U.S. EPA Contaminated Site Cleanup Information (CLU-IN)


U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Fractured Bedrock Project Profiles

Last Updated: January 2, 2011

Point of Contact:
Jill Lowe
USEPA 1650 Arch Street
Mail Code: 3HS21
Philadephia PA 19103 
Tel: 215-814-3123 
Email: lowe.jill@
epa.gov

Recticon/Allied Steel Corp.
East Coventry Township, PA


Hydrogeology:

The overburden aquifer is composed of
weathered and reworked bedrock material. This material consists of clay to gravel-size material that has been eroded and redeposited in meandering stream deposits that make-up the Schuylkill River floodplain.

The underlying bedrock aquifer is composed of interbedded conglomerates, sandstone, siltstone, and shale
units and are collectively referred to as the Gettysburg Formation. These rock units were laid-down in an ancient meandering stream and river environment. Sedimentary layers within the Gettysburg Formation are divided by bedding planes. The sedimentary layers over time have been rotated into an east-west orientation with a northward dip between 12 and 20 degrees. Some of the bedding planes have separated
into what are referred to as bedding plane fractures. Oriented perpendicular to and connecting the bedding planes fractures to various degrees are joint fractures. The degree of jointing is dependent on the thickness and brittleness of the sedimentary layers. Ground water flow in the bedrock aquifer is restricted to movement along the bedding plane fractures and joints. The intergranular porosity, where present, also contributes to ground water movement. Intergranular porosity contributes more to the storativity of the aquifer than to flow though the aquifer.

Targeted Environmental Media:
  • - Fractured Bedrock

Contaminants:

The contaminants were in the overburden and shallow bedrock groundwater. Bedrock monitoring wells were set at 65 feet bgs.

Major Contaminants and Maximum Concentrations:
  • - Trichloroethene (1,900 µg/L)
  • - 1,2-Dichloroethene (730 µg/L)
  • - Tetrachloroethene (Not given)
  • - Vinyl chloride (Not given)
  • - 1,2-Dichloroethane (Not given)
  • - 1,1,1-Trichloroethane (Not given)

Site Characterization Technologies:

  • - Pumping Tests

Remedial Technologies:

  • - Pump and Treat
  • - Bioremediation (In Situ)
    • Reductive Dechlorination (In Situ Bioremediation)
Comments:
The biostimulant used was hydrogen release compound.
Remediation Goals:

MCLs are the cleanup goals for groundwater.


Status:

The pump and treat system, which began operation in April 1999, is turned off and biodegradation continues. On May 26, 2010 an Explanation of Significant Differences was issued to change the remedy to enhanced bioremediation.
The average concentration in wells with detections is 8 ug/L TCE.

http://cfpub.epa.gov/supercpad/cursites/csitinfo.cfm?id=0300596

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