Zhaleh Amini; Reza Anvaripour; masoud Hatami-manesh; Jaber Aazami
Abstract
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 ...
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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.Materials and methods; 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.Results and discussion; 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. Conclusion; 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.
Mahsa Abdoli; Mohammad Panahandeh
Abstract
Introduction: Over the past few decades, human activity had a significant impact on coastal wetlands around the world. Anzali is one of the 18 Iranian wetlands of international importance listed in Ramsar Convention. This unique ecosystemin the world with high ecological diversity is highly threatened ...
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Introduction: Over the past few decades, human activity had a significant impact on coastal wetlands around the world. Anzali is one of the 18 Iranian wetlands of international importance listed in Ramsar Convention. This unique ecosystemin the world with high ecological diversity is highly threatened by various factors such as pollutants, sedimentation, unauthorized development of urban infrastructure, over-harvesting of wetland resources, land use changes, and invasive species. In this study, we analyze structural and functional changes in the Anzali coastal wetland from 1994 to 2018, using the "drive-pressures-status-effects-responses-(DPSIR)" model and data collected from the Anzali Coastal Wetland. Material and methods: Landsat 5 and 8 TM and OLI sensors for 1994, 2008 and 2018 were used. The land cover maps for these years were prepared in 5 categories of water body, wetland, wetland plants, pasture and agricultural land using the supervised classification with maximum likelihood algorithm in ENVI5.3 software. Changes were identified to assess the current status of the wetland and then the conceptual framework of DPSIR was used to determine the relationship between human activities and environmental activities and to describe environmental problems. Results and discussion: According to the results of the first period (1994-2008), the water body had the highest area change with 7.63% decrease, which was the most influential part of the wetland plants class, with 1045/98 hectares of water body converted into wetland. The wetland plants was second with 3.84 percent. During the second period (2008-2018), the water body had the most change in this period, with a decrease of 14.19%, as in the previous period. Over the entire study period from 1994 to 2018, the water body increased from 4749 hectares in 1994 to 1042 hectares in 2018, the largest conversion to wetland plants. The area of wetland, wetland, pasture and agricultural land uses increased by 10.92%, 0.78%, 4.48% and 5.66%, respectively. The results of maps accuracy assessment show that overall accuracy for year 2018, 96.31, year 2008, 94.14 and for 1994, 90.29% and kappa coefficient were 0.94, 0.92 and 0.87, respectively. Is. Also the driving forces in this research are population growth, industry and tourism. Conclusion: The process of change in the Anzali Wetland is first in a natural sequence and then of human origin. So that the area of the water reservoir is reduced and added to the cover of wetland plants and wetlands and eventually to agricultural lands and the fertilizers and pesticides used in agriculture along with domestic wastewater, industrialization through rivers into the Anzali Wetland. It enters the wetland feed, thereby accelerating the process of wetland destruction. Protecting this wetland requires people's participation, education and culture at the grassroots level.
Seyed Daryoush Moghaddas; Asghar Abdoli; Bahram Hassanzade Kiabi; Hossein Rahmani
Abstract
Introduction: The intentional and unintentional introduction of non-native fish species to the aquatic ecosystems of Iran has occurred with purposes such as enhancing aquaculture, ornamentation, biological control, and research. Some of them cause or have the potential to cause, significant environmental ...
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Introduction: The intentional and unintentional introduction of non-native fish species to the aquatic ecosystems of Iran has occurred with purposes such as enhancing aquaculture, ornamentation, biological control, and research. Some of them cause or have the potential to cause, significant environmental and socio-economic impacts on aquatic ecosystems and/or fish farms. The eradication of non-native fishes is impossible or very costly, especially in large areas. Screening and identifying the potential invasiveness of species are being increasingly used all over the world. The main aim of the present research was to assess the potential invasiveness of redbelly Tilapia Coptodon zillii in Anzali international wetland. Material and methods: Aquatic Species Invasiveness Screening Kit (AS-ISK) was used to identify redbelly Tilapia Coptodon zillii as a non-native fish that may pose a high potential risk of becoming invasion in Anzali Wetland. The model is able to discriminate between invasive and non-invasive aquatic organisms including non-native fishes by risk area-related threshold value. Also, the Köppen-Geiger climate system and Climatch software were used to match the climate between the native range of redbelly Tilapia and Anzali Wetland. The projected future climate change scenario was taken from relevant studies to carry out Climate Change Assessment (CCA) of the AS-ISK. Results and discussion: The output of the AS-ISK was 44 for redbelly Tilapia that was higher than the AS-ISK threshold value of the risk assessment area, which meant that the species pose a potential risk of becoming invasive in Anzali wetland. There was a high climate-mating between the native range of redbelly Tilapia and the assessed area when the Köppen-Geiger climate system was used. At least one native habitat of redbelly Tilapia in the system was in the same climate category as the studied area. Also, the Climatch model output was 0.87 that shows a high climate matching for the non-native fish. The CCA had an increasing effect on the total score of the AS-ISK. The factors that increased the AS-ISK score were climate-mating, probable climate change, biological attributes, and invasiveness history of other places that the species was introduced. The comparison of the results of this study and other relevant studies that used AS-ISK to assess potential invasiveness of redbelly Tilapia showed that the species had the potential of becoming an invader in Anzali Wetland as well as some other areas around the country. Conclusion: While non-native fishes are frequently used to enhance aquaculture in the country, a rapid assessment tool is required to avoid nuisance environmental impacts. The AS-ISK can be reliably used as a tool to predict the potential risk of becoming invasive in Anzali Wetland and elsewhere to be used by conservation managers, decision-makers, and policymakers in the aquaculture development plans.
Hamid Reza Pakzad; Mehrdad Pasandi; Ardeshir Romiani; Mahdi Kamal
Volume 12, Issue 2 , July 2014
Abstract
The Anzali wetland is highly important for the particular ecologic, economic and social conditions. Several rivers discharge to Anzali wetland after passing through surrounding forests, towns and villages. Sampling of the sediments of Anzali wetland was carried out at 22 sampling points located in the ...
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The Anzali wetland is highly important for the particular ecologic, economic and social conditions. Several rivers discharge to Anzali wetland after passing through surrounding forests, towns and villages. Sampling of the sediments of Anzali wetland was carried out at 22 sampling points located in the inflowing rivers and the canals connecting the wetland to the Caspian Sea in order to determine the heavy metals concentrations and also physicochemical properties influencing concentration of these elements. The major clay minerals of these sediments are montmorillonite, chlorite and kaolinite in their order of abundances. The result showed that the concentration of Cr, Cu and Ni increased in the samples with higher amount of clay and the Zn concentration increases in the samples containing montmorillonite and illite. Increases of the Cr and Cu concentrations and decreases in the Ni concentration conform to increase in the amount of TOC. The Ni concentration was higher in the samples with higher Fe and Mn concentration. The amount of calcium carbonate is positively correlated with the Sr concentration. According to the enrichment factor, Cu and Zn showed average enrichment in just one sample. Ni, Sr and Cr were depleted in the fine-gained sediments of Anzali wetland.
Fariba Zamani Hargalani; Abdolreza Karbassi; Seyed Masoud Monavari; Parviz Abroomand Azar
Volume 11, Issue 2 , July 2013
Abstract
Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural and industrial wastewater, which affect the distribution of elements. In this study, ten sediment samples from the Anzali wetland ...
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Anzali, one of the most important international wetlands, is located on the southern coast of the Caspian Sea in Iran. This wetland receives discharges of domestic, agricultural and industrial wastewater, which affect the distribution of elements. In this study, ten sediment samples from the Anzali wetland were collected and analyzed for total concentration of metals (As, Cd, Cr, Cu, Ni, Pb, Zn and Fe). The results showed relatively higher concentrations of most elements in comparison to that of crust. The chemical partitioning of metals in each sample was determined in four fractions (Loosely bonded, Sulphide bonded, Organo-metallic bonded, Resistant bonded). Based on the chemical partitioning of metals, As and Cd were the most abundant in the loosely bonded, so these elements were major hazard for the aquatic environment and were a major pollutant in this area. Cd is the metal that showed the highest percentages in the Organo-metallic bonded. As, Fe and Cr are displayed in the greatest percentages in the resistant bonded; this imply that these metals are strongly linked to the sediments.
