The site is underlain by carbonate bedrock of the Ontelaunee Formation, the youngest member of the Ordovician Age Beekmantown group. A thin mantle of clayey residual soil overlies bedrock in the site vicinity. Depths to bedrock in the site's vicinity range from 0-19 feet. The Ontelaunee Formation strikes N60 degree east to N80 degree east predominantly, with an overall dip to the south east of approximately 30 degrees.
The carbonate bedrock units underlying the Lebanon Valley form the major aquifer in the area. The various formations present, although differing somewhat in water-yielding capacity, are considered to form a single, large, heterogeneous, unconfined aquifer. The porosity of the carbonate aquifer is almost entirely secondary, with fractures enlarged through solution channeling forming the primary groundwater storage zones and migration pathways. Groundwater flow directions in the region generally follow topography, then follow stream flow direction in valley bottoms. In the site area, portions of the groundwater flow both in northeasterly and southeasterly directions, before generally following the course of the stream to the east-northeast. Depth to groundwater ranges from 2 to 21 feet below land surface at the site.
Targeted Environmental Media:
 Fractured Bedrock
Some pumping wells draw from 400 feet bgs.
The lateral extent of the plume was not given.
Major Contaminants and Maximum Concentrations:
- Arsenic (Not given)
- Aniline (Not given)
- Tetrachloroethene (Not given)
- Trichloroethene (Not given)
- 1,1-Dichloroethene (Not given)
- Methylene chloride (Not given)
- Benzene (Not given)
- 4-Chloroaniline (Not given)
- Vertical Chemical Profiling
- Pumping Tests
- Fracture Trace Analysis
- Tracer (dye) Test
Comments:
Geophysically interpreted B Horizon.
Pumping tests were conducted in porous media.
- Pump and Treat
Comments:
The pump and treat operation ( 14 extraction wells) started in 1998. Pumping rates have varied from a low of 60 to 75 gpm during drought up to a maximum of 100 to 110 gpm during periods of high precipitation. These wells are pumping from both the shallow zone (less than 150 feet below ground surface (bgs)) and the mid-depth zone (between 150 and 400 feet bgs). The system is designed to cleanup and contain sources on site and does not address offsite contamination.
Cleanup goals were set at MCLs.
The system continues to operate as designed. Concentration of contaminants has declined.
Since 1998, approximately 33,000 pounds of arsenic have been removed from
groundwater beneath the site (2010).
http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0300643
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