Masoomeh Koohi; Atefeh Chamani
Abstract
Background and Purpose: The Zayandeh-Rud River is the sole permanent river in the central plateau of Iran. This river has been extensively exposed to sewage and effluent discharge from various point and non-point sources of pollution. Consequently, the sediment quality of the Zayandeh-Rud River was investigated.Materials ...
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Background and Purpose: The Zayandeh-Rud River is the sole permanent river in the central plateau of Iran. This river has been extensively exposed to sewage and effluent discharge from various point and non-point sources of pollution. Consequently, the sediment quality of the Zayandeh-Rud River was investigated.Materials and methods: Sediment sampling was conducted in triplicates at six stations along the Zayandeh-Rud River during the spring, summer, autumn, and winter of 2019-2020. The concentrations of lead and cadmium were then determined. Subsequently, the bioaccumulation factor, Müller's geochemical index, contamination factor, contamination degree, modified contamination degree, potential ecological risk index, and pollution load index were calculated.Results: The results indicated that the mean concentrations of cadmium in spring, summer, autumn, and winter were 1.18, 1.13, 1.08, and 0.54 mg/kg, respectively. Additionally, the mean concentration of lead was 26.13, 23.04, 23.96, and 11.17 mg/kg, respectively. The ecological risk assessment index revealed that the region was at a moderate ecological risk during spring, summer, and autumn, while during winter, it was at a low ecological risk.Conclusion: A comparison between the mean metal concentrations and the Canadian sediment quality standard values for fresh waters demonstrated that the lead concentration in sediments is lower than the standard value, whereas cadmium exceeds the standard value. These results highlight the pollution status of the river, which is the primary source of freshwater in the central plateau of Iran. Moreover, this study can serve as a basis for implementing policies to mitigate the accumulation of heavy metals in aquatic ecosystems.
Mohsen Mohammadi; Ali Akbar Hedayati; Mohammad Forouhar Vajargah; Ahmad Reza Pirali; Maryam Fallah
Abstract
Background and Aim: Sediment monitoring in aquatic environments is very important due to long-term exposure of various pollutants. This study was conducted to monitor the pollution of some heavy metals (Cd, Cu, Fe, Pb and Zn) in the surface sediments of Anzali wetland.Materials and Methods: For this ...
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Background and Aim: Sediment monitoring in aquatic environments is very important due to long-term exposure of various pollutants. This study was conducted to monitor the pollution of some heavy metals (Cd, Cu, Fe, Pb and Zn) in the surface sediments of Anzali wetland.Materials and Methods: For this purpose, sediment samples were collected from east, west and central parts of the wetland in different seasons of 2020. Heavy metals contamination zoning for sediments in the study area was performed using Arc GIS 10.7Results: The results showed that the highest level of contaminants were obtained in the western part of the wetland. The average concentrations of heavy metals in the sediments were related to Cu (18.47), Zn (74.15), Cd (0.67), Pb (12.05) and Fe (1.97) mg. kg-1 in the western part. The pattern of changes of studied metals was in conformity with Cd 0.05) between Pb, Cu and Zn. According to the zoning map of the parts located in the middle of the center to the west of the wetland, higher amounts of metals have been deposited in its sediments.Conclusion: In general, various human activities and the development of industries and the existence of agricultural lands in the area of Anzali Wetland and incoming rivers can be considered as factors affecting pollution. Therefore, with continuous biological and ecological monitoring of the wetland, it is possible to estimate the amount of heavy metals and the share of each in the wetland. Also, management in order to protect and monitor the wetland seems necessary.