comparative study of cadmiumand arsenic accumulation in toothed carp (aphanius sophiae)in fresh and salt water

background: anthropogenic activities release high concentrations of heavy metals into the aquatic ecosystems, which can be absorbed by the aquatic organisms. in this study, the accu-mulation of cadmium (cd) and arsenic (as) was compared in liver, gill and muscle tissues of toothed carp (aphanius sophiae) in fresh and salt water. methods: a total of 175 fish samples were collected from the shoor river, iran during the spring and summer of 2011. samples were divided into two groups for salt and freshwater ex-periments. the individuals of each group were also divided into seven groups, a control group and the other six exposed to the concentrations of 5, 10 and 20 mg/l of arsenic and 5, 10 and 20 mg/l of cadmium. the liver, gills and muscle tissues of the specimens were dissected. the tissues were wet digested in acid and the concentrations of metals were measured using an icp-oes instrument. results: the concentrations of both metals were significantly different in various organs in both fresh and salt water and it were in order of liver > gill > muscle (p <0.001). based on t-test results, no significant difference was observed between the concentrations of as in related tis-sues of fish cultivated in fresh and salt water. however, cd accumulation was significantly higher in the tissues of fish specimens cultivated in freshwater (p <0.001). conclusion: the bioaccumulation of cd and as depends on organs, metals, and water condi-tion.