Tolerance Index was determined for all the plants by measuring chlorophyll, ascorbic acid, leaf-related water content, and pH.

Results:

 All of the plant species planted on the walls were classified as intermediate in the tolerance. Among all the plants, Carpobrotus edulis and Rosmarinus officinalis had higher APTI, which makes them more resistant and suitable for planting in polluted areas. Considering the statistical analysis, the APTI of the plants was correlated with ascorbic acid and leaf-related water content.

Our findings suggest the suitability of the above-mentioned plants for plantation in areas with high levels of pollutants.

The steel industry is the world's largest consumer of energy. A large amount of iron waste is produced annually, which its use in the steel industry can be economic. The purpose of this study was to investigate the environmental impacts of the steelmaking from iron scrap as a raw material using a life cycle assessment (LCA) method. Simapro software and the ecoinvent database were used to conduct LCA. Data on the steel production process (raw materials, waste, and products) were collected by a questionnaire from a steel plant. Environmental burdens were quantified using ReCiPe, Cumulative Energy Demand (CED), IPCC) Intergovernmental Panel on Climate Change) and water footprints methods. The results of the ReCiPe method showed that the terrestrial ecotoxicity with a value of 14392 kg 1,4-Dichlorobenzene (1,4-DCB) eq/ton of steel and global warming with 5289 kg CO2 eq/ton of steel, had the greatest environmental impact, respectively. The lowest environmental impact of this process was obtained for freshwater ecotoxicity and human carcinogenic toxicity. The carbon footprint resulting from steelmaking is 5.24 ton CO2 eq/ton of steel. The most important sector of the greenhouse gas producer is the consumption of electricity with a rate of 2900 of kg CO2 eq/ton of steel. The cumulative energy demand of one ton of steel ingot was 73393 MJ, which is three times the global equivalent. The total water footprint for one t of steel was 19.5 m3 of water, which is almost near to the equivalent in Europe. the use of iron scrap as raw material in the process of steelmaking instead of iron ore has reduced the amount of human toxicity potential and mineral resource consumption.

In this study, nanoporous silica adsorbent of MCM-48 was synthesized. The adsorbent capacity of heavy metal was increased by modification of the surface with 3-aminopropyltrimethoxysilane. Silica adsorbents are very effective in heavy metal adsorption.
In the present study, removal of Pb (II) and Cd (II) heavy metal ions from aqueous solution was carried out using MCM-48 and NH2-MCM-48 modified nanoporous adsorbents in a batch system. The effect of adsorbent dosage, solution pH and contact time were studied. The equilibrium data were analyzed using the Langmuir and Freundlich isotherms by nonlinear regression analysis.
Findings: The maximum adsorption capacities of NH2-MCM-48 for Cd (II) and Pb (II) were found to be 62.07 and 108.16 mg/g, respectively. Changing the level of each variable resulted in change of adsorption capacity of the adsorbents.
The results of this study indicated that modification of MCM-48 to synthesize NH2-MCM-48 will increase the adsorbent capacity for Cd (II) and Pb (II) ions and this compound can be used as an effective adsorbent for the adsorption of metal ions.

Mesoporous silica adsorbents have been gaining increasing importance in the removal of heavy metal ions from water and wastewater. MCM-48 is a mesoporous silica adsorbent whose adsorption capacity of heavy metal ions can be drastically improved when it is modified by functional groups. The present study investigated the removal of lead and cadmium metal ions from aqueous solutions using the modified NH2-NH-NH-MCM-48. The nanoparticles were characterized by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). The adsorption process was optimized by varying adsorbent doses from 0.125 to 10 g/l, the initial solution pH from 2 to 6, and the initial metal ion concentration from 5 to 60 mg/l. The equilibrium data were analyzed using the Langmuir and Freundlich isotherms using a nonlinear regression analysis. According to the parameters of the Langmuir isotherm, NH2-NH-NH-MCM-48 recorded a higher maximum adsorption capacity for both Cd(II) and Pb(II) than MCM-48. The maximum adsorption capacities of NH2-NH-NH-MCM-48 for Cd(II) and Pb(II) were calculated to be 82.7 and 119.24 mg/g, respectively. The results suggest that MCM-48 modified with the amine functional group to synthesize NH2-NH-NH-MCM-48 significantly improves its adsorption capacity so that it can be recommended as an effective adsorbent for the efficient removal of Cd(II) and Pb(II) metal ions from aqueous solutions.

Fast pyrolysis is an attractive technology for biomass conversion، from which bio-oil is the preferred product with a great potential for use in industry and transport. Corn wastes (cob and stover) and eucalyptus wood are widely being produced throughout the world. In this study، fast pyrolysis of these two materials were examined under the temperature of 500 °C; career gas flow rate of 660 l h-1; particle size of 1-2 mm; 80 and 110 g h-1 of feed rate. The experiments were carried out in a continuous fluidized bed reactor. Pyrolysis vapor was condensed in 3 cooling traps (15، 0 and -40 °C) plus an electrostatic one. Eucalyptus wood was pyrolyised to 12. 4، 61. 4، and 26. 2 percent of bio-char، bio-oil and gas، respectively while these figures were as 20. 15، 49. 9، and 29. 95 for corn wastes. In all experiments، the bio-oil obtained from electrostatic trap was a dark brown and highly viscose liquid.