Siberian Federal University

The composition of organic component of water and bottom sediments of Ob River in the area from the mouth of Tom River to the mouth of Irtysh river was studied by using GCMC. Oil and biogenic compounds were found. The maximum content of biogenic compounds was obtained in water near the Vasyugan River mouth, which is starting and flowing through the area of peat bogs propagation. The latitudinal waters of Ob River are enriched with typical oil compounds, such as hopanes, steranes, secohopanes, cheilanthanes, tetracyclic aromatic hydrocarbons, polymethyl substituted naphthalene and phenanthrene. The bottom sediments near the inflow of Tom River are enriched with polycyclic aromatic hydrocarbons. It was shown, that the occurrence of n-alkanes with dual nature cannot be an indicator of water bodies pollution with crude oil. In addition to this, the composition of aromatic hydrocarbons and cyclic isoprenoids may be used to differentiate the pollutant sources