Evaluation of heavy metal concentrations in Rutilus frisii kutum on the southern coast of the Caspian Sea (northern Iran)

Background: Marine products, especially fish, play an increasingly significant role in human diets and health. This research evaluated the concentrations of cadmium, lead, chromium, and nickel in liver and muscle tissues of Rutilus frisii kutum along the Caspian Sea coasts of northern Iran. Methods: Thirty samples of fishes were taken from five stations (Astara, Rezvanshahr, Anazali, Ramsar, and Tonekabon) during fishing season. An ICP-OES spectrophotometer was used to determine concentrations of the studied metals. Data was analyzed by SPSS 19 using descriptive statistical index, t test, and analysis of variance (ANOVA) test; P < 0.05 was considered significant. Results: Mean concentrations of cadmium, lead, chromium and nickel in the livers were 0.06, 1.1, 2.1 and 1.5 μg/g respectively and in the muscles were 0.05, 0.8, 1.7 and 1.1 μg/g, respectively. In liver: cadmium= 0.01-0.13; lead= 0.3-2.7; chromium = 0.9-4.5; nickel = 0.1-2.8. In muscle: cadmium = 0.01-0.08; lead = 0.2- 1.5; chromium = 0.7-2.7; nickel = 0.5-1.5. Mean contents of these heavy metals were higher in the liver than in muscle. The order of heavy metal concentrations in the liver and muscle tissues were: Cr>Ni>Pb>Cd. The results showed statistically significant differences in the concentrations of these metals in liver and muscle tissues (P < 0.05), but no significant difference was observed between males and females. Conclusion: Based on calculations, the estimated permissible tolerable weekly intakes (PTWIs) of cadmium (0.042 and 0.567 mg) and lead (0.0021 and 0.027 mg) in this study are lower than the levels established by the World Health Organization (WHO) (0.455 mg for cadmium and 1.625 mg for lead).