فهرست مطالب

Environmental Resources Research - Volume:6 Issue: 2, Summer - Autumn 2018

Journal of Environmental Resources Research
Volume:6 Issue: 2, Summer - Autumn 2018

  • تاریخ انتشار: 1397/09/13
  • تعداد عناوین: 9
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  • S. Hashemi Rad, F. Kiani *, M. Meftah Helghi, Y. Hematzadeh Pages 89-102
    The objective of this investigation was assessment of physical and chemical parameters of soil and sediment in loess lands under different land uses, in the north of Iran. A yearly soil sampling was carried out randomly in three land uses (cultivated, forest and pasture) in Qarnave and Yelcheshme watersheds. Sediment samples were taken monthly in the watersheds at the hydrometrical station of Tamer located in downstream of the watersheds. The results showed that soil texture was silty clay loam and silty loam in forests and cultivated lands, respectively. In both watersheds, the highest amount of pH, carbonate calcium, available phosphorus (P) and bulk density (BD) was observed in cultivated lands, whereas the highest amount of total nitrogen (TN), mean weight diameter (MWD) and organic carbon (OC) was observed in forest. The highest amount of TN was observed in autumn, whereas the maximum amount of K was observed in summer, in both soil and sediment samples. The highest amount of P in soil and sediment was observed in summer and winter respectively. Also, the highest percentage of OC in soil and sediment was observed in autumn and summer respectively. The results showed that tillage and soil cultivation in cultivated lands may lead to reduction of OC and BD, therefore, decreasing the MWD.
    Keywords: Land use, Loess, Soil Quality, Sediment
  • S. Abedian *, A. Salmanmahiny Pages 103-117
    Soil erosion and sedimentation processes can be considered as serious eco-environmental problems. This study aimed to estimate the basin-wide erosion using the Revised Universal Soil Loss Equation (RUSLE). The soil erosion parameters included rainfall erosivity map generated from the rainfall data, soil erodibility extracted from the soil map, land cover and management map produced from supervised classification of Landsat ETM+ data, and a Digital Elevation Model (DEM) to generate the slope length and steepness factor (LS) maps. Support practice map was assumed as 1 as there were no significant conservation practices. Then, the six thematic layers were integrated based on RUSLE model in GIS environment, and the spatial distribution of soil loss in the Gorganrud Basin was achieved. The distribution of erosion risk was 42.5% for low, 30.33% for moderate, and 27.17% for severe classes. The highest amount of erosion occurred in the northwest to northeast and eastern regions with lithological units including loess, young terraces and alluvial deposits and agricultural use despite the fact that LS factors in these areas were less than 10. In the central and southern parts of the basin, in spite of the high values of LS factor (15–55), these areas depicted low to moderate erosion potential. This is supposed to be due to the dense forest coverage in the region that decreases the energy of rain droplets. The soil erosion risk map can be used for rapid assessment of the effects of environmental changes and watershed management interventions.
    Keywords: Soil erosion, Erosion risk, watershed management, RUSLE
  • K. Atashnama *, A. Golchin, A. Mousavi Koupar Pages 119-138
    Afforestation, as a tool to mitigate carbon emission is constrained by available land area in several countries, but Iran has the potential of plantation. In doing so, differences in soil stocks between tree species could give an indication of the effects of future management changes. Hence, a better understanding of tree species traits on soil properties is required to predict how changes in ecosystems occur with tree species composition. This study investigated the effect of selected tree species on soil properties, carbon sequestration potential of tree species across soil profiles (0-200 cm) and evaluated the tree species effects on labile soil organic carbon pools to introduce a unique soil quality indicator. The study site was Shalman Research Station in the Hyrcanian forests, northern Iran. Our results showed significant alterations in soil properties by tree species with the greatest changes in the top soil layer. The greatest cation exchange capacity (CEC) difference (Δ 4.17) was found between A. glutinosa and J. polycarpos in 0-20 cm. The greatest differences (Δ 2.58) in mean weight diameter (MWD) of soil layers were found in the top soil layer between A. glutinosa and T. distichum. All species produced also a higher N and organic carbon concentration in the top soil layer (0-20 cm) in the following order: A. glutinosa > Q. castaneifolia > P. caspica > J. polycarpos > T. distichum > P. taeda. The varied amount of total soil organic carbon stocks was greater under Alder (A. glutinosa) and Oak (Q. castaneifolia) than other tree species with 206.24 and 195.26 (Mg.ha-1), respectively; and P. taeda had the lowest amount (136.94 Mg ha-1) across the soil profile. For all labile pools, A. glutinosa and T. distichum had the highest and the lowest percent of labile organic carbon, respectively. Consequently, the Cmin in the range of 10.11-14.04% and microbial biomass carbon in the range of 1.05-1.66% shared the highest and lowest proportion of soil organic carbon across 0-200 cm depth, respectively. We concluded that broadleaf trees had great potential for carbon sequestration across soil depth and among them; alder had high effect on soil properties and soil organic matter.
    Keywords: Labile soil organic carbon, Carbon stocks, Soil properties, Broadleaf, Coniferous, Water soluble organic carbon
  • H. Torabi, R. Dehghani * Pages 139-147
    Sediment transport constantly influences river and civil structures and the lack of information about its exact amount makes management efforts less effective. Hence, achieving a proper procedure to estimate the sediment load in rivers is important. We used support vector machine model to estimate the sediments of the Kakareza River in Lorestan Province and the results were compared with those obtained by gene expression programming. The parameter of flow discharge for input in different time lags and the parameter of sediment for output during 1992-2012 were considered. Criteria including correlation coefficient, root mean square error and mean absolute error were used to evaluate and also compare the performance of models. With regards to accuracy, the support vector machine model showed the highest correlation coefficient (0.994), minimum root mean square error (0.001 ton/day) and the mean absolute error (0.001 ton/day) which was initiated at verification stage. The results also showed that the support vector machine has great capability to estimate the minimum and maximum values for sediment discharge.
    Keywords: suspended sediment, Kakareza, Support vector machine, Gene expression programing
  • M. Safari Sinegani*, A.A. Safari Sinegani, M. Hadipour Pages 149-161
    Solubility and bioavailability of heavy metals are important with respect to their toxicity. The discharge of municipal wastewater in soil and surface waters can affect bioavailability and mobility of heavy metals in soils and sediments. The effect of discharge of Arak municipal wastewater on the KNO3 and DTPA extractable heavy metals in a saline soil sampled from Mighan playa (Iran) compared to a non-saline agricultural soil was studied in two moisture regimes (field capacity and flooding) in three incubation times (1, 150 and 365 day). In the saline soil, the addition of wastewater led to increase of organic carbon (OC) and decrease of Eh, pH and EC. However, in the non-saline soil, the addition of wastewater led to increase of EC and decrease of TOC and Eh simultaneously. With very few exceptions, the addition of wastewater increased the KNO3 and DTPA extractable heavy metals significantly. These changes were higher in the saline submerged soil. So, the addition of municipal wastewater in soils for irrigation of saline and non-saline croplands was safer than when it was applied in waterlogged soils. The changes of the analyzed properties were higher in the saline soil compared to those in the non-saline soil. Hence, the resilience of the saline soil compared to the non-saline soil due to its lower buffering capacity was considerably lower. We can conclude that the release of wastewater to Mighan playa soil with high level of salinity may increase the bioavailability and mobility of heavy metals towards that lake.
    Keywords: Availability, Flooding, Heavy metal, Salinity, Wastewater
  • M. Masoudi *, E. Asadifard, M. Rastegar Pages 163-174
    In the present study, air quality analyses for particulate matters (PM10) were conducted in Ahvaz, a city in the south of Iran. The measurements were taken from 2009 through 2010 in two different locations to prepare average data for the city. The average concentrations were calculated for every 24 hours, and each month and each season which showed the highest concentration of PM10 in the morning while the least concentration was found in the afternoon. Monthly concentrations of the PM10 showed the highest value in July and the least in January. The seasonal concentrations show the highest amounts in summer. Relationships between air pollutant and meteorological parameters were assessed statistically using the daily average data. The wind data (velocity, direction), relative humidity, temperature, sunshine periods, dew point and rainfall were considered as independent variables. The relationships were expressed by multiple linear and nonlinear regression equations for annual and seasonal conditions using SPSS software. Results showed significant relationships between PM10 and some meteorological parameters. RMSE test showed that among the different prediction models, stepwise model is the best option. Unfortunately, mostly the concentration of the PM10 was very higher than primary standards of PM10 (50 µg/m3) for human health, that is why recently, Ahvaz is considered one of worst polluted cities in the country.
    Keywords: Particulate Matters, Ahvaz, Air Pollution, RMSE, Regression model
  • I. Amini *, A. Tahmourespour, A. Abdollahi Pages 175-185
    Anthracene is a widespread environmental pollutant with carcinogenic and genotoxic properties. Biodegradation is a simple, cost-effective and safe technique to clean-up contaminated environments. The aims of this study are isolation and characterization of an oligotrophic bacterium with the ability to degrade anthracene and the assessment of in vitro biodegradation process. For this purpose petroleum contaminated soil was collected from Isfahan-Iran refinery. Soil sample was found to be neutral and slightly saline with high concentration of anthracene. The population of total heterotrophic bacteria and anthracene degrading bacteria were 2.50 × 103 and 1.96 × 103 CFU/g, respectively. Seven anthracene degrading bacteria were isolated by enrichment culture technique in Basal Salt Medium (BSM) supplemented with 50 mg/l anthracene. An oligotrophic bacterium was selected based on growth on carbon free medium. This isolate was identified as Methylobacterium rhodesianum ATAI15, submitted to GenBank under accession number of KC469989.1. The biodegradation rate of 50mg/l anthracene by this isolate during 9 days was 41.2%, determined by Gas Chromatography. This bacterium was adapted to survive in nutrient deficient medium and high concentration of anthracene (up to 12000 mg/l). Use of this isolate in cooperation with other PAH degrading bacteria can be effective in bioremediation of polluted environments.
    Keywords: Oligotrophic bacterium, Methylobacterium rhodesianum, Anthracene, Bioremediation
  • M. Mahmoudi Zarandi, M. Pourmousa * Pages 187-194
    Global warming has today turned to one of the most important environmental issues due to overuse of fossil fuels, and it needs serious attention. Since the mid-1970s, an urgent need was therefore felt around the world to reduce the use of energy for heating and cooling in buildings. Using green covers, especially green facades, in appropriate environmental conditions can be regarded as a method to achieve thermal comfort while maintaining the building energy consumption low as well as reducing greenhouse gases emission. The present paper investigates the features related to living walls in different climates. Based on results, due to reduced heat absorption, evaporative cooling and low thermal conductivity, the hotter and drier the climate, the higher the efficiency of the green wall as well as temperature reduction will be. On the other hand, using of green walls in temperate and hot and humid climates has a positive effect, but because of the humidity factor, open or closed air layers should also be considered. The green wall surface creates more stable relative humidity in the air layer near the wall surface without increasing the relative humidity of indoor air. At the urban scale in the warmer and drier climates, the green covers will have a dramatic effect on urban temperatures. Using green covers of buildings’ walls, there will be a significant potential for reducing urban temperatures, while the highest efficiency will be achieved with simultaneous application of green surfaces for both roofs and walls.
    Keywords: Green façade, Living wall, Hot, humid, Temperate, dry
  • S. Haghighi, D. Akhzari *, B. Attaeian, M. Bashir Gonbad Pages 195-200
    Water scarcity is one of the factors limiting plant growth and development. More than one third of the global terrestrial ecosystems is located in arid and semi-arid regions. The most important limiting factor for plant growth is water shortage. Drought could significantly change the natural vegetation cover. Rainfall reduction in Iraq, Turkey and Syria has reduced vegetation cover so that dust storms have increased. Therefore, these areas have a high potential to increase dust particles in the environment. To investigate the temporal changes of vegetation, we focused on the source of dust particles between Tigris and Euphrates rivers and some parts of the west bank of these rivers in Iraq. The Normalized Difference Vegetation Index (NDVI) was used. In addition, the standard precipitation index was calculated to assess drought events in the region. The results show that the vegetation and rainfall indexes are inversely correlated in the study area.
    Keywords: Dust Storm, Drought, Vegetation1