Soil science
H. Emami; M. Memarzadeh
Abstract
Introduction
Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation ...
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Introduction
Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation of heavy metals through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition. Soils are the major sink for heavy metals released into the environment by the aforementioned anthropogenic activities and their total concentration in soils persists for a long time after their introduction. The heavy metal contamination of soil and its potential risks to humans and the ecosystem is a significant concern. Windy deposition, which is the process of heavy metals being transported by erosive winds and deposited onto soil, is one of the sources of heavy metal contamination. Due to the geographical situation and climatic conditions such as arid soil, erosive winds are blown in periods of year in Tabas. Since wind are erosion is severe in this area, huge amounts of wind deposition accompanied with erosive winds entered into this town. Heavy metals through the windy deposition are suspended, translated and finally deposited in residential regions, which can create some problems for human health. Therefore, the knowledge of wind erosion and the human risk of these deposits is essential. The aim of this research was to determine the rate of wind erosion and the concentration of some heavy metals in these deposits.
Materials and Methods
For this purpose, the rate of suspended load was measured monthly from February 2021 to January 2022. Based on previous information from the erosive winds and storms, suspended depositions were gathered in some directions (north, northwest, northeast, west and southwest) of the Tabas entrance. In addition, the suspended load in the city center of Tabas was also measured. The cumulative load of suspended depositions was measured monthly and the concentration of some heavy metals such as manganese (Mn), iron (Fe), cupper (Cu), and zinc (Zn) were measured in these suspended particles. Soil digestion was made by Aqua regia (nitric acid and chloridric acid; ratio of 3:1), and after then atomic absorption was used to measure the total concentration of above heavy metals.
Results and Discussion
The results indicate that Tabas experiences significant wind deposition of suspended loads, with the highest rates entering from the northeast direction and the lowest rates from the southwest direction. This pattern aligns with the wind rose of Tabas, which illustrates the prevailing wind directions in the region. Additionally, substantial suspended loads are observed in the northwest and north directions. The variations in suspended load discharge reveal that the maximum discharge occurs in the city center of Tabas during the months of June and July 2021. This corresponds to the arid climate conditions of these months, where plant growth is limited, soil cohesion is low, and loose soil particles on the surface are susceptible to wind forces. As a result, these loose particles are easily detached by the wind, contributing to the high levels of suspended load. Regarding the spatial variation of heavy metals in suspended particles, the cumulative concentrations of Mn, Fe, Cu, and Zn are found to be higher in the west, northwest, north, and west directions, respectively. This suggests that these heavy metals are transported and deposited in specific areas within Tabas due to the prevailing wind patterns. In terms of temporal variation, the highest concentrations of Mn and Fe in suspended particles are observed in April 2021, predominantly in the northeast and west directions, respectively. On the other hand, the highest concentrations of Cu and Zn are found in May 2021, with the southwest and northeast directions being the primary deposition areas for each metal, respectively. These findings highlight the spatial and temporal dynamics of suspended load and heavy metal deposition in Tabas, emphasizing the influence of wind patterns and climatic conditions on these processes. Understanding these variations is crucial for assessing the potential risks associated with heavy metal contamination and implementing appropriate mitigation measures in the region.
Conclusion
The results of this research showed that most contents of the suspended load are entered from the northeast direction into Tabas. In addition, the spatial variation of heavy metals indicated that the concentrations of studied heavy metals (Mn, Fe, Cu, and Zn) in suspended particles, especially in the western, northwestern, and northern in spring, are very high and they can cause carcinogenic effects on human life. Therefore, the management practices should be mostly made in these directions to control or reduce soil erosion and reduce its damage effects.
Soil science
B. Rezaei; A. Amirinejad; M. Ghobadi
Abstract
IntroductionIndustrial development has resulted in higher soils pollution with heavy metals. Plants which are subjected to heavy metals may severely lose their yield capabilities. Applying improving compounds in the soil is a new method to reduce effects of heavy metals on plants growth. Biochar as a ...
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IntroductionIndustrial development has resulted in higher soils pollution with heavy metals. Plants which are subjected to heavy metals may severely lose their yield capabilities. Applying improving compounds in the soil is a new method to reduce effects of heavy metals on plants growth. Biochar as a carbon rich source and salicylic acid as an important plant hormone, are two main compounds to alleviate heavy metals stresses in plants. These are the cost-effective and environmentally friendly substances for increasing the resistance of plants. Lead (Pb), as a common and extremely poisonous element in polluted soils, can be accumulated due to its non-biodegradability nature. When Pb content in plants reaches a toxic level, it can inhibit plant growth by reducing enzyme activities and photosynthesis and changing mineral nutrients balance. However, with regard to the program of expanding the area under cultivation of medicinal plants, including thyme, there is a possibility of contamination of soils in the vicinity of industrial centers and roads with lead. Therefore, the present study was conducted to evaluate the effects of salicylic acid as a plant growth stimulant and biochar made of rapeseed wastes, as a stable organic compound, on alleviation of Pb-induced stress in thyme (Thymus vulgaris L.). Materials and MethodsIn order to investigate the effects of salicylic acid (SA) and biochar (BC) on reducing Pb stress in thyme (Thymus vulgaris L.), a factorial experiment was conducted based on a completely randomized design with three replications in the greenhouse of Razi University. The factors included Pb at three levels (0, 150, and 300 mg/kg as Pb(NO3)2), SA at three levels (0, 150, and 300 μM) and BC at three levels (0, 1 and 3% by weight). To apply the Pb treatments, the soil samples of each pot (8 kg) were sprayed with Pb(NO3)2 solutions, 4 weeks before planting, according to the contamination levels. Then, BC treatments were performed by mixing it with the soil samples. In each pot, four thyme seedlings were planted. At four-leaf stage, SA solutions were sprayed three times on foliage of the thyme plants , until the beginning of flowering. After harvesting, some characteristics of aerial and root parts of thyme, including soluble sugars and proline contents, plant height, dry weights of shoots and roots, root volume and root length were determined. All plant parameters were then averaged for each pot. Also, Pb concentrations in extracts obtained from digestion of leaf tissues, were measured by Varian AA220 atomic absorption spectrophotometer. The analysis of variance (ANOVA) and comparison of means (Duncan's multiple range test) were performed using SPSS-16 software.Results and DiscussionThe results revealed that Pb stress reduced all plant characteristics, such as plant height, root volume and root length, as well as, dry weights of shoots and roots, and elevated leaf Pb concentration, proline content and soluble sugars in thyme. However, BC application resulted in improvements in growth parameters. The positive effect of BC was further enhanced when SA was sprayed onto the foliage of the thyme plants. The interaction effects of SA, BC and Pb treatments on the growth parameters of thyme, i.e, shoot dry weight, root volume, Pb concentration, soluble sugars and proline contents were significant (P < 0.01). In other words, SA and BC treatments moderated the negative effects of Pb on the growth traits. The highest Pb concentration (4.83 mg) and proline content (37.8 μmol/g) were obtained in 300 μg/kg of Pb, and SA and BC controls. Also, the highest concentration of soluble sugars (0.46 mg/kg) was found at 300 mg/kg of Pb, 300 μM SA and BC control.ConclusionOur results indicated the positive effects of SA and BC treatments on the growth parameters, such as; shoot and root dry weights in thyme plants, especially under Pb stress. In other words, Pb stress, while reducing all growth characteristics, increased proline content and soluble sugars in thyme. In general, it seems that under Pb stress, treatment of thyme with SA (as a plant growth regulator) and BC (as an organic matter with high viability in the soil) is a simple and appropriate method in order to increase the plant's resistance and reduce the effects of Pb toxicity on the overall growth of thyme.
M. piri; E. Sepehr; A. samadi; KH. Farhadi; M. Alizadeh khaled abad
Abstract
Introduction: Some of the heavy metals such as cadmium (Cd) and lead (Pb) are toxic and represent hazardous pollutants due to their persistence in the environment. These metals have adverse effects on human health, which include growth retardation, cancer, damage to the nervous and heart system. Heavy ...
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Introduction: Some of the heavy metals such as cadmium (Cd) and lead (Pb) are toxic and represent hazardous pollutants due to their persistence in the environment. These metals have adverse effects on human health, which include growth retardation, cancer, damage to the nervous and heart system. Heavy metals can cause malfunctioning of the cellular processes via the displacement of essential metals from their respective sites. Mainly heavy metals discharge into the environment from industrial and urban sewage. There are different methods to reduce water pollution and the removal of heavy metals from water that one of them is sorption by using organic and inorganic adsorbents such as sepiolite. The low cost of sepiolite along with the high specific surface area, chemical and mechanical stability, and layered structure have made these clay minerals as excellent adsorbent materials for the removal of heavy metals from wastewaters. This study aims to investigate the sorption of Cd and Pb by sepiolite as an inorganic absorbent and optimize process variables (initial concentration, pH and ionic strength) using Response Surface Methodology (RSM) and Box–Behnken design (BBD).
Materials and Methods: Response Surface Methodology (RSM) is a statistical method that uses quantitative data from appropriate experiments to determine regression model equations and operating conditions. RSM is a collection of mathematical and statistical techniques for modeling and analysis of problems in which a response of interest is influenced by several variables. A standard RSM design called Box-Behnken Design (BBD) was applied in this work to study the variables for sorption of Cd and Pb by sepiolite from aqueous solution using a batch process. BBD for three variables (initial Cd and Pb concentrations, pH and ionic strength), each with two levels (the minimum and maximum), was used as an experimental design model. Sepiolite sample used in this study was taken from a mine in Fariman region, northeastern Iran. In the experimental design model, initial concentration (0-200 mg L-1), pH (3-6) and ionic strength (0.01-0.06 mol L-1) were taken as input variables. Design-Expert program was used for regression and graphical analysis of the data obtained. The optimum values of the selected variables were obtained by solving the regression equation and by analyzing the response surface contour plots. The variability independent variables were explained by the multiple coefficients of determination, R2 and the model equation was used to predict the optimum value and subsequently to elucidate the interaction between the factors within the specified range.
Results: The results showed that the sorption of Cd and Pb intensified by increasing initial concentration and pH but ionic strength had an inverse effect. The sorption of Pb and Cd ions onto the sepiolite minerals were lowest at pH =3 and IS=0.06 but increased with an increase in pH and initial concentration of the solution. High value for R2 (0.99) and adjusted R2 (0.99) showed that the removal of Cd and Pb can be described by the response surface method. One-way ANOVA showed (p< 0.0001) that the quadratic model is the best model for determining the interaction variables. According to optimization results, the sorption of Cd and Pb are maximized when pH: 6, concentration: 200 mg.L-1 and ionic strength: 0.02 mol.L-1. The predicted adsorption at these settings for Pb and Cd are 44.4 and 34.28 mg.g-1, respectively. It was found that the initial concentration is the most effective parameter in the sorption of Cd and Pb by sepiolite. Sepiolite adsorbed more lead ions than cadmium ions from aqueous solution.
Conclusion: Response surface methodology using BBD, proved a very effective and time-saving model for studying the influence of process parameters (pH, initial concentration and ionic strength) on response factor (sorb). This model significantly reduces the number of experiments and hence facilitating the optimum conditions. The experimental values and the predicted values are in perfect match with an R2 value of 0.99. The high correlation coefficient between the model and experimental data (R2=0.99) showed that the model was able to predict the removal of Cd and Pb from aqueous solution by using sepiolite. The model revealed that concentration, metal type and pH were the most effective parameters on the response yield (adsorption by sepiolite), respectively. According to the results, sepiolite showed a greater efficiency for sorption of Cd and Pb from aqueous solution, also usage of sepiolite as an inorganic absorbent due to its low cost and abundance can be economically justified.
shahab ahmadi doabi; Majid Afyuni; Mahin Karami
Abstract
Introduction: Atmospheric dust is an important source of heavy metals, particularly in urban environments. Heavy metals can easily attach to dust particles and be distributed in large areas. Therefore, assessing the extent of heavy metals pollution present in nuisance dust is important for establishing ...
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Introduction: Atmospheric dust is an important source of heavy metals, particularly in urban environments. Heavy metals can easily attach to dust particles and be distributed in large areas. Therefore, assessing the extent of heavy metals pollution present in nuisance dust is important for establishing pollution control strategies and evaluating the results of previous measurements. Heavy metals contamination in atmospheric dust of Kermanshah provine has not been previously investigated. The main objective of this initial study was to determine the concentrations of heavy metals in atmospheric dust samples that were collected from Kermanshah province and to assess their contamination level. The results can provide a baseline for use in future environmental impact assessments and to guide pollution mitigation targets.
Materials and Methods: Dust samples were collected from 49 sites across the province, during the summer 2013. Dust sampling sites were selected in different urban (35 site) and suburban (14 site) locations in Kermanshah, Songhor, Gilangharb, Ghasre-Shirin, Sahneh, Sarpolzahab, Kangavar, Paveh and Javanrood cities. Dust collectors were installed on the roof of buildings about 3–4 m above the ground level. Each collection tray consisted of a circular plastic surface (320 mm in diameter, 120 mm depth) that was fixed on holders with 33 cm height and covered with a 2 mm PVC mesh on top to form a rough area for trapping saltant particles. The dust samples were analyzed for their Zn, Cu, Ni, Cr, Mn and Fe concentrations using an Atomic Absorption Spectrophotometer. In the present study, geo-accumulation index (Igeo), enrichment factor (EF), pollution index (PI) and integrated pollution index (IPI) were calculated to assess the heavy metal contamination level in the atmospheric dust.
Results and Discussion: The results showed that except for Fe and Mn, all heavy metal concentrations of atmospheric dust in Kermanshah provine were higher than in the background soils of world, showing that these heavy metals are likely from anthropogenic sources. The order of mean Igeo values was Ni> Zn> Cu> Cr> Mn> Fe, similar to the order of their EFs and PIs, which can also be seen as the decreasing order of their overall contamination degrees in atmospheric dust of Kermanshah province. The mean Igeo for Ni points to moderately to strongly pollution. 59% of calculated Igeo for Ni falls into class 2 (moderately polluted) and 37% into class 3 (moderately to strongly polluted), while according to the Igeo values for Mn (98%) and Fe (100%), they were practically unpolluted (class 0). The maximum EFs of Zn, Cu and Ni were higher than 10, which show that Zn, Cu and Ni in atmospheric dusts mainly originate from anthropogenic sources. It seems that EFs can also be an effective tool to differentiate the natural origins from anthropogenic sources. The mean EF (11.2) and 94% of Ni EFs were in the range of 5–20 indicating that Ni was a main contaminant in studied samples. Mn had 41% EFs less than 2 and 59% EFs in the range of 2–5, with mean EF less than 2, indicating minimal enrichment. The analytical results of heavy metals Igeo are same as the analytical results of EFs. The PIs of Zn, Cu and Ni were in the ranges of 2.1 to 11.3, 1.7 to 18.3 and 3.3 to 13.6, with an average of 3.8, 3.3 and 6.9, respectively. These data indicate that Zn, Cu and Ni may cause serious pollution in atmospheric dust of Kermanshah. The IPIs of atmospheric dust samples vary from 1.9 to 6.2 with mean value of 2.9, indicating that all studied samples were polluted by heavy metals.
Conclusion: The concentrations of heavy metals that were investigated in this study were compared with the reported data of other cities and with the background values of elements in the world soils. The concentrations of Zn, Cu, Ni and Cr in urban dust samples, and Fe and Mn in suburban dust samples were higher than their respective values in the world soils. The results indicate that atmospheric dusts in Kermanshah provin have elevated metal concentrations in general. The calculated values of Igeo and EF of heavy metals revealed the order of Igeo and EF as Ni> Zn> Cu> Cr> Mn> Fe. The high Igeo and EF for Ni, Zn and Cu in atmospheric dusts indicated that there was a considerable Ni, Zn and Cu pollution (Especially nickel), which possibly originate from traffic and industrial activities. The Igeo and EF of Mn and Fe were low. The results of PI also supported Zn, Cu and Ni serious pollution in atmospheric dust. Similarly, IPI results confirmed atmospheric dust samples pollution by heavy metals. These findings indicated that more attention should be paid to heavy metal contamination of atmospheric dusts in Kermanshah, especially in case of Ni.
M.A. Delavar; Y. Safari
Abstract
Introduction: The accumulation of heavy metals (HMs) in the soil is of increasing concern due to food safety issues, potential health risks, and the detrimental effects on soil ecosystems. HMs may be considered as the most important soil pollutants, because they are not biodegradable and their physical ...
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Introduction: The accumulation of heavy metals (HMs) in the soil is of increasing concern due to food safety issues, potential health risks, and the detrimental effects on soil ecosystems. HMs may be considered as the most important soil pollutants, because they are not biodegradable and their physical movement through the soil profile is relatively limited. Therefore, root uptake process may provide a big chance for these pollutants to transfer from the surface soil to natural and cultivated plants, which may eventually steer them to human bodies. The general behavior of HMs in the environment, especially their bioavailability in the soil, is influenced by their origin. Hence, source apportionment of HMs may provide some essential information for better management of polluted soils to restrict the HMs entrance to the human food chain. This paper explores the applicability of multivariate statistical techniques in the identification of probable sources that can control the concentration and distribution of selected HMs in the soils surrounding the Zanjan Zinc Specialized Industrial Town (briefly Zinc Town).
Materials and Methods: The area under investigation has a size of approximately 4000 ha.It is located around the Zinc Town, Zanjan province. A regular grid sampling pattern with an interval of 500 meters was applied to identify the sample location, and 184 topsoil samples (0-10 cm) were collected. The soil samples were air-dried and sieved through a 2 mm polyethylene sieve and then, were digested using HNO3. The total concentrations of zinc (Zn), lead (Pb), cadmium (Cd), Nickel (Ni) and copper (Cu) in the soil solutions were determined via Atomic Absorption Spectroscopy (AAS). Data were statistically analyzed using the SPSS software version 17.0 for Windows. Correlation Matrix (CM), Principal Component Analyses (PCA) and Factor Analyses (FA) techniques were performed in order to identify the probable sources of HMs in the studied soils.
Results and Discussion: Comparing the measured HMs contents with their normal range in uncontaminated soils demonstrated the contamination of soils by Pb, Zn and Cd, with average concentrations of 152.8, 294.2 and 5.6 mg kg-1, respectively,whereas Ni and Cu did not show any pollution risk. The total concentration of Zn, Pb and Cd in the soil showed a great degree of variability, indicated by large coefficients of variation (CV) from 228.5 % of Cd to 354.8 % ofPb. These elevated CVs may indicate that these elements’ distribution in the studied area is influenced by an anthropogenic source. In contrast, the relatively low calculated CVs for Ni and Cu may imply that natural sources are responsible for these elements’ distribution in the studied soils. Correlation matrix (CM) analysis revealed high correlation coefficients between Zn-Cd and Ni-Cu, indicating the influence of the same factors in controlling their distribution. On the other hand, Pb contents showed low correlation with Ni and Cu values, whereas its correlation with Zn and Cd was relatively high. Therefore, it seems that Pb distribution in the studied soils is more influenced by the factor which controls the Zn and Cd distribution, rather than another factor that is responsible for accumulation of Ni and Cu in the studied soils. According to the PCA analysis, two significant components were extracted explaining about 84% of total variance. FA analysis showed that studied variables have a relatively high communality with two extracted principal components, indicating that almost all of the measured total variation can be efficiently explained by the extracted principals. Industrial activities in the Zinc Town seem to be the main factor which caused the high concentrations of Pb, Zn and Cd in the soil environment in this area; whereas Ni and Cu were associated with the natural sources including geology of the studied area (parental material’s factor). The obtained results from this study coincide with the prior studies indicating that multivariate statistics is a powerful technique for identification of probable sources of HMs in the soil.
Conclusions: The studied soils are classified as polluted soils with Zn, Pb and Cd,whereas Ni and Cu did not show any pollution risk. PCA and correlation analyses between HMs indicated that HM pollution in the studied area may originate from natural and anthropogenic factors. It can be concluded that Zinc Town controls the distribution of Zn, Pb and Cd in the surrounding soils, but Ni and Cu distribution in the studied area is mainly influenced by natural factors.Totally, industrial activities related to Zn production caused simultaneous entrance of several HMs to the adjacent soils and led to degradation of the lands in the studied area.
A. Afshari; H. Khademi; shamsollah Ayoubi
Abstract
Introduction: Heavy metals are types of elements naturally present in soil or enter into soil as a result of human activities. The most important route of exposure to heavy metals is daily intake of food. Crops grown in contaminated soil (due to mining activities, industrial operations and agriculture) ...
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Introduction: Heavy metals are types of elements naturally present in soil or enter into soil as a result of human activities. The most important route of exposure to heavy metals is daily intake of food. Crops grown in contaminated soil (due to mining activities, industrial operations and agriculture) may contain high concentrations of heavy metals. Also closeness to cities and industrial centers can have a great influence on the accumulation of heavy metals to agricultural products grown in the region. The study aimed to determine the concentration of heavy metals in soil and agricultural products around urban and industrial areas of Zanjan province (North West of Iran) and consumption hazard probability.
Materials and Methods: Soil (75 samples of soil from a depth of 0 to 10 cm) and plant (101 samples) samples, in the summer 2011, were randomly taken from industrial areas as follow: tomatoes (Lycopersicum esculentum M), wheat seed (Triticum vulgare), barley seeds (Hordeum vulgare), alfalfa shoots (Medicago sativa L.), potato tubers (Solanumtuberosum L.), apple fruit, vegetables and fruits such as Dill (Aniethum graveolens L.), leek (Allium porrum L.), Gardencress (Barbara verna L.) and basil (Ocimum basilicum L.). Plant samples were then washed with distilled water, oven dried for48 hours at a temperature of 70 ´C until constant weight was attained and then they digested using 2 M hydrochloric acid (HCl) and nitric acid digestion in 5 M. Concentrations of heavy metals in the soil and crops were determined by atomic absorption spectrometry. DTPA extraction of metals by Lindsay and Norvell (1978) method and sequential extraction method by Tessier et al. (1979) were performed. Statistical analysis was accomplished using the software SPSS 16.0 and the comparison of mean values was done using the Duncan test at the 5% level of significance.
Results and Discussion: The magnitude of variations for total copper was from 11.5 to 352.5 (average 52.4), zinc was from 96.3 to 1353.8 (average 264.8), lead was between 40.0 and 470.0 (average 105.7), nickel ranged from 12.8 to 77.0 (average 46.7) and chromium varied from 10.0 to 49.5 (average 21.7) mg kg-1. DTPA extracted heavy metals for copper varied from 1.50 to 21.23, averaging 4.47, zinc from 0.57 to 76.50 averaging 23.15, lead from 2.43 to 63.38 averaging 16.81 and nickel from 0.28 to 2.32 averaging 1.20 mg kg-1. Chemical changes in the different fractions were as follows: Cu (residual > bounded to organic matter > bounded to Fe-Mn oxides > bounded to carbonate > exchangeable fraction), Zn and Ni (residual > bounded to Fe-Mn oxides > bounded to carbonate > bounded to organic matter > exchangeable fraction,) and Pb (residual > bounded to Fe-Mn oxides > bounded to organic matter > bounded to carbonate > exchangeable fraction). The concentration of heavy metals in plant parts were high with respect to studied location. The highest amounts of Zn (Gardencress), Pb (Dill), Cu (Leek), Ni (Basil) and Cr (Basil), respectively were found to be 150.25, 41.25, 23.13, 6.46 and 3.47 mg kg-1 and the minimum amounts of the metals studied were found in fruits, wheat and barley grains. The total amount of metals in plants were as follow (Zn >> Pb > Cu > Ni > Cr). Bioaccumulation factor (BAF) of metals in plants were as Zn=Cu > Pb >> Cr > Ni. Hazard probability (HQ) in cancerous diseases for each element (except Pb) in both children and adults was less than unit. HQ content of Pb was much higher than the unit and for children and adults 9.07 and 6.94, respectively showing high contribution of Pb contamination of crops that threatens the consumer health in that location. The total amount of risk (THQ) in children was higher than that in adults.
Conclusions: The results obtained in this study indicate that an urgent attention is required for consumer products related to public health, especially vegetables grown in the studied regions. Toxic effects of heavy metals have many deleterious effects which are more pronounced over time. With conventional monitoring of food quality produced in farms and presented in markets, excessive accumulation of heavy metals entering in to the human food chain can be prevented. Also, we can change the risk potential of heavy metals in the region by growing vegetables which accumulate heavy metals.
Keywords: Agriculture products, Biological risk, Heavy metals, Soil, Zanjan province
A. Maadani; A. Lakzian; Gh. Haghnia; R. Khorasani
Abstract
High concentration, of heavy metals and the presence of phosphorus in soils may cause a reduction in the growth and activity of arbuscular mycorrhizal (AM) fungi and consequently, the spore production of these fungi would decrease. In order to evaluate the effect of zinc and cadmium as heavy metals and ...
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High concentration, of heavy metals and the presence of phosphorus in soils may cause a reduction in the growth and activity of arbuscular mycorrhizal (AM) fungi and consequently, the spore production of these fungi would decrease. In order to evaluate the effect of zinc and cadmium as heavy metals and phosphorus on arbuscular mycorrhizal fungi activity through measuring glomalin produced by these fungi a factorial experiment arranged as completely randomized design was carried out. Experimental factors included two fungal species G. mosseae and G. intraradices and non mycorrhiza (NM), six combinations of metals (400 mg of Zn, 25 mg of Cd, 400 mg of Zn + 25 mg of Cd, 50 mg P, 50 mg of P+ 400 mg of Zn + 25 mg of Cd, and no metal kg-1 soil sample) in three replications. The results showed that inoculated treatments produced more glomalin compared to non mycorrhizal treatments. The application of Cd, Zn and P caused a significant reduction in produced glomalin by both fungi species. The most reduction of glomalin in G. intraradices was detected in Cd treatment and in G. mosseae was in Zn treatment. The result also showed a positive correlation between the measured glomalin by Bradford assay and the percent of root colonization. According to the results of this study, glomalin in soil could be an indicator to monitor arbuscular mycorrhizal fungi activity and soil health.
