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.
Fatemeh Izadi; Atefeh Chamani; Rasool Zamani Ahmadmahmoodi
Abstract
One of the most important invasive plant species in Iran is the American mesquite tree (Prosopis juliflora) which has taken the control of a large area of south and southeast Iran. The invasive effect of this species is profound such that it is the dominant species in some areas and the only tree ...
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One of the most important invasive plant species in Iran is the American mesquite tree (Prosopis juliflora) which has taken the control of a large area of south and southeast Iran. The invasive effect of this species is profound such that it is the dominant species in some areas and the only tree species in most coastal ecosystems of southern Iran. Regardless of draining underground water as the only source of drinking water for local communities and destroying livestock feed, simplifying the ecosystem to only one tree species is a serious alarm of losing the ecosystem balance and causing serious economic and social effects. Considering the importance of the management of American mesquite trees in the south of Iran, this research investigated the spread of American mesquite trees using satellite image processing.Materials and Methods: Among the 45 identified species of the genus Proposis, few of them, especially the American mesquite, are known as invasive species. This plant is known as the most threatening invasive plant in Europe. In the red list of the International Union for Environmental Protection, American mesquite is mentioned as one of the world’s 100 invasive species threatening. In this study, an area of 1850 km2 between the two cities of Sirik and old Jask was investigated. Pixel-based processing of Landsat 8 satellite images (OLI sensor) was used to extract the tree cover map of the area. The land units (areas covered with similar soil and vegetation characteristics) were produced using the object-oriented processing of Landsat 8 satellite images. Finally, the dominance of American mesquite compared to other trees was calculated in each unit and their canopy density changes were investigated and analyzed using the MODIS vegetation index in a 20-year period. Results: According to the results, 13417 ha of the study area is covered by various trees. The American mesquite tree class was the second largest tree class (3991 ha, 29% of the total tree cover) with a heterogeneous distribution and is often located in areas with light and salty soils along the streams. Areas with a strong predominance of mesquite (more than 60%) accounted for 11% of the area which was mostly located in the central parts of the region. Discussion:The results of the image classification showed that the American mesquite heavily occupied areas are mostly located along the main rivers and channels, extending from the eastern highlands towards the waters of the Strait of Hormuz. Thus, proximity to rivers and waterways can be considered as one of the most important environmental factors affecting the spread of these trees. In areas with a strong dominance of American mesquite trees, it was expected that the plant biomass will increase significantly as observed by their high NDVI values. However, the noteworthy point is the increasing rate of the average values of the NDVI index during the last 20 years in the most dominant units, which is now increasing at a high rate with an average NDVI exceeding 0.5 since 2017. This indicates the increasing spread of the American mesquite in the region and even in the areas that have hosted this invasive species for decades.
Mokarrameh Behmanesh; Atefeh Chamani; Elham Chavoshi
Abstract
Introduction: One of the most important emerging pollutants in aquatic environments that has recently attracted the attention of global researchers in recent years is plastic waste, especially microplastics. Aquatic fauna can ingest microplastics as they confuse it for their prey. Aquatic organisms can ...
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Introduction: One of the most important emerging pollutants in aquatic environments that has recently attracted the attention of global researchers in recent years is plastic waste, especially microplastics. Aquatic fauna can ingest microplastics as they confuse it for their prey. Aquatic organisms can easily ingest microplastics because their size is similar to that of the larvae of several organisms, including plankton. Consequently, the animal may develop a sense of satiety after ingesting microplastics, causing reduced food uptake and decreased energy intake, which in turn may affect growth, survival, fecundity and reproduction rate, impacting general fitness of the organisms. Once ingested, these particles can be transferred to higher trophic levels. Despite the fact that freshwater is the only source of drinking water, knowledge about the effects of microplastic pollution in freshwater environments compared to marine environments is still in its infancy. Therefore, the aim of the present study is too comprehensive investigate the presence and distribution of microplastics in the sediments of Zayandeh-Rud River.Materials and Methods: From upstream to downstream of Zayandeh-Rud River, 21 sampling stations were selected and in each station, sampling was done in an area of 30 x 30 cm to a depth of approximately 10 cm above the sediment in three repetitions. Sample processing was done during two stages of organic material digestion using hydrogen peroxide and density separation using sodium chloride salt. Microplastics were identified using a standard light microscope with magnifications of 40x, 100x and 400x. Different standard protocols such as pressure, tension, additional light or hot needle tests were used to detect microplastics. After identifying the microplastic particles, their type and shape, color and size were determined and recorded. Raman spectrometer was used to determine the polymer composition of microplastics.Results: The average abundance of microplastics was 70.481±29.39 particles in 50 gr/dry sediment. Station 17 with an average number of 363.50±14.849 particles and stations 1, 6 and 7 with an average number of 1.33 ±1.528 particles in 50 gr/dry sediment had the highest and lowest levels of pollution, respectively. The size of all microplastics was in the range of 50-5000 micrometers. Microplastics less than 500 microns were the most abundant with 64.5%. The dominant form of microplastics with the frequency of 34.9%, 33% and 28.8% belonged to line, fragment and fiber, respectively. In total, 4 polymers, polypropylene, polyamide, polyurethane and polyethylene, were identified. The results were compared with the reference spectra provided in the Openspecy database. In total, 3 different polymers including polypropylene (PP), polyethylene (PE) and polyamide (PA) were found in sediments.Discussion: The result of this research indicates microplastics dispersion in the sediments of Zayandeh-Rud River. Polypropylene (PP), polyamide (PA) and polyethylene (PE) polymers found in Zayandeh-Rud River sediments are often used in textiles. The composition of the polymer in the sediments clearly indicates the discharge of wastewater from the washing of synthetic textile into the river. Polypropylene and polyethylene are used to make ropes and fishing nets. In addition, polypropylene fibers are widely used for the production of floor coverings, carpets and rugs, sports clothes, making agricultural mulch, fishing nets, packaging bags and ropes. Due to its high strength and hardness, polyamide is used to produce items such as ropes, safety belts, parachutes, thread and fishing nets, as well as in the production of synthetic fibers such as clothes, socks and carpet fibers.Therefore, it can be stated that human activities, including the discharge of urban and industrial wastewater, plastic waste by tourists on the river and also the use of fishing nets by fishermen, play an important role in microplastic pollution in this area. Therefore, developing a program to monitoring microplastics in the water and sediment of Zayandeh-Rud River will be of great help for management measures to control this pollution.