Assisted client with risk management activities, including evaluation of area hydrology and site hydraulics, property assessment results, etc., to determine corrective actions likely to be required by GEPD. Assistance included evaluating previous graphical modeling studies of on-site contaminant fate and transport developed from installation and sampling of monitoring wells.

The on-site “recognized environmental conditions” resulted from improper disposal of dry cleaning solvents (trichloroethylene, or TCE, and tetrachloroethylene, or PCE) and petroleum releases from regulated USTs (Georgia ID #03-10007). Calculations indicated ground water concentrations of chlorinated aliphatic hydrocarbons (CAH) would exceed applicable HSRA Risk-Reduction Standards (RRS). The presence of a nearby drinking water well supplying a mobile home park was a particularly important factor in the hydraulic analyses of contaminant transport.

Developed SAP including installation of an additional water-table well, adjacent to the existing on-site “vertical-extent” well, and collection of additional geochemical, geotechnical soils and aquifer hydraulic data. Results indicated no subsurface vertical flow components and the USEPA, two-dimensional model, BIOCHLOR, could be used to determine the feasibility of an MNA corrective action.

Application of the BIOCHLOR model indicated MNA was feasible and these results were incorporated into the compliance status report (CSR) submitted to GEPD according to HSRA regulations.