en عمومى General پژوهشي Research <p><strong>Background:</strong> The Present study was carried out to track and calculate Biomagnification Factor (BMF) of total mercury (T-Hg) between two different trophic levels (i.e., plankton and a planktivorous fish) in a fresh water grazing food chain.</p> <p><strong>Methods:</strong> Experimental organisms were planktonic biomass and silver carp (<em>Hypophthalmichthys molit</em><em>r</em><em>ix</em>) as a planktivorous fish. Silver carp samples were obtained from randomly selected points from different sampling stations. The concentrations of T-Hg in collected samples were determined by Advanced Mercury Analyzer.</p> <p><strong>Results:</strong> Means of T-Hg in planktonic biomass and muscle tissue of silver carp were 78.21 &plusmn; 3.13 and 367.12 &plusmn; 26.43 ng g^-1 dry weights, respectively. Mean T-Hg in plankton, sampled fish during the study months and amongst the sampling stations did not show significant differences. The BMF_{Hg(plankton-fish)} was differ among months; moreover, calculated BMF was greater than 1 during study months, which means biomagnification was occurring in SGR. The concentration of T-Hg in the muscle tissue of all fish samples that weighed more than 850 gr was higher than the acceptable limits based on EPA (300 ng g^-1) and WHO (500 ng g^-1) standards. The highest BMF_Hg was observed in August</p> <p><strong>Conclusion:</strong> It seems that mercury pollution of SGR has a natural source. The calculated BMF_s were greater than 1 and the concentrations of T-Hg in muscle tissues of those samples weighing more than 850 gr were higher than FAO and WHO standards. Therefore, consumption of the SGR&#39;s silver carp must be accompanied by serious health considerations.</p> Biomagnification, Mercury, Plankton, Grazing food chain, Silver carp, Sanandaj Gheshlagh Reservoir Biomagnification, Grazing Food Chain, Mercury, Plankton, Silver Carp 21 28 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-398-1&slc_lang=en&sid=1 Mehdi Khoshnamvand 10031947532846006510 10031947532846006510 No PhD Student Environmental Sciences, Research Center of Eco-Environmental Sciences, University of Chinese Academy of Sciences, Beijing, China. Kamran Almasieh 10031947532846006511 10031947532846006511 No Department of Environmental Sciences, University of Kurdistan, Sanandaj, Iran. Shahram Kaboodvandpour s.kaboodvandpour@uok.ac.ir 10031947532846006512 10031947532846006512 Yes Department of Environmental Sciences, University of Kurdistan, Sanandaj, Iran.