en Comparative Study of Cadmiumand Arsenic Accumulation in Toothed Carp (Aphanius sophiae)in Fresh and Salt Water عمومى General پژوهشي Research <b>Background: </b>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. <br><b>Methods:</b> 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. <br><b>Results:</b> 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). <br><b>Conclusion:</b> The bioaccumulation of Cd and As depends on organs, metals, and water condi-tion. Arsenic, Cadmium, Carps, Water Pollution. Arsenic, Cadmium, Carps, Water Pollution. 1342 1346 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-225-3&slc_lang=en&sid=1 Masoumeh Ariyaee معصومه آریایی 10031947532846004548 10031947532846004548 No Department of Environment, University of Tehran, Karaj, Iran. Department of Environment, University of Tehran, Karaj, Iran. Amir Hossein Hamidian امیرحسین حمیدیان a.hamidian@ut.ac.ir 10031947532846004549 10031947532846004549 Yes Department of Environment, University of Tehran, Karaj, Iran. Department of Environment, University of Tehran, Karaj, Iran. Soheil Eagderi سهیل ایگدری 10031947532846004550 10031947532846004550 No Department of Fisheries, University of Tehran, Karaj, Iran. Department of Fisheries, University of Tehran, Karaj, Iran. Sohrab Ashrafi سهراب اشرافی 10031947532846004551 10031947532846004551 No Department of Environment, University of Tehran, Karaj, Iran. Department of Environment, University of Tehran, Karaj, Iran. Manoochehr Khazaee منوچهر خزایی 10031947532846004552 10031947532846004552 No Department of Environment, University of Tehran, Karaj, Iran. Department of Environment, University of Tehran, Karaj, Iran.