The levels of oil accumulation in soils of different Russian natural zones depend on: a) genetic soil properties; b) degree of soil moisture content in the movement of pollution (the dryer the soil the higher its oil bearing capacity); c) the structure of pore-fissure space; d) texture, etc.

Within the tundra landscapes of the European Russia and West Siberia, where oils with thick organic horizons prevail, the levels of oil accumulation in impact ones reach tens and hundreds of g/kg.

The oil content in soils of West Siberian Northern taiga landscapes is quite different: in mineral soils (podzols) it does not exceed first tens of g/kg; in peat bog soils it can achieve hundreds of g/kg.

In landscapes of Southern taiga, broad-leaved forests and forest-steppe landscapes due to the absence of organic horizons with high sorption capacity, the highest oil concentrations in soils are lower and do not exceed first tens of g/kg.

The maximal oil concentrations are observed on soil-geochemical barriers under all the natural conditions.

The process of oil fractioning according to its specific weight, viscosity, density, and the degree of interaction activity with soils is initiated at the moment of oil input to soils. Soils play the role of "chromatographic column", differentiating spatially the multi-component mixtures. The sorption of high-molecular compounds and their sedimentation in the upper part of a profile and near to pollution take place. Source is appearing. Movement of lighter oil components deeper into soil sand down along the relief causes the expansion of oil into soils horizons and increase in area of the primary pollution. Oil can seep out in the lower parts of slopes, and reach water streams and reservoirs with the in-soil flows.

The velocities of processes of in-soil pollutant migrations, as well as velocities of their destruction are functions of the bio-climatical potential of a territory and characteristic soil-geochemical processes.

The less favorable conditions both for oil migration and destruction exist in the gley-reduction environments under severe climatic conditions of tundras and forest-tundras. The maximal pollutant spread occurs in the over-moisten soils.

Nina P. Solntseva
Faculty of Geography
Moscow State University
Moscow, 119899, RUSSIA
Phone: (095) 939-2131
Fax: (095) 939-0126
E-mail: boch@imb.imb.ac.ru