Water Pollution
Rasool Zamani-Ahmadmahmoodi; Esmaeil Pirali Kheirabadi; Hossein Rahimi Pordanjani
Abstract
Introduction: Aquaculture includes the propagation and husbandry of aquatic plants, animals, and other organisms for various purposes, including commercial, recreational, and scientific use, which has gained significant attention in recent times. However, its uncontrolled development like any other production ...
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Introduction: Aquaculture includes the propagation and husbandry of aquatic plants, animals, and other organisms for various purposes, including commercial, recreational, and scientific use, which has gained significant attention in recent times. However, its uncontrolled development like any other production activity, can have adverse environmental effects, Thus, the removal of water pollutants is crucial. This study aimed to investigate the impact of a mechanized water disinfection device that uses ultraviolet (UV) radiation at different doses to reduce microorganisms in the effluent of rainbow trout farms. Also, the efficiency of the device in deactivating pathogens was investigated in different flow rates and water turbidity levels.Materials and Methods: The study was conducted in a rainbow trout farm with a 30-ton capacity, located in Kiyar County, approximately 30 kilometers from the center of Chaharmahal and Bakhtiari province. The UV device, at various doses (60, 120, 180, and 240 mW/cm2 = joule), was applied to the farm's effluent, considering different levels of turbidity and flow rates (ranging from 2.5 to 25 liters per second). Water samples were collected both before and after the installation of the UV disinfection device. Subsequently, the average counts of total coliforms, fecal coliforms, fungi, and yeast were calculated with three replications. Probit regression was utilized within the SPSS software environment, with a statistical significance level of 0.001, to examine changes in the removal percentage of microorganisms at different UV doses. Graphs were created using Microsoft Excel 2016 software.Results: The findings indicated that increased water flow rates and water turbidity reduced the efficiency of removing the targeted microorganisms. The findings indicated that increased water flow rates and water turbidity reduced the efficiency of removing the targeted microorganisms. Moreover, higher UV doses led to a higher removal percentage of total coliforms, fecal coliforms, fungi, and yeast. For instance, at a dose of 56 mJ/cm2, the total counts of total coliforms, fecal coliforms, fungi, and yeast decreased by 1.7, 3.2, 0.7, and 0.86 logs, respectively. However, complete removal of yeasts required significantly higher UV doses, depending on water flow rates and turbidity (up to a maximum of 240 mJ/cm2). Additionally, the results of the probit regression indicated that at doses of 40.50 mJ/cm2, 20.22 mJ/cm2, 30.31 mJ/cm2, and 14.36 mJ/cm2, approximately fifty percent of the yeast population (P<0.001), fungi (Z=13.5, P<0.001), fecal coliform (Z=22.77, P<0.001), and total coliform (Z=6.8, P<0.001) would be removed.Discussion: In summary, this research demonstrated that at a dose of 20 mJ/cm2, the gradual elimination of microorganisms begins, but at doses higher than 120 mJ/cm2, the intensity of elimination decreases. Therefore, adjusting the doses of ultraviolet radiation based on the water quality of fish farms can help maintain system health and subsequently increase productivity. The insights obtained from this study can be valuable for commercial water treatment systems and recirculating aquaculture systems. More studies are needed for the efficiency of removing viruses in water by UV rays. It is recommended to construct a sediment pond and employ various water filtration methods, including sand filters, before utilizing ultraviolet rays. This approach aims to decrease the presence of suspended particles in the water and enhance the efficiency of the disinfection system.
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.
Rasool Zamani-Ahmadmahmoodi; Nasrin Gharahi; Samira Bayati; Hojatollah Khedri-Gharibvand; Mahnaz Amini; Fatemeh Asadi
Abstract
Introduction: Solid waste management became an important environmental issue in the last century. This study was conducted to evaluate the knowledge and attitudes of people regarding urban waste management in Shahrekord in 2013. Solid waste materials in Shahrekord often include household, commercial, ...
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Introduction: Solid waste management became an important environmental issue in the last century. This study was conducted to evaluate the knowledge and attitudes of people regarding urban waste management in Shahrekord in 2013. Solid waste materials in Shahrekord often include household, commercial, industrial, construction and agricultural waste. These wastes are buried unseparated and a percentage of the waste remains unmanaged. Since there is no recycling factory in Chaharmahal & Bakhtiari Province, many wastes, which have high economic value, are destroyed with indifference. Considering the influential role of urban and provincial managers and planners, with a little reflection and acceptance of the role of community members in the management cycle, many problems related to the next stages of the waste disposal system can be reduced to the minimum possible.Materials and Methods: In order to execute this study, a combined method (field, library and documentary, analytical and descriptive methods) was used. The city was divided into three districts and randomly, 50 questionnaires (n=150) were distributed. The validity of the questionnaires was confirmed by an expert in the field of waste materials from the medical sciences universities in the country and its reliability was confirmed by Cronbach’s alpha test. Finally, the data obtained from these questionnaires were analyzed using Excel and SPSS version 19 software, aided by descriptive statistics, correlation tests and variance analysis. In order to investigate the effect of gender on the participation rate, independent T-test was used, and the effect of education and age structure on the participation rate was evaluated by ANOVA test.Results: Given a Cronbach’s alpha of 0.87, the questions asked in the questionnaires had good validity. The largest number of respondents to the questionnaires were in the age range of 25-40 years old (53.3 percent), and in terms of education, they had associate and bachelors degrees (55.3 percent). Also, 50.7% of the respondents were women and 49.3% were men. The results showed a significant relationship between the level of education of people and their knowledge about solid waste management (chi-square, 0.05). There was no relationship between the awareness of people and their age and gender (chi-square, 0.05). The results of the frequency distribution of people’s responses regarding solid waste showed that approximately 97% of people are fully aware of the difference between dry and wet waste. The mean score of awareness of people in this study was 31.88 ± 0.98 (mean ± SD) of 68 score.Discussion: According to these results, awareness of people in Shahrekord was estimated as medium. These results indicated that in a society with a high level of culture, it is easier to manage solid waste. Therefore, there is a need for planning to change the behavior and attitudes of families and implement programs to increase people’s knowledge based on the social and cultural context of the study area. Therefore, to improve solid waste management, it should be use appropriate educational media to promote public culture in relation to solid waste management.
Rasool Zamani-Ahmadmahmoodi; Ehsan Fathi; Samira Bayati; Zeinab Akbari
Abstract
Various indices are used to assess the suitability of water quality for drinking and agricultural uses. The aim of this study is to investigate the water quality of rivers in Beheshtabad watershed for irrigation purposes. Some water quality parameters were measured in 4 selected stations monthly during ...
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Various indices are used to assess the suitability of water quality for drinking and agricultural uses. The aim of this study is to investigate the water quality of rivers in Beheshtabad watershed for irrigation purposes. Some water quality parameters were measured in 4 selected stations monthly during spring and summer 2013 and 2019 with using the standard methods. Then, SAR, RSC, SSP, KR, PI and MAR indices were calculated. According to the results, the water quality of the stations was in good condition in terms of PI with values less than 80 mg/l, was in good condition in terms of KR with values less than one and in terms of SSP with values less than 200. The water of the studied rivers was hard in terms of total hardness, sweet in terms of total dissolved solids, and had a good condition in terms of permeability index, residual sodium carbonate, soluble sodium percentage, Kelly’s Ratio, magnesium adsorption ratio indices. According to water quality indices, water quality did not change in 2019 compared to 2013. According to the Wilcox diagram, the water of these rivers were in class C2S1, suitable for agricultural use, and according to the Piper diagram were located in Bicarbonate-Magnesium-Calcium group, in the category of water with temporary hardness. In general, evaluation of water quality of these rivers showed that the water of these rivers did not have limitation in terms of agriculture and were almost acceptable and suitable for irrigation.