The content of heavy metals in the muscle tissue and liver of various species of commercial fish of the Irtysh river (Omsk region)

The article considers the current content of Zn, Cu, Cd, Pb, As and Hg in the muscle tissue and liver of various commercial fish species: common bream (Abramis brama), crucian carp (Carassius auratus gibelio), roach (Rutilus rutilus), sampled in the Irtysh River within the borders of the Omsk region in 2024. A total of 45 sex-and-age, approximately one-sized individuals were examined, 15 fish of each species, without gender separation. The difference in the levels of trace elements in the muscle tissue and liver of fish was shown, depending on their type of nutrition. Thus, in the common bream the concentration of Hg was higher in the muscle tissue, Cu - in the liver, compared to other species of peaceful fish, such as roach and crucian carp. It was found that the maximum contents of Cu, Pb and Cd were characteristic of the liver of fish, regardless of their species. The muscles of the fish had relatively low concentrations of these trace elements. The opposite situation was observed for Zn, Hg and As – the highest concentrations of these elements were found in the muscles of fish. The content of heavy metals in the muscle tissue and liver of the studied fish species of the Irtysh River did not exceed the maximum permissible levels. However, in the muscle tissue of the common bream, an increased content of Hg was recorded – 0.232 mg/kg with a maximum permissible concentration of 0.3 mg/kg.