Document Type : scientific research article
Authors
1
Assistant Professor, Department of Natural Ecosystems, Hamoon International Wetland Research Institute, Research Institute of Zabol. Sistan and Baloochestan, Iran.
2
2- Assistance professor, Department of Aquatic Science, Hamoun International Wetland Research Institute, Research Institute of Zabol, Zabol, Sistan and Baluchestan, Iran.
3
3- Assistance professor, Department of Environment, Faculty of Natural Resources, University of Zabol, Zabol, Sistan and Baluchestan, Iran
Abstract
Due to the drought and severe reduction of water resources, deep wells were dug in the Sistan region for the first time. Currently, the water is extracted from the deep well No. 3 located in Nimrooz city, is used for salmon cultivation on an experimental basis. Therefore, the concentration of heavy metals in the edible tissue was measured. Cadmium (Cd), chromium (Cr), arsenic (As), nickel (Ni), lead (Pb), and mercury (Hg) were considered in the edible tissue of salmon. Cultivated and juvenile fish were collected along with fish feed and water samples were taken in two stages from the experimental pond close to the deep well No. 3. For measure the concentration of the studied metals, ICP-MS device was utilized. The concentrations of some heavy metals in water were lower than standard values. The metal concentrations in food samples were higher than those in the fish tissues, whereas no significant difference was detected between the juvenile and cultivated fish muscles. The average concentrations of arsenic and chromium in cultivated fish muscles were 4.05 and 5.10, 0.22 and 0.25 μg/g dw, with no significant differences between the two groups. The nickel concentrations in two groups of cultivated fishes were 0.085 and 0.07 μg/g dw and lead were 0.166 and 0.3 μg/g dw respectively, with no significant difference. The comparison of the metal concentration in the edible tissue of different weight groups of fish did not show any significant difference. As a result, the continuation of the breeding period to gain more fish weight does not affect the increase of heavy metals in salmon muscle.
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