Toktam Shahriari; Abdolreza karbassi; Maryam Shirazinejad
Abstract
Introduction: Industrial plating wastewater contains various types of detrimental heavy metals in high concentrations. One of this toxic metal is Nickel that its discharge into the surface waters and soil is considered as an environmental problem. Hence removing of this metal from wastewaters is crucial ...
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Introduction: Industrial plating wastewater contains various types of detrimental heavy metals in high concentrations. One of this toxic metal is Nickel that its discharge into the surface waters and soil is considered as an environmental problem. Hence removing of this metal from wastewaters is crucial and vital for protecting the environment and human health. Applying of nanotechnology in elimination of environmental contaminants is one of the methods which attracted a great deal of attention in recent years. In present research, nanographite was utilized as efficient adsorbent in order to remove Ni ions. Materials and methods: In order to investigate the adsorption process, nanographite with a purity of 99.9% and a specific surface area of 18-24 m2/g and a plate morphology was prepared from Pishgaman Iranian Nanomaterials Company and used as an adsorbent. Also, the wastewater used in the experiments was prepared from one of the plating workshops in Tehran, which contained 765 mg/L of nickel and a pH of about 1. The parameters of pH, time and amount of adsorbent were evaluated. In each experiment, one of the parameters was considered variable and the other two parameters were considered constant. The amount of nickel was determined before and after each test.Results and discussion: In this study, the parameters including pH, adsorption time and adsorbent dosage were investigated as effective factors on Ni adsorption process. In order to analyze the adsorption mechanism, the obtained results were examined by the Langmuir and Fruendlich isotherm models. In addition, pseudo-first-order and pseudo-second-order models were studied to investigate adsorption kinetics. According to the results, the Ni uptake by nanographite was enhanced significantly with increasing of the pH value from 5 to 7. Thus the pH of 7 was determined as optimum pH for Ni removal. Investigations also showed that increasing the time up to the first 80 minutes had a relatively good effect on nickel adsorption by the nanoparticle, and after that the adsorption almost reached equilibrium. Finally, it was observed that in a constant time, increasing the amount of adsorbent led to an increase in adsorption, and to achieve the maximum adsorption of nickel, the amount of 2g was chosen for the adsorbent. Based on the obtained results, 97.52% primary nickel was adsorbed by nanographite. Results also revealed that the data were best fitted to the Fruendlich models. After determining the amount of nickel adsorption at different times, the resulting data were analyzed by the kinetic model.Kinetic studies also indicated that the adsorption data were described well by pseudo-second-order model. Conclusion: Examining the results showed that pH plays an important role in the adsorption process and the adsorption rate increases with increasing time until the equilibrium time is reached. One of the effective factors is the amount of adsorbent, which has a direct effect on adsorption. Following the Freundlich isotherm in this research indicates that the adsorption sites in the adsorbent have different energies. Also, the pseudo-second-order model in adsorption kinetics refers to the process of chemical adsorption in addition to physical adsorption.
hamid Sodaeizade; fariba hokmollahi; amir hossein nateghi; Manouchehr Mohammadi
Abstract
Introduction: Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. The presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands ...
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Introduction: Natural and human activities lead to soil degradation and soil salinization. In the last two centuries, world metal pollution level has increased extremely. The presence of some heavy metals in aquatic ecosystems is a constant threat to the health of human societies. The decrease of farmlands threatens food security. There are approximately one billion ha salt-affected soils all over of world, which can be utilizable after chemical, physical and biological remediation. Many mines in the world and also in Iran exist and as a result, soil erosion and dust release from waste dams is a matter of concern. Bioremediation using biological agents to detoxify and degradation of environmental pollutants provides a suitable alternative method for substitution of current heavy metals removal strategies..Material and methods: As a result of extraction operations by cyanidation in Mouteh gold mining complex, wastewater and waste soil sediment are widely achieved. In this study soil samples were collected from Mouteh Goldmine tailing dam soil in September 2018. The collected soil samples were cultured in BG11 medium and incubated for microalgae identification and biomass production. Also, 5 g soil was inoculated with 0.5 g biomass of cyanobacteria and the physicochemical characteristics of the soil including pH, Na, K, Pb, and Cd, before and after the inoculation of soil with cyanobacteria were determined.Results and discussion: In this study, cyanobacteria Phormidium tenue Gomont, Osillatoria tenuis C.Agardh ex Gomont, Lyngbya aestuarii Liebman ex Gomont and the green alga, Scenedesmus obliquus (Turpin) Kützing were identified. Culture results of filamentous cyanobacteria on goldmine tailing dam soil showed that cyanobacteria grew easily and produced a significant surface crust. The results of the physical analysis of the soil samples showed that O. tenuis decreased Na as a salinity element, and P. tenue absorbed high amounts of Pb as a heavy metal pollution element. Mouteh Goldmine soil cyanobacteria, Osillatoria tenuis and Phormidium tenue, could play a role in mine recovery from salinity and heavy metals and in mine tailing dam soil bioremediation. They can also prevent soil erosion and dust release from waste dams. Conclusion: Dust release from waste dams can affect the health of living organisms like mining workers, plants, and even soil microalgae that are close to the mine. Cyanobacteria create biological soil crust and the results of this research showed that cyanobacteria, especially Phormidium tenue species produced a bio-crust that prevent soil erosion.
Nateq Lashkari Sanami; Jamshid Ghorbani; Seyed Mohammad Hodjati; Ghorban Vahabzadeh Kebria; Babak Motesharezadeh
Abstract
Introduction: Mining activities causes substantial damage to the environment worldwide. Abandoned mine wastes from mining activities limit the growth of plants due to unfavorable conditions and the concentration of a wide range of heavy metals. Identifying plant species growing on mine waste and assessing ...
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Introduction: Mining activities causes substantial damage to the environment worldwide. Abandoned mine wastes from mining activities limit the growth of plants due to unfavorable conditions and the concentration of a wide range of heavy metals. Identifying plant species growing on mine waste and assessing their seed germinations are important for vegetation restoration on mining areas. This study aimed at assessing the germination characteristics of Artemisia absinthium, Lepidium draba, and Silybum marianum naturally growing on coal mine wastes in Mazandaran Province under different concentrations of copper (Cu), lead (Pb), and cadmium (Cd).Material and methods: Seeds were collected from plants growing in coal wastes during 2 years. Completely randomized design was conducted with three replicates. Treatments were CuSO4 and Pb(NO3)2 at 0 (control), 50, 100, 200, and 300 mg/L, and Cd(NO3)2 at 0 (control), 5, 10, 20, and 30 mg/L. In each replicate 20 seeds were placed in a Petri dish containing a layer of filter paper. Then treatments were applied and Petri dishes were taken to a germinator under controlled temperature, moisture, and light. Germinated seeds were counted daily and then germination percentage, germination rate, allometric coefficient, seed vigor index, phytotoxicity percentage and seed tolerance index were calculated.Results and discussion: The results showed that increasing the concentration of lead, copper, and cadmium significantly affected the seed germination of studied plants. S. marianum had better germination percentage and rate in lead, and copper while germination of A. absinthium, L. draba, was better in cadmium, and copper, respectively. The greatest reduction in germination percentage was found for A. absinthium in 20 and 30 mg/L Cd. As the concentration of metals increased, significant reduction in germination percentage and rate for A. absinthium started in lower concentrations than other species. Root and shoot length of all species was significantly reduced even in low concentration of metals and S. marianum had greater root and shoot length under all treatments. Reduction in seed vigor index was greater under Cu than that in Pb and Cd. High tolerance index was found for L. draba in response to Cd and for S. marianum under the stress of Pb and Cu. In all treatments, an increase in metal concentration significantly increased the phytotoxicity index. Under Cu and Pb S. marianum showed the least phytotoxicity index, while the lowest phytotoxicity index was found for L. draba under Cd stress. Cu and Cd in high concentration were more toxic for A. absinthium than that for the other two species. Under similar concentrations of Cu and Pb, all species showed reduced germination in copper stress. Cd in lower concentrations were tolerable for plants but generally it had the greatest inhibition especially on A. absinthium.Conclusion: Overall the responses were different regarding the plant species, metal and concentrations. All three species were able to germinate at high concentrations of heavy metals. The presence of these species in coal wastes and their ability to germinate in high concentrations of heavy metals makes it possible to use these plants in future restoration and phytoremediation programs.
Mahmood Sinaei; Mehran Loghmani; Mehdi Bolouki
Volume 16, Issue 3 , October 2018, , Pages 153-166
Abstract
Introduction:
Aquatic ecosystems, particularly marine and coastal areas, are exposed to various environmental pollutions (e.g., organic and heavy metals pollution), which are caused by natural phenomena as well as human activities in aquatic environments. The aim of this study was to evaluate the concentration ...
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Introduction:
Aquatic ecosystems, particularly marine and coastal areas, are exposed to various environmental pollutions (e.g., organic and heavy metals pollution), which are caused by natural phenomena as well as human activities in aquatic environments. The aim of this study was to evaluate the concentration of heavy metals in water and brown algae Polycladia indica as a bioindicator along the northern coast of the Makoran Sea and compare their concentrations with global standards and previous studies.
Material and methods:
For this purpose, concentrations of heavy metals (i.e., cadmium (Cd), copper (Cu), zink (Zn), lead (Pb), nickel (Ni), chromium (Cr)) were assessed in P. indica and water samples in ten stations along the northern shores of Makoran Sea in the autumn of 2017. Samples were transferred to the laboratory and heavy metals were measured by atomic absorption spectroscopy (AAS).
Results and discussion:
In brown algae samples, Zn had the highest concentration within the whole area followed by Cr, Ni, Cu, Pb, and Cd, respectively. For water samples, the concentration of Cr was the highest followed by Zi, Ni, Cu, Pb, and Cd. One way-ANOVA test showed significant differences in the concentration of metals between sampling stations (p < 0.05). The concentration of heavy metals in water samples was lower than the global standards. Strong correlations were found between the examined heavy metals, indicating the lack of diversification of pollution sources in the northern coasts of the Makoran Sea and the uniformity of the geochemical composition of the coastal geology units of the sampling regions.
Conclusion:
The results of this study indicate the high affinity of P. indica towards the absorption of heavy metals, and therefore, this species can be considered as a bioindicator of heavy metals contamination in the northern shores of the Makoran Sea.
Reza Tamartash; Fatemeh Montazeri; Mohamadreza Tatian; Ghorban Vahab Zadeh
Volume 15, Issue 4 , January 2018, , Pages 1-14
Abstract
Introduction: Soil pollution by heavy metals in the soil due to long-term sustainability and ecologically harmful effects, has become an environmental problem. In the study of vegetation in polluted areas with heavy metals, plants have the ability to grow and absorption the heavy metals, viewpoint the ...
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Introduction: Soil pollution by heavy metals in the soil due to long-term sustainability and ecologically harmful effects, has become an environmental problem. In the study of vegetation in polluted areas with heavy metals, plants have the ability to grow and absorption the heavy metals, viewpoint the scientific aspects, functional and economically very important. Material and methods: In this study 500, 1250 and 2000 meter from the center Kiasar cement of sari in Mazandaran province, soil and vegetation sampling was conducted using systematic random. Plant species such as Astragalus, Artemisia and Convolvulus with 3 replications and 3 treatments (a total of 27 samples and 27 samples of soil from the plant Rhizosphere) in the form of randomized complete block design was tested. The collected Samples transported to the laboratory for testing. The concentration of Pb, Cu, and Zn of the samples were determined by using ICP Device. Results and discussion: Results of statistical analysis of this study showed that heavy metals in soil had difference was greater than the species studied. So compare means of data show amount of cu and pb in soil and species had significant differences with increasing distance (p < 0.05). Copper increased with increasing distance and lead showed decreasing trend. Zn did not show any significant differences with the changes of distance in soil but it was significant differences in species and does not follow the regular process. Conclusion: Correlation of heavy elements of species with soil elements showed that Astragalus and Artemisia have significant Correlation with Copper and lead but Convolvulus just significant positive correlation with the Zn.
Zeid Ahmadi; Akbar Yazdi; Reza Akrami
Volume 13, Issue 2 , July 2015, , Pages 49-56
Abstract
The pollution of aquatic ecosystems with heavy metals has always been a major concern for the aquatic organisms and human health. Measuring the levels of contaminants such as heavy metal (Pb) accumulated along the food chain (fish) and then transmitted to the human body is of particular interest. Concentrations ...
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The pollution of aquatic ecosystems with heavy metals has always been a major concern for the aquatic organisms and human health. Measuring the levels of contaminants such as heavy metal (Pb) accumulated along the food chain (fish) and then transmitted to the human body is of particular interest. Concentrations of heavy metal (Pb) were measured in the water, sediment and fish species (Liza aurata) from the Gomishan Wetland, Iran. Samples of water, sediment and fish were collected during two periods: summer (2013) and winter (2014). The result revealed thatPb concentration was varied significantly among sediment, water and fish body, the average Pb concentrations in sediment, water and fish in both seasons was in the order sediment > fish >water, Pb concentration was varied significantly among gills, liver and muscle tissues of fish samples in any station and in both seasons was in the order gill > muscle >liver. These values were lower than the established standard for aquatic environment by W.H.O and F.A.O. The results indicated that the consumer of fish and water from the stream is not at risk of being poison by this metal.
Fariba Jafari; Hossein Khademi
Volume 12, Issue 3 , October 2014
Abstract
Dust deposition phenomenon is an important climatic and environmental issue in arid to semi-arid regions which causes great losses for human. This study was carried out to compare the concentration of selected heavy metals in soil samples with that of dust and also to identify the possible sources of ...
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Dust deposition phenomenon is an important climatic and environmental issue in arid to semi-arid regions which causes great losses for human. This study was carried out to compare the concentration of selected heavy metals in soil samples with that of dust and also to identify the possible sources of heavy metals in dust of Kerman city. A total of 245 dust samples were monthly collected from 35 study sites during the months of May to November 1391, using glass traps. To compare the results of atmospheric dust with those of soil, 60 surface soil samples (0-10 cm) from outside Kerman and 35 soil samples from urban areas were also collected. After sample preparation, the total concentration of major heavy metals including Cu, Pb, Zn, Ni, and Mn was determined by an atomic absorption spectrometer following the digestion of soil and dust samples with 6N HNO3solution. Cluster analysis and principal component analysis were performed to identify possible sources of heavy metals in dust. The results showed that heavy metal concentrations in atmospheric dust samples were higher than those in soil samples indicating the influence of human factors. There was a highly significant correlation among Cu, Pb, and Zn and also among Cu, Mn, and Ni indicating different sources for these 2 groups of heavy metals. Also, principal component analysis and cluster analysis confirmed the results and further indicated that Ni and Mn derived from natural sources while Cu, Pb, and Zn had an anthropogenic origin. Since the role of human activities on increasing the concentration of pollutants is evident, it is necessary to take appropriate management measures to reduce the amount of pollutants produced in factories and various industries.
