Degradation of Aromatic Hydrocarbons in an Aquifer during a Field Experiment Demonstrating the Feasibility of Remediation by Natural Attenuation

Abstract : The purpose of this experiment was to perform a controlled field experiment, involving the injection of several aromatic hydrocarbons and a nonreactive tracer into an uncontaminated aquifer. By monitoring the plume development of these solutes, and by measuring a number of physical and chemical characteristics of the aquifer, this study was designed to provide data on those properties which significantly control the propagation of dissolved contaminants in groundwater systems. A secondary objective was to measure the in situ degradation rates of the selected organic compounds. The disappearance and transformation of the organic solutes during this experiment demonstrated that natural degradation processes were able to effectively reduce these levels of dissolved organic contaminants in a reasonable time frame. This represents the most important result of this field study, since active remediation would not be needed in situations where natural degradation rates were sufficient to reduce contaminant concentrations to safe levels. The monetary and environmental cost savings of allowing natural biological restoration of the residual contaminants are potentially enormous. it appears that this study is the first field experiment to prove conclusively that hydrocarbon solute losses were due to chemical degradation rather than physical losses. Natural attenuation, Groundwater contamination, In situ biodegradation, Jet fuel components, Natural gradient experiment