11.12 - Volatile hydrocarbons and fuel oxygenates

Petroleum hydrocarbons and fuel oxygenates are among the most commonly occurring and widely distributed contaminants in the environment. This chapter presents a summary of the sources, transport, fate, and remediation of volatile fuel hydrocarbons and fuel additives in the environment. Much research has focused on the transport and transformation processes of petroleum hydrocarbons and fuel oxygenates, such as benzene, toluene, ethylbenzene, and xylenes and methyl tert‐butyl ether, in groundwater following release from underground storage tanks. Natural attenuation from biodegradation limits the movement of these contaminants and has received considerable attention as an environmental restoration option. This chapter summarizes approaches to environmental restoration, including those that rely on natural attenuation, and also engineered or enhanced remediation. Researchers are increasingly combining several microbial and molecular-based methods to give a complete picture of biodegradation potential and occurrence at contaminated field sites. New insights into the fate of petroleum hydrocarbons and fuel additives have been gained by recent advances in analytical tools and approaches, including stable isotope fractionation, analysis of metabolic intermediates, and direct microbial evidence. However, development of long-term detailed monitoring programs is required to further develop conceptual models of natural attenuation and increase our understanding of the behavior of contaminant mixtures in the subsurface.