Plume of oil metabolites in groundwater: formation, evolution, and toxicity

The transformation of oil hydrocarbons in groundwater is mainly related to the processes of biodegradation. At sites where residual crude oil or petroleum hydrocarbon fuel contaminants are present in the environment, biodegradation reactions result in the formation of partial oxidation products, i.e., metabolites. These transformation products are more soluble than the parent petroleum hydrocarbons, due to their greater polarity and corresponding low volatility. Transformation products from residual source zones are distributed in aqueous phase to form a plume of contamination in groundwater. The content of metabolites depends on the redox conditions and the presence of the terminal electron acceptors, as well as on the structure of the original hydrocarbon compounds. The article considers the conditions for formation of metabolites, their degradation, migration to groundwater and plume formation, toxicity of metabolites. Examples of modeling the migration of metabolites in the saturated zone are given.