The level of pollution of commercial fish of the Ob-Irtysh basin with oil products
This paper provides data collected over many years (1989-1998) on the level of aromatic hydrocarbons (arenes) in muscles and lever of commercial fish of the Ob-Irtysh basin. To assess the ecological condition of the fish habitat, data on the level of oil products in the water and bottom sediments of the Ob river in its middle (Surgut District) and lower (Trans-Ural region) reaches during the period from 1995 till 1998 were analyzed. The analysis results on the level of arenes in fish organs varied in a wide range (muscles: 0.1-29.29 mg/kg, lever: 0.8-66.9 mg/kg). The average values of aggregated aromatic hydrocarbons were: muscles - 7.58±1.68 mg/kg, lever - 20.75±4.24 mg/kg. Such high changeability of the level of oil hydrocarbons was caused both by the complexity of oil composition and the peculiarities of biological accumulation and conversion of hydrocarbons in the living organism biomass. Six systematic groups have been analyzed: whitefish (Coregonidae), carp (Cyprinidae), sturgeon (Acipenseridae), perch (Percidae), cod (Gadidae), pickerel (Esocidae). A positive connection between the level of oil hydrocarbons in the fish and their concentration in water and bottom deposits was observed. Significant difference between the sizes of arenes in the fish lever from the Middle and Lower Ob was discovered. The maximum concentration of oil products was found in the liver of the perch which is caused by localization of this species in reservoirs located in oil-field areas.