Four USTs (Georgia ID #70-00039) containing virgin and waste solvents were operated on site for a period of almost ten years. The tanks were closed by removal in 1993. During the time the USTs were in operation, solvent releases resulted in dissolved concentrations of methyl isobutyl ketone (MIBK) in the underlying aquifer exceeding acceptable standards.

Assessment of area hydrology and facility hydraulics indicated groundwater flow under the site is controlled by a surface stream to the east. A receptor survey indicated underground sources of drinking water are not present within 1.0 miles of the site for public sources, or 0.25 mile for private sources.

Evaluated MIBK transport in ground water from the on-site solvents release using a simple one-dimensional spreadsheet model (TRANS1D). Estimated parameters using site investigation results for aquifer hydraulic and geochemical parameters, along with literature values for soil geotechnical values.

The model predicted an assumed worst-case water quality standard will not be exceeded at a perennial stream, Mud Creek, located 800 feet downgradient of the release source. As a result, a corrective action of MNA was feasible with very little risk to public health and the environment. Subsequent monitoring results confirmed the model validity and resulted in GEPD issuing a NFAR letter.