Saeed Bagherifam; A. Lakzian; A. Fotovat; R. Khorasani
Abstract
Introduction: Arsenic is a highly toxic metalloid in group 15 of periodic table. The information on environmental behaviour of arsenic, however, is still scarce. Contamination of soils and water with arsenic and antimony due to their widespread industrial application and mining activities has raised ...
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Introduction: Arsenic is a highly toxic metalloid in group 15 of periodic table. The information on environmental behaviour of arsenic, however, is still scarce. Contamination of soils and water with arsenic and antimony due to their widespread industrial application and mining activities has raised serious environmental concerns. Nearly all Arsenic-contaminated soils results from human activities and it has different environmental and sociological impacts. Various strategies and methods have been proposed for environmental management and remediation of contaminated soils. Among all methods, the phytoremediation is receiving more attention due to its cost effective and environmental friendly characteristics. In the case of arsenic contaminated soils, there are effective factors such as soil fertility, nutrients content and microorganisms function, which can improve the uptake of As by plants. Up to now, several studies have been evaluated the effects of symbiotic fungal association in plants on increasing nutrients and toxic elements uptake. Many of authors reported that the mycorrhizal symbiosis increases the uptake of toxic elements in root and shoot of plants and consequently improve the efficacy of phytostabilization and phytoextraction processes. There are conflicting results about the effect of arbuscular- mycorrhizal fungi (AMF) on As uptake by various plants. Chen et al. (4) found that Glomus mosseae symbiosis with plant reduces As concentration and enhance phosphorus content in shoot and root of plant. Whilst Cozzolino et al. (7) reported that the AMF increases as concentration in shoot and root of cabbage. Phosphorus has important role on mycorrhizal symbiosis and also As uptake by plants. Therefore, current study was conducted to evaluated effect of Glomus intraradices and Glomus mosseae symbiosis with sunflower and also soil phosphorus concentration on uptake of arsenic from arsenite and arsenate contaminated soils.
Materials and Methods:The soil sample (Typic Haplorthids) was collected, air dried and passed through 2 mm sieve and then were heated in 80 centigrade degree temperature for two times. A pot experiment was conducted in a completely randomized design with factorial arrangement and three replications in greenhouse condition. The experimental factors included two species spices of inorganic As (50 mg kg-1 of Arsenite and Arsenate), two levels of phosphorus (0 and 60 mg Kg-1) and three spices of arbuscular mycorrhizae (control, Glomus intraradices and Glomus mosseae). Soil samples spiked with Na2HAsO4.7H2O, NaAsO2 (Arsenite and Arsenate) and Ca (H2PO4)2 (phosphorus) and incubated in greenhouse condition for 4 week. Sunflower seeds were planted and seedlings harvested after 60 day of sowing and then dry weight of sunflower, concentration of As and phosphorus in shoot and root of plant and root colonization percentage determined using standard methods.
Results and Discussion:The results revealed that Glomus intraradices (GI) and Glomus mosseae (GM) symbiosis significantly (P
S. Bagherifam; A. Lakzian; M. Rezaei
Abstract
Abstract
Uranium is a natural heavy metal widely dispersed across the earth crust. In many cases due to anthropogenic disturbance, it has been found beyond its natural abundance which resulted in soil-water pollution. The objective of this study was to investigate the capability of Iranian natural zeolite ...
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Abstract
Uranium is a natural heavy metal widely dispersed across the earth crust. In many cases due to anthropogenic disturbance, it has been found beyond its natural abundance which resulted in soil-water pollution. The objective of this study was to investigate the capability of Iranian natural zeolite clinoptilolite for removal of uranium (VI) from aqueous solutions. In order to optimize removal efficiency of uranium, bath techniques were used as a function of various parameters, i.e., initial uranium concentration, pH solution, shaking time and dose of zeolite. The sorption of uranium was investigated by using Langmuir and Freundlich model. Maximum uranium uptake by zeolite achieved at 200 mg U L-1, pH 5 and 20 h contact time. The results of the experiment also revealed that Langmuir model was able to predict uranium adsorption mechanisms by zeolite more accurate than Freundlich model. Considering low cost and great natural resource of zeolite in Iran, it is suitable for environmental applications.
Keywords: Uranium, Zeolite, Langmuri, Freundlich
S. Bagherifam; A. Lakziyan; S.J. Ahmadi; B. Salimi; F. Asghari zadeh
Abstract
Abstract
Uranium as a natural radioactive heavy metal widely disperses throughout the earth's crust. In many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. Uranium through the plant uptake ...
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Abstract
Uranium as a natural radioactive heavy metal widely disperses throughout the earth's crust. In many cases, the natural abundance has been re-distributed due to anthropogenic activities, resulting in radionuclide contamination in groundwater and surface soil. Uranium through the plant uptake can enter the chain. The degree of speciation of radio nuclides in soils in areas with differing levels of uranium is of great interest in order to further the knowledge of the processes that determine the mobility and distribution of these contaminants from the installation, and consequently the potential short and long term risks. In the present work, we used a sequential extraction procedure based on Tessier’s method to determine the fractionation of uranium in a calcareous soil. The effects of two levels of uranium, 585 and 3240 Bq/kg 238U on the uranium distribution in soil fractions at 30 and 90 days of incubation were studied. The results indicated that U primarily associated with the carbonate fraction (62%) and increased by increasing the uranium level in soils. A comparison of extraction results from different incubation times showed that the pattern of uranium association with different fractions changed during the time of incubation.
Keywords: Distribution of uranium, Sequential extraction, Calcareous soils
Saeed Bagherifam; A. Lakziyan; S.J. Ahmadi; A. Fotovat; M.F. Rahimi
Abstract
Abstract
Uranium is a radioactive heavy metal. Development of nuclear industries and application of phosphate fertilizers contain uranium impurity resulted in soil contamination with uranium. A Pot experiment had been conducted under controlled condition. The experiment carried out in completely randomized ...
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Abstract
Uranium is a radioactive heavy metal. Development of nuclear industries and application of phosphate fertilizers contain uranium impurity resulted in soil contamination with uranium. A Pot experiment had been conducted under controlled condition. The experiment carried out in completely randomized design with two factors, including two plants (soybean and sunflower) and six levels of uranium (0, 50,100,250,500 and 1000 mg/kg). Plants harvested after 40 days of experiment and before the generative stages. Soil samples were extracted by DTPA and AAAcEDTA. Uranium concentration in plant tissue increased by increasing the uranium in soil. The ratio of uranium in root:shoot was between 20-100 in sunflower and soy bean. Extraction efficiency of DTPA and AAAcEDTA increased by increasing of uranium in soil. The results of the experiment showed that AAAcEDTA extracts more uranium in all applied uranium concentrations. Both extractants had a good correlation with uranium in plants; however, extraction efficiency of AAAcEDTA was well correlated by uranium concentration in plant tissues. The results of the experiment suggest that AAAcEDTA is suitable extractant for uranium as phytoavailability indicator.
Key word: Uranium, phytoavailability, laser fluorometry, sunflower and soybean