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: October 30, 2003

Point of Contact:
Gardiner Cross
NYSDEC
50 Wolf Road
Albany NY 12233-7010 
Tel: 518-457-4343 
Email: gwcross@
gw.dec.state.ny.us

Lehigh Valley Derailment
LeRoy, NY


Hydrogeology:

Highly fractured, cherty Onondaga limestone with very little soil cover. Groundwater transport is through underlying evaporitic shales, which have extensive bedding plane dissolution zones.

There is a disappearing stream about 500 feet from the spill, where surface water infiltrates through the limestone and into the evaportitic shales below. This stream has proven very important to understanding contaminant distribution at the site.

Very rapid groundwater transport has been documented along the bedding plane dissolution zones--3.5 miles in roughly 30 days. Appears to be a lot of dissolution in the underlying shales. One of the slug produced harmonic oscillations in water levels - a splash pool 60 ft. below grade.

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

Contaminants:

TCE release (30,000 gallons) from a 1970 train wreck. Dissolved phase plume is over 3.5 miles long and about 0.5 miles wide. One spring at the end of the plume (3.5 miles away) has 1900 ppb.

There is virtually no evidence of TCE degradation at this site--no VC detections, and very low levels of DCE. Presumably, this is due to the oxidizing groundwater environment (assuming much of the shallow groundwater is rapidly infiltrated surface water).

Downward DNAPL penetration has been limited by cherty beds within the limestone. There is some suggestion that the TCE NAPL did not reach the water table.

Major Contaminants and Maximum Concentrations:
  • - Trichloroethene (DNAPL)

Site Characterization Technologies:

  • - Borehole Geophysics
    • Natural Gamma
    • Caliper
    • Video Camera Televiewer
  • - Fluid Loggings
    • Temperature
    • Conductivity/Resistivity
  • - Vertical Chemical Profiling
    • Cluster Wells
  • - Fracture Trace Analysis
  • - GPR Surveys
  • - Coring
  • - Other

Comments:
"Other" refers to a VLF survey to find vertical fractures (likely karst features) which we thought would account for the uneven distribution of contaminants within the plume. We didn't find anything, but that may be because there was nothing to find. As the investigation proceeded, it became apparent that flow along bedding planes was the dominant mechnism for contaminant transport.


Remedial Technologies:

  • - Pump and Treat
Comments:
ROD calls for removal of soils (what little there is) and bedrock vapor extraction (BVE). Vadose zone is roughly 60 feet thick during low water events, and BVE pilot testing was extremely successful.

Fracturing would be considered if BVE effectiveness falls off with time.
Remediation Goals:

None provided


Status:

As of 10/03 there have been no remediation efforts.

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For more information on Fractured Bedrock, please contact:

Ed Gilbert
Technology Assessment Branch

PH: (703) 603-8883 | Email: gilbert.edward@epa.gov