The Concentrations and Composition of Hydrocarbons in Ural River Mouth Zone during Spring Flood

Abstract

High concentrations of hydrocarbons in suspension in surface water were recorded in the mouth area of the Ural River during spring flood, where they averaged 198 (in 2016) and 270 µg/L (in 2017). Weathered petroleum alkanes dominated in hydrocarbon composition. The concentration of hydrocarbons in sandy sediments was low, averaging 7.8–14.6 µg/g. Dominating in their composition were terrigenous high-molecular most stable alkanes. The year-to-year variations in the concentration of organic compounds were governed by river runoff and the input of petroleum pollutants with flood waters. The runoff of the Ural River during spring flood is supposed to have a considerable effect on the environmental conditions in the Northern Caspian.