Journal of Natural Environment
Year:2022 | Volume:75 | Issue:1|Papers Count:13

Wastewater treatment plants are known as an important source of microplastics. Though a major proportion of microplastics are removed in wastewater treatment plants, the effluent of plants contain a significant amount of microplastic particles which eventually release into the environment. Until now there is no investigation on the role of wastewater treatment plants on the release of microplastics in Tehran. This study aims to assess the discharge amount of microplastic particles from wastewater treatment plant in district 22 of Tehran. Sampling was conducted from the influent and effluent of the plant with grab method and sieving through 300, 105 and 25 µm stainless still filters.  Retained samples were treated to remove organic and inorganic materials. Then particles were detected, counted and analyzed under microscope (*10). Results indicate that treatment process has a significant impact on microplastic particles removal. After the treatment process, the average of 2.15 MP/liter were found in the effluent. Larger particles were removed effectively (at the size of ≥300 and 105-300 µm) and smaller particles (25-105 µm) indicated a higher abundance. Among the detected particles fibers had the highest abundance and then fragment were at the second order. This finding indicates that waste water treatment plants can act as a source for microplastic pollution in the urban environment.

The purpose of this study is to investigate the long-term economic effects of corporate environmental responsibility of polluting companies from the perspective of earnings persistence and investors' response. To achieve the research objectives, 156 companies listed in the Tehran stock-exchange during 2014-2019 were selected and using the panel data approach, research hypotheses were tested. The results indicate that of all the studied companies have earnings persistence, but the corporate environmental responsibility of the polluting companies does not have a significant effect on the earnings persistence. Also, the profits of polluting companies have a direct impact on the reaction of investors. Investors, however, do not show a significant reaction to the disclosure of the environmental responsibility of the polluting companies. Findings of this study can help managers in rationally managing the tension between environmental investment in relation to shareholders and the quality of profitability. The findings also have important implications for environmental activists, policy makers and regulatory bodies.

Protected areas are considered as an important tool for maintaining the integrity of the habitat and species diversity, and the construction of these areas does not mean leaving them alone, but continuous and efficient management practices to achieve the set goals. The effects of threats make protected areas vulnerable. Therefore, reviewing and evaluating threats in protected areas is necessary and essential to provide management solutions. Vulnerability is important for developing integrated management policies for decision makers in order to prioritize activities and improve vulnerability. Golestan National Park is one of the most valuable and unique areas under management and protection not only in Iran but also around the world and has countless natural values, lush and pristine forests and diverse species. It is plant and animal. This research is a descriptive-analytical study with the aim of assessing the vulnerability of Golestan National Park by combining the DPSIR model and the new vulnerability method in order to provide management solutions. In this method, first, using DPSIR model, driving force, pressure, status, effect and response, threats and values ​​of the region and the relationship between them were studied and evaluated. Finally, strategies in the form of possible responses to each component of the DPSIR model are presented. 5 The main driving forces such as population development, tourism development, road development, overgrazing, settlement development and lack of coherent management for the identified area and consequently the pressures, situation and effects of the area are identified and studied. Were located. The results of this study indicate that in Golestan National Park, the most effects of regional threats on ecological values, including the extinction of animals, plants, wildlife habitat and biodiversity loss, and in terms of vulnerability, illegal hunting of animals. In addition, fires cause the most damage to the area. Finally, management strategies to deal with threatening factors were presented.

Benthic macroinvertebrate communities are a biological indicator in aquatic ecosystems. The aim of this study was to investigate the abundance and biodiversity of macroinvertebrate communities in Khormarud River, Golestan Province. Macroinvertebrate samples were collected seasonally from 5 stations with three replications in 2020 using a Vanveen grab with a cover area (225 cm2). A total of 819 specimens of macroinvertebrate belonging to 6 orders and 10 families were identified, with the highest diversity belonging to the order of insects with 7 families and the highest abundance belonging to Chironomidae (31.5%) and then Tubificidae (22.47%). Spring with 45% had the highest and winter with 22% had the lowest abundance. The highest distribution of macroinvertebrate was obtained in station 1 in upstream (40.66%) and the lowest in station 5 in downstream (5.86%). The results showed that the highest Shannon and Simpson diversity indices were obtained in station 1 in upstream of autumn season (1.96 ± 0.32) and (0.85 ± 0.11), respectively. Also, the highest values ​​of Margalf species richness index in station 3 in midstream of winter (2.06 ± 0.4) and Pielou's evenness index in station 3 (0.94 ± 0.19) were spring. According to the Multidimensional Scale Analysis (MDS), the distribution of macroinvertebrate among the stations showed three distinct groups. PCA results showed that organic matter and clay are the most important environmental factors in the changes of macroinvertebrate communities in Khormarud river, Golestan province. The results showed that this river due to increased organic matter from agricultural areas, adjacent urban and rural wastewater caused increased contamination of the benthos resistant to the pollution, including Tubificidae and Chironomidae, these indicators could be used as useful tools for evaluating water supplies quality.

In this study, for determination of environmental coastal sensitive areas in Sistan and Baluchestan province (Iran), the initial list of ecological and human criteria were identified in coastal and shore areas. Based on the identified criteria, a questionnaire was prepared and its qualitative and quantitative validities were determined. The final list of criteria and their weight achieved using Delphi and AHP method respectively. After preparing the criteria map (in ArcGIS software), both ecological and human weights aggregate individually during the overlaying process; and five sensitivity classes achieved. By using a decision-making matrix and the classification of ecological and human sensitivity map, final status of coastal environmental was determined. Results of the ecological zoning showed that 24.8% of land and 1.9 % of shore area were included in very high sensitivity class; and the widest range of human sensitivity (in both coastal and shore areas) was placed in very low sensitivity class. Based on the results of status analysis matrix, the weak and intensive classes of environmental sensitivity have the largest area, respectively. Considering that in this study area, care measures and development considerations have not been studied separately in three ecological, human and environmental sensitivities and this research is the first study, which has addressed this issue; the measures and considerations related to these areas, proposed for use in the Coastal Management Environmental Management Program (CEMO).

The presence of drug compounds in the environment is considered to be a serious threat to mankind and the entry of these substances into water resources leads to contamination of plants, soil and animals and creates problems for public health, which provides sewage treatment facilities in production resources It makes this material necessary to prevent them from releasing them in the environment. Hence, the use of nano-adsorbents is a novel high-performance method for removing antibiotics from aqueous media. Because of its unique properties, Multi-walled carbon nanotube (MWCNT) is one of the substances that can be used to remove antibiotics. In this study, MWCNT was synthesized and then became magnetic by magnetic thermal solvent method and was functionalized with the ethylenediamine amine group. The synthesized nanocomposite was characterized by Fourier Transform Infrared spectroscopy, vibrating sample magnetometry, thermal gravimetric analysis and CHNS elemental analysis. The nanocomposite was used for removal of Oxytetracycline (OTC) antibiotic from aqueous solution in batch system. The effect of various factors, such as pH, dosage of Magnetic MWCNT, contact time and initial concentration of antibiotic were investigated. The maximum equilibrium adsorption capacity for Oxytetracycline removal was 122.8 mg/g. The results showed that the synthesized nanocomposite in this research has a relatively high adsorption capacity for Oxytetracycline adsorption and the application of this adsorbent in wastewater treatment system could be reasonable in terms of the economic aspect.

One of the challenges issues of the 21st century is climate change. One of its effects could be a change in climatic parameters that will have a great impact on the planet's climate. Temperature and precipitation are the two most important elements for describing climate that their changes also alter the climatic structure of any region. It is very important to study the temperature and precipitation trends in different time and regions. Therefore, in this study, the effect of climate change on temperature and precipitation in Bandar Abbas was investigated using four General Circulation Models (GCM) in the period 2020-2020. Moreover, LARS-WG6 statistical model was used for exponential microscale and two emission scenarios RCP8.5 and RCP4.5. The results of evaluation models by Correlation Coefficient (R2), Root Mean Square Error (RMSE), Mean Absolute Error (MAE) showed that LARS-WG6 software is a appropriate tool for reproducing precipitation and temperature for the future. The highest correlation coefficient is belonged to the minimum temperature in GFDL-CM3 models (0.92), MIROC5 (0.98) and the maximum temperature of GFDL-CM3 model (0.95). The highest and lowest correlation belonged to the minimum temperature and precipitation, respectively. The forecasting results of temperature and precipitation except for a few cases show that the maximum and minimum of monthly temperatures will increase in all four models and two scenarios. Highest increase in minimum and maximum temperature is determined in June, HadGEM2-ES model, RCP4.5 scenario (3.65 ° C) and January, HadGEM2-ES model, RCP4.5 scenario (2.48 ° C), respectively. This increase is repeated in the annual and seasonal average.  The average of minimum and maximum annual temperatures will increase by 1 and 0.86 ° C, respectively. The results of the models generally predicted an increase in precipitation in most cases. The GFDL-CM3 forecast the biggest increase in the RCP4.5 scenario (25.82%) in March. Forecast data also showed an increase in annual and seasonal rainfall. The RCP4.5 scenario recorded more increase in precipitation than RCP8.5 scenario. According to these results, Bandar Abbas will face an increase in rainfall and temperature in the future. This increase in temperature and rainfall can have devastating consequences in various sectors such as agriculture, tourism, water source, environment and health. As a result of events such as heat stress and devastating floods, damage to plants and animals, the spread of diseases caused by these changes, as well as reduced visits to tourist areas such as Hengam Island are some of the consequences that Bandar Abbas will face in the next twenty years. Therefore, the results of this study can be useful in recognition and solving problems related to climate change. According to the results of this study, managers in different sectors can assume the necessary strategies to adapt and reduce the consequence effects of climate change.

Petrochemical manufacturing processes incorporate toxic and dangerous chemicals, making petrochemical wastewater treatment one of the world's most critical environmental issues today. As a result, this research presents an optimization model of soil characteristics for designing a natural filter for the wastewater treatment of Shahid Tondgoyan Petrochemical Company using the response surface method (RSM). After selecting and sampling soils in Bahmaei city of Kohgiluyeh and Boyer-Ahmad provinces, the physicochemical characteristics of the studied soils were determined, including their acidity (pH), electrical conductivity (EC), percentage of organic matter (OM), and percentage of clay (Clay). Following that, 12 small natural soil filters were designed in the laboratory, and effluent filtration tests were conducted after preparing the effluent from Tondgoyan Petrochemical Company. As response variables, four parameters were determined for the effluent from the filters: acidity (pH), total suspended solids (TSS), iron content (Fe), and manganese content (Mn). We fitted regression models between the four soil parameters (independent variables) and each of the effluent parameters using Design-Expert statistical software (response variables). The PSO algorithm was used to optimize regression models to obtain the optimal values for soil physicochemical parameters to produce the best effluent with the least amount of pollution. The results indicated that parameters such as acidity, electrical conductivity, organic matter, and a high percentage of soil clay would increase the acidity and decrease the total suspended solids, iron, and manganese in the effluent, thereby assisting in the treatment of petrochemical effluent. Additionally, the optimization algorithm determined that an EC of approximately 0.03 dS/cm, an acidity of 7.9, an organic matter percentage of 2.95, and a clay content of 50% are the optimal values for soil parameters whose effluent output parameters included neutral acidity greater than 7, TSS 90, iron 1, and manganese 2.3 mg / l. The findings may aid in the construction of a large-scale soil filter.

In order to influence the possible leakage of Chahar Gonbad copper tailings dam on water resources in the dam area, surface and groundwater quality studies were performed in two seasons, dry and wet. Some 10 water samples from different parts of the tailings dam area were evaluated for water quality analysis including Wilcox and Schuler. The results showed that the drinking and agricultural water samples in the region is in line with global environmental standards. The amount of chloride in the drainage water of the tailings dam was 499 mg / l, which is 99 units higher than the defined standard of Iranian drinking (400 mg / l) and 149 units higher than the standard agricultural level (350 mg / l). Also, the results showed that the amount of magnesium in the dry season compared to the wet season has a relative increase. That high amounts of magnesium compared to calcium in water in the irrigation system have a negative effect on soil quality and lead the soil to alkalinity. Molybdenum in tailings dam samples in both wet and dry seasons is higher than the standard level of agricultural use (10 mg / l), which is more evident in the dry season. The high concentration of molybdenum in waste samples is due to the proper mobility of this element in oxidative-acidic conditions. The amount of bicarbonate in the dry season increased more significantly than in the wet season. This increase can be due to the increasing temperature, pH and increase in water alkalinity, the source of those river bed rocks that with increasing water volume in the dry season has increased the concentration of these salts. Based on the results, it is suggested that 23 observation wells with a maximum depth of 50 meters be dug as monitoring grade 1 around the tailings dam of Chahar Gonbad copper mine.

Over time, land cover patterns and subsequent land uses change fundamentally. Therefore, in order to make the best use of natural resources, it is necessary to obtain accurate information about land use potential. The main goal of the REDD project is to reduce greenhouse gasses (methane, carbon dioxide, and nitrogen dioxide) and increase carbon sequestration in areas with high land use change. Therefore, to protect the Kojoor area, it is important to properly understand not only human factors, but also the role of natural factors such as vegetation. Based on the objectives of REDD, the study of forest cover changes in the study area was conducted using Landsat satellite images (4, 5 and 8) for the years 1985, 1990, 1995, 2000, 2010, 2015 and 2017. Finally, using the BioCFon method (BioCF) and the base period 1364-1396, the change in forest cover was modeled for the next 4 years (until 1425) and the amount of carbon dioxide emissions was calculated until 2046. The results of examining the vegetation indices showed an improvement in cover condition over the study period. Therefore, the improvement in cover condition can be attributed to the application of protective measures. According to the results obtained in 2046, the land cover classes without land cover will have about 8%, the land cover class with pasture will have 40.8%, and the forest cover class will have an area of 51.1%. In addition, between 2017 and 1425, if the project strategy is not implemented, about 199569 hectares (20%) of forest area will be destroyed and 1995695 tons of carbon dioxide will be emitted, while this amount will be 405512 tons if the project REDD is implemented. The emission of 1590183 tons of carbon dioxide equivalent (42%) into the upper atmosphere of the Earth can be prevented.

The Qaleh Chai watershed as one of the watersheds of Lake Urmia has 36 rural settlements that are often active in agriculture. This area has been experiencing a reduction in available water for the past 20 years or so. Water scarcity has doubled the need to improve water productivity. The present study was conducted with the aim of forecasting water productivity in 36 rural settlements of the Qaleh Chai watershed. Data collection was in the form of a Delphi questionnaire with the participation of experts, which was analyzed with Micmac software. The number of components studied included 20 components affecting the promotion of water productivity. Data analysis led to the identification of 9 key components affecting the improvement of water productivity in the Qaleh Chai watershed. The most important key components identified are canal renewal, reducing irrigation time and increasing frequency, reducing the land area in steep areas, improving the quality of management and taking a comprehensive approach, transferring water from the source to the farm using Indoor canals, using of agricultural inputs with less water requirement, subsidies for sprinkler and drip irrigation, use of advanced equipment to reduce water consumption and improve villagers' water productivity skills respectively with scores 767, 766, 655, 654, 632, 609, 608, 541 and 496. The results of prioritizing the villages in terms of key components showed that the Harglan village, the Almalo village, and the Tutakhaneh village have the highest score (0.042, 0.045, 0.051), respectively. According to the research findings, It can be said that the realization of strategies to improve water productivity in the group is the simultaneous attention to all components and the adoption of a comprehensive approach.

Today, due to the negative effects of oil mulches on the environment, has attracted a lot of attention the use of environmentally friendly mulches. The purpose of this study is to determine the best combination of vinasse, filter cake, bagasse and bagasse ash as mulch in terms of environmental indicators in the north of Khorramshahr. In this study, 81 treatments were provided with combination of vinasse (0, 100, 200 g), bagasse (0, 25, 50 g), ash bagasse (0, 25, 50 g), filtercake (0, 12.5, 25 g) and one-liter water. In the first step, among 81 treatments, were determined treatments in the appropriate range of salinity and acidity and in the second step, after mulching (35 optimal treatments in the first step) on laboratory trays (2×30×100 cm), have been measured shear strength, compressive strength, impact resistance, surface crack coefficient for optimal treatments with at least three replications. In the third step, the selected mulches are qualitatively scored. In the fourth step, the selected treatments in the previous step are examined in terms of the indicators of heavy elements (cadmium, chromium, lead, zinc, arsenic, mercury, vanadium, nickel), salinity, acidity and chemical properties (calcium, magnesium, sodium, sulfate, chlorine, phosphorus, (Potassium, organic carbon, nitrogen and sodium uptake ratio). In the last step, the treatments were ranked in terms of environmental indicators using the TOPSIS model and the treatment with the highest proximity index was selected as the optimal mulch. The results of TOPSIS model showed that treatment 19 (100 g vinasse, 50 g bagasse, no ash bagasse and 12.5 filter crack) with a proximity index of 0.89 was the first. Based on the results of this study, it can be concluded that the use of vinasse (100 g) in the optimal treatment will increase the rank of vinasse mulch in terms of environmental indicators with a proximity index of 0.89 and on the other hand, The presence of bagasse and filtercake in the optimal mulch has a significant effect on increasing the shear strength (up to 2 kg / cm2 compared to the control) and reducing the crack coefficient (up to 1.8% compared to the control).

Global analysis of particulate matter indicates the fifth highest risk of death in the world due to exposure to PM2.5. The purpose of this study is to analyze the monitoring and study of changes in air pollutants in the metropolises of Tehran, Karaj, Isfahan, Mashhad and Shiraz using a combination of optical depth of satellite images. Methods first, satellite images of MODIS, MISR and SeaWifs sensors were used, and the data of quality control stations of Iranian metropolises and statistical indicators were used for validation. Kendall and Sense slope methods were also used to analyze the trend. The results showed that the annual variability of suspended particles (PM2.5) during the statistical period of 2000-2000 has an increasing trend in all metropolises of Iran. The city of Tehran showed the highest PM2.5, which is more than other metropolises. After that, Karaj and Isfahan showed the maximum PM2.5. Also, the trend value and trend slope of PM2.5 trend is increasing in all metropolises; this value of trend is statistically significant for Tehran at the level of 0.05; So that the Z score of Man-Kendall test for Tehran is 1.998. The lowest value of suspended particles trend in Isfahan metropolis with Z-score of Mann-Kendall test is 0.02. The effects of urban areas and elevation changes show the most spatial variation of the estimated PM2.5. The amount of PM2.5 in all metropolises has a high spatial diversity; the reason for this variability is due to the proximity to the main sources of dust on the one hand and urban and industrial pollutants on the other.