جستجوی مقالات مرتبط با کلیدواژه "آلودگی خاک" در نشریات گروه "محیط زیست"

One of the most important problems caused by industrial and service development in Ray city is the production of a high volume of wastewater that its non-systematic discharge to the environment can lead to contamination of surface water and groundwater resources or by using it in agricultural uses Soil contamination. Therefore, in this research, the industrial and service centers of the waste water producer in Ray city were identified to provide a solution to improve the status.

To this end, wastewater contamination centers in the Ray city were identified and the chemical and biological properties of wastewater of these centers including pH, COD, BOD and Total Coliform were evaluated based on the average two-year period (1395-1394) and the spatial distribution map of concentration The wastewater pollutants associated with these centers in the Ray city were prepared using the GIS software and the IDW zoning method.

In this study, 17 main waste water   producers were identified, including seven livestock and a waste disposal center and a vegetable oil factory in Ray city.

The results show that the effective strategy   to improve the situation, equipping the pollutant units with the wastewater treatment system, and improving the wastewater treatment system in units that have a purification system, as well as reducing water consumption in the production process, which leads to a reduction in the amount of wastewater produced. And monitoring of responsible organizations in this field.

Cadmium is a toxic metal that has significantly increased its entry into the soil and food chain with the rise of environmental pollution. In this study, 11 grapevine cultivars (Vitis vinifera L.) were exposed to three levels of cadmium (0, 50, and 100 milligrams per kilogram) in a factorial experimental design based on a completely randomized design in the research greenhouse of Malayer University. After applying the different cadmium treatments over a period of approximately 4 months, leaf and rhizosphere soil samples of different grapevine cultivars were collected, and the concentrations of cadmium and zinc were measured using an atomic absorption spectrometer. Significant differences were observed among grapevine cultivars in terms of cadmium and zinc content in leaves and rhizosphere soil. The cultivar "Bidaneh Sefid" had the lowest cadmium content in leaves, while the highest cadmium content in rhizosphere soil was observed in the cultivar "Rish Baba." Moreover, the cultivar "Turkmen 4" had the highest zinc content in leaves, and the cultivar "Rish Baba" had the highest zinc content in rhizosphere soil. Geochemical indices including Igeo, Ipoll, CF, and BAC were evaluated in the surface soil compared to the standard shell and earthworm. Based on the results of this study, in the examination of soil indices in different grapevine cultivars and the impact of different cultivars, according to the Ipoll and Igeo (Müller) indices in the shell, in non-stressed soil without cadmium, it was considered slightly contaminated, and according to the standard shell in the earthworm, it was considered quantitatively contaminated. According to the Igeo index in the shell, in soil under 50 milligrams per kilogram of cadmium stress, it was considered slightly contaminated, and according to the Ipoll index, it was considered slightly to moderately contaminated, and according to the standard shell in the earthworm, it was considered heavily contaminated. According to the Igeo and Ipoll indices in the shell, the results of soil under 100 milligrams per kilogram of cadmium stress, were considered heavily contaminated, and according to the standard shell in the earthworm, it was considered severely contaminated. The results of these indices indicated that zinc was in the non-contaminated category.

Protected areas are vital tools in the management and conservation of both terrestrial and marine environments. However, the conflict between conservation priorities and resource extraction from protected areas is increasing worldwide. Due to its high biodiversity, Mouteh National Park and Wildlife Refuge hold significant conservation value; nevertheless, in recent years, it has been heavily exploited due to rich mineral attractions. Consequently, the current study investigates the Cd concentration in the soil and plants in the Mouteh Basin, its transfer factor, and the influencing factors.

45 soil samples were collected from a depth of 0-30 cm, and leaf samples of the Artemisia sieberi plant were obtained at 15 locations within the plain region of the Mouteh National Park and Wildlife Refuge, which spans an area of 423 km2. The concentrations of Cd in these samples were determined using an atomic absorption spectrometer. The uptake of Cd by the plants was calculated and interpreted using the transfer factor. The Inverse Distance Weighting method in ArcGIS software was used to identify areas contaminated with Cd, with concentrations exceeding 5 mg/kg in soil and 2.0 mg/kg in plant leaves, based on the standard limits set by the WHO and U.S. EPA. Finally, linear, logarithmic, power, exponential and polynomial regression models were employed to examine the impact of road transportation on Cd pollution.

The mean Cd concentrations in plants and soil (mg/kg) were found to be 0.39 ± 0.11 and 2.97 ± 0.15, respectively. The highest soil concentration of this element was recorded in the central areas of the region, reaching 15.00 ± 0.69 mg/kg. This concentration gradually decreased towards the southern parts of the region. The highest concentration of Cd in the leaves of Artemisia sieberi was observed in the northern sections of the region, at 0.62 ± 0.05 mg/kg, while the lowest value was recorded in the central part (0.32 ± 0.05 mg/kg). The transfer factor of Cd ranged from 0.005 to 0.544, with a mean of 0.934. According to the standard limit of 5 mg/kg for Cd in soil, an area equivalent to 20.80% of the region was identified as Cd-contaminated. However, considering the permissible limit of 0.2 mg/kg in plants, a significant portion of the vegetation cover in the area (more than 95%) was found to be contaminated with Cd. The best regression model was achieved in the exponential form with a coefficient of determination of 0.301, indicating that road transportation is one of the most significant human factors contributing to the increase in Cd pollution in the Mouteh soil and plant species Artemisia sieberi.

The exploration of gold and the establishment of multiple mines in the Mouteh region, as well as the construction of highways in the northern province of Isfahan, have led to significant threats to the ecosystem and species of this area. Based on the results, the soils of the Mouteh plain region have been contaminated with Cd. The high concentration of this element in soils near the roads and its decrease with increasing distance from the road are indicators of the impact of road transportation on soil pollution. Therefore, preventing the construction of transportation routes in areas with rich biodiversity, improving the quality of fuels and vehicles, and reducing traffic congestion are among the most important measures for protecting the environment and reducing pollution from potentially toxic elements in natural areas.

Ways to produced urban wastes is concern in most urban areas of Iran. Increasing population density, industrialization and the amount of waste produced are of great importance. The introduction of heavy metals through urban wastewater into natural ecosystems, especially soils, is one of the most important environmental concerns. The purpose of this study is to investigate the concentration of some heavy metals (lead, chromium, zinc, nickel) in the soil of landfill site of Sarayan.

For this purpose, 20 soil samples were collected from urban landfills and analyzed in a laboratory using Contraa 700 atomic absorption spectrophotometer and then analyzed by statistical techniques and Excel and IBM SPSS statistical software version 25.

To determine the contamination of the studied area, contamination factors (CF) and land accumulation (Igeo) were used and the results showed that the highest amount of contamination was related to surface-level chromium and the lowest was related to surface water and the amount of earthquake index Igeo) was found for chromium metal between 1 and 3.

According to the study, the chromium metal in the slightly infected and highly infected classes and other samples collected in non-infected classes of metals were slightly contaminated.

During the past two decades, computer aid models for simulation of heavy metals have been remarkably developed. Prediction of soil pollution plays an important role in pollution control and land management. But in large areas, collecting data in a direct way is challenging in terms of cost and time. In recent years, the use of indirect methods such as artificial neural network (ANN) and other similar models to estimate heavy metals has been considered. There are 27 salt mines in Garmsar city. Of these, 16 mines are active. Salt extracted from these mines are used as one of the food spices. On the other hand, due to mining activities, the soils of this region may be contaminated with heavy metals. Therefore,in this study, the effectiveness of terrain and spectral indices for predicting total soil Cadmium (Cd) around the soils of Garmsar salt mines was evaluated by ANN – multilayer perceptron (MLP) model.

For this research, 49 soil samples were collected from the 0-20 cm Physicochemical properties of soil samples such as percentage of clay, sand, silt, soil acidity (pH), electrical conductivity (EC) and lime percentage were determined. Total Cd concentration was measured by atomic absorption spectroscopy (AAS) (Varian, Spectra 220). All terrain attributes used in this study were derived from a digital elevation map (DEM) and to calculate the spectral indices, Landsat-8 OLI/TIRS bands image with a resolution of 30 meters were used. Twenty-five auxiliary data variables derived from a DEM and Landsat-8 were used to predict total soil Cd in the study area. Based on the auxiliary data obtained and the correlation coefficients between these data and the predicted total Cd value, 2 models were evaluated. The collected data were randomly divided into categories training and validation and were used to evaluate the MLP model.

The results of this study show that the auxiliary data extracted from landsat-8 bands (with the highest accuracy and lowest error rate) were the effective parameters in predicting soil contamination with Cd. Based on the results obtained from the evaluation of ANN performance in estimating total Cd, the value of root mean square error (RMSE) and coefficient of explanation (R2) were 0.05 and 0.95 for the first model and 0.10 and 0.80 for the second model. In model 1, saturation index (Sat I), grain size index (GSI), carbonate index (CrI), soil color index (color I) and gypsum index (GI) were important and main parameters in total Cd modeling. The results of the present study showed the high efficiency of the ANN model in predicting total soil Cd.

Due to the development of machine learning models in the field of environmental engineering especially in simulation of heavy metals, having a turning point for their advancement is very important. The results of this research show that the MLP model is suitable for total soil Cd prediction and this method can save the cost of soil sampling and analysis. Therefore, it is recommended to validate the method applied in this study to prepare total soil Cd map in similar areas.

Objective of this study is fractionation of geogenic and anthropogenic share and also determination of contamination level of trace heavy metals in surface soil of Pars Special Economic Energy Zone in southern Iran. Soil sampling in 14 points for two depths of 0-10 and 40-50 cm across a 395.4 km2 located in Asalouyeh county Pars Special Economic Energy Zone along coastal strip of Bushehr Province in southern Iran was conducted in 2020. Geogenic and anthropogenic share of heavy metals of Cd, Se, As, Co, Pb, Cr, Ni, Cu, Zn in surface soil were determined using concentration differences of them between the two depths of 0-10 and 40-50 cm compared to the three reference elements of Fe, Nb and U. The results showed that the highest anthropogenic content of the measured heavy metals was found in the middle of the study area just beside the refineries and petrochemical installations. Dominant wind blow direction of west to east resulted in a shift of accumulation of anthropogenic share of elements in surface soil with an eastward tendency but a decreasing of content with increasing distance from refinery and petrochemical installation was seen. As a whole anthropogenic share of the studied heavy metals in the surface soils of the region was less than their geogenic share. Contamination level of these elements based on Integrated Pollution Index was non to mild pollution in 11 points (less than 1), mild pollution in 2 points (1.06 and 1.22) and mild to strong pollution in 1 point (2.38).

As a result of the development of industries and the entry of waste water from industrial factories into the environment, the ecosystem around the factories and surface and underground waters are in danger of pollution.  In this research, the effect of released wastewater plating industry in Safadasht Industrial Park of Karaj on the concentration of heavy metals in the area was studied in spring and summer.

Sampling was carried out at a distance of 70, 120, 220, 320 and 430 meters from the industrial complex around the discharge path. The method of digestion and atomic absorption of flame was used to measure chromium and nickel content in samples.

The average results of soil samples were 1.15 to 2.12 for chromium and 1.07 to 1.73 for nickel in spring and 1.39 to 3.46 for chromium and 1.83 to 3.13 for μg / g for nickel in summer.

The results of the comparison of the levels of chromium and nickel in the soil in spring and summer, according to global standards, show that at all stations in both seasons the amount of chromium and nickel is lower than global standards. The zoning results show that the concentration of the elements in the samples increased with increasing distance from the wastewater to the environment at a distance of 430 meters. The reason for this can be the release of wastewater and its washed off by runoff during seasons from the industrial complex around the distances.

Soil is one of the most important components of the ecosystem, which is a suitable environment for storing nutrients and performing biological and chemical processes, and as a natural filter by storing and transporting pollutants, reduces their harmful effects. The aim of this study was to investigate the sources, chemical structure and health and environmental effects of some heavy metals in the soil.

The research method was theoretically and using library resources. First, the sources and then the structure and health and environmental effects of heavy metals in the soil were studied.

Results show that heavy metals, unlike organic pollutants, are immutable and non-biodegradable and have physiological effects on living organisms and thus are important in low concentrations. Heavy metals are formed naturally in the soil by pedogenic processes. Human factors such as the development of industrial areas, mining waste, use of chemical fertilizers, animal, pesticides, Sewage sludge and irrigation of agricultural lands with sewage, residues resulting from the burning of coal, petrochemical and atmospheric deposition can increase the concentration of these metals and cause soil contamination with heavy metals.

Soil plays a very important role in providing food for humans and other organisms, and its contamination by heavy metals can have irreversible effects. Adequate knowledge of the concentration, sources, chemical structure and potential health and environmental hazards of heavy metals is essential to prevent pollution and to select the appropriate method for soil remediation. Creating accessible resources for agricultural production and increasing food security is one of the goals of improving contaminated soils.

Joghatay plain is located in Sabezvar Ophiolitic Zone and next to the chromite mine. In this research, the soil pollution by heavy metals have been investigated with respect to geochemical, statistical and environmental indicators in Joghatay plain.Material and

Samples were collected seasonally from soil in Joghatay plain within May 2014, and the concentration of heavy metals were measured using ICP-MS method. To the geochemical phases of metals in soil were determined using BCR sequential extraction method.

The result of the analysis of heavy metals in soil samples has shown high concentrations of some elements such as Chromium, Nickel and Cobalt in the southern part of the region. Assessment and correlation of heavy metals in Joghatay region soils by multivariate statistical methods (Pearson correlation, cluster analysis and principal component analysis) show a strong positive correlation between Cobalt, Nickel, Chromium, Iron, Manganese and Magnesium due to the same source  (ophiolitic unit area).

The pollution index (geoaccumulation index, enrichment factor, contamination factor and modified contamination degree) indicates that soil has strongly polluted with regard to Chromium and Nickel and moderately polluted to Cobalt. Sequential extraction method has indicated that more than 50% of Nickel and Chromium concentration in intercahnageable phase. On the other hand ophiolitic rocks and Chromit mining leads releasing of these elements in the area. Though, as far as it gets away from ophiolitic rocks these elements concentration will be decreased. Also element speciation in different phases reveals that the rest elements have concentrated in residual phases and have a lithogenic source.

In the recent decade, the issue of soil contamination with heavy metals such as nickel and lead is one of the most important environmental problems. According to data from the environmental protection agency, nickel is hazardous at large amounts and a dangerous pollutant and lead is the most important pollutant in the environment. This study was conducted to investigate the soil pollution status of Gachsaran refinery using environmental indicators of pollution coefficient, pollution degree index and modified pollution degree index and to investigate the potential of alfalfa refining plant which is native to Gachsaran region.

From the soil of Gachsaran refinery in 2017 as the center of pollution, were selected four ranges of 0-500 meters, 1000-500 meters, 1500-1000 meters and 2000-1500 meters. In each range, 5 soil samples were taken from a depth of 0 to 30 cm. The ICP-OES device was used to determine heavy metals. Statistical analysis was performed using SPSS software.

The analysis of the environmental indicators of the studied area showed a significant degree of contamination for nickel and a high contamination rate for lead. Comparison of mean concentrations of nickel and lead in cultivated soil samples with alfalfa cultivars showed significant difference with mean nickel and lead concentrations in the studied area.

In general, Alfalfa as a native plant of the region in inappropriate pollution conditions can absorb and extraction nickel and lead from the soil. The final results of this study indicate that ability of alfalfa plant for phytoremediation of nickel in the soil contaminated with petroleum products is higher than that of lead in the Gachsaran refinery.

Phytoremediation can be one of the most promising techniques for elimination of pollutants from water and soil and environmental management. Through absorption and desorption processes, we can determine the level of maintenance for cations and anions. Based on transition factor of elements it is possible to specify that elements like Barium and Lithium have the least and elements like Cadmium and Boron have the highest accumulation. Soil pH also affects the level of availability and mobility of elements by controlling solubility of soil organic matters and it is in direct relationship with oxidation and reduction conditions. Absorption of ions by plant roots can be both passive (in direction of diffusion gradient) and active (against diffusion gradient using energy) processes. Phytoremediation is accomplished in four states including 1) phytostabilization and deposition of pollutants in the root, 2) phytoextraction that can be divided into two categories: continuous that requires the use of plants throughout their lifetime and induced by addition of accelerants or chelators to the soil, 3) phytovolatilization and transfer of contaminants from the root to leaves and the atmosphere and 4) phytofiltration to remove contaminants from water. For instance, to remove Arsenic, Cadmium (Zinc), Chromium, Mercury, Nickel, Lead, and Selenium plants such as P. vittata, T. caerulescens, Betula sp. tree, Amanita muscaria, Alyssum lesbiacum, Arabidopsis sp., and B. juncea could be used respectively.

Heavy metals are one of the most important environmental contaminants, particularly in soil and water sources. Among heavy metals, lead is one of the most challenging toxic contaminants. Using lead-contaminated soils requires their decontamination and improvement. The objective of this study was to investigate the possibility of lead decontamination from soil and to estimate the optimal clean up time using Portulaca oleracea L. and Amaranthus retroflexus. For this purpose, a completely randomized design with five treatments of 30 (standard), 150, 300, 600 and 1200 mg/kg each with three replicates was performed. The results indicated that for both plants a non-linear positive relation exists between the lead concentrations in soil and that accumulated in plant roots and shoots. The highest extracted lead which was accumulated in roots of Portulaca oleracea L. and Amaranthus retroflexus were 173.39 and 149.76 mg/kg, and in their shoots were 20.01 and 5.82 mg/kg, respectively. Translocation factor was obtained from 0.62 to 0.12 for Portulaca oleracea L. and from 0.14 to 0.04 for Amaranthus retroflexus. The translocation factor in both plants was obtained to be less than one, indicating poor lead transfer from root to the shoot. Due to the ability of the above plants to absorb large amounts of lead from the root zone, high plant yield and the ability to accumulate lead in harvestable organs, both plants were highly effective for remediation of lead from soil surface up to concentrations several times of the allowable lead concentration. However, due to the clean-up time and the amount of biomass produced, the Amaranthus retroflexus had a better ability to remediate contaminated soils.

Spatial distribution of contaminants is essential for soil pollution monitoring and maintaining environmental quality. Therefore this study was carried out for evaluation of Cr and Ni concentrations in soil samples collected from around the Arak III Industrial Estate in 2013 and preparing the zoning map of metals.

After selecting 10 sampling stations within a radius of 5 km from the industrial estate, a total of 20 soil samples were collected from topsoils and subsoils. Then some physical and chemical properties of soil were determined. For determination of heavy metals concentration in soil samples, using ICP-OES (Varian, 710-ES, Australia) when soil digestion was complete. All statistical analyses were done by SPSS software, version 18.0 (SPSS Inc., USA). Also, the spatial distribution maps of elements in soil samples were prepared using IDW method.

The results showed that maximum mean concentration of Cr in topsoils and subsoils samples were found in sampling station II with 15.50±1.97 and 13.00±1.65 mg/kg, respectively, and maximum mean concentration of Ni in topsoils and subsoils samples were found in sampling stations IX and II with 19.25±1.90 and 18.50±2.02 mg/kg, respectively.

Comparative evaluation of Cr and Ni contents in different studied soil samples showed that the mean concentrations of Cr and Ni in all topsoils and subsoils due to implementation of environmental management of industrial units in Arak III Industrial Estate and minimal use of agricultural inputs such as chemical fertilizers and pesticides were significantly lower than WHO permissible limits for soil contamination

In order to study the effect of pesticides on soil biological quality, three herbicides and insecticides with the highest consumption rates, on soil eco-physiological and chemical indices were investigated.

The experiment was carried out as factorial in a completely randomized design with seven treatments of which were triplicated. The pesticides were applied as constructed by the manufacturer and then the pots maintained in a greenhouse condition for two months. Then, some of the soil eco-physiological and chemical indices were measured after one month and also after two months.

The results showed that in comparison with the application of the pesticides caused a significant decrease in soil bacterial and fungal population, basal respiration, substrate-induced respiration, microbial biomass carbon, microbial biomass nitrogen, and microbial quotient and a significant increase in soil metabolic quotient. The results also showed that the application of the pesticides has no significant effect on soil organic carbon. The results showed that, although soil eco-physiological indices decreased after one month, the indices increased after two months reaching the level that was before application of the pesticides. The results also showed that 2, 4-D had the highest and Chloropyrifos had the lowest adverse effects on the indices.

It could be concluded that application of the pesticides which are used in this work decreased soil biological quality short terms.

The presence of spatial changes in soil properties is normal, and it is inevitable to recognize these changes, especially in green spaces, for careful planning and management. On the other hand, with the increasing need of communities for transportation, communications and the use of vehicles, it has become increasingly common for cars to be the main source of heavy metal pollutants in cities. The aim of this study was to evaluate the physical and chemical limitations of green space soil and also to determine the concentration of lead and cadmium as indicators of traffic pollution of Imam Reza (AS) passenger terminal in the southwestern part of Mashhad.
Analysis

Sampling was performed at 129 points at a depth of 20-0 cm. On the other hand, to determine the deep characteristics of the soil, three soil samples were described and sampled. Element mapping maps were prepared using statistical methods in ArcGIS software.

The results of this study showed that the most important limitation of these soils is their shallow depth, which mainly lacks sufficient depth for the growth and development of trees with deep root systems. On the other hand, the concentration of nutrients in the soil was lower than sufficient. The prepared zoning maps also indicate that these changes are spotty and that the area needs local management. The concentration of cadmium contaminants is also high in the threshold area, but for lead, soil contamination is not currently serious.

This study was conducted in Mohammadabad waste disposal site in Ghazvin in order to determine the concentration of Ni and Pb in Artemisia sieberi and in region’s soil.

Three plots were selected. Ten random samples from root and shoot of the plant and also from the soil were collected. Two-way and one-way ANOVA were used to assess the differences of metal concentrations in roots and shoots of the plants, and in the soil of the plots, respectively. Duncan Test was applied to compare the average concentrations of metals in different plots.

The results revealed that the soil of the different plots does not have a significant difference in Ni and Pb concentrations. No significant difference was observed between the metal concentrations in roots and shoots of the plants. The mean concentration of lead in the A.sieberi aerial and root organs was 2.35 mgkg-1 and 3.19 mgkg-1, respectively, and for the nickel metal 3.14 mgkg-1 and 2.99 mgkg-1 respectively.

Bio concentration and transmission factors for Ni and Pb (TF=0.78; 0.81 and BCF=1.10; 0.33, respectively) suggested that A.sieberi is an appropriate plant to remove Pb from soil.

Contaminated soil with heavy metal is one of the most important environmental issues in the world. The refining plant is one of the methods of refinement and prevent potential pollution hazards of heavy metals in soil. The purpose of this study, effects of various concentrations of EDTA on some morphological characteristics and the efficiency of EDTA for Increased Ni from soil and to compare their effects for enhancing of Ni extraction with Indian mustard (brassica juncea L). For this purpose, a greenhouse experiment was conducted in completely randomized design with four replications. Soil samples were mixed with 600 mg/kg of nickel sulfate and the seeds were planted in soil of pot. The experimental factor was including 0, 1, 5, 10 and 12 mmol EDTA that after the seed cultivation have been added to the soil. The results of the research showed that The application of different EDTA concentrations decreased morphological characteristics and increased soluble nickel concentrations in soil and transfer it to the inside of the plant and this changes was significant compared to the control treatment. The increase in soluble nickel concentrations in soil and transfer it to the inside of the plant inhibits the absorption of essential elements to the plants shoot and thus, repelled the growing process. In general, Indian mustard (brassica juncea L) due to high nickel resistance can be introduced as a Ni hyper accumulator to EDTA induced phytoextraction technology.  But according to the preventive effects of these substances on the growth of the plant should be used for low concentrations.

Phytoremediation was introduced as an effective, inexpensive and environmentally friendly to remove, displace or disable pollutants from polluted soils. There are numerous physical and chemical methods for the treatment of heavy metal contaminated soils, which in addition to high costs, lead to the destruction of the physical and chemical structure and vital activities of the soil. This study was applied in order to investigate the effects of inoculated Arbuscular mycorrhizal fungi of resilience to lead and zinc on some morphological traits (colonization, diameter growth, shoot dry and fresh weight, root dry and fresh weight, height and leaf area) of Elaeagnus angustifolia L. One-year-old seedlings of E. angustifolia species with an average height of 70-50 cm, minimum diameter of 1-1.5 cm and leaf number of at least 30 were provided from Jebel Amelian nursery affiliated to the Natural Resources Office of Isfahan Province. The seedlings were transferred to the greenhouse of the Agricultural and Natural Resources Research Center of Isfahan Province and were kept there for 20 days to adapt to the new conditions. In doing so, six treatments of mycorrhizal fungi (Glomus versifome, G. etunicatum, G. intraradices, G. mossea, composition and control treatments) and five treatments of soil (naturally polluted soil, soil polluted with lead, soil polluted with zinc, soil polluted with lead and zinc, control (without pollution) treatment) were considered. The results showed that there was a significant difference between the measured variables among the different treatment of mycorrhizal fungi. The highest and lowest colonization were observed for G. mossea (40.5%) and control treatment (25.6%), respectively. For G. mossea, the diameter growth (2.8mm), height (36.1cm) and leaf area index (28.8) increased in comparison to the control treatment. There was a significant difference between shoot dry and fresh weight and root dry and fresh weight in all of the treatment of mycorrhizal fungi. The highest dry and fresh weight of shoot was observed in G. mossea treatment (108.4 and 55 g) and the lowest was observed in control treatment (59.4 and 30.3 g). The highest and lowest of fresh weight were observed in control (95.3) and polluted soil with lead and zinc treatments (78g). Highest values of measured variables in all fungi and soil treatments were belonged to the inoculated treatment of G. mossea and the control treatment, respectively. Results of this study showed that inoculated treatment with G. mossea fungi and control treatment of soil caused the growth enhancement in E. angustifolia. However, there was no significant difference between mean fresh and dry weight of root and leaf area index in different soil treatments. Roots, as absorbent levels of water and food, have great effects on the absorption of water and various salts, and various environmental factors influence the growth of the plant through its effect on root growth. Heavy metal stress is one of the factors limiting root growth which affects plant growth activity. Also, in plants that were inoculated with mycorrhizal fungi, the mean of all measured variables was significantly higher than the control treatment. The highest shoot weight was observed in G. mosseae treatment, which suggests that G. mosseae contributed to the plant's absorption of water and food, especially phosphorus, and increased the accumulation of dry matter and has more efficiency in the biomass production of E. angustifolia.

Increasing industrial activities associated with the production of pollutants, including heavy metals, is one of the main causes of water and soil pollution. Mineral activities are one of the human activities that cause pollution of the natural resources such as soil. In this study, the zoning concentration of copper as soil contamination around Meyduk copper mine was investigated. The direction samples were taken according to the situation of surrounding villages. Systematic sampling of 360 samples had been collected through the directions. Measuring the concentration of sample was done using atomic absorption method in the laboratory. To indicate the degree of soil pollution with heavy metals, Muller’s geoaccumulation index was used. Finally, in order to estimate the normal concentration of Cu and pollution of soil, Kriging method was used. Results showed that the maximum amount of Cu concentration is 697.5 mg/kg and the minimum is 6.35 mg/kg. The Cu concentration trend in direction D was more than direction M due to the direction of local dominant wind. By receding from location of mine, the overall trend of Cu concentration decreased. This indicated the role of mine activities on soil pollution.

It is inevitable to analyze the existing contaminant elements in soil as the most important source of nutrition for human. Heavy metals are considered and referred among these elements. The contaminated soils of urbanized regions are directly related to human, while these elements are absorbed by plants in agricultural fields, through which they enter the human food cycle. The excessive increase of these elements in soil results in the growing incidence of certain diseases such as cancer. Moreover, the irresolvability of these materials may have dangerous impacts on the human digestion as well as nervous systems. Contamination, due to heavy metals in soil, have even resulted in some animals’ death.
There are various factors involved in soil contamination. One of main factors is the incorrect use and increasingly irregular exploitation of nature by human beings. In Iran, inappropriate economic exploitation of agricultural fields and aberrant use of chemicals have led to the higher concentration of heavy metals in soil, turning to a crucial problem in certain areas. The most significant cause of soil contamination is the wrong use of chemical fertilizers, resulting in the agglomeration of heavy metals in soil. Therefore, it is inevitable to identify the spatial distribution of these elements. The geo-statistical instruments have facilitated the quantification of soil spatial characteristics, whereby leading to the probability of spatial interpolation.
Objective of the study are: (i)To prepare zoning maps of elements including Zinc, Copper, Iron, Manganese, Potassium, and Lead using mathematics and geo-statistics methods as well as choosing the most optimum technique of spatial interpolation by comparing RMSE, MAE and MBE;(ii)To analyze the probable spatial correlation between the concentration of these elements in agricultural soils;(iii)To distinguish the regions affected by the excessive contamination higher than the threshold limit of general index and WHO standard and also Iran’s Soil and Water Research Institute’s standard.
Harris Town is located in the north-western Iran between 38°04° and 38°24° latitudes of northern hemisphere and of 46°22° and 47°22° geographical longitudes of eastern hemisphere.
Statistical Analyses
In this research, first of all, 370 samples of soil were randomly selected from this region and the concentrations of abovementioned elements were measured in the laboratory. Then, the accuracy of the measured data was examined by applying 3Sigma Validation Test. At the next stage, the spatial distribution of the elements of Zinc, Iron, copper, Manganese, and Potassium was examined using Mathematics and geo-statistics interpolation models. These methods which are based on the first principle of geography include certain mathematical methods such as the Inverse Distance Weighting, Local Polynomial, and Radial Basis Functions and geo-statistics methods such as Ordinary Kriging (OK), Simple Kriging (SK), and Universal Kriging (UK) with Circular, Globular, Gaussian, and Exponential Variogram Models.
Kriging is one of the geo-statistical interpolation methods, which is based on Weighted Moving Average. One of the features distinguishing it from other interpolation methods is that it is regarded as the Best Linear Unbiased Estimator. The first stage in statistical analyses is the computation and drawing of variogram. In fact, variogram represents the variability of samples based on their distance. The next stage is the selection of the best theoretical model for fitting to experimental variogram. The modeled variogram shows the spatial self-correlation of data, and describes range, sill and nugget. The Kriging interpolator is divided into different methods. The models being tested in this research are Ordinary, Universal and Simple Kriging.
Inverse Distance Weighting
The Inverse Distance Weighting is a radix point method which acts based on the first principle of geography. In this interpolation method, the weighting parameter operates according to the criterion that an increase in the distance from the sampled points to the passive point leads a decrease in its effect in the expected (predicted) value.
Local Polynomial Polynomial interpolation is a method for finding a formula, the figure of which passes through the data. The Universal Polynomials identify the fitted surface to data by considering all existing data in the analysis, while local polynomials performs this action for a limited number of points within a considered oval. This method allocates the least proportional squares among the identified points in the oval shape area as the point weight. Thus, interpolation is performed based on the allocated weight of the relations of the first, second and/or third grades among the variables in the neighboring points of X, Y, and Z along with the minimization of estimated errors.
Radial Basis Functions
This method is a manner of artificial neural networks in which the predicted values are higher than the maximum observed and lower than the existing minimum observed. Indeed, the surface fitting by these functions acts like a plastic membrane so as to minimize the total surface curvature. The Radial Basis Functions performs interpolation based on five principal functions. The main core of these functions is the sum of squares values. In this method, a function is considered for each location (place), where the linear combination of these functions is used for predicting the amount of function in the passive location as the final function. In this study, five functions including Spline Function, Quite Regular, Spline with tension, Multi-Quadric function, Reverse Multi-Quadric Function and Spline Function with the thin surface were used.
Validation Criterion of Interpolation In this research, the observed data were divided in two groups of experimental and control, with the proportion of 80 to 20. At the beginning, by applying the experimental data, a surface was fitted for the data using each interpolation method. Jackknife Cross-Validation Method was used to determine errors vector. The basis of this method is that when fitting the surface, one of the data is omitted each time, fitting is performed by using other data and the data deviation from the predicted value is recorded. Then, the control data is inserted in the fitted model and the amount of data deviation from the fitted model is being reported.
In order to examine the accuracy and validation of each method in the zoning of the aforementioned heavy metals, Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and Mean Basin Error (MBE) were applied. The closer the values of (RMSE), (MAE), and (MBE) to zero, the more efficient (effective) the performance of the fitted model.
All obtained numbers for the spatial correlation between the elements are of positive value, and this represents a direct relation in the reciprocal transformations of elements. Among the results obtained, the spatial correlation between two metals of Zinc and Copper is more intense, as with 46%, include the most intense relation as compared to each pair of other elements. Meanwhile, the correlation between the two elements of Manganese and Potassium has the least value with 1%.
By using the QQ chart, it was found the data of Potassium, Zinc, Iron and Manganese have a relatively high skewedness and far from normal distribution.
As it was previously indicated, variogram explains the relation between sample variability as well as their interaction. In order to choose the best model of experimental variogram, the proportion of nugget to sill was used, in which the least value represents the best model (Figure 3).
By using Arc GIS Software, the most optimum model for the preparation of zoning maps was examined. Among the various models, deviation vectors were drawn from the measured value for the fitted surface. These vectors were drawn for both sets of data. By comparing the measured data and the global index of soil contamination and WHO standard, it was found that the highest volume of elements of Iron, Copper, and Manganese are not located in the permissible range, while the amount if this element is located in the impermissible range in the whole region under study. (Figures 4 to 8).