Soil Pollution
Ali Jamshidian; Atefeh Chamani; Mozhgan Ahmadi Nadoushan
Abstract
Introduction: 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 ...
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Introduction: 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.Materials and Methods: 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.Results: 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.Discussion: 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.
Soil Pollution
Mahmood Kasaei; Nasrin Gharahi; Rafat Zare Bidaki
Abstract
Introduction: Nitrogen is the nutrient in plants production which usually can be added as a fertilizer into the soil. Nitrate is one of the pollutants which is mainly caused by agricultural activities which contaminants groundwater and surface water and threatens human health. Investigating an effective ...
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Introduction: Nitrogen is the nutrient in plants production which usually can be added as a fertilizer into the soil. Nitrate is one of the pollutants which is mainly caused by agricultural activities which contaminants groundwater and surface water and threatens human health. Investigating an effective factor on water and minerals movement in soil and applying the new modifiers such as inorganic nanoparticles and biochar might be useful in reducing nitrate leaching and avoiding underground waters pollutions. Due to this difficulty, some situations to preserve nitrogen in the upper layers of soil such as increasing the absorbent surfaces for minerals, zeolite modifier, and biochar are considered by researchers. As many research have been conducted on using biochar in agricultural systems in terms of organic carbon sequestration in soil and reducing the greenhouse gases, its influence on other processes such as nitrate leaching has been considered as well. The purpose of this study was to investigate the effect of mineral nano-particles and biochar on nitrate leaching in soil and aggregate stability.Materials and Methods: This study had been conducted in the laboratory in faculty of natural resources and geology science, Shahrekord University. Treatments in this study included zeolite, cloisite, and biochar at three levels. PVC pipes with 3 cm in diameter and 40 cm in height were used for the soil columns. Urea fertilizer included 46% pure nitrogen was applied to the soil columns. The amount of the Urea fertilizer was employed as an applied fertilizer for corn plants (200 g Nitrogen per hectare). Urea fertilizer was added as a solution to the soil in irrigation 1, and 5 from irrigation events. At the end of each irrigation event, nitrate effluent was measured using Spectrophotometry method.Results and Discussion: The results showed a significant reduction of nitrate leaching in treatments, 1g biochar, 1g zeolite, and 1g cloisite compared to the control treatment. There was no significant difference between reduction of nitrate leaching in the three treatments, 1g biochar, 1g Zeolite, and 1g cloisite. Furthermore, nitrate leaching in treatments, 5g biochar, 5g zeolite, and 5g cloisite compared to the control treatment was decreased significantly. In all irrigations, 5g biochar had the smallest amount of nitrate leaching comparing 5g zeolite, and 5g Clozite. In general, the results showed that nitrate leaching would be decreased significantly by adding biochar and mineral nano-particles (5%) into the soil. According to the present results and previous findings, it can be mentioned that adding biochar into the soil will cause improving the soil physical properties and reducing nitrate leaching. Thus, we show here, that biochar and nano-particles soil application decreased nitrate leaching and enhanced soil aggregate stability.
Soil Pollution
Ravanbakhsh Shirdam; Sara Emami; Somayeh Mohammadi
Abstract
To reduce the solubility of nickel, cadmium, lead, zinc and cobalt of filter cake tailings, resulting from zinc processing, a sample of the mentioned tailings was collected from the accumulation site in Zanjan province. Their chemical properties were measured using XRF and XRD analysis. Then, these tailings ...
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To reduce the solubility of nickel, cadmium, lead, zinc and cobalt of filter cake tailings, resulting from zinc processing, a sample of the mentioned tailings was collected from the accumulation site in Zanjan province. Their chemical properties were measured using XRF and XRD analysis. Then, these tailings were mixed with 0-10%, 0-3%, 0-2% and 0-6% of lime, red mud, cement and GGBFS, respectively, as stabilizers. In order to investigate the reduction of solubility of heavy metals, the extraction process of the samples was performed using 0.05 M EDTA solution, and the heavy metal of these extracts were measured by atomic absorption. The results demonstrate that in samples made with a combination of both lime and red mud, the solubility of all heavy metals except lead was reduced by 45 to 50%. A comparison between the XRD spectra of the control sample and that of the stabilized sample shows that the sulfate form of PbSO4 in the control sample has converted to the carbonate form of PbCO3 in the sample containing lime and red mud, which has more solubility. This change was the main factor in increasing the solubility of lead (87%) in these samples. Cement and slag have been the most effective additives in reducing lead solubility in filter cake. According to the XRD spectrum, the form of PbSO4 in the control sample decreased significantly (100%) after being mixed with cement and slag, which was the reason for the maximum reduction of the solubility of extractable lead in the sample.