Heavy metals (Cd and Cr) concentration in different tissues (muscle, gill, kidney and intestine) of Zayandehrood chub, Petroleuciscus esfahani

The aim of this study was to evaluate two heavy metals (Cd and Cr) concentrations in different tissues including muscle، gill، kidney and intestine of Zayandehrood chub، Petroleuciscus esfahani in different stations along the Zayandehrood River. For this purpose، 80 specimens of the fish were collected from 4 different stations including Cheshmeh-dimeh، Khersoonak، Chamgordan and Pol-e-Safaiyeh (each 20 fish) in autumn 2011. The metals were extracted using dry digestion method and measured by Atomic Absorption. The results showed that the concentration of heavy metals increased significantly from up to downstream of the River، with the highest level was observed in Chamgordan station (p<0. 05). The highest concentrations of Cd (22. 7±0. 55) and Cr (50. 69±22. 78) µg/g dry weight (DW) were measured in the kidney of the fish collected from Pol-e-Safaiyeh and Chamgordan stations respectively (p<0. 05). While، the lowest level of Cd (0. 8±0. 11) and Cr (1. 30±0. 19) µg/gDW were determined in the muscle of the fish from Cheshmeh-dimeh station located at upstream. The metals concentrations in the muscle were increased significantly from upstream to the downstream (p<0. 05). In general، in all studied stations، the highest levels of Cd and Cr were observed in the kidney while، the lowest levels were measured in the muscle. By comparison between the results obtained from this study to the international standards defined by WHO or FAO، it was cleared that the concentrations of both metals in Zayandehrood chub (even at the lowest levels in the muscle) were much higher than permitted levels. The results of this study could show inappropriate environmental conditions of the Zayandehrood River، even in the upstream stations