جستجوی مقالات مرتبط با کلیدواژه « soil » در نشریات گروه « زمین شناسی »

This research aims to assess the concentration of potentially toxic elements (PTEs) in the soils around the Shahid Rajaei Combined Cycle Power Plant, located 25 km from Qazvin. For this purpose, 25 topsoil samples (0 to 10 cm) were collected, and after sample preparation, the physico-chemical parameters of the samples (including soil’s texture, pH, organic matter, calcium carbonate and cation exchange capacity) were measured. The concentrations of PTEs were determined using an ICP-OES device after strong acid digestion. The obtained results indicate that the average concentration of PTEs decreases in the following order: Mn > Zn > V > Cu > Cr > Pb > Ni > Co > As > Sb > Cd. Enrichment factor values showed that the studied soils are slightly enriched in Cd, Cr and Cu, and are significantly polluted with Pb, Sb, and Zn. Correlation coefficient values, cluster analysis, and principal component analysis show that Cu, Ni, Pb, and Zn are mainly from industrial activities, while As and Cd are probably entered into the soil through agricultural practice (i.e., application of chemical fertilizers and pesticides). Indeed, the highest concentrations of Cu, Ni, Pb, and Zn are recorded in the soil samples collected close to the power plant station in the downwind direction (S-N and NW-SE), indicating that the power plant activity is a possible source of these elements in the studied soils. The health risk assessment of PTEs indicates that As, Cr and Ni cause a cancer risk to children through ingestion. The carcinogenic risks of As, Ni, Cr, Pb, and Cd through all the three exposure routes are higher for children than for adults.

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.

The present study aims to determine the concentration of heavy metals and toxic metalloids in rice of Sari paddy fields in the Mazandaran province of Iran. In this study, sampling was performed from 32 stations of the rice seed section. The soil-plant relationship was investigated in 6 stations using samples taken from rice soil and other plant parts such as roots, stems, leaves, and bran. Soil and plant samples were prepared using ICP-OES and ICP-MS methods, respectively, and then analyzed chemically. The results of the chemical analysis of rice samples showed that the mercury (Hg) concentration is usually about 0.07 ppm. However, it reaches about 0.09 ppm in some points (30% of the samples). The mean concentration of lead (Pb) is 0.91 ppm, which is close to its allowable limit. In some samples, elements arsenic (As), cadmium (Cd), nickel (Ni), and zinc (Zn) are different from normal concentrations. The study results attribute the origin of lead elements to the use of chemical zinc fertilizer in rice fields and paddy fields, as Pb concentration in areas with zinc (Zn) fertilizer consumption is about 3.99 ppm. The as concentration in Isa Khandagh is 1.15 ppm, suggesting a high deviation from the normal level. In addition, the concentration of trace elements in rice crops in different regions of Sari city compared with rice crops in some foreign cities shows a high correlation for chromium (Cr), cobalt (Co), Arsenic (As), magnesium (Mg), manganese (Mn), sodium (Na), and Zinc (Zn).

This study was conducted to investigate the heavy metal contamination and their region in Jafar Abad, southwest of Kashmar in Khorasan Razavi province. For this purpose, heavy metals of surface soil samples 32 (10- 30 cm) were analyzed in the Jafar Abad, southwest Kashmar by ICP-MS origin indices and degree of contamination including enrichment factor (Ef) and its percentage, geoaccumulation index (Igeo), contamination factor (Cf) were calculated to evaluate soil contamination. Based on the results, in between heavy metals, Manganes has the highest and Cadmium the lowest average contamination. Maximum and minimum enrichment factors are also Molybdenum and lead respectively. The results show that the study area is almost contaminated with respect to copper and molybdenum metals. The results of this study indicate that heavy metals contamination is lithogenic and mainly due to the lithology of the region such as shale, sandstone, conglomerate, gypsum marls, granite and volcanic rocks, and anthropogenic contaminants, except from limited mining activities and some agricultural activities did not play a significant role in the contamination of this region. Based on cluster analysis and principal component analysis, the presence of some metal such as copper, molybdenum and manganese together indicates their common origin.

Soils are discontinuous cover at the surface that may be composed of rocks and sediments in situ or by material transport. Heavy metals are one of the most important soil pollutants that can have a major impact on the health of living things and, above all, humans. Heavy metals, which enter the human body, can accumulate in the tissues and affect the nervous system and circulation. These metals also impair the normal functioning of the internal organs or may be auxiliary to other diseases. Elements such as mercury, lead, cadmium, chromium, nickel, zinc, selenium and the like are elements that are highly resident in the soil and have low mobility, so they may remain in the soil for many years. Such contaminants in the soil are caused by the addition of sludge, phosphate fertilizers, atmospheric sinks, color wastes and smoke from natural fuels, coal and other sources. Numerous studies have been carried out on the distribution of heavy metals in various soils such as urban, industrial, etc. Considering the importance of heavy metal contamination in soil and its effect on the health of living organisms, especially humans, this study was conducted to evaluate the concentration and contamination of heavy metals in soils north of Fereydoon Shahr (Isfahan province) using environmental indices; Geoaccumulation index, pollution load index, enrichment factor and pollution index were performed. The spatial distribution of heavy metal concentrations in the study area is also investigated.

This study was conducted to investigate the heavy metal contamination and their origin in eastern Azna city in Lorestan province. For this purpose, heavy metals of surface soil samples 113 (5-15 m) were analyzed in the eastern Azna city by AAS flame atomic absorption spectrometry. Origin indices and degree of contamination including enrichment factor (Ef) and its percentage, Geoaccumulation Index (Igeo), contamination factor (Cf) were calculated to evaluate soil contamination. Based on the results, the mean concentrations of heavy metals including Zn, Y, V, Sn, Sr, Sc, Pb, Ni, Cu, Cr, Cd, B, Br were 86.9, 51, 161, 14.5, 160, 26, 32.6, 65.4, 34, 22.9, 0.7, 102, 393 mg/kg, respectively, which Br has the highest and Cd the least. Maximum and minimum enrichment factors are also Cd and Br, respectively. The results showed that the studied area is not heavily contaminated with heavy metals but the concentration of some metals is very high in some places and in the case of a natural source of contamination (rock and soil), these sites can be used as potential mining and resource sources.

The aim of the present study was to assess the health risk imposed by toxic metals present in agricultural soils of the Aleshtar plain. The average concentration of Cd, As, Sb, Zn, Ni, Fe, Mn, Cr, Ag, Co, Th and U in the studied samples were higher than corresponding values in world average soils. Based on geochemical indices calculations, the samples are highly polluted by Ag, Sb, As and Ni. Health risk assessment indicates that the hazard quotient for As via ingestion for children is higher than 1; therefore, there were adverse non-carcinogenic health effects of arsenic for this age group. The results showed that carcinogenic risk imposed by arsenic via ingestion for both adult and children age groups. Cr is carcinogenic for children via dermal contact and ingestion; whereas it is carcinogenic for adults through ingestion. The intake of Ni via ingestion by adults and via dermal contact by children would be associated with carcinogenic risk. The results indicated that Cd is carcinogenic for children through the ingestion route. The obtained results in this study show that agricultural activity has considerably increased the concentration of As, Cr, Ni and Sb in the Aleshtar agricultural soils. Regarding the probable negative effects of metal accumulation on public health status, the management of agricultural practice in the study area is of crucial importance.

Accumulation of potentially toxic elements in agriculture soil is one of the main serious environmental concerns in the greenhouse cultivation. The environmental investigation of potentially toxic elements (V, Ag, Se, Ni, Pb, As, Cr, Co, Cd, Cu, Fe, Mo, Mn, Sn, Sb, Bi and Zn) in the greenhouse cultivated soils of the Bagher-Abad area, Jiroft is the main objective of this study. After preliminary field investigations, 20 soil samples were collected by mean of composite method. Collected samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) method at the Labwest laboratory, Perth, Australia. The results were discussed using statistical methods and environmental indices with respect to the natural background and worldwide concentrations of target elements. The data showed that only Zn, Cd, Mo, As and in some cases Sb have medium enrichment in the investigated soils. For some of the selected soils the bioavailability or solubility of target elements was determined using 0.005M DTPA leaching solution. Among the investigated elements Cd and Zn showed the maximum bioavailable fraction corresponding to the medium to high risk assessment codes. Antimony is the only trace element that showed poor enrichment (39.3 µg/L) in the irrigation water used for the target greenhouse soils.

The study of variations of damage intensity for different earthquakes indicates the importance of the site effects on earthquake induced damage and ground motion parameters such as peak ground acceleration and induced amplification. In the occurrence of an earthquake, local site conditions such as soil characteristics, dimension of topographic irregularities, seismic bedrock depth, etc. as well as characteristics of incident wave have important e ects on seismic ground responseLocal site effects play an important role in earthquake-resistant designs and should be assessed carefully. By assessment of induced damages to structures and major infrastructures, seismic geotechnical researchers have concluded that the site conditions significantly influence on the failure distribution in urban and rural areas. Consequently, to determine the characteristics of seismic motions of the ground, it is essential to study the effective geotechnical factors. Consideration of the effects of the site response in the design of civil structures systems is of important to mitigate the damages to a certain extent on structures and the environment. Hence, it is relatively crucial to reliably attain the dynamic soil parameters of an earthquake-prone city/state. The nature of local site effects can be explained by using different methods such as simple theoretical analysis of ground response, measuring of surface and subsurface actual motion at the same site, and measuring the movements of the ground in sites with different conditions in comparison with the proposed site. In this paper, the effective factors on ground motion and site response in the soil classes II and III for Tehran city under the influence of Tabas and Bam earthquake were reviewed with numerical method and by using the finite difference software (FLAC 2D). Some of the effective parameters of the site dynamic characteristics on the seismic response of the ground surface have been studied and the response of peak ground acceleration and the resonance function has been compared. The results of this study show that at both sites, the horizontal maximum acceleration of the ground surface increases with respect to the bedrock shear velocity, reflecting the influence of the site on ground movement. At both sites, with increasing soil internal friction angle, the maximum acceleration at ground level increases and the acceleration response decreases. Also, as the shear wave velocity increases, the horizontal maximum acceleration at ground level for both structures decreases. Increasing the shear wave velocity in the surface layer, assuming the thickness of the layer is constant, results in a decrease in the natural frequency, which is far from the normal frequency range of conventional structures in Tehran. This indicates a decrease in the earthquake's dynamic force on surface structures. The natural frequency of five to seven story buildings in Tehran is about 0.5 to 0.7 Hz. As the surface layer thickness and bedrock depth increase, the horizontal maximum acceleration of the ground surface also decreases, meaning that the structural response can also be reduced.

Introduction: Pollution of soils with potentially toxic elements (PTEs) is one of the most important hazards threatening the health of natural ecosystems. In recent decades, the anthropogenic activities have led to the disruption of the geochemical and biochemical circles of these elements. Mining activities are one of the most important anthropogenic sources for PTEs. The mine tailings are the most important pollution sources of surrounding soils and groundwater (Ferreira da Silva et al., 2004; Boularbah et al., 2006). Indeed, agricultural activities have a significant impact on the soil pollution with PTEs (Keskin, 2010). Soil plays a vital role in human life. Thus, the monitoring and assessment of soils pollution is of great importance. The Irankuh Pb-Zn mine, located in the SW of Esfahan, is one of the most important mines of Iran. Mining and subsequent processing of ores in this region generates high volumes of mine wastes which are deposited near the mine site. On the other hand, agricultural activities in the Irankuh area are extensive and the mine's tailing ponds usually neighbor the farms. The present study aims to investigate the concentration, mobility and availability of PTEs in the Irankuh mine tailings and to determine the source of these pollutants in the surrounding soils. Material and Methods: After the preliminary field studies, 28 soil samples including 8 mine- and 20 agricultural soils as well as two representative tailing samples were collected. One manure sample was also collected to identify the impact of agricultural activities on the concentration of PTEs in the soils, if any. First, the soil samples were air-dried at room temperature. Then, the large fragments and plant residuals were removed from the samples and the remaining portion was passed through a 2 mm stainless steel sieve. The sieved samples were ground to about 0.074 mm using an agate mortar and pestle and finally stored in polyethylene bags prior to laboratory analysis. The total concentrations of elements were measured by ICP-OES instrument after digesting by strong acids. The five-stage method of Tessier et al. (1979) was employed for sequential extraction analysis. In order to assess the pollution of the soils and tailings, the enrichment factor was calculated. Having obtained the results of the analysis, descriptive and multivariate data analyses were conducted. Results and discussion: The average concentration of Ag, As, Ba, Cd, Co, Mn, Pb, Sb and Zn in the mine soils are higher than the agricultural soils. The application of manure to the agriclutural soils led to increase in Cu and Cr concentration of the soils; the high concentration of these two elements in the manure sample is indicative. The concentration of Ag, As, Cd, Ba, Pb, Ni, Zn and Sb in both agricultural and mine soils are higher than the average world soil composition (Kabata-Pendias, 2011), pointing to the impact of anthropogenic activities on the PTEs concentrations in the soils. The tailing samples are highly encirched with respect to As, Cd, Cu, Sb, Mn, Pb and Zn. Enrichment factor values confirms pollution of soils with respect to Ag, As, Cd, Pb, Sb and Zn. Tailing samples are also extremly contaminated by these elements. On the basis of the analysis of variance, there is a significant statistical difference between the element concentrations in mine and in agricultural soils. The cluster analysis indicates the impacts of mining activity on the PTEs concentrations in soils. On the basis of principal component analysis, the elements originate from three sources: 1- geogenic stable elements 2- anthropogenic elements and 3- the weathering products of carbonate units. Total concentrations of PTEs provide no information on their likely environmental impacts. The speciation studies through sequential extraction analysis could be used to determine the mobility and availability of PTEs. By employing sequential extraction procedure, it is possible to predict occurrence manner, mobility, solubility, bioavailability, toxicity and transport as well as the origin of PTEs (Favas et al., 2011). The results show that, on the average, 24.9, 20.3, 18.6, and 15.2 % of Cu, Mn, Cd and As, respectively, are present as exchangeable fraction. Therefore, the weathering of mine tailings may increase the bioavailability of these elements in agricultural soils and groundwater around the mining area. The mobility of arsenic and iron is lower than other studied elements. Chromium and nickel are not mobile. Acknowledgement: This research has been funded by the Research Office of the Shahrood University of Technology.

The presence of potentially toxic elements in the environment and especially in soil has been one of the greatest concerns due to their health implications. Potentially toxic elements from anthropogenic sources tend to be more mobile than those from lithogenic or pedogenic sources. Generally, the distribution of potentially toxic elements is influenced by the nature of parent materials, climatic conditions, and their relative mobility depending on soil parameters, such as mineralogy, texture and class of soil. In the inhabited, and industrial areas, vicinity to the un-engineered landfills, excess accumulation of toxic elements in surface soils can directly threaten wellbeing of exposed inhabitants via ingestion, inhalation and dermal contact routes. A few studies conducted on risk assessment of potentially toxic elements in soils of Kermanshah province, west of Iran. Soil in the study area is susceptible to contamination by anthropogenic activities in the form of industrial wastewater, agricultural activities, solid waste, runoff, atmospheric deposition and especially un-engineered landfills. The presence of toxic elements in soil around of un-engineered landfills without proper consideration to the environmental protection measures, will certainly lead to a significant environmental hazard in Kermanshah province. Therefore, the main purposes of this study are to evaluate the contamination levels, health risk assessment, and source identification of As, Cd, Cr, Cu, Ni, Pb and Zn in the Gasre Shirin, Gilane Gharb, Paveh, Javanrood, Eslamshahr, Ravansar, Kermanshah and Sanghar un-engineered landfills.
Material and A total of 30 topsoil samples were collected (0-20 cm depth) from the eight un-engineered landfills of the Kermanshah province. In order to achieve a representative sample, composite samples were prepared by mixing the four subsamples taken at each corners of 2×2 m square cell because composite sampling yields homogenized samples for analyses. The subsamples were mixed and a final sample of 1 kg was taken by repeated coning and quartering. To determine background concentration of heavy metals, eight soil samples were collected from areas far from known sources of contamination (40-60 cm depth).
The collected samples were immediately stored in polyethylene bags and air-dried in the laboratory at room temperature. Then, samples passed through a 2mm stainless steel sieve. The 1, it is likely that there will be adverse health effects, whereas if the ADD is less than the RfD, HQ1 show possible adverse health effects. Carcinogenic risk is regarded as the probability of an individual developing any type of cancer in the whole life time due to exposure to carcinogenic hazards and was calculated for As and Cd as follows: (1) The value of SF represents the probability of developing cancer per unit exposure level of mg/kg day. The acceptable risk range for carcinogens is set to 10-6 to by the USEPA, so that RI values below 10-6 do not require further action, while risks greater than 10-4 are considered to be of concern and require additional action to reduce the exposure and resulting risk.
The soil pH ranges from 7.01 to 8.06, with an average value of 7.51 suggesting neutral conditions. Organic carbon (OC) contents of soil samples ranged from 0.06% to 4.91% (average 1.59%). In this study, based on the USDA textural triangle the main soil textures are loamy, clay loam and sandy loam, respectively.
The average abundance order of selected elements content is: Zn>Ni>Pb>Cr>Cu>As>Cd. Comparison of mean concentration of the potentially toxic elements in the soil samples with mean worldwide values reveals higher Zn, Pb and Ni contents in this area.
The results of contamination factor indicate very high contamination for Cd, Cu, Pb and Zn. Modified Degree of Contamination (mCd) calculated based on background values proves very high degrees of contamination for selected trace elements in Gasre Shirin and Eslamshahr landfills soil samples The results of enrichment factor evaluation similarity to contamination factor indicate that Cd, Cr, Pb, Cu and Zn have more influence from anthropogenic sources. The maximum EF of Pb, Zn and Cd and Cu is 346.7,124 and 51.9 respectively, which means very high enrichment in Ghasre Shirin landfill soil samples.
Exposure doses of 7 heavy metals in soil samples of un-enggenerd landfills for children and adults were calculated. The total exposure HQs calculated based on adults from ingestion, dermal contact, and inhalation for Cd, Cu, Ni, Zn, As and Pb was less than 1(except Ghasreshirin landfill). The hazard quotient values based on the adult risk for Cr were greater than 1.0. The results show that HQ for Pb and As in children by dermal and ingestion pathway is exceeded 1.0 in soil samples of Paveh, Javanrood, Ravansar, Kermanshah and Sangher landfills and Ghasreshirin and Eslamshahr landfills, respectively.
The concentration, pollution level, potential sources and health risk of potentially toxic elements in eight landfills top soil of Kermanshah province were investigated in this study. The following conclusions were drawn from this research.
- Compared with the background values of As, Cd, Cr, Cu, Ni, Pb and Zn in soils of Kermanshah Province, landfills soil have elevated metal concentrations as a whole.
- According to high contamination level and health risk of some studied potentially toxic elements, and also due to the proximity of contamination sources to residential district of the study area, more attention should be paid to manage and reduce contamination.
- These results provide basic information of toxic elements pollution control and environment management in the area..

Exploitation or processing of ores is usually associated with the production of a large amount of waste materials. These materials often have a high concentration of metals which can enter the environment through weathering or erosion. It is well-known that the measurement of the total concentration of metals cannot be an adequate for evaluating the pollution status of soil. Therefore, in most studies on soil contamination, bioavailability content of metals is determined by which can predicate the fate of the metals entering into the other parts of the environment such as plants, water or human food chain. The bioavailability of metals in the soil environment is the exchangeable and absorbable metals for plants, which depends on their exchangeability and absorption by soil organisms especially plants. This is also the function of the chemical form of each element in the soil. The main purpose of the present study was to measure the total concentrations along with the bioavailable content of metals in soils and plants around the Irankuh mine tailing dams.
Area of study: The Irankuh lead and zinc mine is located 20 kilometers southwest of Isfahan. This mine is of MVT type Pb-Zn deposit which occurred mainly in limestone and dolostone of lower cretaceous age. The Irankuh mine is an open-pit mine with annual extraction of 358 thousand of PbO and ZnO. The exploitation of mine is also associated with the production of a large amount of waste material which is piled in open dumps around the mine. The main minerals of ores are galena, sphalerite and pyrite.
31 sampling sites were selected randomly for collecting agricultural soils around the tailing dams. Each soil sample is actually composite sample of four samples which are taken from a depth of 15 to 20 cm. Seven cultivated plants (Ocimum basilicum) were sampled from green houses in the vicinity of tailing dams. After drying and sieving, about 50g of the soils are chemically analyzed in order to determine the total concentration of the metals by the ICP-OES method. Plant samples after drying were changed to ash in the furnace at temperature > 500 C. The concentrations of metals (Zn, Pb and Cd) were then measured by Atomic Absorption Spectrometers in their stem, roots and leaves.
pH samples of soil were also determined using the EPA 9045 method. Walkley and Black method were used to measure the amount of organic matter. The cation exchange capacity (CEC) of soil samples was also determined based on EPA 9087 method. Soil texture determined using hydrometric method and then classified according to USDA classification. Diethylene Triamine Pentaacetic Acid (DTPA) extractable metals (bioavailable content) were determined using the method by Lindsay and Norvell (1978) and their concentrations in the DTPA extracts were determined by Atomic Absorption Spectrophotometer (AAS).
The metal transfer from soil to plant was calculated using the transfer factor (TF: metal content in plant divided by metal content in soil).
The soil pH of the studied samples varies from 7.36 to 8.35. Cation exchange capacity (CEC) of soil samples was estimated to be in the range of 4 to 22.2 Meq/100 g. Also, the amount of organic matter in the studied soil samples varies from 0.17 to 3.43%. The relative high levels of soil organic matter are probably due to addition of organic manure to soil through agricultural activity. The total concentration of these three matls are significantly higher than their corresponding values in the crust implying that the mining activity and tailing dams greatly elevated the concentration of these metals in soils. Statistically, there is a significant positive correlation among Zn, Pb and Cd (at confidence level of 0.01) indicating that their potential source is the same or having similar geochemical behavior in the soil. The soil clay content showed a significant correlation at the level of 0.05 with Zn, Cd and Pb. This indicates that clay fraction plays a significant role in absorption of these metals in soil. According to the results of single extraction (DTPA method), the proportion of available content for Cd is higher than that of Zn and Pb. Cadmium is often characterized by its high mobility in soil media. Based on the correlation coefficients at the confidence level of 0.01, it is also observed that the increase in total concentration of Cd increased its bioavailability content in the soil consequently increase the availability of other elements in the soil. Therefore, it can be inferred that the availability of Cd in the soils of the study area is likely to be increased in the presence of Zn and Pb because in sites where the total concentration of Pb and Zn is high, the content of Cd availability has also elevated.
Based on the comparison of the average concentration of the metals in different parts of the plants, the concentration of metals is ordered as follows stem> leaf> root, which indicates the high root capacity for the accumulation of metals. The average transfer factor (TF) for Cd is obtained much higher than those of Zn and Pb. There is also a negative significantly correlation between the concentrations of Cd in the aerial parts of the plants and its bioavailability concentration in the soil. Also, there is positive and significant correlation between Zn and Cd for all three different parts and its bioavailability concentration in the soil. In the case of Pb, a significant correlation is observed between stem and root parts. This means that Cd and Zn after being absorbed by the root, are more likely being uptake by the plants due to high mobility of zinc. However due to less mobility of Pb, it is seemingly entered into the plant aerial parts after absorption by the root.
The concentration and degree of contamination of the studied soils is very high in terms of total Pb, Zn and Cd concentrations in agricultural soils around the Irankuh mine. The increased heavy metal contents in soils can be attributed to mining activity and tailing dams near cultivated lands. The measurement of the bioavailable content of these metals indicates that the Cd has the highest availability as compared to Zn and Pb. The average concentration of Pb and Cd in different parts of plant which is higher than the permissible limits, implying that the transfer of the available metal part (especially Cd) from the contaminated soil into the plant. Based on the calculated health risk assessment index in this study, it can generally be concluded that the gradual accumulation of these metals, especially in aerial parts of basil might have health hazards for local consumers.

There are various methods for the analysis of the interactional behavior of the surrounding land, using the lining structure which is the most common method of deigning lining structure tools for the static loads by using the hyper static methods. In recent years, there has been a question that depicts whether this method provides the best results in designing the tunnel structure or not.Due to the nonlinear behavior of the earth surrounding the lining structure, utilizing the lining method could lead to conservative results in the design. If it is possible to somehow find the forces caused by the real behavior of the land surrounding the lining structure influencing the structure and conduct the design based on them, more optimal results would be obtained. This study is based on the actual behavior of the land surrounding the lining structure and the displacement of the structure caused by forces with linear behavior in the static design according to the non-linear behavior of the land around the tunnel structure. The behavior is modeled using the non-linear programs and the forces affecting the lining of the structure will be inference. Also there is a case study based on this method in which the soil interaction with the tunnel analysis and designing the lining structure was first performed and eventually the obtained results were compared with the hyper static method. In this paper, analysis of maintenance system with lower thicknesses considering land-shield, indicated that applying the reinforced concrete with 40cm thickness has the potential to tolerate the applied load but lining with 45cm thickness is capable of tolerating the loads of design and it can be concluded that applying the simulation method combined with the soil and structure besides considering the nonlinear behavior of the soil leads to more economical results in a project.

Soil is regarded as one of the natural slow biodegradable source which plays an important role in the cycle of mineral and organic elements. As a dynamic ecosystem, it provides the life for big and small creatures, so removing its pollution is of considerable attention. The pollution of heavy metals not only affects directly the physical and chemical features of soil and reduces biological activities and access to nutrition materials in soil, but also is considered as a serious danger for human health. In fact, they can enter food chain or penetrate underground water sources.Iran is one of the oil-rich countries in the world in which high amount of oil is extracted in southern regions and refined in other places yearly. Once oil is extracted, transmitted and refined, its release in the soil causes pollution. A group of soil pollutant sources is related to oil discoveries, production, saving, transmission, distribution and final burial of wastes. If these industries are pollutants, they will cause dangers. The increase of soil pollution by heavy metals has led to a lot of research.
Kermanshah province is located to the west of Iran sharing borders with Lorestan, Kurdistan, Ilam and Hamedan and an international border with Iraq. Its geographical coordinate is between (33˚37̕to 35˚17̕) northern longitude and (45˚20̕ to 48˚01̕) eastern longitude. Since Kermanshah Refinery is built on alluvial terraces, fans of new low foothills and Inceptisols and Vertisols,15 samples of surrounded soil were collected by an iron shovel from the depth of 15 to 25 cm. ICP-MS method, were used to analyze and determine the density of heavy elements in of the samples. Grinded to the sizes less than 4 mm by crusher, the samples were become powder to the size of 75 microns (200 mesh) by disc mill. Weighing the samples by Teflon pipes in digest 4 acid, hydrochloric, perchloric, nitric and choloridric acid were added to the samples equally. All samples were kept in Hot Box case. After complete digest operations, the samples were cold in the environment temperature and achieved volume by distilled water.
The findings from geo-accumulation index shows that the intensity of Refinery soil is classified in the range of no pollution to average regarding chromium and nickel. Besides, enrichment index indicates average enrichment for cadmium (station 14), copper (stations 13, 11, 2 and 14), lead (stations 6 and 13), zinc (stations 11, 6, 2, and 13) and chromium (the stations from 6 to 15). In addition, pollution bar index of chromium, copper, nickel, zinc and lead is more than 1 proving the inappropriate soil quality and soil pollution of the region. However, chromium has the most considerable value, 2/75. Average value of EF is less than 2 for arsenic, cobalt and vanadium proving that the region does not show enrichment for the aforesaid elements. Enrichment index values for cadmium, chromium, copper, nickel, lead and zinc are between 2 to 5 indicating average enrichment of these samples than other metals. Since enrichment element for these sample are higher than 2, they have anthropogenic source.
According to Pearson correlation coefficient, there is a high correlation between nickel and chromium, scandium and cobalt, vanadium and chromium, and zinc and copper and lead indicating the equal source or similar geochemical behavior of the elements toward each other. Since vanadium is considered as one the oil pollution indices, it can be concluded that high pollution of this element and chromium around the region comes from petroleum.
The findings from the present study shows that soil surrounded Kermanshah Refinery are polluted to some elements. According to the values of geoaccumulation in the studying area, elements nickel and chromium have pollution. The finding from enrichment factor indicates the average enrichment of the region soil by chromium and lead. Besides, enrichment factor higher than 2 for lead and copper proves anthropogenic interference factors in the region pollution to them. The results from pollution bar for chromium, nickel, zinc, copper and lead is more than 1 indicating soil pollution to these metals. Pearson correlation coefficient reveals that there is a high correlation among vanadium, cobalt, chromium, and nickel proving same origin. Making zoning map of heavy metal density in the region soil demonstrates that high density of the elements in some stations is related to petroleum producing installations and storage tank. Cluster analysis shows the division of the elements into 7 clusters. Besides, the elements with structural relationship are related in next subcategories. Clusters 6 and 7 together indicate the same origin for these elements. Since vanadium is derived from oil compound, it can be concluded that chromium and nickel pollution have the same pollution origin with oil compounds. Factor analysis introduces 3 main factors in which the first factor with total 40/1% of total variance is the most effective factor in density of the soil elements. This factor has a high positive correlation with Sc, V, Ni, Cr, and Co proving the same density origin with petroleum compound.

Sarcheshmeh Copper Mine is the largest porphyry deposit in the world and in this study heavy metal contamination is investigated. To determine concentrations of these elements, intact samples of soil, surface water and groundwater of the region have been sent to the laboratory for analysis. After determining the concentration of samples, the data are analyzed using Excel and ArcGIS. Using Kriging method, the variations of chosen elements’ concentration are interpolated and the maps and charts are drawn.. The results show that concentrations of copper, molybdenum, lead and cadmium in the soil of this region, on average, are respectively 235ppm, 13ppm, 65ppm and 7.1ppm which exceeded the limits and according to international standard, soil is unfavorable. The concentration of Aluminum, lead, molybdenum and cadmium in river water source on average, are respectively 0.73ppm, 0.8ppm, 1.32ppm and 0.42ppm; and in of groundwater on average are respectively 0.9ppm, 0.4ppm, 0.8ppm and 0.2ppm is. The comparison of concentration of these elements in surface and groundwater with global quality criteria standards indicates that the concentration of these elements according to different uses are not desirable. The analysis indicates an increase in the concentration of these elements in the southern part of the map area (mine), the source of the river downstream and adjacent to the mine fields to other parts of the region.

High concentrations of metals are usually encountered in surface soil and vegetation in areas affected by mining activity (Liu et al.، 2006). Different distribution of elements in chemical fractions result in different bioavailability; therefore knowledge of the total content of an element in soil is not a sufficient criterion to estimate the environmental implications of trace metal presence (Maiz et al.، 2000). Sequential extraction analysis gives information on the element distribution among different phases of soil. Several schemes of sequential extraction are used for the determination of commonly distinguished metal species، which are in general: (1) easily exchangeable or water soluble; (2) specifically sorbed; e. g.، by carbonates or phosphates; (3) organically bound; (4) occluded by Fe-Mn oxides and hydroxides; and (5) structurally bound in minerals or residual (Kabata-Pendias and Mukherjee، 2007). The main objectives of this study are: (1) to describe the distribution pattern of elements in rocks and soils of the Miduk area; (2) to assess the fractionation of elements in soil and the mining impact on the mobility of trace elements; (3) to investigate the uptake of analyzed elements by selected indigenous plant species. In this study، 32 soil samples at two depths (0-5 cm and 15-20 cm)، were analyzed for total concentration of 45 elements. In order to assess the possible bioaccumulation of the elements، the roots and the overground parts of 3 plant species (Astragalus-Fabaceae، Acanthophyllum -Caryophyllaceae، Artemisia -Asteraceae) were also collected and analyzed. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The Tessier et al. method (Tessier et al.، 1979) was chosen for sequential extraction of 6 subsoil samples. Correlation analysis was used to examine the relationship between the analyzed elements in soil. The plant’s ability to take up chemical elements from growth media was evaluated by calculating transfer factor (TF) (Kabata-Pendias and Pendias، 2001). Topsoil samples displayed higher mean levels of Mo، Cd، Se، Fe، As، Pb، Cu and Zn compared to subsoil samples. Generally، Cu is accumulated in the upper few centimeters of the soil، but in deeper soil layers it has a tendency to be absorbed by organic compounds and oxy-hydroxides of Mn and Fe (Kabata-Pendias and Mukherjee، 2007). The total mean concentrations of Cu (201. 19 mg kg-1)، As (26. 90 mg kg-1) and Pb (83. 87 mg kg-1) are higher than those recorded for natural uncontaminated soils worldwide (Kabata-Pendias and Pendias، 2001). The strongest correlation (higher than 0. 80) is observed in samples taken from two depths for Zn and Pb، Zn and Cd، Cr and Ni، and Ni and Mg. The geochemical behavior of Pb and Zn is known to be similar in most natural processes (Reinmann and Caritat، 1998). Element concentrations in the roots and leaves of plants differ considerably between the three analyzed plant genuses. Element concentrations in Astragalus genus are higher than Artemisia and Acanthophyllum، expect for Pb and Cd، which displayed the highest concentration in Artemisia. Astragalus is the most contaminated species among the collected plants. The lowest concentration for all elements is found in the leaves of Acanthophyllum species. The results probably demonstrate the influence of the plant’s genetics on element uptake. The following decreasing order shows median transfer factor in plants with little differences between the three plant species: Cd>Mo>Cu>As>Mg>Mn>Pb>Fe>Ni>Ag>Co>Cr. The results of sequential extraction analysis showed that more than 54. 01% of extracted Cu is bound to Fe-Mn oxides fraction، followed by the organic matter and residual fractions. The hydrous oxides of Fe and Mn control Cu fixation in soil (Davies، 1997). Arsenic and chromium mostly remained in the residue of the sequential extraction process. The high Pb concentration in the residual and Fe-Mn oxides fractions indicated that the soil may be considered unpolluted by lead. Among the measured elements، soil contamination is mostly observed for Cu، Pb، and As. The soil of the study area is also significantly polluted by lead، especially in the old mining areas. The high concentrations of Mg، Se، and Cd extracted into the first three fractions of sequential extraction showed that the metals could be easily mobilized upon changes in ionic strength or decrease in pH and redox potential. Artemisia leaves are significantly contaminated by Cu. Arsenic and copper also accumulate in Astragalus leaves. The consumption of Artemisia and Astragalus leaves can constitute an exposure risk، especially for small domestic animals. Miduk inhabitants consume Artemisia leaves for treatment of digestive upsets. It is suggested to keep this area inaccessible to domestic animals and preferably to collect plants from distant areas. Obviously، systematic monitoring during mining should be instituted، and continuous environmental surveys should be performed to prevent future pollution problems.

Biogeochemical cycle begins with rock, so geology and geochemistry of rock and soil erosion play the most important role in the distribution and concentration of potentially toxic elements in each ecosystem. In this study, rock and soil samples from Gorveh, Bijar and Takab cities were analyzed using ICP-MS instrumental method. Geochemical analyses indicate high amounts of heavy metals such as As, Ni, Cd, Se and Co in soil and travertine samples, of which arsenic is prominent (>10000 ppm). XRD analysis revealed how heavy metals are present in the travertines of the area and by integrating mineralogical and geochemical results, the main reason for high concentration of As in these deposits was shown to be the presence of arsenic bearing minerals. The environmental indices including enrichment factor, contamination factor, pollution load index, potential ecological risk index were calculated and indicated that the majority of the samples are categorized as highly contaminated. Average arsenic concentration in rock and soil samples is 423 and 1089 (mg/kg) respectively. The main reason for such high heavy metals contents -especially arsenic- in the area is believed to be the existence of many hot springs representing waning stages of volcanic activity.

Use of pesticides is a common practice in agriculture nowadays and indeed most pesticides are overused. Two major groups of pesticides are organochlorin and organophosphorus. In this study 13 surface soil and 10 surface and groundwater samples were collected in winter 1390 and spring 1391 within a radius of 60 Kms from the center of Isfahan metropolis. The measured concentrations of 8 organochlorin and 9 organophosphorus pesticide in the collected water samples indicate that all fall below the maximum recommended level and pose no threat to the environment. However, results from soil samples revealed that among the organochlorides the concentration of DDT metabolites i.e combined DDE and DDD concentration is rather high. The concentration of organophosphorus pesticide in soil depends upon several factors including, degradation half life and the amount of used pesticide. The concentration of residual organophosphor pesticide in soil is above recommended safe values.