Heavy metals (Cd, Ni and Zn) concentrations in the edible muscle tissue of Pike perch (Esox lucius) from Anzali Wetland

Pike (Esox lucius) is a native species in Anzali Wetland and has been considered for its flesh. This study was carried out to compare the rate of accumulation and concentration of heavy metals such as cadmium, nickel and zinc in edible muscle tissue of pike at three stations (west, center and east) of Anzali wetland in 2012.Ten fishes were randomly caught by gillnet from different stations in standard weights. After removal of the tissue samples, for chemical digestion through mixed acid digestion (HNO3 / HClO4) was performed on samples. Heavy metal concentrations were measured using flame atomic absorption spectrophotometer. The average concentration of cadmium in pike in western station was 0.05 and in eastern and central part of wetland was 0.09 (μg/g dry weight), Mean concentrations of nickel metal in west, center and east, were 0.44, 0.37 and 0.22 (μg/g dry weight), Average concentrations of zinc in western, central and eastern part of wetland were 28, 25.55 and 13.55 (μg/g dry weight) respectively. In this study, concentrations of cadmium, nickel and zinc in edible muscle tissue of pike did not show significant differences between stations (P>0.05). The cadmium, nickel and zinc standards in American Food and Drug Administration (FDA), World Health Organization (WHO) were compared. The results showed that toxicity of nickel in samples of central was near but in western part was more than the permissible limit compared with the standard WHO = 0.38, therefore consumption of this fish could be a warning of a threat to the health of these fish in vulnerable groups of society.