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Showing 10 results for Soil
S Davtalabnezam , A Shakeri , M Rezaee ,
Volume 2, Issue 2 (2-2017)
Volume 2, Issue 2 (2-2017)
Abstract
The soil quality of urban parks is of vital importance as the children playing in the parks get themselves easily contaminated. This study aimed to investigate the concentrations, sources, pollution levels and human health risk of potentially harmful elements in the soil of two urban parks present in Tehran. For this purpose, the soil samples (n=26) were collected from shahr and lale parks analyzed for total potentially toxic elements concentration (As, Cd, Co, Cr, Cu, V, Pb, Ni and Zn) using an Inductively Coupled Plasma Spectroscopy and Optical Emission Spectroscopy. The degree of pollution by potentially toxic elements was assessed with respect to the background concentration by calculation and comparison of the geo-accumulation index (Igeo), enrichment factor (EF), pollution index (PI) and integrated pollution index (IPI).Sources of different elements in the soils were identified by employing principal component analysis (PCA). The results of EF and Igeo analysis showed about 50% of the soil samples to be enriched in heavy metals Cd, Cr, Cu, Pb and Zn compared with background levels, suggesting heavy metals contamination of soil two urban parks are from anthropogenic sources. Based on the PI values, Cd, Cr, Cu, Pb and Zn in the soil of two parks were higher than their background concentrations. IPI decreased in the order of Shahr and Lale parks. Geochemical indicators and PCA confirmed that the main pollution source of soil was traffic, fertilizers, waste, corrosion of metal surfaces of cars, fuel additives and corrosion of building materials. Health risk assessment indicated that the potentially toxic element contamination in the Shahr and Lale parks, were below the acceptable threshold for carcinogenic and non-carcinogenic risks. However, the carcinogenic risk from Cr due to oral ingestion of soil exceeded the value of 1×10−6, in both parks. It indicates that the exposure to Cr-contaminated soil may cause adverse health effects in humans, especially in children. The Hazard Quotient (HQ) and Hazard Index (HI) for different metals through ingestion, inhalation and dermal pathways was also found to be less than 1, indicating no health risk exists in present condition.
Dr Ata Shakeri, Hemmat Nasiri, ,
Volume 7, Issue 1 (8-2021)
Volume 7, Issue 1 (8-2021)
Abstract
Introduction
Pollution sources are basically divided into two groups: geogenic and anthropogenic. Geogenic sources include pollution from geological formations, mineral indices, mineral springs, brackish and saline water sources, and industrial activities, transportation, using agricultural fertilizers, mining activities, and wastes and effluents can be mentioned as anthropogenic pollution sources. Essential nutrients and other metals may enter the food web through the soil. The natural concentration of potentially toxic elements in the soil is usually low, except in the case of soils composed of ore minerals. The amount of trace elements in soils can also increase sharply due to human activities. In recent years, industrial and agricultural development in Iran has grown exponentially and various researches have been focused on assessment of environmental pollution. Therefore, it is necessary to use a set of different quantitative and qualitative methods of soil pollution assessment to gain a better understanding of the extent of pollution. Regarding the pollution of Khiavachay River in Sabalan geothermal region by natural springs and Meshginshahr iron mine, and due to irrigation of arable lands by this river, the aim of this study was to evaluate the pollution of arsenic, cobalt, lead, zinc, copper, iron, manganese and chromium using geochemical indices and statistical methods in the surface soil of Meshginshahr city.
Material and methods
A total of 14 soil samples (0-20 cm) were collected using composite sampling method from agricultural lands irrigated by the water of Khiavachay River. The samples were dried at room temperature, then a part of them passed through a 230 mesh sieve for digestion by four acids and elemental analysis by induction coupled plasma mass spectrometer (ICP-MS) in Zarazma laboratory. In this study, Geo-accumulation index (Igeo), contamination factor (CF) and enrichment factor (EF) were used to determine the severity of soil contamination with heavy metals. Also, in order to investigate how the elements relate to each other and also to determine their origin, the results were analyzed using statistical analysis. Descriptive statistics, correlation coefficient and principal component analysis were performed using SPSS 20 software.
Results and discussion
Comparison of the concentration of elements in the region with their world average in soils and Earth crust shows that the average concentrations of arsenic, zinc and phosphorus in the agricultural soil of Meshginshahr are higher than their values in the world soil and Earth crust. Among the studied elements, As, P and Fe with values of 68.61, 34.27 and 30.76% respectively show the highest coefficients of variation in the region. The high variation coefficient, especially for As, indicates high concentration differences in different parts of the study area and possibly differences in the source of the contaminant. The results show that the amount of arsenic in the soil of station S1 (Moil village, adjacent to the iron mine) is in the range of severe to extremely polluted (Igeo level is 4.62). It is also present in 78% of the collected samples (11 samples) in the range of moderate to severe contamination (Igeo level between 2.37 to 2.95) and in two stations in the range of moderate contamination (Igeo level between 1.79 to 1.87). Zinc is in the moderate contamination range at all sampling points (CF between 1.04 and 2.27). Iron, lead and copper are in both the medium and low pollution ranges, and cobalt, chromium and manganese are only in the low pollution range. Therefore, the region shows significant enrichment to arsenic. These results are in good agreement with the previous study on the Khiavachay River and are reasonable considering the type of formations and irrigation of agricultural lands with arsenic-contaminated water. The results obtained from the pollution indices indicate that the maximum arsenic pollution is present in station number one and close to the iron mine of Moil village. High correlation of arsenic with iron (r = 0.911) and lead (r = 0.637) and its negative correlation with phosphorus (r = -0.65) was observed. The negative correlation of arsenic with phosphorus can be due to the competition of these two elements in the form of anions (arsenate and phosphate) in adsorption by soil colloids. Among the iron ores of the region, the highest concentration of arsenic has been measured in limonite. In the process of limonite formation, insoluble free hydride is formed by the oxidation of divalent iron, and during this reaction, arsenic, which originates from hot springs and hydrothermal waters of the region, is co-precipitated with iron. Therefore, As in the Moil iron mine has secondarily deposited in limonite under the influence of geothermal resources and hot springs. The results of correlation coefficient have been confirmed by principal component analysis.
Conclusion
Existence of hydrothermal springs with high concentration of arsenic, which are considered as causes of water pollution in Khiavachay River, and irrigation of agricultural lands with river water are important factors of arsenic enrichment in the soil of the region. Considering the amount of geo-accumulation index, the soil of the study area has moderate to severe As contamination. The results of the enrichment factor indicate significant enrichment for As and moderate enrichment for P, which is influenced by geological formations and natural factors for arsenic and anthropogenic factors for phosphorus. The results of statistical analyzes showed the important role of Moil iron mine and hydrothermal springs in the region in increasing the concentration of As, iron and lead in the soil of the region. Considering the negative effects of soil pollutants on the environment and due to the high concentration of arsenic in the study area, it seems necessary to study the concentration of this element in crops in the region and assess the health risk. For this purpose, evaluation of mobility and bioavailability of elements by sequential extraction methods, study of the role of soil physicochemical parameters in elemental mobility and investigation of the role of plant species in the uptake of pollutants from soil can be of great help in better analysis of the results.
Dr Saeed Hashemi, Dr Jafar Bolouri Bazaz,
Volume 8, Issue 2 (12-2022)
Volume 8, Issue 2 (12-2022)
Abstract
One of the most important issues in urban areas is the stabilization of vertical and sloping earth walls. Nailing technique used for slope stabilization, has become popular day by day in urban environments, around the world. Normal drilling wells, even at shallow depths, have collapsed many times when subjected to applied loads, resulting in reduced work progress, loss of life and unpredictable economic costs. On the other hand, the collapse of drilling holes causes to loosen the soil structure and reduce its density, which in turn causes more horizontal and vertical deformations to occur in the earth’s surface. This research, introduces the deep excavation stabilization with the aid of laboratory and numerical modeling and presents the effect of overburden and soil density on the nails behavior. It was observed that under the conditions of the same soil density, the pullout capacity of all types of nails increases with the increase of the overburden pressure applied on the soil. For example, by increasing the overburden from 0.2 to 0.5 kg/cm2, in a soil sample with a specific weight of 1.4 gram/cm3, it causes a 100% increase, and in a soil sample with a specific weight of 1.6 gram/cm3 causes a 150% increase in the nail pullout capacity. Also, under the same conditions of the applied overburden pressure, the pullout capacity of the nails will increase due to the increase in the specific dry weight of the soil, which is an increase in the density of the soil. In other words, by increasing the specific dry weight of the soil from 1.4 to 1.6 gram/cm3, by applying overburden of 0.2, 0.5, and 0.8 kg/cm2, the pullout capacity of the nail increases by 16, 35, and 40 percent compared to the initial state.
Dr. Seyed Davoud Mohammadi, Ms. Fatemeh Rouhi Moein,
Volume 9, Issue 1 (9-2023)
Volume 9, Issue 1 (9-2023)
Abstract
Water and wind erosions are the two main factors of soil degradation. But these two processes alone, without human intervention, cause natural erosion and pose little risks to soil. Soil provides food security, preserves water resources, and affects the global climate. Soil reduces water pollutants and is also a carbon storage. The economic need for soil is greater in the world's developing countries because, in these regions, deprived farmers do not have enough resources to carry out erosion control methods. As a result, the risk of soil erosion continues to increase. Various parameters affect the erodibility of soils, including fertilizers. To investigate the effect of urea and potassium sulfate fertilizers on the soils of the Heidareh area of Hamedan, three sampling stations were selected, and then basic experiments including soil sample size, determination of Gs, Atherberg limits, pinhole test, determination of calcium carbonate percentage, determination of the organic matter, chlorine determination, sulfate content, and pH were conducted on soil samples. In this regard, the percentages of 1%, 3%, 5%, 7%, and 9% of urea fertilizer and potassium sulfate fertilizer were added separately to the soil samples of the studied stations. Then pinhole and erodibility tests were conducted using a rainfall simulator with different percentages of urea fertilizer and potassium sulfate fertilizer on soil samples of all three stations in dips of 10, 20, 30, and 40 degrees. The results of the erosion test show that with increasing the amount of fertilizers, the amount of eroded soil in all sampling stations has decreased significantly. The reason for reducing erosion can be related to increasing soil permeability and reducing runoff, by increasing the amount of fertilizers and the lack of fertilizers' effect on soil dispersion
Ms Zahra Shakeri, Dr. Giti Forghani Tehrani,
Volume 9, Issue 2 (12-2023)
Volume 9, Issue 2 (12-2023)
Abstract
The present study aims to investigate the environmental geochemistry, source, and health risk of potentially toxic elements in urban soils of Shahrood, Semnan Province. For this purpose, the total concentration of major and trace elements in 26 topsoil samples was determined using an ICP-MS device. The average concentrations of As, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb and Zn are 7.9, 0.1, 7.4, 77.5, 59.8, 448.9, 0.8, 31.5, 35.7 and 104.1 mg/kg, respectively. On the basis of the geochemical indices (i.e., enrichment factor, geoaccumulation index, single-factor analysis, nemerow integrated pollution index, and potential ecological risk index), the studied soils are polluted with potentially toxic elements, especially As, Pb and Cu, and the most polluted sites are located in the northern parts of the city. Statistical analyses (cluster analysis and principle component analysis) indicate that Co and Mn are mainly from natural sources, while Cr, Mo, Ni, Zn, Cu, As, Cd and Pb are probably from anthropogenic sources (especially industrial inputs and traffic). The health risk assessment shows that there is a non-carcinogenic risk of Pb for children through the ingestion route. The carcinogenic risk of As, Cr and Ni for children through the ingestion route is higher than the reference value (1×10-4). In conclusion, the pollution of the studied soils with As, Pb, Cu, Cr and Ni must be considered as a concern in the study area.
Ms Zahra Yaftian, Dr Ata Shakeri, Dr Mehrdad Hadipourdeshal, Dr Meisam Rastegari Mehr,
Volume 9, Issue 2 (12-2023)
Volume 9, Issue 2 (12-2023)
Abstract
Mining is a necessary activity for the development of countries, but it imposes direct and indirect negative impacts on the exploited areas and their surroundings. Sangan iron mine is one of the largest iron ore deposits in the Middle East, where the ore is extracted by open pit mining. The present study aims to investigate the soil’s concentration of heavy metals and to assess the level of soil’s contamination in the Sangan mining area. For these purposes, 44 samples of the soils (including both topsoils and subsoils) of the Sangan mining area were collected, and were analyzed by an ICP-MS device. The obtained data were analyzed by calculating the geochemical indices and statistical methods. On the basis of descriptive statistics of the analytical data, Pb with an average content of 138.39 mg/kg and Cd with an average concentration of 0.19 mg/kg had the highest and lowest concentrations in top soils, respectively. Moreover, Cr with an average value of 102.19 mg/kg, showed the highest, and Cd with an average of 0.2 mg/kg showed the lowest concentrations in subsoils. The average concentrations of As, Cr and Fe in the study area were higher than their respective values in the World-Soil Average composition. Among the elements, Pb had very high and severe enrichment in two stations with enrichment factor values of 149 and 23.85. The results indicated no severe soil pollution and ecological risk in the study area, except in some sampling sites. The most polluted soils were collected near the placer extraction units and tailing ponds of Ehya-Sepahan Company, as well as the waste rock pile of Sanabad Comprehensive Development Industrial and Mining Company.
Fabric anisotropy in sands and assessing its dependence on grading and surface appearance parameters
Farideh Talaee Firozjaee, Ehsan Pegah, Ali Misaghi,
Volume 10, Issue 1 (4-2024)
Volume 10, Issue 1 (4-2024)
Abstract
Fabric anisotropy plays a crucial role in the variations model of anisotropy degree of soil elastic coefficients. This study aims to quantify this anisotropy in sandy soils, examining its variations in terms of the available stress conditions, and assessing its dependence on grading, shape and soil particles weight characteristics. To this end, by presuming the transverse isotropy in the soil medium, the elastic coefficients obtained from 419 laboratory tests on 28 different samples of 17 different sands were collected from literature. Indeed, those were attained from the seismic velocity measurements and supplemented with corresponding data on void ratio, stress state, grading, shape and weight properties. Based using on a famous experimental equation, the collected data was analyzed, and the fabric anisotropy ratio was computed for each soil sample. By drawing these results versus the respective experienced stresses, the variability model and the amplitude of the ratio were identified with respect to the applied stresses. Finally, by performing a series of simple and multiple regression analyses, the potential correlations between the fabric anisotropy ratio and the representative characteristics of grading, shape and particles weight were investigated resulting in a couple of mutual relationships.
Javid Khaghani, Giti Forghani,
Volume 10, Issue 1 (4-2024)
Volume 10, Issue 1 (4-2024)
Abstract
In order to investigate the concentration and the health risk of potentially toxic elements in the agricultural soils of the Bastam Plain, 14 surface soil samples (0-20 cm) were collected. Physico-chemical characteristics and total concentration of major and trace elements were measured using standard methods. The obtained data were interpreted using single and integrated environmental indices and statistical analyses. The soil’s pH varied between 7.9 and 8.4. The average values of organic matter, calcium carbonate, and cation exchange capacity (CEC) were 2 %, 42.5 %, and 10.4 meq/100g, respectively. The concentrations of Cr, Mo, Ni, Sr and Mn in all samples, and the concentration of As, Cd, Co, Cu and Fe in some samples were higher than the corresponding values in the World Soil Average composition, confirming the anthropogenic pollution of the studied soils. The calculation of environmental indices indicated that the studied soil samples were polluted with toxic elements, especially Mo and Sr. According to the integrated pollution indices, the soils of the study area were moderately polluted. The results of human health risk assessment indicated the possibility of carcinogenic risk of As and Cr through the ingestion route for children. Statistical analyses showed that Fe-Mn oxides may play a major role in the accumulation of pollutants in the soil. Moreover, the agricultural activity probably enhanced the concentration of toxic elements in soils. The results of the present study showed that application of chemical fertilizers and pesticides is the main source of contamination of the agricultural soils of the study area, and therefore, the environmental management of agricultural practice seems necessary.
Ms Hanieh Farhadi, Dr Hossein Pirkharrati, Dr Masoumeh Ahangari, Dr Yousef Rahim Souri,
Volume 10, Issue 2 (12-2024)
Volume 10, Issue 2 (12-2024)
Abstract
Barite mineralization and mining can be a significant source of potentially toxic elements (PTEs) pollution in soils due to the presence of sulfide minerals. This study deals with the evaluation of soil pollutions and health risk assessment caused by barite mineralization and mining in the mining site of the Kuh-e-Marghavol, located in the east of Mahabad. Samples of topsoils (sampling depth 0-5 cm) from mining and agricultural areas were taken separately. Soil sampling in the mining area (7 samples were taken) was done systematically perpendicular to the main barite vein. Soil samples of central parts of agricultural areas (6 samples) were collected from the mining area's downstream. To determine the PTEs concentration, inductively-coupled plasma mass spectrometry (ICP-MS) was employed. The samples were digested using the four-acid method, which includes hydrofluoric acid, perchloric acid, nitric acid, and hydrochloric acid. In the examined samples, the concentrations of the majority of PTEs exceeded the corresponding values in the worldwide soil average and continental crust composition. Soils from mining site have a very high enrichment factor for As, a significant enrichment factor for Cu and Ba, and moderate enrichment for Cd and Mn. Agricultural soils have a significant enrichment factor for As and moderate enrichment for Mo. According to the individual environmental indices (geoaccumulation index, pollution factor, Nemerow index) the studied soil samples (mining site and agricultural soils) were polluted with PTEs especially As, Ba, and Cu. All samples exhibit high levels of pollution based on the values of the pollution load index (2
Dr. Reza Jahanshahi, Mr. Ebrahim Gamshadzahi Mahboub, Dr. Hamid Reza Soloki, Prof. Mehdi Azhdary Moghaddam,
Volume 10, Issue 2 (12-2024)
Volume 10, Issue 2 (12-2024)
Abstract
The Tehlab plain is located in the Hamoun Mashkil catchment in the south of Mirjavah region and along the Iran-Pakistan border. In most of the rural areas of this plain, especially in the northern parts of the plain along the border of Iran and Pakistan, the effects of land subsidence in the form of cracks and fissures in buildings as well as collapse in sewage wells were observed. In order to evaluate these land subsidences, the Tehlab plain was first zoned in terms of subsidence risk. Based on the land subsidence risk zoning map, it can be seen that most of the areas of the Tahlab plain have a low risk of subsidence, except for the northern region, where there are many exploitation wells in this area. To study the collapse in sewage wells and its relationship with soil type in the northern regions of the plain, the collapsibility of soil samples was investigated. According to Jennings and Knight criteria in the oedometer device in the laboratory in the saturated state. the coefficient of collapsible of soil samples was measured between 0.21 to 7.3, which showed that the soil samples were collapsible in this area. Finally, to investigate the occurrence of collapse in sewage wells in the northern of the plain, an in-situ permeability test (ring) test was performed at different depths of a dug well. This test showed that a soil layer with high permeability rate (9.24 cm/hr) was located between low permeability layers. These low permeability layers caused an increasing the water level in the sewage wells. Moreover, the liquid limit of most surface soil samples was less than 30%. Therefore, the soil permeability and liquid limit were the most important factors controlling collapse in the sewage wells.
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