Original Articles
Mitra Cheraghi; Alireza Safahieh; Ali Dadolahi Sohrab; Kamal Ghanemi; Abdol Majid Doraghi
Volume 11, Issue 4 , January 2014
Abstract
A. marina from aquatic plants is widely distributed throughout Bardestan estuary (Bushehr, Iran). This study examined the uptake of some metals by A. marina and their translocation from the roots to other parts of the plant.For this purpose, samples of sediment, and mangrove roots and leaves were taken ...
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A. marina from aquatic plants is widely distributed throughout Bardestan estuary (Bushehr, Iran). This study examined the uptake of some metals by A. marina and their translocation from the roots to other parts of the plant.For this purpose, samples of sediment, and mangrove roots and leaves were taken from the Bardestan mangrove. Samples were dried in the laboratory and digested in concentrated acids and their metal content was measured using Atomic Absorption Spectrophotometry. The enrichment coefficients in leaves of A. marina were smaller than 1.0 for all the studied metals. Similarly, theenrichment coefficients of all the metals (Zn, Ni, Cu, Pb, Cd), in roots of A. marina were smaller than 1.0. This study demonstrated that A. marinabehaves as an excluder plantand could be considered as either a bio-indicator or a bio-accumulator in sediments and waters polluted by heavy metals.
Original Articles
Mohsen Ghadrdan,; Mohammad Reza Sabour; Hasan Ghasemzadeh; Elahe Khosravi
Volume 11, Issue 4 , January 2014
Abstract
The contamination of soils and groundwater by toxic and/or hazardous organic pollutants is a widespread environmental problem. One group of these contaminants is petroleum products. Soil pollution caused by petrochemical activities, oil spills and leakage is not only an environmental issue but also a ...
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The contamination of soils and groundwater by toxic and/or hazardous organic pollutants is a widespread environmental problem. One group of these contaminants is petroleum products. Soil pollution caused by petrochemical activities, oil spills and leakage is not only an environmental issue but also a geotechnical issue. Physical and chemical reactions between soil and contaminant lead to change in soil properties and behaviour. In this paper, a set of laboratory tests including the direct shear test, uniaxial compression test, Atterberg limits and Scanning Electron Microscope (SEM) have been carried out on Kaolinite samples polluted with different percentages of gasoil. The direct shear test results demonstrate that increasing the pollutant percentage leads to an increase of cohesion and a decrease in internal friction angle of the soil. Also, increasing the amount of gasoil to a certain percentage results in a decrease in the uniaxial strength and the plasticity index of the soil.
Original Articles
Moslem Heydari; Seyed Javad Sadatinejad; Afshin Honarbakhsh
Volume 11, Issue 4 , January 2014
Abstract
River basin lag time is an important factor in the linear modelling of river basin response. In this study, the modelling of lag time using fuzzy regression is applied. For this purpose, the data for rainfall-runoff events of Khanmirza basin (nine events) were collected and analysed. Following on, events ...
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River basin lag time is an important factor in the linear modelling of river basin response. In this study, the modelling of lag time using fuzzy regression is applied. For this purpose, the data for rainfall-runoff events of Khanmirza basin (nine events) were collected and analysed. Following on, events were divided into two groups: one for formulas based on fuzzy regression and another for the validation of these formulas. The results obtained from this study, based on RE and RMSE statistical measures, showed that the efficiency of newly developed formulas based on fuzzy regression methods is higher than for other formulas used for the calculation of time of concentration.
Original Articles
Samira Hossein Jafari,; Mohammad Reza Tatian; Reza Tamartash; Ali Akbar Karimian
Volume 11, Issue 4 , January 2014
Abstract
To assess the impact of grazing on the diversity, richness and evenness of vegetation, several indices and information on plant composition are necessary because of their different sensitivity to grazing gradients and kinds of herbivores.Thus, the purpose of this study was to compare these indices between ...
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To assess the impact of grazing on the diversity, richness and evenness of vegetation, several indices and information on plant composition are necessary because of their different sensitivity to grazing gradients and kinds of herbivores.Thus, the purpose of this study was to compare these indices between two wildlife and livestock grazing sites in steppe rangelands of Mehriz. Sampling was performed using a random systematic method in April 2012 (10 transects of 100m and three plots of 2m2 were placed on each transect on each site). The species name, plant families, longevity and canopy cover percentage were determined in each plot and along each transect. Finally, the data were analysed using an independent sample t-test. The results showed that the canopy cover percentage of Colchicum kotschyi, Iris songarica(p<0.05) and Stachys inflata(p<0.01) significantly increased while the percentage of Artemisia sieberi, Stipa barbata(p<0.01) and Scorzonera sp.(p<0.05) canopy cover was revealed to have significantly decreased in deer grazing areas. The results of a statistical analysis showed that deer grazing has caused plant diversity indices to increase such as Shannon, Simpson and evenness (p<0.01). However, the Margalef and Menhinick indices did not show any significant difference between the two sites.
Original Articles
Mohammad Ghofrani; Donya Ansari Movahed,; Mohammad Hasan Payan; Saeed Khojasteh Khosro
Volume 11, Issue 4 , January 2014
Abstract
The present study investigated the use of MDF sanding dust in the manufacture of wood polymer composites. Specimens made with 40%, 50% and 60% sanding dust and 2% coupling agent (dry wt) were compared with control specimens. All physical and mechanical properties were determined according to European ...
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The present study investigated the use of MDF sanding dust in the manufacture of wood polymer composites. Specimens made with 40%, 50% and 60% sanding dust and 2% coupling agent (dry wt) were compared with control specimens. All physical and mechanical properties were determined according to European norms. The results showed that sanding dust had a significant effect on all properties. The best mechanical properties and dimensional stability were found in boards composed of 40% sanding dust. The improvement in the physical and mechanical properties of composites containing sanding dust was related to the presence of urea formaldehyde resin from the MDF process in the dust. The results indicate that the use of sanding dust as a filler produced good quality composites that perform better than composites made with wood flour.
Original Articles
Malihe Jamali,; Korous Khoshbakht,; Reza Deihimfard; Reza Momeni Vesalian
Volume 11, Issue 4 , January 2014
Abstract
South lands of Tehran are the main source of agricultural productions in which some kinds of vegetables, legumes, cereals and other crops are growing. This research measured and zoned heavy metal soil pollutionin 1500 ha of these cultivated fields south of the city of Tehran in Iran. In this study, 128 ...
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South lands of Tehran are the main source of agricultural productions in which some kinds of vegetables, legumes, cereals and other crops are growing. This research measured and zoned heavy metal soil pollutionin 1500 ha of these cultivated fields south of the city of Tehran in Iran. In this study, 128 samples were collected using the systematic-random method from 64 areas at depths of 0-30 cm and 30-60 cm and the concentrations of cadmium, chromium, nickel, lead and zinc were measured. The parameters of pH, electrical conductivity, and phosphate were also recorded. Zoning maps were developed using the inverse distance weighted method. The results showed that concentrations of heavy metals, with the exception ofnickel, were higher at the shallower depth than at the lower depth. The zoning map shows that cadmium, chromium, lead and zinc occurred in greater concentrations in the northern areas and nickel in the southern areas. A comparison of these results with Iranian soil resource pollution standards indicates that the levels of chromium, nickel and zinc exceeded the standards in some parts of the study area.
Original Articles
Gholam Hossain Kiani
Volume 11, Issue 4 , January 2014
Abstract
In this study, the conventional and environmentally adjusted productivity and the efficiency and technical changes of the Iranian agricultural sector are measured, using the Malmquist-Luinberger index and the panel data from 28 provinces over the period 2000-2008. Results show that the annual average ...
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In this study, the conventional and environmentally adjusted productivity and the efficiency and technical changes of the Iranian agricultural sector are measured, using the Malmquist-Luinberger index and the panel data from 28 provinces over the period 2000-2008. Results show that the annual average of nitrogen balance index, as a proxy of nitrogen pollution, is 32.7 kilograms per hectare of agricultural land and nitrogen use efficiency is 62%. On average, the conventional total factor productivity, efficiency and technical change indices are 0.9687, 0.9610 and 1.008, respectively, while the environmentally adjusted counterpart indices are 0.9716, 0.9738 and 0.9977. Hence, by ignoring pollution, conventional measurements of productivity tend either to overestimate or to underestimate the true productivity of the agricultural sector.
Original Articles
Houman Liaghati; Halimeh Jahangard; Naghmeh Mobarghei Dinan
Volume 11, Issue 4 , January 2014
Abstract
Nowadays, water pollution is one of the most serious environmental challenges in managerial policies of the world. On the other hand, the effect of economic development of the countries on pollution emission is undeniable. The mail goal of this study is to investigate the amount and direction of theeffect ...
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Nowadays, water pollution is one of the most serious environmental challenges in managerial policies of the world. On the other hand, the effect of economic development of the countries on pollution emission is undeniable. The mail goal of this study is to investigate the amount and direction of theeffect of gross domestic production and energy consumption on water pollution in Iran. The investigation was performed using 1973-2007 time series data and the vector error correction model (VECM). The results showed that, when gross domestic product rises, although the amount of pollution increases at the beginning, eventually the amount of water pollution decrease as this process goes on. The results also showed that a 1% increase in energy consumption results in 0.55% increase in water pollution. Considering this positive effect of energy consumption on water pollution, the implementation of policies for increasing energy efficiency should result in a pollution decrease. Estimation of the error correction coefficient indicated that it would take more than 1.54 year to adjust the shocks caused by water pollution in Iran.
Original Articles
Alireza Pourkhabbaz; Najme Boosaeidi; Moslem Jahani
Volume 11, Issue 4 , January 2014
Abstract
It is now well recognized that heavy metals in the environment cause pollution that can be harmful to living organisms. Without control, heavy metals that are transferred to the environment may undergo significant changes and have a serious impact on aquatic environments, public health and economics. ...
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It is now well recognized that heavy metals in the environment cause pollution that can be harmful to living organisms. Without control, heavy metals that are transferred to the environment may undergo significant changes and have a serious impact on aquatic environments, public health and economics. In view of the serious detrimental effect to the environment and health of wastewater containing Cr (VI), there is an urgent need for regulation. The objective of the present study was to investigate Cr (VI) removal from aqueous solutions using barberry leaves. The effects of parameters such as acidity, contact time, sorbent dose and initial concentration were evaluated for batch mode. Results showed maximum adsorption in an acidic medium at pH level 2; initial Cr(VI) concentration of 80 mg L−1 and temperature of 25◦C with a contact time of 10 min at 200 rpm stirring speed. Test results were analysed by adsorption isotherms and kinetics modelling and the best adaptation was made by the Langmuir isotherm and the second best by the para-stage synthetic model.
Original Articles
Ghazal Raheb
Volume 11, Issue 4 , January 2014
Abstract
Population growth in the major cities of Iran has led to the limitation of land resources, higher consumption of non-renewable sources of energy and many other environmental problems. The emergence of overly built-up urban areas and a decreasing amount of green spaces cause the appearance of an undesirable ...
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Population growth in the major cities of Iran has led to the limitation of land resources, higher consumption of non-renewable sources of energy and many other environmental problems. The emergence of overly built-up urban areas and a decreasing amount of green spaces cause the appearance of an undesirable landscape within cities. Green roof technology is one solution for responding to environmental concerns in urban areas. This technology combines green spaces with buildings as private or semi-private spaces. Its successful implementation in different areas depends on the accommodation of green roof type technology within the environments and urbanand building typologies in Iran. This paper aims to provide some recommendations for selecting the appropriate type of green roof and for implementing approaches that take account of the climatic zoning and urban situation in Iran. Two primary aspects that are considered are environmental and urban typology factors. The research method is based on the study of indicators related to each factor mentioned in different zones of Iran, thereby leading to a feasibility study for the application of green roofingin Iran.
Original Articles
Amir Salemi
Volume 11, Issue 4 , January 2014
Abstract
Different classes of pesticides are used during production of various tea products. Beside their health impact on the consumers, these pesticides are likely to be released into the different natural media and affect the exposed environment. To help predict chromatographic behavior of these pesticides, ...
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Different classes of pesticides are used during production of various tea products. Beside their health impact on the consumers, these pesticides are likely to be released into the different natural media and affect the exposed environment. To help predict chromatographic behavior of these pesticides, the gas chromatographic retention behavior of 57 of these pesticides were modeled using quantitative structure-retention relationship approach. The most important descriptors encoding structural and topological properties of the studied compounds were showed to be in a linear relation with their retention time. A stepwise variable selection strategy in MLR modeling resulted in models with acceptable R2 values of which a model based on five molecular descriptors was selected to compromise between high R2 values and low variable numbers. The selected descriptors were VRD2, X1sol, Rww, MLOGP and More09e. The model was tested for its prediction capability, by examining a prediction set of randomly selected compounds (10 pesticides) and the average of the prediction error was used as the criteria. The model, regarding its simplicity, was successful in predicting the retention times of the proposed set of compounds.
