en Acute Toxicity and Accumulation of Iron, Manganese and, Aluminum in Caspian Kutum Fish (Rutilus kutum) تخصصي Special پژوهشي Research <b>Background:</b> Iron, manganese, and aluminum are three abundant metals on earth and their concentrations have increased in aquatic environments as a result of natural and industrial activities. This study was undertaken to report the median acute toxicity (LC50) and accumulation of the sub-lethal concentration (10% 96-h LC50) of iron (Fe), manganese (Mn) and aluminum (Al) in kutum (Rutilus kutum) fingerlings. <br><b>Methods:</b> For the 96-h LC50, the fish were exposed to concentrations of 105, 111, 117, 123, 129 and 135 mg/l of Fe and 40, 45, 50, 55, 60, and 65 mg/l of Mn and 18, 22, 26, 30, 34 and 38 mg/l of aluminum for 4 days. For sublethal exposure, they were exposed to mediums with concentrations of 12.3, 5.4 and 2.9 for Fe, Mn, and aluminum, respectively. Metal concentrations were determined by atomic absorption spectrophotometry in the gill tissues. <br><b>Results:</b> Probit analysis showed the 96-h LC50 values of 122.98, 54.39, and 28.89 mg/l for Fe, Mn, and aluminum, respectively. Sub-lethal tests were conducted with nominal concentrations of 12.3, 5.4, and 2.9 mg/l of Fe, Mn, and aluminum for four days, respectively. Significant accumulations were observed in gills for all tested metals as compared to the control groups in short-term exposure (P<0.05). <b>Conclusion:</b> Obtained results clearly show that aluminum is the most toxic metal among tested ones for kutum fingerlings and it has the highest branchial AF value during sub-lethal exposure. Aluminum, Fishes, Iron, Lethal Dose 50, Magnesium, Water Pollution Aluminum, Fishes, Iron, Lethal Dose 50, Magnesium, Water Pollution. 1028 1033 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-2-147&slc_lang=en&sid=1 Saeed Zahedi سعید زاهدی szahedi.stu@hormozgan.ac.ir 10031947532846003586 10031947532846003586 Yes Young Researchers and Elite Club, Torbat-e Heydarieh Branch, Islamic Azad University, Torbat-e Heydarieh, Iran. Young Researchers and Elite Club, Torbat-e Heydarieh Branch, Islamic Azad University, Torbat-e Heydarieh, Iran. Hossein Vaezzade حسین واعظ زاده 10031947532846003587 10031947532846003587 No Department of Fisheries and Environmental Sciences, University of Tehran, Karaj, Iran. Department of Fisheries and Environmental Sciences, University of Tehran, Karaj, Iran. Maryam Rafati مریم رفعتی 10031947532846003588 10031947532846003588 No Department of Natural Resources, Savadkooh Branch, Islamic Azad University, Savadkooh, Iran. Department of Natural Resources, Savadkooh Branch, Islamic Azad University, Savadkooh, Iran. Musa Zarei Dangesaraki موسی زارعی دنگسرکی 10031947532846003589 10031947532846003589 No MSc.Shahid Rajaee Sturgeon Hatchery Center, Sari, Iran. MSc.Shahid Rajaee Sturgeon Hatchery Center, Sari, Iran.