Characterizing and predicting contaminant transport in the Newport Wellfield aquifer, Ohio

The aquifer that supplies the Newport Wellfield in Ohio has been contaminated with trichloroethylene (TCE), cisdichloroethylene (DCE), and vinyl chloride (VC). These contaminants were introduced into the aquifer during the 1960s and 1970s when local industries donated their waste products to the local volunteer fire department that used the chemicals in training exercises. Past remediation efforts included a pump and treat scheme but the contamination persists. This study characterized the groundwater flow and the transport of TCE, DCE, and VC in the aquifer through analyses of site-specific geologic, hydrogeologic, pump test, and contaminant concentration data using AQTESOLV, Hydro GeoBuilder, and Visual MODFLOW. Based on our model results, the uncontaminated production wells (PW-1 and PW-3) will not become contaminated in the future. However, under the current pumping scheme, the aquifer will not meet the maximum contaminant level allowed by the US EPA (5 mg/L) for 6.5 years. This time could be reduced to less than 3 years if the pumping rate of the contaminated well (PW-2) is increased to 140 gallons per minute and it is pumped continuously.