The Site subsurface is comprised of a
Karst limestone geologic formation and regional ground water flow is generally toward the Philadelphia Suburban Water Company Upper Merion Reservoir(UMR), which is north of the Site.
Targeted Environmental Media:
 Fractured Bedrock
The vertical extent of the plume is at least to 400 feet bgs. The lateral plume is a different shape for each flow zone. See 2008 five year review.
Major Contaminants and Maximum Concentrations:
- Benzene (152 µg/L)
- Chloroform (30 µg/L)
- Ethylbenzene (53 µg/L)
- Tetrachloroethene (35 µg/L)
- Toluene (844 µg/L)
- Trichloroethene (14 µg/L)
- Trichlorofluoromethane (368 µg/L)
No technologies selected.
- Pump and Treat
Comments:
In September 1991, the ground water treatment plant was constructed and began operation. The treatment plant utilizes bioremediation to reduce organic contaminant levels and carbon adsorption to remove any residual contaminants before discharge to an adjacent intermittent stream. A total of
seven ground water recovery wells pump contaminated ground water to the treatment plant. The pumping rate is 50 to 60 gpm total.
The system has been shut down for short periods to evaluate rebound.
Cleanup criteria are based on the most conservative value from the following standards: MCLs, MCLGs, aquatic water quality criteria, drinking water equivalent levels, Suggested No Adverse Effect levels, Risk Assessment models, Superfund Public Health Evaluation Manual (SPHEM), and EPA accepted values where no other criteria exists (MCLs, where available, were used).
Since inception, over 280 million gallons of groundwater have been treated and approximately 2,500 pounds of contaminants have been removed. As of May 2010 EPA was evaluating a PRP proposal and the system was not operating.
http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0300847
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