Andrew Frishkorn (the site's Licensed Remediation Specialist, or LRS) and crews from Baker Environmental completed the final round of investigative activity in late October 1998. This field program's primary objectives are:
- Better characterization of contaminant distribution in soils and groundwater
- Better characterization of the site's hydrogeology
- Generation of data for evaluation of human health and ecological risks
- Determination of the presence (or absence) of DNAPL (dense non-aqueous phase liquids) on site
- Evaluation of the potential for off-site migration of dissolved compounds
- To better identify constituents of concern
- Collect information to evaluate clean up technologies
The field activities included groundwater grab samples, monitoring well installations, subsurface soil sampling and surface soil sampling. These were conducted at the site in August and September. The water table was found to be about 30 to 35 feet below the ground surface. Bedrock was found about 60 feet below the ground surface. The preliminary groundwater grab samples detected volatile organic compounds (VOCs) two to four orders of magnitude above risk-based concentrations (RBCs). Most of the VOCs appeared to be in the shallow groundwater. Groundwater quality generally improved with depth. Concentrations upgradient from the site (i.e. towards the town) were relatively clean. VOCs were detected in excess of RBCs along the western (D Street) side of the property. Based on the results along D Street, the Public Advisory Group will proceed with a survey to confirm that there are no wells being used for drinking water near the site (with particular emphasis west of D Street).
The soil samples were still being collected and limited data is available at this time. Three major soil types were present on site (i.e. fill, silt and silty sand). Although chemicals were detected in soils at many locations, most of the soil sample concentrations (to date) were less than Uniform Risk-Based standards.
Field activities scheduled for September and October included: completion of soil sampling, monitoring well development, extraction well installation, and a comprehensive groundwater sampling. The results of this activity will be available by June 1999 with the evaluation of remedial technologies complete by December 1999.