Journal of Water and Soil Science
Year:2018 | Volume:22 | Issue:1|Papers Count:30

Gypsiferous soils are one of the problematic soils which, due to solubility and contact with water, are a threat to various civil structures, especially water structures. Various factors affect the rate and amount of gypsum particles solubility. Gypsum types, the soil texture, the amount of gypsum in soil, the hydraulic gradient, and temperature and flowing water from gypsum soil are the major factors affecting the quality and quantity of the gypsum solution. In this research, the effects of some peripheral conditions including water temperature and hydraulic gradient on the solubility of gypsum soils were studied. To this aim, samples of gypsum soils were provided artificially by adding various rates of the natural gypsum rock including 0, 5, 10, 20 and 30 percent by weight of clay soil. Then, all gypsum soils were leached under five hydraulic gradients levels including 0. 5, 1, 2, 5 and 10. The results indicated that the rate of Gypsum in the soil had a direct effect on the rate of solution in a way that by increasing the percent of Gypsum, the rate of solubility was increased. Also, the rate of leaching (the rate of the derived Gypsum from soil to the primary rate of Gypsum) was decreased by increasing the rate of Gypsum. In addition, by increasing hydraulic gradient, the speed of water and its amount in soil environment within a specified time were raised; further the rate of gypsum was increased too. Also, it was found that the rate of the solubility was increased directly by the temperature. The solubility rate of the gypsum soil at 50 C0 was found to be 2. 5 and 1. 6 times greater than that of the soil at 5 and 20 C0, respectively.

Today, the growth of population, the excessive growth of cities and subsequently, the industries development in all parts of the planet are evident. Such development leads to the entrance of chemical martials with various compounds, particularly heavy metals, in aquatic ecosystems. In this study, the contamination of the sediments around the Mighan wetland basin with heavy metals such as lead, zinc, copper and nickel was investigated using CF indexes (contamination factor), IGeo geo-accumulation indexes, and IPOLL sediment contamination severity. The results indicated a high concentration of copper and nickel metals, in comparison to zinc and lead metals, in the studied area. Also, regarding the location of sampling stations and their proximity of the industries around the wetland, the comparison of the results related to the measured metal concentration and the sediment quality indices, indicated a high concentration of the pollutants under examination in the southern part of the wetland, thereby emphasizing the need to control the pollutants in the wetland.

Water loss and nutrients loss are one of the important signs of natural resource degradation in the catchments. The amount of loss of these resources is affected by several factors including the characteristics of rainfall. In this study, the data of stream discharge (Q), total dissolve solids (TDS), and total nutrient loss ratio (NR) along with rainfall characteristics were analyzed for the events from1988 to 2002 in the Tahamchai catchment, which is owned by a regional water company. Moreover, soil properties were determined by soil sampling from different points in the catchment surface. Based on the results, there was a significant correlation between Q of the river and rainfall height (r=0. 24, p<0. 05), while its correlations with the rainfall intensity and duration were not statistically significant. On the one hand, this result was due to the inverse relationship between rainfall intensity and rainfall duration; on the other hand, due to the temporal variations in vthe egetation cover in the area, it controlled Q in the intensive rainfalls. The highest Q was in spring (1. 68 m3 sec-1) and March (2. 58 m3 sec-1). In this period, rainfall height was high and the rainfalls interval was short. Moreover, vegetation cover was weak, so it could not control surface runoff and reduce Q in the catchment. TDS and NR also significantly varied during the months and their highest values were observed in December (282. 55 mg l-1) and (61. 77 mg l-1), respectively. Mg2+ had the highest amount of water loss in the catchment area. A negative correlation was found between Q and TDS (r=0. 41, p<0. 001) and NR (r=0. 31, p<0. 001). This study revealed that spring and autumn were the sensitive period for water loss and nutrient loss in the catchment, respectively. Therefore, promoting the vegetation cover in early spring and reducing improper agricultural practices (tillage and fertilization) could be substantial strategies contributing to conserving the catchment’ s resources.

In this study, the trends of changes of the standardized precipitation index in a 12-month timescale (SPI-12) and seasonal and annual precipitation were investigated in 21 humid and semi-arid stations of Iran during the 1976-2014 time period. After removing the serial correlation of some series, the trend of precipitation and SPI-12 was detected using the Mann-Kendall nonparametric trend test. The results revealed that the trends of annual precipitation had been declining in all stations over the past 39 years. The seasonal precipitation trend in winter, spring, autumn and summer was downward in approximately 90, 95, 47 and 37% of the studied stations, respectively. In addition, the descending trend of wintertime precipitation was significant in Sanandaj, Khoy, Urmia, Hamedan, Mashhad, Torbat-e-heydarieh, Nozheh and Qazvin. Also, the temporal trend of SPI-12 was decreasing in all surveyed stations except Shahrekord. Furthermore, SPI-12 showed a significant downward trend only in Sanandaj and Fasa. Moreover, the most severe meteorological drought occurred in the period 1999-2000, in Ramsar, Urmia and Hamedan, and in the period 2008-2009, in Tabriz, Sanandaj, Shiraz, Fasa, Qazvin, Mashhad, Torbat-e-heydarieh, Shahrekord, Gorgan and Kermanshah stations. Overall, the results of this study indicated that the trend of precipitation in most studied sites, particularly in semi-arid parts of the northeast and southwest of Iran, has changed due to the severe and long metrological drought that has occurred in the recent decade (2005-2015).

With the increase of population, the optimal use of water resources is necessary. This study was carried out to evaluate the impact of different levels of irrigation on the yield, yield components and water productivity of corn using single and double row drip irrigation systems (Tubes type). . The experiment was conducted in a split plot design based on the randomized complete block design (RCBD) with three replications in 2012 in Hajiabad, Hormozgan Province. The treatments were comprised of three levels of irrigation as the main plot (100, 80 and 60% water requirement) and two patterns of irrigating water pipe installation (normal and every other row) as a sub-plot of the design. The results showed that irrigating with the 80 percent water requirement, in comparison with full irrigation, increased the total yield by 1. 4%, the seed weight by 1. 8%, the number of seeds per row by 8. 7%, and the number of seed row per maize by 13%. In spite of yield superiority in the pattern of normally irrigating water pipe installation (10055. 56 kg ha-1), against every other row installation (9366. 67 kg ha-1), water productivity was more in every other row installation (1. 089 kg m-3). Therefore, partial root-zone drying was recommended by the irrigation of the 80% plant water requirement for the maize in the region.

This research was aimed to simulate and prioritize the effective factors on water erosion using USLE-M in the system dynamic model. In this integrated model, by using the system dynamic simulation software (Vensim), all variables and factors involved in erosion and soil loss were considered according to the USLE-M model. After model implementation, the estimated values and observations were compared and then sensitivity analysis was done to determine the sensitive parameters. Then, calibration was performed on the sensitive parameters. This study found that that the results of the model were acceptable for soil erosion simulation due to considering all the effective factors in soil erosion. The results of the sensitivity analysis also indicated high model sensitivity to the slope and vegetation cover in high and low slopes, respectively. By investigating the changes in various parameters such as vegetation cover and slope on erosion, the optimal vegetation cover with 67 and 40% slope, was estimated to be 20 and 60%, respectively.

Landfill sites are one of the most important sources of contaminant entry to the environment. In this research, the concentrations of Cu, Pb, Ni, Cd, and organic compound BPA in Hamadan landfill were evaluated to determine the status of its burial environment in 2014. Seven water samples (2 samples from spring and 5 samples from well), 2 leachate samples and 15 soil samples were collected from Hamadan landfill. Evaluation of the concentrations of Cu, Pb, Ni, Cd and the organic compound BPA was done by atomic absorption and gas chromatography with mass spectrometry. The concentrations of metals (Cu, Pb, Ni and Cd) in water samples (wells and springs) Pb

In this study, the values of moisture and soil temperature were estimated at different depths and times under unsteady conditions by solving the Richards’ equation in an explicit finite difference method provided in Visual Studio C#. For the estimation of soil hydraulic parameters, including av and nv (coefficients of van Genuchten’ s equation) and Ks (saturated hydraulic conductivity), soil moisture and temperature at different depths were measured by TDR probes and the stability apparatus, respectively. The objective function [equal to Root Mean Square Error (RMSE)] was minimized by the optimization of a parameter separately, using the Newton-Raphson method, while, the other parameters were considered as the constant values. Then, by replacing the optimized value of this parameter, the same was done for other parameters. The procedure of optimization was iterated until reaching minor changes to the objective function. The results showed that soil hydraulic parameters (coefficients of van Genuchten’ s equation) could be optimized by using the SWCT (Soil Water Content and Temperature) model with measuring the soil water content at different depths and meteorological parameters including the minimum and maximum temperature, , air vapor pressure, rainfall and solar radiation. Finally, the measured values of soil moisture and temperature were compared to the depth of 70cm in spring, summer, and autumn of 2015. The values of the normalized RMSE of soil water content were 0. 090, 0. 096 and 0. 056 at the soil depths of 5, 35 and 70 cm, respectively, while the values of the normalized RSME of soil temperatures were 2. 000, 1. 175 and 1. 5 oC at these depths, respectively. In this research, the values of soil hydraulic parameters were compared with other previous models in a wider range of soil moisture varying from saturation to air dry condition, as more preferred in soil researches.

Recently, virtual water trade has been introduced as a tool to solve the water scarcity of dry regions. The concept holds that water-rich countries and regions should produce and export water-intensive commodities to water-scarce countries and regions. In this study, the status of domestic and international virtual water trade was studied to assess water management in Iran in 2006 (which was considered as a normal year). The calculations showed that 18666 Mm3 of virtual water was traded through the exchange of agricultural products between the provinces. Fars and Tehran provinces were the largest exporter and importer of virtual water, respectively. Iran imported 9626 Mm3 and exported 2226 Mm3 of virtual water. Water footprint was 752 m3/cap/yr and water self-sufficiency was 82% in Iran. The virtual water content of the exported and imported products was 1159 L/kg and 677 L/kg, respectively. The results showed that water-scarce provinces such as Kerman, Hormozgan and Semnan were exporters of virtual water to other provinces and abroad, whereas water-rich provinces such as Guilan, Chaharmahal and Bakhtiari, Lorestan, Kordestan, West Azarbayjan, Kohgiloyeh and Boyr-Ahmad, and Kermanshah were the importers of virtual water. Therefore, water management can be improved by the improvement in international and inter-province virtual water trade. For this purpose, the cropping pattern and consumption pattern should be adapted to the virtual-water content of agricultural products for the long-term water conditions in Iran.

Cadmium (Cd) is of special importance among heavy metals because its toxicity to the plant is 20 times higher than other heavy metals. The present study was conducted to evaluate the trend of available soil Cd changes over time and its relationship with soil properties. Treatments consisted of 13 soil samples and two Cd rates (12. 5 and 25 mg kg-1) as a factorial in a complete randomized design with two replications. DTPA extractable Cd was measured upon 5, 10, 20, 30, 60 and 90 days after adding Cd rates to the soils. The results showed that DTPA extractable Cd was increased as Cd application rates was raised in all soils. DTPA extractable Cd was decreased over time; however, at the end of the experiment, much of the added cadmium to the soil remained in use. Among the soil properties, calcium carbonate showed a significant negative correlation with DTPA extractable Cd in most of the incubation times in both Cd rates. DTPA extractable Cd also showed a significant negative correlation with pH and soil sand and a significant positive correlation with OC. Also, the results of the fitting of cadmium adsorption data with the kinetic equations showed that the exponential function equation was the most suitable kinetics descriptive equation for variations in cadmium adsorption in the studied soils.

The purpose of this study was to evaluate two perforated sills in the stilling basin and their impact on characteristics of the hydraulic jump, such as the length of the roller of hydraulic jump, decrease in the secondary depth of the hydraulic jump, and the required tailwater depth. Also, the optimal distance of two perforated sills from the beginning of the stilling basin with a fixed height for the perforated sill and ratios of the opening of holes equal to 50% were determined. The experiments were carried out in the form of 48 tests for different discharges in the range of 47 to 145 lit/s and for Froude numbers in range of 3. 6 to 11. 2. The results of the experiments on two perforated sills showed that they could only reduce the length of the roller of the hydraulic jump to an acceptable level, with the distance between them providing the conditions to create a stable jump; also, the length of roller of jump was not decreased by reducing the distance between the sills. Also, they decreased the secondary depth of the forced hydraulic jump up to 27. 8%, which was less than the secondary depth of the free hydraulic jump; the length of roller was up to 76. 9 % less than the length of the roller of the free hydraulic jump for the Froude number of 11. 2.

Discharge of contaminants in the acceptor ambient has negative environmental impacts. Extremely shallow acceptor ambient conditions will have a significant impact on the diffusion of the contaminants flow. To achieve the effect of the hydraulic, geometric and environmental conditions of the contaminant flow in the acceptor ambient, an experimental model of surface draining was applied. The model consisted of a flume with 3. 2 meters length, 0. 6 meters width and 0. 9 height. Accordingly, by considering three simple single drainers with the diameters of 1. 2, 1. 6 and 2. 2 centimeters, a dense flow with 20, 40 and 60 g/L concentrations occurred in an acceptor ambient with H/d = 2. The results showed that equilibrium length was extremely decreased by increasing the concentrations; this was such that with increasing the concentration three times from 20 to 60 g/L, this length was decreased from 25 to 10. However, based on the results, it was found that the effect of the changes of the viscosity parameter over the relative length was significant, as its effect was high in all concentrations to 100; then it tended to become a constant value. . In this regard, the effect of changes in the surface tension parameters over the relative length was investigated; the results showed that this parameter was always effective in the extremely shallow acceptor ambient at all stages from the beginning to the end of the progress. It is important to note that this had a constant slope in all concentrations and surface tension had an effect on flow diffusion with a certain trend in all concentrations. In fact, surface tension in all concentrations reached to 5 after the equilibrium length and jet energy dissipation area.

In this study, five infiltration models including Kostiakov, Kostiakov-Lewis, Philip, Soil Conservation Service (SCS) and Horton were fitted to the experimental data using the double rings, and the empirical coefficients of these models were determined. Infiltration experiments were conducted in the gravelly sandy loam soil under and between the olive and orange trees in Fasa city, Fars Province, Iran. The results showed that all five models were fitted accurately to the measured data. The accumulated infiltration under the trees was higher than those measured between two trees. Higher infiltration under the tree canopies was probably due to the higher soil organic matter, the lower soil bulk density, and the tree root channeling, which were more pronounced when compared to the small pores in these soils. Despite the positive effect of sand particles on soil infiltration, the big gravel occurrence in soil would decrease the cross section area of water flow path, thereby reducing the infiltration. Therefore, changing the land use and planting olive and orange trees in the gravel soils would increase the infiltration rate and consequently, decrease runoff and erosion rates in such soils.

Underground dams are structures built in underground and are capable of saving and making the underground water available. In this research, by using the SWOT analysis model, suitable locations were investigated for the development of an underground dam in the Keriyan area of Hormozgan province. At first, the necessary data and information were provided by visiting the region and presenting a questionnaire to the residents of the area and experts to investigate the strengths, weaknesses, opportunities and threats in the region for the underground dams. In the final step, by using the SWOT model and QSPM matrix, a comprehensive and appropriate strategy for underground dams was determined. The results showed that among the internal factors, not decreasing the volume of the reservoir due to deposits and reducing the evaporation from the reservoir with a final value of 0. 85 and 0. 66, and among the external factors, the willingness and cooperation of the relevant organizations and the disruption of downstream water rights with a final value of 0. 68 and 0. 66 had the greatest impact on selecting the strategy. Based on the results related to the internal and external factors, the strategy was placed in the maximum-maximum quadrant; in line with the strategy, by using the strengths and opportunities, the weaknesses should be overcome and the threats should be tackled. Some strategies were presented. In order to prioritize these strategies, the quantitative matrix QSPM was used. Finally, the hydrological, economic, social and environmental evaluating strategies of underground dams, before and after the construction, with a final score of 19. 3 were prioritized.

Biochar is a soil amendment that has a high capacity to adsorb heavy metals. The aim of this study was to identify the influence of cow manure and its biochar on nickel adsorption and to determine the best models to describe the kinetics of Ni retention. Accordingly, cow manure and its biochar were added to the soils at the levels of 0, 2 and 4%, and samples were incubated for 90 days. Soil samples were equilibrated with 100 mg L-1 Ni solutions for periods of 1 to 2880 min. Then, the concentration of nickel was measured. The Ni adsorption data were fitted to seven commonly used kinetic models. The results showed that cow manure and its biochar application in all times and levels increased nickel adsorption more than the control. There was also a significant difference (P<0. 05) between cow manure and its biochar. Application of 4% biochar, as compared with the same level of cow manure, and the control, increased the Ni adsorption by 23 and 44%, respectively. Power function was the best fitted model describing the patterns of Ni adsorption, as evidenced by the relatively high values of R2 and the low values of SE. However, the Elovich function had some R2 similar to that of power function, but it could not be used as an adequate function to investigate the kinetics of nickel adsorption due to their high values of SE. The zero order, the first order, the second order, the third order, and parabolic diffusion equations were not well fitted to the Ni adsorption data.

The purpose of this paper was to assess the groundwater quality near Qaemshahr landfill site using the Iran Water Quality Index for Groundwater Resources-Conventional Parameters (IRWQIGC). In this study, samples were taken from 11 wells with three replications in February 2015 and water quality was assessed by evaluating nitrate, fecal coliform, electrical conductivity (EC), pH, total hardness, sodium absorption ratio, biological oxygen demand, phosphate, chemical oxygen demand, and dissolved oxygen parameters with the standard measuring methods; also, the quality of ground water was determined using the IRWQIGC. Statistical description of the parameters was performed using the SPSS software. Spatial extension mapping parameters were drawn using geostatistics extension with the ArcGIS software. The results of water quality assessment revealed that 0. 15% of the area was classified as bad, 98. 85% as relatively poor, and 1% as middle in terms of quality. The results of spatial dispersion also revealed that water quality from the South to the North and North East was reduced. Evaluating the changes in water quality near landfill sites showed that 2149. 56 square meters of total area had a relatively poor potential for the region’ s groundwater recharge.

The investigation of local scour below hydraulic structures is so complex that makes it difficult to establish a general model to provide an accurate estimation for the local scour dimension. During the last decades, Data Driven Methods (DDM) have been used extensively in the modeling and prediction of unknown or complex behaviors of systems One of these methods is Group Method of Data Handling (GMDH), that is a self-organization approach and increasingly produces a complex model during the performance evaluation of the input and output data sets. So, the objective of this study was to investigate the potential of the GMDH method in the accurate estimation of local scouring geometry (maximum scour depth, the distance of maximum local scour depth till Ski-jump bucket and length of local scour) below the Siphon spillway with Ski-jump bucket energy dissipaters for a set of experimental data. 80% of data set was used for the training period and the remaining data set was used for the test period. The average values of MSRE, MPRE, CE and RB for the nonlinear second order transfer function (FUNC1) were calculated to be 0. 92, 0. 02, 8. 74,-0. 01; also, for the nonlinear first order transfer function (FUNC2), they were 0. 85, 0. 02, 10. 43 and-0. 02, respectively. The results indicated that the performance of FUNC1 was better than FUNC2. Also, the value of the coefficient of determination (R2) for the estimation of local scour dimension using different methods such as s linear regression, nonlinear regression and ANN indicated the high performance of the developed model of GMDH in the accurate estimation for local scour dimensions.

Potassium fixation is one of the most important factors influencing the availability of this ion for plants. This research was carried out to evaluate the relationship between potassium (K) fixation with some physical and chemical characteristics of soils and clay minerals and to investigate the effect of the dry and wet cycle on potassium fixation in Kakan Plain, in Kohgilouye & Boyerahmad Province. To measure the amount of Potassium fixation, four levels of K were added to the samples and the samples were shaken for 24 h and then dried in the oven at 50° C for 24 h. The drying and wetting cycle was repeated three times. Another set of soil samples was similarly incubated for a period similar to the previous treatment, but drying was performed at room temperature in an equilibrium state. The results showed that potassium fixation was increased with the potassium concentration increment, whereas K fixation percentage was reduced. Also, potassium fixation showed a positive significant relationship with cation exchange capacity (CEC) as well as clay content, in both normal and dry and wet treatments, and a negative significant relationship with organic carbon. Moreover, potassium fixation was enhanced with the increase of smectite content in both normal and dry and wet treatments. Besides, due to more organic carbon and less smectite, surface horizons fixed K less than the subsurface horizons.

Groundwater is a major source of drought. Karstic aquifers are important sources of groundwater in the West and Kermanshah province. This study was performed to investigate the effects of the meteorological drought on the karstic aquifer with different conditions of development. The studied areas in this research included two karstic aquifers, Bistoon-Parau and Patagh mountain in Kermanshah province. In this study, we used monthly precipitation and springs discharge during a period of 20 years. Accordingly, the SPI and SDI indices were used to investigate the different states of meteorological and hydrological droughts, respectively. To determine the relationship between meteorological droughts and groundwater, Pearson correlation was used; aalso, to determine the time delay, the correlation between the different time conditions (no delay and delay 1 to 6 months) of the SDI index and the SPI index was investigated. The results of the relationship between the meteorological drought and groundwater showed that both had a significant correlation (p-value: 0. 01). Also, based on the results of the correlation between different time conditions (no delay and delay 1 to 6 months), the SDI index was compared to the SPI index, showing that the time delay between the occurrence of meteorological drought and groundwater in the studied areas without time delay or a maximum one-month delay had happened. Based on the results, Pearson correlation coefficients between the SPI and SDI indices in the Bistoon-Parav region were more than those of the Patagh mountain region indicating the development of the Bistoon-Parav karst region, as compared with the Patagh Mountain.

The study of the kinetics of non-exchangeable potassium (NEK) release is very important for a better understanding of K availability for plants in different soils. Moreover, aggregates with different sizes have different effects on the release of nutrients. Therefore, the aim of this study was to examine the release of NEK in 5 calcareous soils of chaharmahalva-bakhtiari province, and small and large aggregates (<250 μ m and >250 μ m) using CaCl2 0. 01 M at 25± 1º c for 2-2017 h. The results showed that cumulative released NEK in soils, and small and large aggregates was 173. 5-372. 7, 215. 1-426. 1 and 178. 9-381. 5 mg kg-1, respectively. The results revealed that coefficients of the cumulative released NEK in small aggregates was lower than those of the soils and large aggregates. Based on the coefficient of determination (R2) and standard error (SE), the released NEK was well described by the first order, the power function, parabolic diffusion, and simplified Elovich equations. The rate coefficients of the release of K were different in different soils. The cumulative released amount of K and its rate of release in a solution of calcium chloride in small aggregates was more than those of large aggregates.

Exploitation of dam reservoirs is one of the major problems in the management of water resources. In this research, Crow Search Algorithm (CSA) was used for the first time to manage the operation of reservoirs. Also, the results related to the exploitation of the single-reservoir system of Shahid-Rajaei dam, located in Mazandaran province, northern Iran, which meets the downstream water demands, were compared to those obtained by applying the Particle Swarm and Genetic algorithms. Time reliability, volume reliability, vulnerability and reversibility indices, and a multicriteria decision-making model were used to select the best algorithm. The results showed that the CSA obtained results close to the problem’ s absolute optimal response, such that the average responses in the Crow, Particle Swarm and Genetic Algorithms were 99, 75 and 61 percent of the absolute optimal response, respectively. Besides, except for the time reliability index, the CSA had a better performance in the rest of the indices, as compared to Particle Swarm and Genetic Algorithms. The coefficient of variation of the obtained responses by CSA was 14 and 16 times smaller than the Genetic and Particle Swarm Algorithms, respectively. The multi-criteria decision-making model revealed that the CSA was ranked first, as compared to the other two algorithms, in the Shahid-Rajaei Reservoir's operation problem.

One of the most important issues in the field of optimizing water resources management is the optimal utilization of the dam reservoirs. In the recent decades, the optimal operation of dams has been one of the most interesting issues considered by water resources planners in the country. Due to the complexities of the typical optimization methods, employing an evolutionary algorithm is regarded here. One of the most significant algorithms is the ant colony algorithm. So the aim of this study is to optimize the delivery of Golestan and Voshmgir reservoirs to meet the needs of the down lands using the elite ant colony algorithm, maximum – minimum ants, ranked ants, and particle swarm algorithms, and to compare the performance of these algorithms with each other. The considered decision variable was the release of the reservoirs in the above-mentioned dams. In this study, the data over a 5-year period, from 2006-2007 to 2011-2012, was used for modeling. The results showed that all algorithms could optimize the release amount optimally; however, the elite ant algorithm with the objective function value of 0. 6407 estimated the release values with great accuracy in both dams. Also, the particle swarm algorithm with 1. 275 of the objective function value was wellmatched with the release values. The ranked ant algorithm with 18. 924 and Max-Min ant with 26. 431 of the objective function valuewere, respectively, at the next levels of performance optimization of the release values from Golestan and Voshgar dams.

The use of plants and soil microorganisms is a promising technique for the phytoremediation of heavy metalcontaminated soils. This study was carried out in order to evaluate the soil microbial potential with four Cd concentration levels (0, 10, 30 and 100 mg kg-1); the study also addressed the inoculation of arbuscular mycorrhizal fungi (AMF) species (a mixture of Glomus species including G. intraradices, G. mosseae and G. fasciculatum) as well as plant growth promoting rhizobacteria (PGPR) (a mixture of Pseudomonas species including P. putida, P. fluorescens, and P. aeruginosa) with the Centaurea cyanus plant. The soil sample was spiked uniformly with Cd nitrate salt to create different Cd concentrations. The contaminated soils were then sterilized and subsequently inoculated with AMF and PGPR. The results indicated that with increasing the soil Cd concentration, colonization percent, abundance of rhizobateria, shoot biomass, and shoot relative biomass were significantly decreased, while the proline content and the shoot Cd concentration were significantly increased (P≤ 0. 05). The mean of Cd extracted in AMF and PGPR treatments was 1. 8 and 2. 8 and the translocation factor was 1. 2 and 1. 5 times higher, as compared to the corresponding control treatments, respectively. It could be concluded that microbial inoculation, in addition to improving plant growth, plays an important role in the Cd phytoremediation efficiency by plant.

Siderophores are low molecular weight iron-binding ligands produced by aerobic soil microorganisms and some plants roots. They may also develop complexes with other metals such as Cd, thereby influencing the bio-availability, toxicity and mobility of Cd in the soils and aqueous environments. The main objective of this study was to investigate the effects of desferal siderophore (DFOB) on the adsorption of Cd on muscovite. The adsorption of Cd on muscovite was studied as a function of pH (Cd concentration: 5. 0 mg L-1) in the range of 3. 0-8. 0, as a function of metal concentration (Cd concentration in the range of 1. 5-10. 0 mg L-1); this was done in the absence and presence of siderophore (DFOB concentration 250 μ M) using a 24h batch equilibration experiment. The results of pH dependent experiments showed that the siderophore deceased the adsorption of Cd onto muscovite at pH ≥ 5. The results of the isotherms experiments also showed that the removal of Cd from solution was affected by siderophore in all equilibrium concentrations of Cd at both pHs. Siderophore decreased the adsorption of Cd by the mineral. The Freundlich and Langmuir isotherms described the equilibrium data satisfactorily. The values of Freundlich (KF) and Langmuir (KL) bonding constants were greater in the suspensions without siderophore, as compared to those containing siderophore, thereby indicating the low adsorption affinity of Cd on muscovite in the presence of the siderophore.

PCBs are persistent organic pollutants which, due to high environmental hazards, must be traced, determined, and decomposed to reduce their risks. . To detect this material in the soil, the method of extraction and appropriate measuring conditions should be investigated. Two soil samples with two kg weight were selected with two different soil textures and the solutions of soil were made with the 1000 μ g/ml aroclor 1254 mixture in a GC device. . Agilent GCMS with stationary phase (CP 7477) was used to measure aroclor 1254. The analysis of variance and the test of the extraction mean of aroclor 1254 were compared in two soil textures. The results suggested that coarse texture soil (sandy loam) had a higher extract than the fine one (silty loam). The difference was statistically significant (P< 0. 01). These findings suggested that the soil texture affected the extraction of aroclor from soil. In addition, four different levels of moisture (5%, 10%, 15% and 20%) produced in two soil textures and aroclor were measured. The highest level of extraction was obtained at 20% moisture, which was significantly higher than that in other levels (P< 0. 01). The difference between the mean of extractions in the soil samples with 10% and 15% levels of moisture was nonsignificant (P> 0. 05).

To continue or develop the exploitation of underground water for different different uses and purposes, as well as building any water structure, set of quantitative features of aquifers can be detected. To achieve this goal, quantitative monitoring of groundwater level is only possible. Accordingly, this study compared the impact of both the concept of marginal entropy and ordinary kriging for groundwater level monitoring network design in the case Gotvand-Aghili Plain, Khuzestan province. It is important to note that a key aspect in groundwater level monitoring of the quantity measured was the variability or uncertainty in it. This created a considerable confidence to monitor and ultimately achieve favorable conditions in the future. In this study, the variability of the groundwater level was considered to evaluate the combined effects of marginal entropy and ordinary kriging. In order to determine the suitable areas for further monitoring or thinning as well as the compatibility of these two methods, the monitor network design was designed. The map classified according to the marginal entropy method, in a range between 0. 07 to 5. 26 of the marginal entropy change, areas with the higher rates of 2. 13 in terms of density; this indicated the need for more observation wells. Ordinary Kriging method also changed the range of values; they also represented areas that needed monitoring more than 13. 16. Comparison of the results obtained by the two methods showed that the marginal entropy of the kriging method with less uncertainty and by using it, there was less the need to be monitored and classified. Comparison of the two methods by the zoning map showed that fewer errors were taken to the marginal entropy method and it could be recommended for the groundwater level monitoring network design. The network was also based on the Cross validation estimation error evaluated. These tests and additional analysis were employed in this study to determine the suitable areas for the higher density of wells and the need for thinning areas. The results further confirmed the proper performance of the methods employed, as well as the superiority of the marginal entropy in the design of a small groundwater monitoring network.

The purpose of this research was source identification of aerosols in atmosphere using geochemical properties in the city of Kermanshah. The concentrations of twenty elements consisting of K, Na, Ca, P, Cu, Ni, Pb, Cd, Se, Zn, Fe, Mg, B, Cr, Co, As, Mo, V were analyzed by ICP for 55 soil samples (in the height range of 600-1600m) and 41 aerosols samples. Source identification of aerosels using geochemical tracers was performed in two steps. In the first step, appropriate combination of tracer elements with high ability in the resolation of aerosol sources was chosen using the means comparison test and discriminate analysis. In the second step, the multivariate mixing model was used to determine the contribution of aerosol sources (geological and geomorphology types) to the production of aerosols in the study area. The results obtained from determination of the contributions of sources of aerosols (geological and geomorphological types) showed the UF formation (consisting of red marl and sandstone), with the height of 0-1400 mand the slope of 0-5%, could be regarded as the main contributor to the production of aerosols located in the city of Qasreshirin.

Precipitation is one of the most important components of water balance in any region and the development of efficient models for estimating its spatiotemporal distribution is of considerable importance. The goal of the present research was to investigate the efficiency of the first order multiple-site auto regressive model in the estimation of spatiotemporal precipitation in Kurdistan, Iran. For this purpose, synoptic stations which had long time data were selected. To determine the model parameters, data covering 21 years r (1992-2012) were employed. These parameters were obtained by computing the lag zero and lag one correlation between the annual precipitation time series of stations. In this method, the region precipitation in a year (t) was estimated based on its precipitation in the previous year (t-1). To evaluate the model, annual precipitation in the studied area was estimated using the developed model for the years 2013 and 2014; then, the obtained data were compared with the observed data. The results showed that the used model had a suitable accuracy in estimating the annual precipitation in the studied area. The percentages of the model in estimating the region's annual precipitation for the years 2013 and 2014 was obtained to be 7. 9% and 17. 3%, respectively. Also, the correlation coefficient between the estimated and observed data was significant at the significance level of one percent (R=0. 978). Furthermore, the model performance was suitable in terms of data generation; so the statistical properties of the generated and historical data were similar and their difference was not significant. Therefore, due to the suitable efficiency of the model in estimating and generating the annual precipitation, its application could be recommended to help the better management of water resources in the studied region.

This study was done to evaluate the effect of topography, water table, and irrigation on gypsc soil development and clay mineral diversity in Ram-Hormuz Plain, Khuzestan Province. To localize, 10 profiles in this region that covered all purpose irrigation and topography situation were described. The results showed that the soils could be classified in Entisols, Inceptisols and Aridisols orders. All soil epipedons were ochric and subsurface horizons were cambic, gypsic, and salic. The salic horizons were formed under a low water table. The XRD results showed that smectite, kaolinite, illite, chlorite, palygorskite, vermiculite and sepiolite were the dominant minerals, respectively. Kaolinite and illite were inherited from the parent material, but chlorite was the result of both inheritance and transformation of other clay minerals except uncultivated or non-irrigated soils. Sepiolite was decreased in gypsic horizons, but palygorskite was increased in these horizons. Sepiolite was raised with increasing the depth under the good drainage class; this could be related to neoformation, but it was decreased with depth under the weak drainage class. These results could be due to the instability of this mineral in high moisture and its low Mg activity. There was also a negative correlation correlation between Palygorskite and smectite; this was such that most palygorskite was observed in the surface horizons, but smectite was in the subsurface. Smectite was the dominant clay mineral in the studied soils; it was formed from the weathering of other minerals as well as from neoformed ones in the lowlands. Vermiculite was formed in these soils due to k depletion by leaching or plant absorption. This happened in the illite to smectite transformation process. Therefore, topography and irrigation could be regarded as the main factors putting these soils in high category; also, clay mineral assemblage was different under this situation in these soils.

The purpose of this research was to study the effects kerosene by a factorial experiment in the nested design in three replications. The factors included region (Shush, Dezful and Bavi), plant (parsley, dill, coriander and carrot), and management practice (control, contaminated field with kerosene 1, contaminated field with kerosene 2). Heavy metals concentration (Pb, Zn, Cu and Cd) was measured in soil (DTPA extraction method) and plants samples. The results indicated that the average values of the heavy metals concentration in both soil and plants samples subjected to kerosene contaminated treatments were greater than those of the control treatment in all of the regions. The Bavi region had the highest Cd (14. 29 in soil; 11. 9 in Dill) and Pb (40. 46 in soil; 35. 53 in Coriander) and the lowest Zn (34. 75 in soil; 28. 44 in Carrot) and Cu(22. 30 in soil; 16. 96 in Carrot) concentration values in both soil and plants subjected to kerosene contaminated treatments. Also, the lowest concentration values of Cd (9. 33 in soil; 8. 01 in Carrot) and Pb (30. 36 in soil; 23. 54 in Carrot) and the highest values of Zn (109. 08 in soil; 86. 33 in Dill) and Cu (47. 71 in soil; 38. 57 in Dill) were recorded in Shush and Dezful regions, respectively. Based on these findings, kerosene usage could lead to a significant increase in the heavy metals (Cd, Cu and Pb) uptake, exceeding the critical level for the vegetables. This might increase the transformation risk of the mentioned heavy metals in the food chain