Survey of heavy metals concentrations (Fe, Zn, Cu and Cd) in various tissues of Caspian Roaches (Rutilus rutilus caspicus) in the southern part of Caspian Sea

This study investigates the presence of heavy metals such as iron، zinc، copper and cadmium in muscle، skin، gonad and gill tissues of fish (Rutilus rutilus caspicus) in two sites in Sari and Turkmen Seaport of Southern part of Caspian Sea. Samples were collected in autumn 2013 and winter 2014. After preparation and parting of tissues، concentration of heavy metals were determined in tissues of 37 samples (20 samples in autumn and 17 samples in winter) following wet digestion using Flame Atomic Absorption Spectrophotometry. The results of this study showed that the average concentrations of iron and zinc were at maximum in gill and at minimum in muscle. However the average concentrations of copper were at maximum in gonad and at minimum in muscle and the average concentrations of cadmium were at maximum in muscle and at minimum in gonad. Iron concentrations were shown to be higher than those of zinc، copper and cadmium in various organs of fish. Accumulation of iron، zinc، copper and cadmium in muscle، skin، gonad and gill was highly significant between them (P<0. 05). Concentrations of iron in muscle and skin were significantly different (P<0. 05)، unlike those in skin and gonad (P>0. 05). Concentrations of cadmium in muscle and skin were not significantly different، unlike those in muscle and gonad. These values were compared with the WHO and the FAO and UK (MAFF) safety standards regarding the amount of the above mentioned heavy metals in fish tissues. Based on the results of this study، the average concentrations of zinc in the gill tissues proved to be higher than international standards. The average concentrations of cadmium in the muscle، skin and gill tissues proved to be higher than international standards. It is recommended not to use these fish due to the toxicity and high levels of cadmium in their muscle tissues.