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Showing 26 results for Environment

A. Khatoon Abadi, E. Parvizi, M. Ataie,
Volume 22, Issue 4 (3-2019)
Abstract

In the recent decades, dams have paradoxically been considered as a constraint and or a driving force of surface water conservation. On the other hand, dams have had a number of socio-economic and environmental impacts, the main reason for conducting the current case study on Shah-Qasem Dam in Yasouj, Iran, was to employ the survey field research through a questionnaire to assess the rural peoples’ viewpoint; this was done in four villages of the Southern Sar’roud County. Based on the (Cochran) formula, 192 individuals were relatively selected from each village. According to the findings, the most important impact of the dam was mainly economical (the average impact was between 2.37 and 3.7), whereas the least one was environmental (the average impact was between 1.81 and 3.54). Also, the results of the hypotheses’ analyses by means of 2 and Wilcoxon showed the following results: rise of the villages’ income, increase of the cultivated farms, increase in the employed individuals, enhancement of the cultivated crops, the regions production rising, improved tourism, lack of people’s participation in the decision making process, and reaming of the same plant varieties in the area, as compared with the pre-dam era. It is worth considering, however, that based on the statistical population used, this study was concerned mainly with the short benefits of the dam, rather than its long-term destructive ones.

Z. Ghorbanpour, O. Abessi, F. Kardel,
Volume 24, Issue 4 (2-2021)
Abstract

Drilling material from the tunnel of the Tehran-Shomal highway was estimated to be about 2.5 Million Cubic Meters by the project authorities. Sadly, from the beginning, the drilling materials had been deposited on the open space in the floodplain of the Chaloos river with slightest environmental considerations. During the previous years, weathering and leaching from the drilled materials besides the discharge of drain water from the tunnel had led to seriouse contaminations and the deterioration of the water quality of the Chaloos river. In this paper, the ecological risk of nonorganic pollutants due to drilled materials was investigated. The sampling was done from the excavated materials and river sediment in five different locations throughout a complete year. From the many pollutants, Nickel, Cadmium and Copper were chosen to be investigated. The results showed that almost 15 percent of the samples had a high degree of pollution, while 60 percent of them were clean and the other 25 percent included the highly contaminated ones. All samples were also estimated to have a low to high ecological risk.

M. Masoomi, M. Pourgholam-Amiji, M. Parsinejad,
Volume 26, Issue 1 (5-2022)
Abstract

In this study, the Drainmod-S model was used to vary soil salt concentration and the effect of underground drainage on the amount of leaching in a physical model (large lysimeter). A soil extractor was installed at depths of 40, 50, and 70 cm at a distance of 35 cm from the drainage to measure the salinity of the soil solution. In this study, three scenarios were applied including salinity profiles under conventional conditions (mid-season and end-season drainage), soil salinity profiles under different drainage conditions, and prior scenarios with saline irrigation. The second and third scenarios were applied in four drainage stages, respectively. These stages include transplanting and mid-season drainage (days 15 to 20), mid-season drainage (days 35 to 40), mid-season and end-season drainage (days 55 to 60), and end-season drainage (days 75 to 80). The results showed that after simulating the total solute concentration overtime at a depth of 40 cm and comparing it with the measured values, the coefficient of determination (R2) was 0.77 indicating an acceptable Drainmod-S model simulation. This parameter for simulating solute concentration at 50 and 70 cm depth was 0.76 and 0.75, respectively. The mean absolute error parameter (MAE) value was also negligible.

S. Azadi, H. Nozari, S. Marofi, B. Ghanbarian,
Volume 27, Issue 3 (12-2023)
Abstract

One of the strategies for agricultural development is the optimal use of irrigation and drainage networks, which will lead to higher productivity and environmental protection. The present study used the system dynamics approach to develop a model for simulating the cultivated area of the Shahid Chamran irrigation and drainage network located in Khuzestan province by considering environmental issues. Limit test and sensitivity analysis were used for model validation. The results showed the proper performance of the model and the logical relationship between its parameters. Also, the cropping pattern of the network was determined in two modes of non-stepwise and stepwise changes to determine the optimal cultivated area of the Shahid Chamran network with environmental objectives and minimize the amount of salt from drains. The results showed that the amount of optimized output salt from the network has decreased in both non-stepwise and stepwise changes compared to the existing situation in the region. The total output salt in the current situation, from 2013 to 2017, was obtained at 2799, 2649, 2749, 2298, and 2004 tons.day-1, respectively, in the stepwise changes, are 2739, 2546, 2644, 2223, and 1952 tons.day-1, and finally, in the non-stepwise changes, are 2363, 2309, 2481, 2151, and 1912 tons.day-1. The results showed that the non-stepwise changes due to considered limitations have been more successful in reducing output salt than the stepwise changes. The analysis of the results showed the model's success in optimizing and achieving the desired goals. The results showed that the present model has good accuracy in simulating and optimizing the irrigation network, cropping pattern, and defining other scenarios.

S. Najmi, M. Navabian, M. Esmaeili Varaki,
Volume 27, Issue 3 (12-2023)
Abstract

The increasing need for water resources and controlling the discharge of wastewater into the environment shows the necessity of wastewater treatment. Green methods such as constructed wetlands and phytoremediation use biological processes in the environment for wastewater treatment. Considering the effect of cultivated constructed wetland performance from wastewater quality and climatic factors, the objective of this study was to evaluate the performance of hybrid and subsurface vertical and horizontal wetlands to improve the biological and chemical oxygen demand of the wastewater treatment plant in Rasht City. The effect of Phragmites australis and Typha latifolia plants on the treatment performance was investigated. Wastewater retention time in wetlands varies from monthly in winter and weekly in spring and summer. The results showed that the performance of wetlands in reducing biological oxygen demand (BOD) was more than chemical oxygen demand (COD). Plants improved the performance of the wetland by more than 50%, but no significant difference was observed between the performances of the two plants. The arrangement of the plant's cultivation was not effective in the amount of biological and chemical oxygen removal. The hybrid wetland was able to improve the wastewater quality twice as much as the vertical wetland. Comparing the concentration of the effluents from the wetlands with the standards showed that the effluents from the hybrid wetlands could only be used for agricultural consumption.

B. Akbari, H. Khademi,
Volume 27, Issue 4 (12-2023)
Abstract

Street dust enters the urban environments due to the resuspension of particles smaller than 100 micrometers. The magnetic properties of street dust and their relationship with the concentration of heavy metals have received less attention from researchers worldwide, and not much study has been performed on this issue in Iran. The objectives of this study were: (i) to investigate the spatial and seasonal changes in street dust, and (ii) to determine their relationships with the concentration of selected heavy metals in several cities in the Isfahan province. Sampling was carried out in the first half of the second month of each season including 20 samples from Isfahan city and 10 samples from Natanz, Shahreza, Falavarjan, Khomeinishahr, and Najafabad. The concentration of selected heavy metals was measured using an atomic absorption spectrometer. Also, the magnetic susceptibility values of the samples at low and high frequencies were determined and frequency-dependent magnetic susceptibility was calculated. The results showed that the presence of ferromagnesian minerals in the parent materials could be the reason for the high values of magnetic receptivity in Natanz City. However, the high level of this characteristic in the street dust of other cities could be due to human activities, especially in Isfahan city. Based on the results of principal component analysis, the high correlation of the first component with magnetic susceptibility and the concentration of zinc, copper, and chromium elements most likely indicates the absorption of these elements by particles close to superparamagnetic (SP). The high correlation of the second component with frequency-dependent magnetic susceptibility and concentration of nickel and cobalt is most likely related to the adsorption of magnetic elements and heavy metals into coarse polyhedral particles that remained on the street floor after the re-deposition of street dust particles. Also, the high correlations between magnetic parameters and the concentration of copper and zinc confirm their anthropogenic origin. On the other hand, low or negative correlations of Pb, Ni, Cr, and Co concentrations with magnetic susceptibility might confirm their natural or non-anthropogenic origin. The higher values of magnetic parameters of street dust in the spring season reflect the significant contribution of magnetic minerals in this season, compared to autumn and winter, and indicate the higher influence of human activities.


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