Showing 87 results for Lut
F. Mehri Yari, H. Pirkharrati, Kh. Farhadi, N. Soltanalinezhad, F. Naghshafkan,
Volume 24, Issue 1 (5-2020)
Abstract
Soil pollution by heavy metals is a serious environmental problem that threatens the human health. The present study was carried out to investigate and detect the contamination of heavy metals of arsenic, copper, lead, zinc and iron due to human and natural activities in the sediment of lake bed and the surface soils of the eastern part of Urmia Province, West Azarbaijan Province. A total of 20 soil samples and surface deposition from the depths of 0 to 30 cm were collected randomly from the studied areas. After preparing the samples, extraction was carried out to determine the concentration of the heavy metals in the soil by using hydrochloric acid and nitric acid, and the total concentration of metals was measured using ICP-OES. The results of the calculation of the contamination factor showed that copper, iron, zinc and lead in the class of low and medium pollution and arsenic in 65.5% of the samples were very high in the class. The high concentrations of copper, lead and zinc contamination in the margin of the city and the contamination of arsenic in the lake bed were observed. The analysis of the contamination factor maps and contamination index with land use and geological map showed that copper, lead and zinc were mostly affected by human activities and arsenic influenced by the maternal materials in the region.
M. Mirjani, M. Soleimani, V. Salari,
Volume 24, Issue 1 (5-2020)
Abstract
Growing concerns about water pollution and its potentially harmful effects on human being have stimulated serious efforts to develop reliable biological monitoring techniques. The bioluminescent analysis is one of the most promising approaches for the biomonitoring of the environment, due to the sensitivity of the luminescent system to even micro quantities of the pollutants. The aim of the current study was to assess the petroleum compounds toxicity using Vibrio fischeri bacterium. The growth pattern of the bacterium was determined in photobacterium broth using the optical density measurement at 600 nm, which showed the optimum growth time of 16-18 hours after inoculation. In this research, the effects of environmental parameters such as temperature, pH and various concentrations of oil on the growth and luminescence of Vibrio fischeri were examined. The results revealed that the optimum growth conditions of the bacterium after 16 hours included the temperature of 25 °C and pH 7. Besides, the growth and luminescence intensity of Vibrio fischeri were a function of total petroleum hydrocarbon concentrations in the medium, which were significantly reduced in oil concentrations by more than 4% w/v. Therefore, the Vibrio fischeri could, therefore, have the potential for monitoring of petroleum pollutants in the aqueous media.
M. Javaheri Tehrani, S. F. Mousavi, J. Abedi Koupai, H. Karami,
Volume 24, Issue 2 (7-2020)
Abstract
In the last few decades, the use of porous concrete to cover the sidewalks and pavements as an interface to collect the urban runoff has been increased. This system is economically more efficient than other runoff-pollution reduction methods. To design a runoff control system and reduce its pollution, it is necessary to determine the hydraulic and dynamic properties of the porous concrete (with and without additives). In this research, the effects of cement type (2 and 5), water to cement ratio (0.35, 0.45 and 0.55), fine grains percent (0, 10 and 20%), the type of additive (pumice, industrial pumice, perlite and zeolite), and the added additive percent (5, 10, 15 and 20%) on the physical properties of the porous concrete (porosity, hydraulic conductivity and compressive strength), each with three replications, were investigated using robust design. Qualitek-4 software was also used to discuss the results. The results showed that to obtain the highest porosity in the mixing scheme of the porous concrete, no fine grains, cement type 2 and 15% industrial pumice should be used, and water to cement ratio should be 0.35. Also, the water to cement ratio of 0.55, 0% fine grains, type 2 cement and 15% industrial pumice resulted in the highest value of hydraulic conductivity in the porous concrete. Finally, the water to cement ratio of 0.55, 20% fine grains, type 2 cement and 5% zeolite led to the maximum compressive strength. In general, it was not possible to reach a logical conclusion in this research with the least costs without employing the robust design.
A. Donyaii, A. Sarraf, H. Ahmadi,
Volume 24, Issue 4 (11-2020)
Abstract
Optimizing the water resources operation, especially in the agricultural sector, which has the largest share in the water resources operation, is extremely important. Therefore, in this research, while introducing Whale, Gray Wolf and Crow Search Optimization Algorithms, their performance in the optimum operation of Golestan single-reservoir system Dam was evaluated with the aim of providing water demand for the downstream lands based on reliability, Reversibility, and vulnerability indices. In this optimization problem, the objective function was defined as the minimization of the total deficiency during the operation period. Meanwhile, the constraints of continuity equation, overflow, storage and reservoir release volume were applied to the objective function of the problem. Then, the results were compared with the absolute optimal value based on the nonlinear programming method obtained from GAMS software; finally, a multi-criteria decision-making model was developed to rank the optimization algorithms in terms of performance. The absolute optimal response obtained by the GAMS software based on the nonlinear programming method was 19.41. The results showed that the Gray Wolf algorithm performed better than the other algorithms in optimizing the objective function, so that the average responses in Gray Wolf, Crow Search and Whale algorithms were 92, 84 and 67% of the absolute optimal response, respectively. Furthermore, the Gray Wolf optimization algorithm performs better than the Whale and Crow Search algorithms in all parameters. In addition, the coefficient of variation of the responses obtained by the Gray Wolf algorithm is 2 and 1.43 times smaller than that in the Whale and Crow Search Algorithms, respectively. Finally, the results of the multi-criteria decision-making model showed that the gray wolf algorithm had the first rank, as compared to the other two algorithms studied in solving the problem of the optimal operation of the Golestan dam reservoir.
A. Arab, K. Esmaili,
Volume 25, Issue 1 (5-2021)
Abstract
The study of floods has always been important for researchers due to the great loss of life and property. Investigation of flood bed can provide appropriate solutions to reduce this phenomenon to managers and researchers. In this research, the compound channel (with flood plain on one side of the main channel) Been paid, Therefore, two experimental models of compound channel in laboratory flume were examined by considering dimensional analysis. With the goal Investigation of lateral slope of flood wall in laboratory model In the first model, transverse slope 0 And in the second model, a value equal to 50% Was considered. Also in order to investigate the effect of longitudinal slope of river bed sediments Longitudinal slope in three steps 0.00 2, 0.004 and 0.006 Was changed. Examining the ADV speedometer data, the results showed that with increasing the longitudinal and transverse slope (slope of the flood wall) of the channel, the maximum longitudinal velocity changes to the floor of the channel. In order to investigate the effect of average sediment diameter on the scouring process during experiments Mm was used. The results showed that increasing the longitudinal and transverse slope had a great effect on increasing the volume of washed sediments 3 and 0.9 of sandy sediments with a diameter Along the canal and with the increase of these longitudinal and transverse slopes in the channel, more sediment transport volume occurs. In the following, using Investigation of dimensionless numbers obtained from dimensional analysis, dimensionless weight landing number was introduced to evaluate this value value of other hydraulic parameters and Was introduced. A relationship based on nonlinear regression with correlation coefficient Acceptable was introduced at around 0.88.
H. Kazemizadeh, M. Saneie, H. Haji Kandi,
Volume 25, Issue 2 (9-2021)
Abstract
To prevent demolishing bridge piles due to developing the scour hole under the foundation of these piles some solution has been proposed in the literature. One of the important approaches could be installing different geometric of roughness at the downstream and upstream piles sections. This causes the downward flows which are performing the main role in developing scour holes to be marginally decreased. The present study explores the effect of geometric roughness and also, continuity and un-continuity of roughness length on maximum scour holes around bridge pile. Results indicate that due to increasing the length of roughness the developed scour holes were formed by less scour hole depths. Furthermore, continuity of roughness increases the scour hole depths; however, un-continuity causes the height of scour holes to be developed by fewer values. Also, the comparison shows that the length of installed roughness in maximum value is decreasing the scour hole depth constitute 34 percent. Based on the non-linear regression technique an equation has been proposed to predict the maximum scour hole due to different conditions. Comparison between experimental and proposed values shows that the accuracy of the proposed equation has an acceptable error which has been calculated less than 11 percent.
H. Noori Khaje Balagh, F. Mousavi,
Volume 25, Issue 3 (12-2021)
Abstract
In the present study, CanESM2 climate change model and stormwater management model (SWMM) were employed to investigate the climate change effects on the quantity and quality of urban runoff in a part of Karaj watershed, Alborz Province. The base period (1985-2005) and future period (2020-2040) are considered for this purpose. Based on the existing main and lateral drainage system and to be more accurate, the watershed was divided into 37 sub-watersheds by ArcGIS software. To simulate rainfall-runoff, the intensity-duration-frequency (IDF) curve has been prepared for a 2-hour duration and 10-year return period, for the base period and RCP2.6 and RCP8.5 climate change scenarios based on the obtained precipitation data from Karaj synoptic station. Results showed that mean 24-hour precipitation values in RCP2.6 and RCP8.5 scenarios will increase by 21% and 11%, respectively, and maximum 24-hour precipitation values will decrease by 17% and 23%, respectively, as compared to the observed values in the base period. Also, based on the results of quantitative and qualitative runoff modeling in the study watershed, and according to the outflow hydrograph in the RCP2.6 and RCP8.5 scenarios, the outlet runoff discharge will decrease by 5.8% and 7.1%, respectively. Also, the flooded areas in the watershed will decrease by 13% and 15.28%, respectively. The concentration of pollutants in the RCP2.6 and RCP8.5 scenarios, compared to the base period, including total suspended solids (TSS), will increase by 7.48% and 9.24%, total nitrogen (TN) will increase by 6.93% and 8.48%, and lead (Pb) will increase by 7.32% and 8.91%, respectively.
H. Alipour, A. Jalalian, N. Honarjoo, N. Toomanian, F. Sarmadian,
Volume 25, Issue 4 (12-2021)
Abstract
Dust is one of the environmental hazards in arid and semi-arid regions of the world. In some areas, under the influence of human activities, dust is contaminated by heavy metals. In this study, the dust of 10 stations in the Kuhdasht region of Lorestan province in four seasons of spring, summer, autumn, and winter, as well as adjacent surface soils (a total of 40 dust samples and 10 surface soil samples), were sampled and some heavy metals including Zn, Pb, Cd, Ni, Cu, and Mn were analyzed. The results revealed that the amount of Zn in the dust was much higher than the surface soils of the region (800 vs. 85 mg/kg). Contamination factor index calculation indicated that high contamination of Cd and Zn, significant contamination of Ni and Pb, and lack of contamination by Cu and Mn. The annual enrichment factor of Cd (33.9) and Zn (24.6) was very high, Ni (11.3) was significant, Pb (6.4) was moderate, Mn (1) and Cu (0.82) were low. Based on the enrichment factor values, Cd, Zn, and Ni seem to have a human origin, Pb has both human activities and natural origin, and Cu and Mn have an only natural origin.
F. Sadeghdoust, N. Ghanavati, A. Nazarpour,
Volume 25, Issue 4 (12-2021)
Abstract
Street dust is mainly affected by the pollution of polycyclic aromatic hydrocarbons (PAHs). PAHs are a group of organic pollutants consisting of two or more benzene rings and are mainly produced during incomplete combustion. PAHs have attracted widespread attention due to their high carcinogenic and mutagenic properties in humans. Therefore, the purpose of this study was to investigate the sources and extent of the impact of these compounds on human health and the environment. To achieve this goal, 30 dust samples were collected from the sidewalks of the main streets of Dezful and the concentration of PAHs was determined by gas chromatography-mass spectrometry (GC-MS). The total concentration of PAHs in street dust of Dezful varied from 562.85 to 51447.10 μg / kg. The ratio of carcinogenic compounds to total PAHs was in the range between 0.73 to 0.91. Low molecular weight and high molecular weight PAHs accounted for 12% and 88% of total PAHs, respectively. The most important sources of PAHs in Dezful are the combustion of fossil fuels and petroleum products and emissions from vehicles and traffic. Moreover, incremental lifetime cancer risk (ILCR) in pathways ingestion in children was higher than in adults, but the ILCR in pathways dermal contact and inhalation in adults was higher than in children. The total cancer risk (CR) for children (5.77×10-3) was higher than adults (5.56×10-3), which shows the high potential for CR in the study area.
A. Safadoust, S. Ghanizadeh, M. Nael,
Volume 26, Issue 1 (5-2022)
Abstract
This study was conducted to investigate the effects of vegetation type (Alfalfa and Wheat) and slope (5% and 20%) on runoff and drainage pollution in clay loam soil. Sampled soils were repacked in the box with one soil drainage outlet and one surface flow outlet and were cultivated by wheat or alfalfa. A solution containing 0.05 M KCl was poured quickly and uniformly, over the surface of each box, after plant growth. Simulated rainfall was applied to the soil box with the intensity of a constant rate of 64 mm h-1 for 2 hours immediately. Then the concentration of Cl- and K+ were measured in the collected samples of runoff and the drainage outlet. Results showed that the measured concentration of K+ was lower than the Cl- concentration as a result of its absorbable property. The breakthrough curves (BTCs) of Cl- and K+ showed that slope and vegetation type affected the transport of Cl- and K+. The peak of the BTCs for Cl- and K+ in runoff ranked in the order of wheat and 20% slope> alfalfa and 20% slope> wheat and 5% slope> alfalfa and 5% slope, and in the drainage changed to alfalfa and 5% slope> wheat and 5% slope> alfalfa and 20% slope> wheat and 20% slope. For each slope, the intensive vegetation cover of alfalfa than wheat considerably reduces Cl- or K+ pollution in runoff; whereas drainage development of larger and deeper root systems was the cause of higher leached concentrations for both tracers. Based on our research changes in soil surface vegetation cover from wheat to alfalfa are suggested in slope land to prevent surface water pollution; although other factors such as the climate, soil texture, and structure should also be considered.
A. Malekian1, A.a. Jafarazdeh, Sh. Oustan, M. Servati,
Volume 26, Issue 2 (9-2022)
Abstract
To study the soil-landscape change in the Chaldoran region, 9 representative soil profiles were studied in 5 dominant geomorphic units of the study area including piedmont plain, mantled pediment, alluvial fan, plain, and flood plain. The results showed that the accumulation of pedogenic carbonate in some soils was concretion and light in color. In control soils in the piedmont plain (profile 5 and 7), mantled pediment (profile 6), and flood plain (profile 8) clay transferred from the surface horizons and accumulated in the lower horizon, due to relatively good rainfall in the region and distinct dry and wet seasons has led to the formation of argillic horizons along with the formation of crust on the surfaces of aggregates and building units and has formed the Alfisoils order. Mineralogical results showed the presence of chlorite, illite, kaolinite, and smectite minerals. According to the evidence, illite, chlorite, and kaolinite minerals were inherited and smectite minerals were formed due to weathering and evolution of illite, chlorite, or palygorskite minerals. Also, the results of the CIA index in the region indicated that the soils of the region are in the stage of weak to moderate weathering. In general, the results indicated the critical role of drainage, land use, and parent materials in the soils of the study area.
J. Abedi Koupaei, M.m. Dorafshan, A.r. Gohari,
Volume 26, Issue 3 (12-2022)
Abstract
One of the most significant techniques for saline wastewater treatment is bioremediation. Halophytes are known as the plants that can tolerate the high concentration of salts, in such salinity common plants cannot be often able to survive. In this research, the feasibility of desalination by using halophyte (Chenopodium quinoa Willd.) was studied. Quinoa plants were grown in the hydroponic system in 12 containers including 9 containers with plants and 3 containers without plants as control. Fifteen plants were planted in each container and three salinity levels including 2, 8, and 14 ds/m for two different periods (15 and 30 days) were studied in a multi-factors completely randomized design. Three replications of each salinity level were conducted and the Electrical Conductivity (EC) parameters, including Calcium, Magnesium, Sodium, and Chloride ions were determined before and after treatment by Quinoa plants. The results showed that the Quinoa plants reduced 5.33%, 8.12%, and 9.35% of the EC at EC~2 dS/m (Marginal Water), EC~8 dS/m (Brackish Water), and EC~14 dS/m (Saline Water), respectively. Moreover, Calcium, Magnesium, Sodium, and Chloride ions decreased up to 10%, 7.62%, 5.60%, and 7.01%, respectively depending on the salinity levels. Therefore, the Quinoa plant has a relatively low potential in unconventional water treatment especially saline wastewater.
S. Dehghani, M. Naderi Khorasgani, A. Karimi,
Volume 26, Issue 3 (12-2022)
Abstract
Knowledge of the distribution of heavy metal concentrations in different components of soil particles is significant to assess the risk of heavy metals. The objective of this study was to evaluate some pollution indices and spatial variations in their estimation in different components of soil particle size fractions (<2000 and> 63 μm) in the Baghan watershed in the southeast of Bushehr province with an area of about 929 square kilometers. The location of 120 surficial composite soil samples (0-20 cm) was determined by using the Latin hypercube method. Soil pollution was assessed using geochemical indices of contamination factor (CF) and pollution load index (PLI). The kriging method was used in the Arc GIS software to interpolate the spatial variations of CF and PLI. Based on the results, the CF displayed the particles in the size < 2000 microns compared to all metals in moderate pollution conditions (1≤CF <3) and with the fineness of soil particles (particles with a diameter <63 microns) concerning to Cd metal shows significant contamination status and moderate pollution with other metals, respectively. CFZn, CFCu, and CFFe in particle size <2000 microns and CFPb in finer class were fitted with a spherical model and other metal contamination coefficients with an exponential model. CFCd and CFFe have the highest impact ranges at <2000 and < 63 microns, respectively. The results of this research confirm that corrective operation is needed to monitor cadmium status in the studied area.
M. Pasandi, H.r. Pakzad, A.m. Halvaie Lengeh, M.r. Taherizadeh,
Volume 26, Issue 4 (12-2022)
Abstract
The relationship between the concentration of heavy metals and physicochemical factors was studied in the fine-grained sediments of the tidal section of the Mehran delta where mangrove trees have grown. Surface sediments of the tidal zone of the Mehran delta were sampled. The grain size distribution, calcium carbonate, organic matter contents, pH/Eh, and heavy metals concentration were determined in the mud fraction of the sediments. The presence of high calcium carbonate in sediments is an effective factor in the abundance of Mn, Cd, and Pb. Clay and organic matter as adsorptive have contributed to the high concentration of Zn, Cu, while Fe oxy-hydroxides have affected the concentration of Co, Cr, and Ni. According to the index of Enrichment Factor (EF), the average enrichment of the elements in the studied sediments from high to low order is Cr, Ni, Cd, Zn, Mn, Pb, Co, and Cu. According to the Pollution Load Index (PLI), none of the delta sediments including sediments from inside and outside of the mangrove forestare classified as polluted to the heavy metals. According to the Igeo Index, most samples, and only Cd, Cr, and Ni show slight pollution in some samples. Accordingly, there is no current threat of contamination of potentially toxic elements of natural and anthropogenic origins to the mangrove environment and Mehran delta.
J. Abedi Koupaei, Z. Iravani,
Volume 27, Issue 1 (5-2023)
Abstract
Water pollution with petroleum products is one of the serious environmental problems in Iran. According to the importance of this issue, refining benzene by bio-absorbent has attracted much attention in recent years. The maximum permissible limit assigned by World Health Organization (WHO) for benzene in drinking water is 0.001 mg/L. In recent years, attempts made to develop inexpensive adsorbents utilizing abundant natural materials. Agricultural waste materials often employed as adsorbent may have potential marketing preference for wastewater treatment among other adsorbent types due to the low cost, environmentally friendly, naturally accessible, and efficiency. The objective of this study was to investigate the removal of benzene by batch and continuous techniques. In this study, the ash cone pine (APC) was used for the removal of benzene from aqueous solutions and its ability as an adsorbent, while the variable initial concentration of benzene, the amount of adsorbent, contact time, temperature, and pollutant's solution pH were investigated. Langmuirand and Freundlich Isotherm models were fitted to benzene adsorption equilibrium data. Kinetic models including pseudo-first order, pseudo-second order, intra-particle diffusion, and power function were used to describe kinetic data of benzene adsorption. The results showed that optimum benzene adsorption was observed at pH=7, and the optimum amount of adsorbent was 0.1 g. The observed equilibrium time was 10 minutes. The equilibrium adsorption capacities were 366 mg/g at 2000 mg/L initial benzene concentration. Linear and non-linear isotherm studies showed that equilibrium data better fitted the Langmuir isotherm model. Kinetic studies showed better applicability of the pseudo-second-order kinetics model. Column adsorption experiments were performed to check the absorbent performance during continuously injecting benzene solution into the adsorbent column until the adsorbent has been saturated to complete the studies on the introduced adsorbent. The results for columns with continuous inflow indicated that the maximum capacity of adsorption of benzene for the adsorbent column with a diameter of 3cm, and input concentration of 1000 mg/L, and an input rate of 100 mL/h for ash cone pine (APC) was 295 mg/g. The results of this experiment showed that APC has a high capability for the removal of benzene from aqueous solutions.
F. Esmaeili, M. Vafakhah, V. Moosavi,
Volume 27, Issue 1 (5-2023)
Abstract
Digital elevation models (DEMs) are one of the most important data required in watershed modeling with hydrological models and their spatial resolution has a significant impact on the accuracy of simulating hydrological processes. In the present study, the effect of spatial resolution of five DEMs derived from the topographic map (TOPO) with a scale of 1:25000, ALOS PALSAR, ASTER, SRTM, and GTOPO with a spatial accuracy of 10, 12.5, 30, 90, and 1000 m, respectively, on the estimation of parameters of geomorphological and geomorphoclimatic unit hydrographs models has been evaluated in Amameh watershed. Thirty-four single flood events were used during the years 1970 to 2015. The results showed that in the GUH method, the application of the TOPO and ALOS PALSAR DEMs had the best results with root mean square error (RMSE) of 1.7 and 1.8 m3/s and Nash-Sutcliffe Efficiency (NSE) of 0.4 and 0.3, respectively. While the GTOPO DEM had the least efficiency with RMSE of 2.8 m3/s and NSE of -2. Similarly, the lowest and highest RMSE in the GCUH method belonged to TOPO and GTOPO DEMs with RMSE of 3.8 and 18 m3/s and NSE of 0.2 and -6, respectively. Generally, the GUH method had more favorable results than the GCUH method in all DEMs.
M. Naderi Khorasgani, T. Azarbeig, J. Mohammadi,
Volume 27, Issue 3 (12-2023)
Abstract
Soil pollution by heavy metals is a significant issue that threatens human health directly and indirectly. The objectives of this research were to map the extension of some heavy metals in soils of a part of Sirjan Plain, Kerman province, to study the role of natural agents on the distribution of heavy metals, and to assess the risk of soil heavy metal concentration for human health. 120 surficial (0-15 cm) compound soil samples were collected during fieldwork. Soil characteristics like soil texture components, pH, electrical conductivity, organic matter, and total soil heavy metal (Fe, Cu, Zn, Cd, and Pb) concentrations were measured using standard protocols. The mapping of soil texture components and heavy metals was done by the usual Kriging method. Results indicated significant correlation coefficients between soil texture components (silt and clay) and total soil Fe and Cu concentrations. Dominant wind direction and spatial distribution of Fe, Cu, and Zn strongly induced the possible dust-born origin of such elements. Results revealed that the sources of Fe, Cu, and Zn were different from those of Cd and Pb. Maximum soil Fe, Cu, and Zn concentrations were in the southern part of the study area, increasing in an upwind direction while for Cd and Pb, maximum soil concentrations were in the northern part of the study area. The Nemerow integrated pollution index revealed that soils were clean for Cd, lowly polluted for Fe, Pb, and Cu, and moderately polluted for Zn.
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.
M.r. Shoaibi Nobariyan, M.h. Mohammadi,
Volume 29, Issue 2 (7-2025)
Abstract
The objective of this study is to investigate the effects of solutes and water quality on evaporation amount and rate in two sandy and clayey soils. Soil samples containing aggregates and sand particles with diameters ranging from 0.5 to 1 millimeter were collected. Six columns were prepared during the experiment; three columns were filled with sandy soil and three with aggregated soil, each measuring 60 cm in height and 15.5 cm in inner diameter. One reference column was filled with distilled water. A saturated calcium sulfate solution was added to two columns, a 0.01 molar calcium chloride solution was added to two other columns, and distilled water was added to the remaining two. The amount of water lost through evaporation was recorded every 8 to 12 hours by weighing the columns. After approximately 130 days, the columns were sectioned, allowing for the establishment of moisture and solute concentration profiles for each soil column. The results indicated that the first and second stages of evaporation were distinguishable in sandy soil, whereas in clayey soil (aggregated soil), only the first stage of evaporation occurred due to the gradual transfer of water and the continuous hydraulic connection from the surface to the water table. The presence and type of solutes affected the evaporation rate and moisture profile, reducing evaporation and increasing water retention in deeper soil layers. Hydraulic connectivity (calcium sulfate > calcium chloride > distilled water) and the resulting capillary rise of and supply of evaporated water from higher layers caused a greater evaporation rate in the calcium sulfate compared to the calcium chloride and distilled water treatments in both soil types. Additionally, the formation of a salt crust on the soil surface due to solutes disrupted the hydraulic connection with the surface, resulting in decreased evaporation rates and cumulative evaporation.
Jahangir Abedi Koupai, Noshin Shafiee, Behrooz Mostafazadehfard, Mohammad Mehdi Matinzadeh,
Volume 30, Issue 2 (7-2026)
Abstract
One of the key factors in agricultural production is the availability of sufficient and usable nutrients for plant growth, and among these, nitrogen plays a particularly important role. The waste of nitrogen fertilizers due to the low efficiency of using fertilizers has caused environmental problems such as pollution of surface and groundwater by nitrate or ammonium. In this study, the influence of fertigation as a combination of urea, ammonium nitrate, natural zeolite of Semnan (CP), and modified zeolite by surfactant (SMZ) in the reduction of waste and manure fertilizer was evaluated. Two separate experiments with a completely randomized design with three replications were used for loam soil columns. Treatments consisted of four levels of zeolite application (0, 4, 8, and 16 g/Kg) and a fertilization level with a concentration of 60 mg per liter nitrate applied at three fertigations during six irrigations. In the first part of the study, the role of nitrogen fertilizers in fertigation as a combination of urea and ammonium nitrate (UAN) for ordinary soil was examined to reduce the concentration of nitrate and ammonium in the drainage water, and the results were compared with one of the fertigation applications. The results showed that the loss of fertilizer in the form of nitrate was reduced by 40 percent for the UAN treatment during the first period of fertigation. Since the results of the first part of the experiment showed that the concentration of ammonium nitrate does not reduce to the same level as drinking water, in the second part of the experiment, the soil amendments were used. The measured nitrate removal showed that the highest nitrate removal belonged to the soil mixed with 16 g/kg of modified zeolite in the surface layer of soil (SM16) treatment, and it was equivalent to 90 percent. The highest ammonium removal belonged to the soil mixed with 16 g/kg of natural zeolite in the surface layer of soil (CP16) treatment, and it was 85 percent. Therefore, the use of fertigation as a combination of nitrogen fertilizers with soil amendments for conditions where there is a potential for groundwater pollution by nitrate leaching is recommended.
