Analysis of some metal elements (Al, V, Ni, Zn, Tl, and SN) and their relationship with gender and biometric indices in different tissues of the golden grey mullet (Liza aurata)

The present research was conducted to evaluate the concentration of some metal elements in aquatic animals, which is important for human health. The aims of this study were to examine the concentration of metal elements namely zinc (Zn), nickel (Ni), tin (Sn), aluminum (Al), vanadium (V), and thallium (Tl), and their relationship with gender and biometric indices on edible (muscles) and nonedible (liver and gill) tissues of the golden grey mullet (Liza aurata). Samples were obtained from mature golden grey mullet in different regions on the shoreline of the Caspian Sea in autumns and springs of 2014 and 2015. According to standard methods, metals were extracted of muscles, livers, and gills of the species using the digestion method and an acid mix. The concentration was determined using a graphite atomic absorption spectrometer with µg/g dry weight. Research results revealed that absorption of metal elements was higher in spring than autumn and it was in the Zn>Ni>Sn>Al>Tl>V order in the muscle tissues and the Zn>Ni>Al>Sn>V>Tl order in the liver and gill tissues. The order of concentration of metals in the three aforementioned tissues was as follows: liver>gill>muscle. Concentrations of aluminum, vanadium, zinc, nickel, tin, and thallium in the muscle tissues were 0.09, 0.04, 19.33, 0.09, 04.43, and 0.04 µg/g dry weight, in the liver tissues were 0.2, 0.13, 75.44, 0.82, 0.15, and 0.1 µg/g dry weight, and in the gill tissues were 0.14, 0.07, 51.47, 0.6, 0.09, and 0.07 µg/g dry weight, respectively. The highest concentration of metals was observed in the male species. Weight and length showed a significantly negative relationship with accumulation of aluminum, vanadium, and zinc in the three tissues (p<0.05). The comparison of concentrations of metal elements in muscle tissues to the standard WHO concentration showed that concentrations of all of the metals under study were lower than the standard levels.