جستجوی مقالات مرتبط با کلیدواژه « فلزات سنگین » در نشریات گروه « محیط زیست »

The chemical precipitation using lime, caustic soda and soda ash was investigated for the simultaneous removal of Cu and Zn from copper mine industrial wastewater by conducting jar tests in the present study. Jar experiments were performed with a set of polyethylene beakers (500 ml) in order to investigate the effect of two reaction parameters (precipitant doses and initial pH) on the removal of heavy metals. X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) equipped with X-Ray Energy Diffraction Spectroscopy (EDX) were used to identify the important chemical compounds and to study the surface morphology, chemical composition and particle size of the sludge samples. An increase in the removal of Cu and Zn was observed by increasing the precipitant dose (10-400 mg/L) for each reagent used. Removal efficiency of 90% were obtained for both heavy metal ions. The chemical precipitation efficiency was affected by pH. At high final pH levels (8<pH<10), Cu had higher removal efficiency than Zn by all precipitating agents. In the sludge produced, Zn and Cu were precipitated as amorphous hydroxides including Zn(OH)2 and Cu(OH)2. SEM images showed that the produced sludges have small size and compact structure. EDX analysis determined that in all sludge samples, the content of Cu was higher than Zn. Effluent treatment with soda ash resulted in the sludge production with lower volume and larger particle size. As a result, the use of this precipitating agent can be less expensive for sludge drying steps.

The consumption of small fish such as sardines does not have a significant place in the family's food basket, but they are a very rich source of mineral salts, protein, and fat, which until now are the most consumed in the world for the production of fish meal and fish oil as feed for aquatic animals, poultry and livestock. But by processing them, especially the extraction of oil, fatty acids, and remaining fish proteins, they can be used in the production of anti-inflammatory and pain-relieving drugs, lubricants, cosmetic products, and cosmetic waxes. In the present study, the isolation of unsaturated fatty acids and steroids and the identification of sardine steroids of Sardinella sindensis species and the production of moisturizing cream were performed in order to create value-added products. Sardinella sindensis was caught by coastal blockade method in January 2017 from around Qeshm Island. Bligh and Dyer method was used to extract oil from sardines. Unsaturated fatty acids were measured in extracted fish oil. Finally, the production of moisturizing cream from the extracted oil was investigated. The results showed that the amount of oil extracted from sardine fish using Bligh and Dyer method is 16%. The highest amount of fatty acids is palmitic acid C16:0 (26/905). The results of the moisturizing test of the produced creams on the skin of the volunteers showed that the moisturizing of cream with 3% fish oil is 40.12% and the moisturizing of cream with 5% fish oil is 42.31%, which according to the moisturizing creams Johnson commercial 43.85% and Dr. Jila 44.90%, no significant difference was observed and the produced creams were of good quality (P≥0.05). Industrial extraction of this product, while producing pharmaceutical products, can improve the added value of fishery products and effectively help in reducing environmental pollution.

In this research, the biological adsorption process of lead heavy metal was investigated using brown algae Nizimuddinia zanardini and green algae Ulva rigida. Optimum adsorption conditions by measuring pH, the amount of adsorbent, time, and the concentration of lead ion were investigated. Langmuir, Freundlich, and Temkin isotherms were used to investigate surface adsorption. Adsorption kinetics were investigated according to pseudo-first and second-order kinetic equations. Examining the pH results, it was found that brown algae at pH = 5 and green algae at pH = 6 could reach the maximum adsorption of lead. Examining the time-related results, it was found that the best adsorption time for both algae was 60 min. The results of the adsorbent dosage showed that the two bioadsorbents of brown and green algae have the highest amount of adsorption in the amounts of 0.5 and 0.7 g, respectively, and in the initial concentration of metal ions, the highest efficiency was obtained in the dosage of 2 mg/l. The results of the isotherm model showed that lead adsorption by brown algae corresponds to the Langmuir isotherm and green algae to the Freundlich isotherm. Also, according to the kinetic results, both adsorptions follow second-order kinetics.

Cosmetics are products that are applied to the body or face to improve appearance. The concept of beauty and makeup is as old as mankind and civilization. All kinds of beauty products such as skin care products, hair products, and perfumes may contain toxic chemicals that can be harmful to human health, especially women. Most cosmetic products contain dangerous chemicals such as parabens, coal tar dyes, phthalates, perfumes, and some heavy metals such as lead, nickel, cadmium, and mercury. Bioaccumulation of these harmful chemicals and metals in the body over time has been associated with cancer, reproductive and developmental disorders, contact dermatitis, hair loss, lung damage, allergies, etc. At present, cosmetic industries have increased the use of compounds with preservative functions, surfactants, perfumes, stains, etc. in the formulation of cosmetic products. Such substances enhance the quality, properties, and durability of cosmetics, but on the other hand, many of these substances are toxic to the human body and pose health risks ranging from simple mild allergic reactions to an anaphylactic process or even fatal poisoning. Therefore, the indiscriminate use of cosmetics may present itself as an emerging public health issue.Along with the increase in the use of cosmetic products and exposure to their ingredients for a long time and repeatedly, the side effects caused by these products are increasing in the population around the world. Women and men around the world use numerous of cosmetics and health products to achieve beauty, ignoring the possible health risks. Also, cosmetics are emerging pollutants and their environmental monitoring is in the early stages. However, it is known that they enter the environment through multiple routes, often through water, which poses health risks to marine and freshwater ecosystems and ultimately to humans. Hence, in the science of public health, the term “cosmetovigilance" began to represent a type of health supervision in which the goal is to ensure the safety of cosmetic products for commercial purposes. This monitoring is very important for the control of potentially dangerous substances and therefore can put our minds at ease about the products released on the market.In today's world, the importance of taking care of skin, hair, and beauty has doubled. Of course, beauty has a meaning along with health. Using and buying cosmetics and skin care products has become one of the attractive daily activities of most women, but perhaps few people pay attention to the fact that cosmetics can affect the health of women of all ages and even the health of the fetus during pregnancy. Among a wide range of different brands and products, it is very important to choose the right cosmetics and to know the type of skin and the type of makeup that looks natural and ensures the health of our skin. Using the right cosmetics has benefits such as reducing acne symptoms; skin care against the sun's ultraviolet rays; reducing sweating and bad body odor; increasing the beauty of the appearance; reducing bad breath; Reduction of skin bacteria etc. On the other hand, using inappropriate cosmetics can cause disadvantages such as skin diseases and allergies; damage to eyes, skin, and hair; nail weakness; Cancer and other chronic diseases; premature aging; Headache; risk to genital organs; Addiction to cosmetics and etc.The indiscriminate use of cosmetics and health products around the world has led to an increase in the types of chemicals used in the manufacture of these products. Therefore, the risk of poisoning, allergic processes, long-term exposure to chemicals, and side effects from excessive use of cosmetic products also increases. Therefore, considering the importance of chemicals in cosmetics and their health effects on human health, this study was conducted with the aim of investigating the health effects of cosmetics and health products on human health.

The current research is a descriptive-review study whose data was obtained through library studies and different sources were used to process the materials. Considering the importance of chemical substances in cosmetics and their frequent use and their health effects on human health, we tried to use the most relevant and up-to-date sources containing valuable tips regarding the products as much as possible cosmetics and their effects on human health. In this review study, the classification of cosmetics and their effects have been discussed first. Then the harmful substances in the cosmetics were investigated and then the ingredients prohibited in the composition of the cosmetics were pointed out and then the topics related to the health and environmental hazards of some chemicals in the cosmetics were studied. Finally, necessary solutions and recommendations were presented in order to reduce the adverse effects of cosmetics on human health.

Cosmetics and beauty products, although not essential for physical health, help a lot in providing mental health and self-confidence. They are widely used in all countries of the world, especially among women of all ages, even with awareness of their harmful effects on human health. In addition, cosmetics and beauty products are used even by children and elderly people who are more exposed to toxicity due to the easier absorption of chemicals and toxic substances through their skin. Cosmetic products are not very good for human health because they contain more than 10,000 substances that can be linked to disease. Due to the continuous use of cosmetics, people are exposed to side effects such as skin rashes, contact dermatitis, allergies, skin redness, high blood pressure, diabetes, kidney failure and cancer, type IV hypersensitivity, etc., which are toxic substances. Used in the preparation of related cosmetics.The contents of chemicals and heavy metals in cosmetic products may harm consumers. Various studies as well as this research showed that cosmetic products may contain or absorb heavy metals, which can be a potential global threat to people's health and hygiene. It has also been proven that the long-term effect of using cosmetic products has the capacity to affect the health of the consumer. Therefore, long-term continuous use of cosmetic products should be avoided because the heavy metals in these products, such as mercury, lead, arsenic and cadmium, are easily absorbed through the skin. Products containing heavy metals can lead to the development of diseases. A large number of chemicals are incorporated into the complex formulation of cosmetic products to improve the beauty, health, and quality of human life. However, based on a review of the literature related to cosmetics and this study, many of these substances, especially heavy metals, are bioactive and environmentally persistent and show potential bioaccumulation, meaning any traces of exposure accumulate. Heavy metals are stored in bones and remain in our bodies for decades. There is no completely safe and effective way to detoxify heavy metals. Therefore, excessive, extensive, and long-term exposure to such compounds can be a serious threat to human health and the environment.Also, the chemicals used in cosmetic products have a direct effect on the hormonal systems of the human body. People should be warned about the presence of toxic substances in cosmetic products. The implementation of a global cosmetic care system is crucial to encourage changes and reforms in the production, marketing and use of cosmetic products by the general population. Such a system increases the safety of these products and their ingredients and prevents the adverse effects of these products. Also, more comprehensive studies should be conducted on the acute or chronic toxicity of these worrisome pollutants to enable more careful monitoring and explicit inspection of their tangible health and environmental risks. It is very important to conduct studies to investigate the adverse effects of cosmetics. It is recommended that researchers around the world, especially from developing and underdeveloped countries, conduct more recent studies, especially on the adverse effects of cosmetics. Finally, information about the environmental and health impacts of cosmetic products on their packaging will reassure consumers and encourage more conscious and responsible use of these products, and consumers should also play their role by keeping their knowledge and awareness of the ingredients up to date to perform in the products it uses.

In different regions of the Persian Gulf, oil pollution along with other urban, agricultural and industrial pollution has destroyed this valuable ecosystem and the valuable aquatic resources in it have been exposed to the risk of various corruptions and have threatened the aquatic populations in it. (Pourrang, 2005). The Caspian Sea is one of the unique lakes in the world due to its biological resources (plants and animals) and supply of protein materials, sturgeon fishing, and caviar production (Bazrafshan, 1374). In recent years, the increasing development of human activities in the countries bordering the Caspian Sea has changed the ecology of this sea. The Caspian Sea has oil and gas refineries and oil reserves in oil fields and exploration and drilling activities by five common countries, especially Azerbaijan and Kazakhstan. And the discharge of sewage and industrial effluents has caused the pollution of the sea (Varedi, 2015). Some microorganisms are present in the contaminated site, but for more effective remediation, the growth of the microorganism must be stimulated. Biostimulation is the process of adding nutrients, electron acceptors, and oxygen to stimulate bacteria in bioremediation. This is the process of optimizing the environmental conditions of the place of correction. Additives are usually added to subsurface layers through injection wells. Subsurface characteristics such as groundwater velocity, subsurface hydraulic conductivity, and subsurface lithology are essential for the development of a biological stimulation system. The natural microorganisms in the soil are responsible for the decomposition of pollutants. But biostimulation can be improved with biological additives. The quality of life on earth depends on the quality of the environment. Large amounts of organic and inorganic substances are released into the environment every year as a result of human activities. Contaminated lands are generally the result of industrial activities, the use, and disposal of hazardous substances, and such. It is now widely recognized that contaminated land is a potential threat to human health, and its continued discovery over the past 13 years has led to international efforts to remediate many sites, or as a response to health hazards.or environmental effects caused by pollution or to activate this place for use, to be developed again. Bioremediation is a general concept that includes all those processes and actions that take place to transform an environment, which is currently changedby pollutants to its original state (Adhikari, 2004; Gunasekaran, 2003). Also, bioremediation means the process of cleaning hazardous waste with microorganisms or plants, and it is the safest method of cleaning soil pollution.So far, there have been several studies on biological indicators (various plant and animal species as biological monitors) of heavy metals in both aquatic and terrestrial environments, which we can mention here. The use of biological information and biological control programs for water pollution for the management of ecosystems started at the beginning of the 1920s in the United States and then in a more serious way since 1948 all over the world. Today, many researchers from international organizations, including the EPA and the World Health Organization (WHO), introduced these indicators as the most appropriate indicators for environmental assessment and ecosystem management (Freund, 2007). Hilsenhoff's research, which started in 1979 with periodic sampling of the end of aquatic habitats and measurement of physical and chemical parameters, and finally using the biological coefficient formula; is considered a turning point in the biological evaluations of the environment (Hilsenhoff, 1988).Also, by examining the management of drilling waste, which is one of the new biological methods being developed in Iran, we will deal with it. The wastes of drilling operations are mainly the result of the washing and cooling activities of drilling machines. These wastes are generally divided into two groups in terms of physical phase: solids and liquids. In the new method invented in this collection, these wastes are managed separately. Solids are recycled by biological methods (composting) and liquids are recycled by three chemical methods, biological absorbents, and evaporation-condensation, depending on their initial quality. This new method first recycles water with the help of flow management and mixing, and then with different chemical, physical, and sometimes biological methods.The results of various surveys show that by measuring different pollutants in the plants of the same region, it is possible to understand the state of pollution of various compounds, including heavy metals (Lehndorff, 2009). In 2010, Bonanno and Gaddis in South Phragmites examined reed aquatic plants in terms of the accumulation of heavy metals cadmium, chromium, copper, mercury, manganese, nickel, lead, and zinc in the root, rhizome, stem and leaf tissues and concluded They found that the mentioned plant can be a monitor to control water pollution (Bonanno, 2010). Wild oysters can also be used to monitor pollution. In 2011, Victoria et al. investigated the concentration of heavy metals in the soft tissue of a species of wild oysters from the Spanish North Atlantic coast and stated that wild oysters are a benchmark for international evaluation. Besada, 2011). Also, in 2015, Phillips et al. tested the concentration of four heavy metals cadmium, copper, lead, and zinc in the tissue of three aquatic plants, and based on the results of the research they have conducted, these species are suitable for use as indicators of the presence and level of pollutants. Heavy metals are introduced into estuary water places (Phillips, 2015). In Iran, many types of research have been conducted so far, by examining their results, the potential of different species in the direction of bioremediation can be achieved, and we are now mentioning some of them. In 2013, during research, Azami et al. investigated the amount of total mercury in different tissues of three of the most important waterfowl species in the north of the country, including the great cormorant, the mallard, and the green duck, and compared the results with the international standard of the American Environmental Protection Organization. Global health and domestic standards are compared and finally, while warning consumers of waterfowl, especially vulnerable people, the results of their research are an achievement for managers to control and monitor metal pollution in Gamishan and Anzali wetlands, which are one of the most important habitats. The wintering birds are listed (Aazami, 2012).

Although bioremediation is not the answer to all pollution, it provides a method of removing pollution by enhancing biological processes and natural biological decomposition. Also, its application in each place must be determined and depends on the local mineralogy, hydrology, geology, and chemistry of that place. Therefore, with the development and understanding of microbial communities and their response to the natural environment and pollutants, expanding the knowledge of microbial genetics to increase the ability to reduce pollutants, and conducting proper tests of new bioremediation techniques that are cost-effective, this technology is an efficient and cost-effective way to purify water, contaminated land, and soil. Therefore, this method is being developed and improved to be able to cover more areas of pollution.

Landfill leachate is a complex refractory wastewater which consists of extensive level of organic compounds, ammonia, and heavy metals. Contamination of water by landfill leachate has become a serious environmental concern worldwide due to its adverse impact on human health, aquatic organisms, and agricultural crop production. Basically, the pollutants found in landfill leachate include heavy metals, extraneous organic compounds (XOCs), organic compounds, and inorganic compounds. on the other hand, Advanced physico-chemical and biological leachate treatment technologies require continuous budget and energy supply and sufficient technical capabilities for the operation and maintenance of the equipments. Therefore, high-tech solutions are not sustainable for many landfill sites, particularly in developing countries. In recent years, constructed wetland (CW) has received promising attention in the treatment of landfill leachate, because of its costeffective and eco-friendly nature and simplicity in operation, in addition to higher treatment efficiency. Besides their small ecological footprint, CW systems possess similar aesthetic value as natural wetland systems. Constructed wetland systems consist of different media types, and typically, same species of emergent plants. The inherent features of wetland plant species such as extremely high transpiration rates, frost resistance, disease resistance, and tolerance to high heavy metal(loid) concentrations make them successful for remediation purposes. Additional characteristics including ease of rooting, fast establishment, quick growth, extensive rates of photosynthesis, and elevated usage of water make them successful in CW systems. Further, the clear advantage of using vegetation species in a CW is provision of supporting media for biological activities. Moreover, ecological advantages including carbon sequestration, erosion control, pollution prevention, and enhancing landscape appearance are some of the prevailing benefits of wetland plant species. Constructed wetland system is mainly classified into free water surface system (FWS) and subsurface flow system (SSF). In FWS, oxygen is prevalently introduced into the wetland via algal photosynthesis and atmospheric diffusion. In SSF, leachate flows underneath and through the plant rooting media, and subsequently leachate level is maintained below the tip of the substratum. In terms of fewer issues arising from odors, disease-related vectors, and public exposure, SSF is highly recommended for landfill leachate treatment. SSF is of two types, horizontal and vertical. In the horizontal flow systems (HSSF), the leachate is fed into the inlet and continues its way under the surface of the bed in a more or less horizontal path until it reaches the outlet zone. Conversely, in the vertical flow systems (VSSF), landfill leachate is fed on the whole surface area through distribution system and passes the filter in a more or less vertical path. In VSSF, greater oxygen transport is involved compared to the HSSF. As a result, VSSF is more efficient for removing ammoniacal nitrogen (NH3-N) and organic matter from landfill leachate. The efficiency of landfill leachate remediation achieved by CW depends upon different factors including the type of media used (sand, gravel, clay, or silt), availability of microorganisms, and selectivity of plants (monoculture or mixed beds). The purpose of this study is to investigate the use and efficiency of different types of constructed wetlands for the treatment of landfill leachate, the selection of suitable plant species, the mechanism of pollutant removal, and finally a summary of the performance of the constructed wetland system in the treatment of various leachate pollutants in laboratory and field studies.

To carry out this study, keywords such as " Constructed wetlands", "landfill leachate pollutant " and "Landfill leachate treatment" were searched in the Web of Science, Google Scholar, ScienceDirect and SID databases. For these keywords, 164 articles were found from 1987 to 2023. After the screening, quality review and removal of repetitive and unrelated articles, 107 relevant articles were used. The main criterion for the selection of articles was the effectiveness of various types of constructed wetlands for the treatment of landfill leachate, the selection of appropriate plant species, and the mechanism and efficiency of pollutant removal. The quality of the articles was evaluated through the SJR index, the citation, the Impact Factor and the SNIP index.

A review of the researches shows that Constructed wetlands for landfill leachate, on average, showed a removal efficiency of 60–80% for BOD5, with FWS and VSSF showing the highest removal. A closer look at the BOD5 range showed that FWS had been used only for very low inlet concentrations. For studies with higher BOD5, mostly hybrid CW have been used. COD removal efficiency, on the other hand, covered a wider range between 20 and 60%. While hybrid and VSSF CW showed similar COD removal, it should be noted that HSSF have been used for leachates with COD values in higher range compared to VSSF and hybrid CW. BOD5/COD ratio, while reduced in the effluent compared to influent, was almost predominantly similar in different types of CW. This can also be due to the lack of reported data in the literature, as many of the studies only report BOD5 or COD as an indicator of organic matter; therefore, the BOD5/COD ratio were not always available. CWs showed 60–75% removal efficiency in removing Ammonia-N, with hybrid CW being the most successful. It should be noted that hybrid CW have been used for leachates with the greater NH3 concentration as well. As expected, the greatest extent of nitrification was observed in VSSF and hybrid CW, while VSSF CW were most successful in removing TN. In terms of TSS and TP, while overall removal ranges of 50–65% and 55–80% for TSS and TP, respectively, are observed for all CW, HSSF and hybrid CWs proved to be the most successful in removing TSS and TP. The number of studies reporting heavy metal removal using CW was found to be small, making it harder to draw firm conclusions. VSSF CW appear to have been the most successful CW type in removing different types of heavy metals. Heavy metals removals have been reported in the range of 15–95%, with Phragmites sp. plants proving to be the most successful species in removing metals.

In the last couple of decades, an on-site treatment of landfill leachate with the help of CW is widely practiced in numerous nations in the world. It is obvious that CW could be the ideal technology for landfill remediation due to its cost-effective and eco-friendly nature. Additionally, establishing vegetation in landfill sites will facilitate erosion and hydraulic control by reducing infiltration of rainfall. It appears that the degree of success in terms of contaminant removal efficiency by CW systems varies depending upon the plant species selected, availability of microbial community, climatic conditions, physico-chemical properties of soil, and CW configuration. Also, treating landfill leachate using CW demands careful attention and design specifications must to be investigated case by case. To enhance the performance of biodegradable organic compound removal from landfill leachate, pre-CW strategies such as using aeration and sedimentation are needed, but their quantifiable removal performance enhancement and economic assessment should be investigated further. Constructed wetland can also be modified by biochar/zeolite/adsorbent addition, and combined with other methods, such as double-chamber anaerobic reactor and microbial fuel cell-coupled constructed wetland in order to increase the removal efficiency of pollutants.

The development of technology in drilling oil and gas wells has created serious problems for the environment. Drilling fluids have some unwanted compounds such as heavy metals, hydrocarbons, and salt. The increase in the volume of these activities has caused the increasing spread of waste in the lands adjacent to the drilling rigs. The discharge of these compounds in the soil causes damage to the environment. Due to the importance of drilling waste management to reduce the environmental pollution caused by them, native plants of the region were selected and compared to the examination of salinity and heavy metal pollution levels, equivalent to the concentrations of drilling mud, which were prepared and implemented in the laboratory. To evaluate germination indicators under salinity stress and heavy metals (Cr.Cd.Pb), an experiment was conducted in the form of a completely randomized design in the year 2020 in the laboratory of the Faculty of Agriculture of IslamicAzad University of Isfahan (Khorasgan).The treatments included the concentration of metals. heavy and salinity at the level of 0,5,10,15%, four plants (Triticum wheat, Hordeum vulgare barley, Avena sativa oats, and Chenopodium quinoa) were selected with three replications. Comparison of the average fresh and dry weight of seedlings, seed germination index, and germination speed of wheat, barley, quinoa, and oat species showed that with the increase of salinity and metal stress treatments and their combination treatment, these traits decreased significantly. According to the research results, the quinoa plant species had the highest fresh and dry weight of seedlings among plant species.The allometric coefficient in the oat plant species was lower than the three wheat, barley, and quinoa plant species. 10% salinity treatment followed by 5% salinity showed the highest allometric coefficient in the quinoa plant with 1.93 and 1.86, respectively, which increased by 8% and 4%, respectively, compared to the control treatment. The oat plant had the highest seed germination index under 10 and 15% salinity conditions. The highest germination rate was related to the wheat plant, followed by the oat plant, and the barley plant had the lowest germination rate in all experimental treatments. In the conditions of salinity and metals and their combined treatments (salinity+metals), the quinoa plant had a higher germination percentage than the other three plant species. It can be concluded that wheat and quinoa plants are more suitable for the bio assay of heavy metals and salinity than the other two plants.

In this paper, the preparation of nano zeolite was carried out at different grinding times using a dry planetary ball mill. Sodium Hexa Meta Phosphate (SHMP) was introduced as the dispersant in the milling of natural zeolite adsorbent. In the next step, to remove and adsorb heavy metal ions such as nickel, copper, and cadmium, the application of nano zeolite was studied in batch mode.

In this paper, zeolite nanoparticles were produced using planetary and ball mills. Adsorption experiments were conducted to investigate the adsorption of nickel, copper, and cadmium using new nano zeolite adsorbent. 

The effect of Sodium Hexa Meta Phosphate (SHMP) on grinding and adsorption of ion metals by nano zeolite was investigated and results showed that the application of SHMP led to lower energy consumption in grinding and had a positive effect on nickel and cadmium removal from aqueous solution by nano zeolite particles.

The effect of sodium hexametaphosphate on the absorption of nickel, cadmium, and copper metals showed that this reagent had a positive effect on the absorption of nickel and cadmium ions on nanozeolite particles, but it did not affect the absorption of copper ions. Nano-zeolites have a larger external surface area and a shorter diffusion path length due to having nano-sized particles, so their absorption capacity is very high.

The phenomenon of dust is one of the biggest serious environmental problems in arid and semi-arid regions. More than two thirds of Iran is located in this climate. This phenomenon can damage infrastructure and agricultural products and cause a lot of economic damage. Therefore, since the study area is in the western part of Iran and is highly exposed to dust. On the other hand, so far no comprehensive study has been conducted in this field in the region, so this research is a necessity. Scientific and practical objectives of the research include: Investigating the diversity of soils in the region and their relationship with landforms in the region, Investigating the temporal distribution of dust characteristics in the region, Investigating the soil characteristics of the study area and Hur al-Azim wetland in Khuzestan This is a phenomenon.

For this study, Kuhdasht basin with an area of 456 square kilometers located in western Iran and southwestern Lorestan province was considered. 12 glass traps with dimensions of one square meter were installed in the area to trap dust at a height of about 2.5 meters above the ground. And seasonal dust samples were prepared during 2015. Sampling was performed for origin from the surface soil of the region and Hur al-Azim wetland. To determine the concentration of heavy metals, the chemical digestion step was performed by the ETHOS 1 microwave device made in Italy. Then, to determine the concentration of elements, atomic absorption apparatus (Perkin Elmer Analyst, 3030) with detection limit of ppm and ppb and flame technique was used and for cadmium metal concentration through graphite furnace technique. Meanwhile, the region's flower was drawn by WRPLOT software, 7.0.0.

The highest rate of dust subsidence is in spring and the lowest in autumn. The average annual subsidence rate of the region is 11.51 tons per square kilometer per year. The textile class of silt sludge dust particles and the particle transfer index from areas with medium to high distances. The average concentration of heavy metals in dust is higher than the soil of the region. In general, the results showed that cadmium and zinc elements have very high pollution factor, nickel and lead have significant pollution and manganese and copper elements have low pollution. The elements cadmium, zinc and nickel, which have an enrichment factor of more than 10, are of human origin, but the element lead is of natural and human origin together, and the elements manganese and copper are of natural origin in the region. The similarity of minerals and the presence of evaporative minerals in fine dust reinforces the hypothesis that it is part of the origin of wetland and offshore particles. However, the study of chemical properties indicates the role of local resources in the generation of dust.

The main flow of dust in all seasons in the study area is from cross-border areas. The amount of dust is highest in spring and lowest in other seasons, which is lowest in autumn. The particle size distribution class is silty loam, which indicated the presence of resources at medium to relatively close distances to the area. The rate of subsidence in the region indicates the type of regional dust. The concentration of heavy metals in dust is high in winter and the element zinc has the highest amount. The level of pollution index of all elements indicates the spread of pollution in the region. Clay mineralogy showed that the presence of evaporative minerals strengthens the hypothesis of wetland origin and transboundary. In general, this study showed that the deserts of the mentioned neighboring countries and dust sources of Khuzestan province (located in the south of the region) are the main sources of dust in the region.

Ways to produced urban wastes is concern in most urban areas of Iran. Increasing population density, industrialization and the amount of waste produced are of great importance. The introduction of heavy metals through urban wastewater into natural ecosystems, especially soils, is one of the most important environmental concerns. The purpose of this study is to investigate the concentration of some heavy metals (lead, chromium, zinc, nickel) in the soil of landfill site of Sarayan.

For this purpose, 20 soil samples were collected from urban landfills and analyzed in a laboratory using Contraa 700 atomic absorption spectrophotometer and then analyzed by statistical techniques and Excel and IBM SPSS statistical software version 25.

To determine the contamination of the studied area, contamination factors (CF) and land accumulation (Igeo) were used and the results showed that the highest amount of contamination was related to surface-level chromium and the lowest was related to surface water and the amount of earthquake index Igeo) was found for chromium metal between 1 and 3.

According to the study, the chromium metal in the slightly infected and highly infected classes and other samples collected in non-infected classes of metals were slightly contaminated.

The aim of this study was to investigate the emission of heavy metals (cadmium and lead) in the soil around Taybad landfill. For this purpose, 15 stations at a distance of 100 meters from each other to the landfill of Taybad city were selected for sampling. Sampling 5 samples and repeating 3 times from each station, the samples were transferred to the laboratory for analysis to check the level of pollution indicators. Hypotheses were analyzed using one-sample t-test and Pearson's correlation coefficient with spss 24 software. It was found that the average total concentration of lead is equal to 52.04 and the average total concentration of cadmium is equal to 1.748. The concentration of the mentioned metals is significantly higher than the average global soil and earth's crust with 95% confidence. In the case of lead and cadmium, the highest contamination was in station 10 and 4, and the lowest contamination was in station 6 and 12, respectively. It is concluded that the amount of soil contamination does not change significantly with increasing distance, because the volume and concentration of contaminant runoff from the landfill (contaminant) along the path is constant. Therefore, it is better to provide environmental training for municipal municipal personnel and citizens of the region and to invest in the restoration of the environment and its further protection.

Among the most important environmental pollutants are heavy metals that enter the environment from industrial activities such as mining, fuel and energy production, the use of herbicides, cleaners, and urban waste production. The most important and valuable natural habitat in the study area is Arasbaran Biosphere Reserve. The purpose of this research is to determine the concentration of heavy elements in Soungoun copper mine, which have the potential of environmental pollution.

The collected samples after preparation were analyzed by ICP-MS method. Then the geochemical data were statistically analyzed by software such as SPSS. Many univariate and multivariate calculations including: linear correlation, cluster analysis and factor analysis were performed on the database.

Investigations show that the rocks of this area are enriched with elements Te, Mo, Cu, S, As, Sb, Bi, W, Ag, Tl, U, Sn and Pb. Among them, the enrichment of Te, Mo, Cu and S is very impressive. Three groups can be distinguished in the cluster analysis diagram: 1- Sc, Ti, V, Cr, Ni, Be, U, Tl, Co and Fe. 2- Bi, W, Ag, Sn, Cu and As. 3- Sb, Zn, Mn, Pb, Mo and Te. The highest correlation values are observed between Sc-Ti-V, Cr-Ni, Be-U, Co-Fe, Ag-Sn and Sb-Zn elements. The extracted grade of copper and molybdenum in Soungoun complex is 0.61% and 0.01%, respectively, while their average in the studied rocks is 0.73% and 0.0113%, respectively, which are close to each other.

The formation of sulphide minerals is a factor for the high amount of chalcophile elements in the intrusive mass rocks of Soungoun copper mine. Due to the fact that mining activities may cause the release of heavy and toxic elements into geochemical cycles, design is very important in the matter of extracting minerals and should be done with sensitivity and correct and accurate environmental assessment. Therefore, if the mining site is not restored, it will turn into polluted land and this pollution will cause many changes in the physicochemical properties and pH of the soil. Correct, efficient and dynamic management of the environment must be continuously applied to mining activities so that these activities do not deviate from the path of sustainable and healthy development.

The most common marine environmental pollutants are metal pollutants, petroleum hydrocarbons, and aromatic hydrocarbons. In the present research, metallic and organic pollutants of Nayband Gulf were investigated. Sampling was done from 20 stations in the winter of 2018. From each station, two sediment samples for organic matter and heavy metals (with 3 replications) were collected and a total of 120 sediment samples were collected using Van Veen Grab. To measure metals and petroleum hydrocarbons, ICP(Agilent7500cx) and GC (Agilent 6890n) devices were used, respectively. Data were analyzed using SPSS 22 software. The mean concentrations (mg/kg) of iron (7980), nickel (19.71), vanadium (14.90), and cobalt (5.71) were measured. Although it did not exceed domestic and international standards, nearby stations Asaluyeh region showed a significant difference (P<0.05) with other stations. The total amount of petroleum hydrocarbons (TPH) with an average of 14.33 mg/kg and the maximum concentration of 42.16 were recorded at a station (19) near Asaluyeh wharf and the amount of polycyclic aromatic compounds (PAH) with an average of 223.09 µg/kg and maximum concentration of 657.68 were recorded at a station (20). Based on the data, Nayband gulf has low levels of pollution (TPH> 15) in terms of TPH compounds and moderate levels of pollution (PAH> 100) in terms of PAH compounds. The difference between stations near Asaluyeh and other stations in terms of pollution shows that the gradual increase of pollution caused by industries and its impact on the functioning of Nayband gulf ecosystem should be considered as a serious issue.

The increase in the consumption of heavy metals in the Persian Gulf is the result of oil release, coastal investments such as refineries and large industrial factories, in fishing and commercial, household industries, as well as agricultural runoff, which is the result of pesticides and pesticides. It is one of the dangers that have made the ecosystem with this threat. Considering the proof of the nutritional value of marine products in the past decades and the need to consume food sources and fatty acids needed by the body, it is necessary to study the increase in the amount of risks caused by the consumption of aquatic products. Considering the importance of treatments related to heavy metals in edible aquatics due to the possibility of the accumulation of these metals, 30 oily sardine fish samples and 30 food samples from the beaches of Bushehr were analyzed. Oily sardines and edible oysters are both for human consumption, and according to the reports of the past few years about the presence of pollutants, including heavy elements, in the waters of the Persian Gulf, it is necessary that these species are healthy for human consumption. Thoroughly tested. The main purpose of this research is to measure the accumulation of lead, cadmium and nickel in the muscles of oily sardines and oysters in the Persian Gulf and its consumption. The composition of lead, cadmium and nickel metals in oily sardine fish muscle was calculated as 0.4327, 0.0192 and 0.0006 respectively and in edible oyster mollusk as 0.7414, 0.0550 and 0.0025 micrograms per weight respectively. A comparative comparison with the standards specified by global organizations such as WHO, FDA and UKMAFF shows that all the following were within the standard. The HQ index was less than 1 for both species, which indicates that the consumption of oily sardines and edible oysters does not pose a serious risk to the health of consumers in terms of lead, cadmium and nickel levels.

The process of extraction and exploitation of oil and gas resources requires the cycle of production, sending, and recycling of drilling mud or drilling fluid, so achieving the right combination of drilling mud and its recycling is an essential and fundamental matter in the industrial oil and gas and also the environment.

Determining the level of contamination of heavy metals and organic matter in the drilling mud and drilling cuttings can be necessary so that intelligent methods to estimate these contaminants can be indirectly effective. This study tried to estimate the contamination rate of drilling cuttings, despite the formation parameters of 10 oil wells drilled at different depths (66 data sets), using the regression learning limit of an artificial neural network.

A total of 60 data sets were prepared to estimate the rate of change in the concentration of heavy metals, polycyclic aromatic hydrocarbons in the learning and testing process, and another six sets of data related to a well that was randomly selected and used in the artificial neural network validation process. Limit learning regression algorithm for ten heavy elements and ten aromatic compounds contaminating cutting and drilling mud on two different data sets in a drilling area in one of the oil fields in southern Iran was evaluated.

The results are suitable for estimating the contamination of drilling cuttings and subsequent environmental protection processes. Such processes of contamination and recycling of drilling mud will play an efficient role.

 Landfill leachate is a highly toxic and hazardous form of wastewater due to its complex composition characteristics. Effective removal of heavy metals from landfill leachate is of great concern due to the fact that toxic metals can seriously threaten the food chain, and therefore the human health. The main objective of this work was to study the utilizing of low-cost pruning residues in the production of biochar and its application in removal of lead (Pb) from landfill leachate.

 Leachate produced in Babol municipal solid waste landfill was used as an adsorbent solution. Pruning residues were collected and used for biochar preparation. Biochar produced under the pyrolytic temperature of 700°C with a 1-hour retention time. The adsorption mechanism of pruning waste biochar to Pb was analyzed through BET surface area and scanning electron microscope (SEM) tests. Batch experiments were performed to study the effects of adsorption parameters on Pb removal. The influence of contact time (30-300 min), adsorbent dosage (1-50 g/L), as well as particle size (1-2 mm and 63-75 µm) was investigated. Moreover, the kinetic and isotherm models were applied to the experimental data to predict the adsorption parameters.

 The results obtained from the analysis of the untreated Babol landfill leachate was revealed that the Pb concentration was about 4.94 mg L-1. The surface area of the produced biochar was determined to be 292.44 m2 g-1. SEM microstructure of the biochar showed the developed surface area with visible pores. All of these data seem to suggest a great potential for pruning residues biochar to Pb removal. The adsorption of Pb was mainly affected by contact time, adsorbent dose, and biochar particle size. Higher contact time and adsorbent dosage showed higher uptake of Pb. Whereas, the uptake of Pb ions onto pruning residues biochar was substantially reduced with increase the biochar particle size. Maximum Pb percentage removal was observed at a contact time of 90 min and with an optimum biochar dosage of 20 g L-1 (89.06% removal) for biochar with 1-2 mm particle size. While, biochar with particle size of 64-75 µm can removed Pb to almost 100% at a contact time of 120 min and with an optimum biochar dosage of 20 g L-1. The kinetic study showed that adsorption can be well described by the pseudo-second order kinetic model. This supports the chemisorption theory behind the pseudo-second order kinetic model for the adsorption system. The results of isotherm models implied that the behaviors of the isotherms are more appropriate for the Langmuir model, showing a monolayer adsorption capacity for Pb.

 Findings of this research demonstrated the applicabil ity of pruning residues biochar as an economic adsorbent for the removal of the Pb from landfill leachate. On the other hand, the crop residue burning poses a threat to the environment and human health due to the emission of toxic gasses and particulate matter. So, conversion of pruning residues to biochar and its application to heavy metal removal is a useful and environment-friendly alternative to crop residue and biomass burning.

Introduction:

 Due to the potential toxicity and ecological risk of heavy metals in aquatic ecosystems, measuring and evaluating their concentration in different parts of aquatic environments is very necessary. Therefore, the present study measures the concentrations of Cd, Cr, Pb, Ni, As and Zn and evaluates the spatial distribution of their ecological risk in the surface sediments of Anzali International Wetland.

50 stations in different parts of the wetland were selected for sampling. After preparation and acid digestion of samples, the concentrations of these metals were determined by an atomic absorption spectrometer. In order to zoning the toxicity and ecological risk of metals, the inverse distance weighting (IDW) method was used.

The total mean concentrations of metals were Zn (79.24 71 6.71), Cr (19.4 21 21.04), Ni (18.96 62 5.62), Pb (13.3 72 72.50), As (7.62 96 4.96) and Cd (1.12 ± 3.16) mg/kg, respectively. Investigation of potential acute toxicity, RI, mHQ and PLI indicated low pollution status in wetland sediments. The environmental risk of the metals in the sediments were evaluated as (Cd> As> Pb> Ni> Zn> Cr). In addition, the distribution of toxicity and ecological risk of metals in different parts of the wetland does not follow the same pattern and the western parts of the wetland have more risks.

According to the results, Potential acute toxicity, PLI, mHQ and ecological risk of heavy metals in the sediments of the region are assessed as low and medium. The intense expansion of human activities in the areas around the wetland, along with the deposition and entry of various pollutants in this ecosystem, confirms the need for continuous monitoring of the wetland and assessment of its ecological health risk.

Contamination of aquatic ecosystems with heavy metals is a threat to the health and life of aquatic animals and, as a result, human health. This research was conducted to investigate the concentration of heavy metals (copper, nickel, lead, cadmium and iron) in Anzali Wetland. In order to measure the amount of heavy metals in Anzali Wetland, sampling was done from four stations during four seasons (2019-2020). The concentration of heavy metals was determined using a plasma atomic spectrometer. The results showed that the average annual concentrations of Cu, Ni, Pb, Cd and Fe in water were 66/16±36/17, 16/60±12/25, 45/46±21/63, 15/51±7/24 and 75/43±26/80 μg/L, respectively. The decreasing trend of metal concentration in water was obtained as Fe>Cu>Pb>Ni>Cd. The concentration of these metals was higher in winter and autumn compared to other seasons. The concentration of all the investigated metals was lower than the national standard of Iran. Compared to WHO and USEPA standards, the amount of Cu, Ni and Fe metals was lower and the amount of Pb and Cd metals was higher than these standards. Based on the results of this survey, the amount of heavy metals in the surveyed areas is very low, which indicates the absence of serious pollution in the area.

Environmental pollution has become one of the main problems of today's societies in a way that in addition to natural ecosystems, it also endangers human health. Therefore, in this study, the contamination of heavy metals and organophosphate toxins accumulated in two different types of rice consumed by humans was measured. The risk of carcinogenicity and non-carcinogenicity associated with these toxins for children and adults in rice fields in northern Iran was also assessed. For this purpose, 17 stations were selected for sampling rice consumption from farms in Mazandaran province in the first and second cultivation groups. After sampling, rice samples were wrapped in foil to measure toxins and placed in plastic packs to measure heavy metals. Heavy metals were measured using ICP-MS and toxins were measured using GC-MS and mercury was measured using mercury autoanalyzer. Carcinogenic and non-carcinogenic risk indices for both groups of children and adults in the first and second culture groups were evaluated and calculated. The results showed that nickel and lead showed the highest values in the collected samples at station 14 at 0.38 and at station 6 at 0.17 mg/kg, respectively. In addition, the toxic and carcinogenic metals arsenic, cadmium and mercury in stations 6, 5 and 6 showed values of 0.094, 0.017 and 0.001 mg/kg, respectively. Station 1 and Station 2 have the highest and lowest values of diazinon in the range of 0.038 and 0.004, respectively, and chloroprifus have the highest and lowest values in stations 8 and 14, respectively, in the range of 0.019 and 0.001 mg/kg. The non-carcinogenic risk of the first and second cultures was highest for children and adults for safe toxins and for nickel metal. THQ levels also showed a high risk for consumers. The risk of carcinogenicity for the target groups was highest in different concentrations of chromium and in the second group for children the group had high risk levels. The results of this study showed that rice produced in farms in northern Iran contains different amounts of toxins and heavy metals that have carcinogenic and non-carcinogenic potential for consumers.