Environmental Sciences
Year:2015 | Volume:13 | Issue:1 |Papers Count:14

Climate change with changing climate patterns and confounds Ecosystems discipline, imports Serious consequences on the environment. Changes in weather patterns Could lead to severe flooding, extreme heat or cold, more frequent droughts. Each of these phenomena could Put at risk the regional food reserves. North east of Iran due to the large area has very varied natural conditions and each of the areas included specific natural features. The extent of the area and factors such as mountains rising, desert areas, stay away from the water zones and different winds lead to variety of weather in each of those area. Based on the results if the man-kendall test and AHP model in north east of Iran, climatic elements with ascending trend (82.25%) much more than climatic elements with descending trend (35.5%) affect on climate change in north east of Iran. Areas that experience most climate changes due to descending elements (number of frost days, average moisture, the number of days with snowfall, 24-hour rainfall, annual precipitation) is seen in the South and South east of region. Climatic elements with ascending trend (The average temperature, the minimum temperature, the maximum temperature, hours of sunshine) cover most extent of this region. Only Ghochan and Sabzevar stations demonstrate the least climate changes.

AERMOD is an advanced model of the dispersion of air pollutants that supports a variety of source types and is appropriate for estimating impacts from short-range transport for distances less than 50 km. The US Environmental Protection Agency (EPA), in conjunction with the American Meteorological Society (AMS), has developed a new air quality dispersion model known as the AMS/EPA Regulatory Model (AERMOD). There is significant evidence on the impacts of buildings on dispersions of pollutants and, among the current air pollution models, AERMOD is that one that takes into account building characteristics. Due to its capabilities, the model has also been suggested by the USEPA. The current research examines the impacts of building characteristics as well as change in the dimensions of industrial structures close to a point source on the model output. Three different shapes (namely cubic, long and wide) were assumed as the building forms. Results showed that while the building dimensions increased the downwind pollution concentration was also increased significantly. Furthermore, buildings with a wide shape had greater impacts on pollution than the other two building forms. In other words, the output model shows greater sensitivity than the width of the building.

In this study, the photocatalytic degradation of Direct Blue 71 was investigated in the presence of ZnO nano particles in a slurry reactor, and the effects of pH, catalyst dosage, initial dye concentration and UV-lamp power on dye removal efficiency were determined. Maximum removal equal to 100 percent was obtained at pH=9, catalyst dosage of 0.288 gr/L and initial dye concentration of 50 mg/L after four hours under a 60 W UVC lamp; 60.14 percent of COD removal was observed after 30 hours. The kinetics and liquid chromatography-mass results showed that the reaction followed the second order model with a correlation coefficient (R2) of 0.987 and the complex compounds in the solution had been degraded.

Heavy metals are persistent pollutants the continued presence of high concentrations of which in ecosystems can be harmful to organisms. Therefore, the identification of heavy metal concentrations in the ecosystem is very important. One of the new methods for assaying contaminants is to use dominant organisms in the ecosystem among aquatic plants. By focusing on Avicennia marina which is a dominant plant, this study attempted to determine the heavy metal (Cu, Pb, Ni, Cd, Zn) concentration in Mahshahr Estuary. For this purpose, samples of sediment along with mangrove roots and leaves were taken from three artificial mangrove habitats in Bandar Imam Khomeini swamp during September 2010 and February 2011. Nine sediment, root (approximately 6 pieces) and leaf samples (containing 25 leaves) were taken from each habitat. Samples were dried in the laboratory, digested in concentrated acids and their metal content was measured using atomic absorption spectrophotometry. Significant correlations were found between all metal concentrations in the sediment with their levels in the mangrove root or leaves, suggesting that this plant can be a suitable biomonitor for heavy metal contamination. However, it should be noted that heavy metal accumulations in the roots of Avicennia marina are higher than in the leaves and the correlation efficient among root and sediment is higher than between leaf and sediment, which can suggest that root of Avicennia marina is more suitable than its leaf.

One of the most important environmental issues in Tehran is air pollution. Alongside classic pollutants, toxins are also challenges facing Tehran. In this work the concentration of asbestos in terms of its temporal and spatial distribution has been studied. The use of asbestos in brake and power transmission systems of vehicles and the increase in the number of cars in the city, has led the authors to measure the concentration and dispersion of asbestos fibres in recent years. Accordingly, airborne asbestos fibre concentrations in the urban environment of Tehran were evaluated between September 2012 and September 2013. The airborne fibre concentrations of 200 air samples collected from 50 different sites in five areas of Tehran were analyzed with phase-contrast optical microscopy (PCM) and scanning electron microscopy (SEM). There were significant differences in the asbestos fibre concentrations between areas and seasons. Since there is no global standard relating to asbestos we had to compare the results against both the World Health Organization and environmental agencystandards in the US and Europe, leading to a standard of 5×10−5 PCM f/ml. To evaluate the seasonal variations in fibre concentrations, we collected air samples at the same sites in each of the four seasons. The samples were collected on membrane filters (Millipore type AA; pore size 0.8 mm; diameter 47 mm; Millipore, Bedford, MA) using an open face filter holder (model FP050/2; Schleicher and Schull, Dassel, Germany). Sampling was performed at a flow rate of 10 l/min using a suction pump (SKC, English); sampling times ranged from 8 to 12. The highest geometric mean concentration of asbestos was found in traffic areas and in winter measuring 9×10−3 PCM f/ml. and the mean of highest sampling concentration within a year was found in traffic areas which is 45×10−3 PCM f/ml. We conclude that the high volume of traffic, industrial consumption of asbestos, and geographical and climatic conditions are responsible for the high airborne asbestos levels in non-occupational environments in Tehran.

Optimizing of energy consumption in agro-ecosystems can help reduce farm operating costs, improve air quality, reduce GHG emission levels and results in sustainable development. Therefore, studying the management of different cropping systems represents a good method to optimize input requirements, yield and net energy supply. The objectives of this study were to document the production process and analysis of energy indices in rice production systems. In this experiment, rice production systems that included SRI, improved and conventional, were studied at a paddy field in the Neka region during 2011-2012. The total energy consumption in rice production systems was calculated, including the fertilizers, seed, plant protection, machinery, transportation and all on-farm activities. The results indicated that the average input energy in the systems studied, including direct, indirect, renewable and non-renewable energies, was 24262.29 MJ ha-1. Total output energy in rice-based agro-ecosystems was 191.34 MJ ha-1. The share of direct and renewable energy uses of SRI was more than in improved and conventional systems, but the share of indirect and non-renewable energy uses in SRI was less than in improved and conventional systems. The highest energy efficiency, energy productivity and net energy were observed in SRI. But, specific energy was lower for SRI than for other systems. This variation was dependent on input intensities and growing conditions. It was concluded that energy management at the farm level could be improved to give greater energy productivity and economic efficiency and, so, SRI was the most productive in terms of energy. In this regard, renewable energy sources appear to be one of the most efficient and effective solutions for sustainable energy development and environmental pollution prevention in Iran.

The paper industry is a complex operating unit with many interactions. Its wastewater contains pollutants and coloured compounds and it is considered to be one of the most contaminated effluents. Several units of wood and paper exist in the world to meet the growing needs of diversified paper products and estimation has shown that paper consumption is growing strongly. In this study, the effect of alum and polyaluminum chloride (PACl) coagulants to reduce pollutant concentrations in the industrial paper mill wastewater has been investigated. For this purpose, paper mill wastewater was characterized and the reduction of chemical oxygen (COD), turbidity and sludge volume index (SVI) parameters were evaluated. Optimum dosage of coagulants and pH value are obtained with the standard jar test technique. Under optimum condition, the dosage of alum and polyaluminum chloride and initial pH were, respectively, 1000, 500 mg/l and 6. This result reveals that PACl with a 96% removal of turbidity and a 99% reduction of COD could provide the best possible results. Furthermore, SVI reached 250 ml/g when PACl was used as a coagulant. The findings showed that coagulation can be used as a new technology for the treatment of different industrial wastewaters, such as in the paper mill industry.

In the following research 18 samples were collected from dust of the nine main squares of Tehran city under dry summer conditions and at a heavy traffic time of evening. The samples were analyzed by ICP-OES for Pb, Zn, and Cu, As, Fe, Ni, Cr, Cd, Mn and Bi. The enrichment factors and Muller geo-accumulation index were calculated for these samples. Data processing shows enrichment in Pb, Zn, Cu, As, Bi relative to the Earth's crust. The results of enrichment factors indicate that the Bi in all of the squares is located in an extremely high enrichment range and that Zn in Rah Ahan Square is also located in a high enrichment range while, in the other squares, it is located in a moderate enrichment range. Cu in the Sadeghieh and Poonak Squares is located in a high enrichment range and Pb shows extremely high enrichment in Poonak Square and high levels of enrichment in the other squares; finally, As shows high enrichment in the Vali Asr, Azari and Rah Ahan Squares. The Muller geo-accumulation index is represented in all of the squares where Pb, Zn and Cu exist within the pollution range. Results indicate that street dust pollution threatens the environmental status significantly and the main sources of dust emissions in Tehran city are vehicle traffic (fossil fuel combustion and the parts used in cars), street asphalt and construction projects and materials in the city.

There are many materials in municipal wastes which are necessary for plant growth and, so, burying wastes without attention to this question leads to a waste of energy and leaching of pollution in landfills. In addition, production of chemical fertilizers requires money which could be saved. Organic fertilizer production should be a priority for attention to present potentials. In this research, different systems of municipal solid wastes in District 22 and different aspects of productivity with attention to bio-compost production have been analyzed. In November 2012, 30 houses were selected in Sharif city during a random sampling. Three coloured bags were given to the residents and they were asked to fill the green, blue and black bags with organic, recyclable and burial wastes, respectively. Results of measurement revealed that weight of organic, recyclable and burial wastes were respectively 656.51, 136.92 and 288.76 grams. Using a T statistical test in SPSS 18 showed the volume of organic wastes increased meaningfully due to an increase in family number. Calculation of the collection, transportation and burial costs of municipal solid wastes revealed that the municipality pays 1048 million Rials per month and so 592 million Rials for every kilogram per month would be saved if the municipality separated organic wastes from source. Three scenarios have been defined to identify the best model of making bio-compost in the study area. The cost-benefit analysis of the first scenario which concerned making a bio-composting factory showed an income for the municipality of 1012 million Rials annually. The second scenario which related to purchasing a bio-composting machine revealed that it would have an annual benefit of 6698 million Rials. The third scenario concerned creating Windrow composting and the cost-benefit analysis result for this was -2806 million Rials and so this scenario was rejected.

This research was conducted with the aim of assessing environmental risks in the olefin unit at the stage of operation, using the HAZAN and Frank and Morgan comparative method. After assigning the study area and identifying its environmental and socio-ecological features, identification of environmental immune-hygienic risks was conducted. Initially, identification and screening of the environmental and immunity risk were done separately by the PHA method and these risks were then assessed using the HAZAN method. Finally, 19 environmental risks and five immunity ones were worth interpreting. In the next stage these risks were assessed using the Frank and Morgan method and, out of the above 19 risks, only the combustion operation in the furnaces was placed in class 4, which shows a higher risk; in contrast, other activities were not put in classes higher than class 1 which means low risk. Out of the 5 immunity risks, only the operation on caustic storage and working in oil and chemicalwaste basin’s were put in class 2 which suggests and average risk. Other activities in the final classification were placed in class 1 which suggests a low risk. In the end, necessary control measures were suggested, including imposing a legal obligation for regular checking of feeding pipes inside the furnaces and also decoking according to an accurate timing programme every 45 days to decrease the risk of combustion operation in furnace.

Tolerance and uptake of heavy metals by plants, differs from one to another species. A plant can be used for decontamination of contaminated soil and waters if it can resist and reduce heavy metals from contaminated resources. The objective of this research was to investigate the capability of halophyte Chenopodium Album L. to phytoextract lead and to determine the clean-up time from contaminated soils. For this purpose, a completely randomized design with six treatments of 0, 150, 300, 600, 900 and 1200 mg Pb/kg soil and four replicates was established. After full development of plants, they were harvested and their lead in roots and shoots were measured. The results indicated a nonlinear positive relationship between the lead concentrations in soil and that accumulated in both roots and shoots. The highest extracted lead which was accumulated in roots and shoots were 64.75 and 4.12 mg/kg, respectively. The highest dry matter of 35 ton/ha produced in one year belonged to 600 mg Pb/kg soil treatment. The minimum clean-up time was nine years in the treatment of 600 mg Pb/kg soil that appeared at the 5% contamination. Since Chenopodium Album L. can be cultivated three times a year, and due to its high biomass and capability of lead accumulation, this plant might be used as a hyper-accumulator to remediate lead from Pb-contaminated soils.

Concerns about pesticide residues in agricultural products have led to a tendency towards organic agriculture in many countries. In organic agriculture, the use of chemical inputs like fertilizers and pesticides and genetically modified plants does not occur and this approach enhances the health of ecosystems and soil biological activity. This present study investigates the willingness of urban households to pay for organic hashemi rice by the use of contingent valuation method. In order to evaluate individuals' willingness to pay for this product in Rasht town, 294 questionnaires using a double dichotomous choices approach and the Logit model were used and, based on the maximum likelihood ration, model coefficients were estimated. Among the studied variables, revenue and education level had positive and statistically significant effect on willingness to pay for organic rice. The average willingness of individuals to pay for a kilogram of organic Hashemi rice equals 75800 Rials which is 8.24 percent more than conventional Hashemi rice. So, in the individuals' point of view, the implicit price of Hashemi rice for being organic equals 5800 Rials per kilogram.

Due to the expansion of cities, public transportation networks cause the accumulation of a large number of vehicles in city bus terminals and, so, bus terminals have the potential to be a source of urban air pollution. In this paper, the results of estimating the concentration of air pollutants in Beihaghi passenger terminal in Tehran by modeling are presented. Air pollution emissions of CO, NOx, SOx and PM10 are estimated using the IVE model with the use of basic information on vehicles, traffic and their presence in terminals. In order to estimate air pollution concentrations, input data of the BREEZE AERMOD model were produced from the results of IVE model emission results. The emission results of the IVE model and other required information, such as meteorological parameters and concentrations of air pollutants, have been estimated. Results of the AERMOD model pollutants give a mean concentration for Nitrogen Oxides at 176.62, particulate matter of less than 10 microns is 79.95 mg/m3, carbon monoxide is 2.03 ppm and sulfur oxide is 29.51 ppb.