بررسی میزان غلظت فلزات سنگین در بافت‌های مختلف ماهی کلیکا و سه خاره دریای خزر

Background and purpose: Heavy metals are released to the environment as a result of industrial, urban and agricultural sewages. They are usually resistant to chemical dissociation. They can easily contaminate aquatic animals especially fishes which are amongst the food chains of human. This study evaluated the concentration of heavy metals in the tissues of different types of Clupeonella cultriventris and Gasterosteus aculeatus in the waters of Caspian Sea in Mazandaran Province. Material and Methods: This cross-sectional descriptive study was performed on 50 Clupeonella cultriventris and 50 Gasterosteus aculeatus obtained from Mazandaran coastal by multi mesh gill nets in 2012. The samples were digested by concentrated 65% nitric acid, and were analyzed for Pb in a graphite furnace atomic absorption spectrophotometer and for Cd and Cr in a flame atomic absorption spectrophotometer. Results: Mean concentration of Pb, Cr and Cd in Gasterosteus aculeatus was 0.113, 5.28 and 0.046 and mean concentrations of Pb, Cr and Cd in Clupeonella cultriventris were 0.126, 4.29 and 0.096 (μg/g dry weight), respectively. The results showed no significant correlation between the concentrations of these metals and length of fish and different tissues of the fish. Conclusion: We found the concentration of heavy metals including Pb and Cr in both types of the fishes less than the amounts reported by WHO, so they do not bare considerable health risk. However, the concentration of Cd is more than the recommended consumption limit for human which could lead to many diseases. We believe that these fishes could be used as a bioindicator for assessing the pollution load of sea water and rivers.