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 1, 2011

Point of Contact:
Huu Ngo
USEPA 1650 Arch Street
Mail Code: 3HS51
Philadelphia PA 19103 
Tel: 215-814-3187 

North Penn Area 6
Lansdale, PA


Lansdale, Pennsylvania lies within the Triassic Lowlands section of the Piedmont physiographic province. Bedrock in the Lansdale Borough area is comprised of the lower beds of the Brunswick Group and the older underlying Lockatong Formation. The
Brunswick group consists of thin, discontinuous beds of reddish-brown shale interbedded with mudstone and

Ground water occurs and flows mainly in the joints and fractures of the bedrock, after infiltrating down through soil and weathered bedrock. Primary porosity and the storage
capacity of the bedrock is very low. The well developed, nearly vertical joints occurring in many of the rock units are the primary pathways for ground water flows. The distribution of
these fractures controls the general flow of ground water. The intergranular porosity in sandstone may act as storage for ground water, but ground water flow in the primary porosity is limited.

Targeted Environmental Media:
  • - Dense Non-aqueous Phase Liquids (DNAPLs)
  • - Fractured Bedrock


Ten separate source areas have been identified. The remedy is source containment and the plume sizes have not been identified.

Major Contaminants and Maximum Concentrations:
  • - Tetrachloroethene (955 µg/L)
  • - Trichloroethene (87,000 µg/L)
  • - 1,2-Dichloroethene (27,300 µg/L)
  • - Vinyl chloride (3,890 µg/L)

Site Characterization Technologies:

No technologies selected.

Remedial Technologies:

  • - Pump and Treat
Two pump and treat systems began operations in 2003-04. Two more have begun operations more recently. More source areas remain to be addressed.
Remediation Goals:

The cleanup goals are MCLs.


The pump and treat systems continue to operate. Municipal production wells in the area treat their water before releasing it to their systems.

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