Background Concentrations of Heavy Metals in the Surface Soil Horizon of Oil and Oil–Gas Condensate Fields in Eastern Siberia

Engineering and ecological survey data obtained on oil and oil–gas condensate fields in Eastern Siberia (Krasnoyarsk krai, Irkutsk oblast, and the Republic of Sakha (Yakutia)) are processed and systematized. We have determined mean (background) concentrations of heavy metals and toxic elements, which are subject to obligatory monitoring during engineering and ecological surveys (lead, cadmium, zinc, copper, nickel, arsenic, and mercury) for the main associations of soils, the prevalent kinds of soils, and units of geochemical and metallogenic zoning. It is established that the differences between soil varieties in concentrations of the studied elements are in general rather small, which is explained by the common source of elements—terrigenous deposits of the Lower Paleozoic—and poorly developed processes of bioaccumulation in taiga conditions. Peat–podzolic iron–illuvial soils are characterized by increased concentrations of copper and nickel. The effect of the lithogenic basis on concentrations of heavy metals and toxic elements is more pronounced than the impact of the transformations of initial material during soil formation. Correlation coefficients are determined, dendrograms of interrelations of the content of elements are constructed, and the following associations of elements are revealed: nickel and zinc; cadmium, mercury, and arsenic; and copper and lead. The resulting mean concentrations of elements may be used as background ones in subsequent engineering and ecological surveys in the region.